Disease Severity In Sickle Cell Disease Research Articles

Mechanisms of Iron-Mediated Renal Injury in a Mouse Model of Sickle Cell Disease

Background: Sickle cell disease (SCD) is a hematologic disorder characterized by polymerization of the mutated hemoglobin S and sickling of red blood cells, leading to hemolysis, release of free heme/iron, and subsequent tissue iron accumulation. The kidney is one of the most frequently affected organs by iron overload, and chronic hemolysis is associated with chronic kidney disease severity in SCD. The potential role of iron overload in causing the observed renal injury in SCD has never been established. The goal of our study is to identify the impact of iron accumulation on the renal phenotype in SCD. We hypothesized that renal iron accumulation causes injury by oxidative stress dependent ferroptosis and/or mitochondrial dysfunction and subsequent kidney damage, that is worse in males than in females. Methods: We used 20-week-old male and female humanized SCD mice (HbSS) and age-matched genetic controls (HbAA). Mice were treated with either vehicle or the iron chelator Deferiprone (DFP, 100 mg/kg/day) for 8 weeks. Urinary excretion of protein and albumin as markers of renal injury were measured. Glomerular filtration rate (GFR) was measured transdermally after injection of FITC-sinistrin. Thiobarbituric acid reactive substance (TBARS) assay was performed for assessment of lipid peroxidation. Mitochondrial bioenergetics was assessed by Oroboros O2k Fluorometer of permeabilized renal cortices. Results: We previously demonstrated comparable iron accumulation in the kidney of male and female mice. However, HbSS males developed a more severe renal injury than females at 20 weeks of age, evidenced by proteinuria (2.52 ± 0.16 vs. 0.55 ± 0.16 mg/24hrs, p=0.0008) and albuminuria (76.44 ± 6.85 vs. 33.9 ± 8.81 μg/24hrs, p=0.0005). There was higher lipid peroxidation, a hallmark of ferroptosis, in the renal cortex of female HbSS than HbAA mice (1.31 ± 0.07 vs. 1.07 ± μM/mg, p=0.04). Bioenergetics studies revealed significantly lower state 3 oxygen consumption rate (108.2 ± 18.1 vs 164.8 ± 9.3 pmol/(s*mg), p=0.05), signifying lower oxidative phosphorylation capacity in HbSS males. In addition, there was significant reduction in state 4◦ respiration (36.4 ± 3.4 vs. 52.8 ± 3.4 pmol/(s*mg), p=0.03) in male HbSS mice. I also detected a decrease in maximum complex IV activity in male HbSS mice (325.5 ± 63.8 vs. 639.5 ± 51.3 pmol/(s*mg), p=0.02). Treatment with DFP improved proteinuria (2.66 ± 0.09 vs. 1.3 ± 0.14 mg/24hrs, p=0.0011) and GFR (165.3 ± 9.4 vs. 236.6 ± 12.6 μl/min, p=0.0058) in male HbSS mice. Conclusion: Iron accumulation causes renal injury which may be attributed to ferroptosis and mitochondrial dysfunction in SCD mice. Funding: NHLBI—R00HL144817 and ASN Norman Siegel Research Grant to MK. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Thrombin activatable fibrinolysis inhibitor plasma levels and TAFI Thr325Ile genetic polymorphism in a cohort of Egyptian sickle cell disease patients and impact on disease severity.

Thrombin is a critical protease modulating thrombosis as well as inflammation, which are one of the main pathophysiological mechanisms in sickle vasculopathy, and its levels were reported to be high in sickle cell disease (SCD). The thrombin-thrombomodulin complex activates the TAFI inhibitor of fibrinolysis, which acts by reducing plasmin affinity for its substrate thus hindering fibrinolysis. We aimed to determine the influence of the Thr325Ile single nucleotide polymorphism (SNP) on TAFI antigen levels and potential effects on the severity of SCD in a cohort of Egyptian patients. Genotyping of Thr325lle polymorphism using Taq-Man SNP genotyping assay and TAFI level measurement using an enzyme-linked immunosorbent assay were performed for 80 SCD patients (45 homozygous HbSS, 16 S/β0 and 19 Sβ+) as well as 80 age- and gender-matched healthy control subjects. Plasma TAFI levels were higher in SCD patients with Thr325Ile polymorphism, yet the difference was not statistically significant (p=.204). SCD patients with polymorphic genotypes had a greater number of hospital admissions (p=.03). Ten patients with acute chest syndrome had the homozygous polymorphic genotype (GG), and all patients with pulmonary hypertension had the polymorphic genotype (six were homozygous [GG] and five were heterozygous [GA]). Patients with SCD complicated with pulmonary hypertension showed significantly higher plasma TAFI levels (p=.044). The analysis of Thr325Ile polymorphisms combined with plasma TAFI levels suggests that the analyzed SNP could influence plasma TAFL levels and SCD disease severity and hospitalization rates, which could be predictors for complex disease.

Clinical Results of a Randomized Placebo Controlled Trial of Inhaled Mometasone to Promote Reduction in Vaso-Occlusive Events (IMPROVE-II)

Introduction: A subset of patients living with sickle cell disease (SCD) who do not meet diagnostic criteria for asthma exhibit episodic cough or wheeze (ECW), and this is associated with higher rates of vaso-occlusive pain crisis and acute chest syndrome. ECW may be caused by pulmonary inflammation from SCD. In the former IMPROVE trial, 54 patients with SCD and ECW were randomized to receive 16 weeks of placebo or mometasone furoate, an inhaled corticosteroid used to treat pulmonary inflammation. Treatment with mometasone was associated with significant reductions in daily pain, markers of hemolysis, and soluble vascular cell adhesion molecule (sVCAM) (a biomarker of disease severity in SCD) compared to placebo. The IMPROVE-II trial evaluated whether treatment with mometasone over a longer period could improve clinical and biological endpoints in non-asthmatic patients with SCD and ECW. We report here the clinical outcomes from the IMPROVE-II trial. Methods: We conducted a randomized, placebo-controlled, single-center interventional trial. Patients with SCD without asthma were randomized to receive either mometasone furoate 220 mcg or placebo inhaled powder for 48 weeks followed by a 4-week wash out. Key inclusion criteria included age > 18 years with SCD genotype HbSS/HbSβ0 at stable baseline who endorsed ECW. Patients were excluded if they had >15 emergency department (ED) visits for vaso-occlusive pain crisis in the past 12 months or if other treatments for SCD (i.e. hydroxyurea, L-glutamine) were being titrated. The primary outcome was the change in soluble vascular cell adhesion molecule (sVCAM) level with treatment. Clinical outcomes included ED visits and hospitalizations for any reason, and health care visits for acute chest syndrome, pneumonia, stroke, or transient ischemic attack, as well as daily pain (self-report 1-10 scale), and 6 Minute Walk. Adaptive covariate randomization was used to balance covariates including hydroxyurea use (yes/no), age, and previous rate of ED use. Results: A total of 80 patients were randomized and 77 received study treatment; 40 were assigned to mometasone and 37 to placebo (Figure 1). There were no significant differences between treatment groups in patient demographics (Table 1). Treatment with mometasone was associated with higher rates of acute care visits for vaso-occlusive crisis (4 (2/19) vs 1 (1/3) /patient year (50%(25%/75%), p<0.001), hospitalization for acute chest syndrome (mean 0.2 vs 0.1/patient year, p=0.05) and ED utilization (2 (1/5) vs 2 (1/4) /patient year (50%(25%/75%), p0.01). Laboratory outcomes including sVCAM are not yet resulted. Adverse events that were reported by more than 5% of patients are listed in Table 1; there was no difference between rates of adverse (<5%) events between mometasone and placebo. There were no deaths during the study. Conclusions: In individuals with SCD and ECW who do not have asthma, long-term treatment with inhaled corticosteroids did not improve clinical outcomes and may be harmful as they were associated with higher rates of acute care visits for pain crisis, ED visits, and acute chest syndrome. Further analyses of biological endpoints and clinical laboratory data are needed to fully elucidate the effects of inhaled corticosteroids in SCD.

Healthcare Utilization and Cost of Care Analysis of Patients with Sickle Cell Disease with High Vs. Low Biomarkers: A Retrospective Chart Review

Sickle cell disease (SCD) is a red blood cell (RBC) disorder that is associated with frequent and unpredictable vaso-occlusive episodes (VOEs) including pulmonary hypertension, acute chest syndrome, chronic anemia, priapism, splenic and renal dysfunction, and stoke. The total cost to manage a SCD patient with a life expectancy of 64 years is between $1.3-$2.1M. Within the United States alone, up to 67% of adults have ≥3 VOEs per yearthat accounts for most of the healthcare utilization, including 78% of emergency room (ER) visits and 95% of hospitalizations. Despite the same single gene mutation of beta-globin, the frequency of VOEs amongst patients is highly variable. The pathophysiology of VOEs involves a complex interplay between circulating blood cells and elevated plasma factors that promote abnormal interactions to the vascular endothelium. Nearly a half century ago studies demonstrated RBC adhesion strongly correlates with disease severity however only recently standardized testing has become available to assess adhesion clinically. More specifically, we developed a suite of RBC health biomarkers and deployed our flow adhesion bioassays in our landmark, observational study (ELIPSIS). We established that flow adhesion of whole blood to vascular cell adhesion molecule-1 (FA -WB-VCAM) at baseline stratified SCD patients with severe disease phenotypes and validated the clinical predictive value of FA-WB-VCAM two years post-ELIPSIS. The objective of this study was to determine whether baseline FA-WB-VCAM biomarker levels could predict patients more likely to receive direct healthcare contact (ER visits/hospital admissions) to manage SCD complications. This study was a retrospective assessment of clinical FA-WB-VCAM in individuals with SCD during steady state between January 2020 through March 2023. Flow adhesion assays were performed using pulsatile, shear flow (1.67Hz, 1.0 dyne/cm 2). SCD patients that received at least 3 steady state FA-WB-VCAM biomarker evaluations within 1-year were included in this analysis. Clinical site received an IRB waiver to obtain patient-reported ER visits and hospitalizations during relevant time periods. We calculated a composite adhesion index by averaging baseline FA-WB-VCAM biomarker evaluations and established SCD disease severity by quantifying the number of ER visits and hospital admissions one year after the most recent FA-WB-VCAM biomarker evaluation. The non-parametric Wilcoxon matched pairs signed rank test was used to test the statistical differences between groups. Data are presented as mean ± standard error of mean. A p-value < 0.05 was considered statistically significant. Out of a total of 3939 clinical tests performed, 366 samples were obtained for “baseline” indications. Of these, only 28 samples were analyzed from 9 unique patients who met the study criteria described above. The average flow adhesion of whole blood to VCAM-1 (FA-WB-VCAM) in SCD patients with high adhesion phenotypes (>400 cells/mm 2) was significantly higher than the low/moderate SCD cohort (mean high=603±78 cells/mm 2, mean low/moderate=343±28 cells/mm 2, p=0.02). More important, the high adhesion cohort had more ER visits (11 vs. 5) and hospitalizations (24 vs 9) and significantly higher healthcare costs ($35,871 vs. $13,563). This is the first healthcare cost analysis assessing the relationship between SCD patients stratified by their adhesive phenotype using the standardized, clinical adhesion biomarker FA-WB-VCAM, and healthcare utilization. The previous ELIPSIS study established that baseline FA-WB-VCAM stratifies patients based on their risk of developing self-reported VOCs during a 6-month longitudinal observation period and their risk of higher clinical disease severity in a 2-year follow-up study. Consistent with this data, the current study demonstrated that a cohort of SCD patients with elevated baseline adhesion phenotypes based on FA-WB-VCAM had a greater utilization of healthcare resources (ER visits and hospitalizations) and had a higher cost of care during the retrospective observation period. These data suggest that RBC health as indicated by “baseline” FA-WB-VCAM levels may predict lower health care utilization and costs, and that this biomarker may be a plausible surrogate endpoint to assess the pharmaco-economic impact of SCD-modifying therapies.

Hemoglobin F and Incidence of Thrombotic Event in Sickle Cell Disease

Introduction Characterized by abnormally sickle-shaped erythrocytes disrupting blood flow in small vessels, Sickle Cell Disease (SCD) continues to be the most common hemoglobinopathy in the United States, affecting approximately 100,000 people (Onimoe & Rotz, 2020). A 2017 cohort study of SCD patients found that there is an increased risk and earlier incidence of venous thromboembolisms compared to their matched controls (Brunson et al., 2017). Fetal hemoglobin (HbF) is the best characterized modifier of disease severity in SCD, and historically, patients with low HbF percentages are at a higher risk of developing vaso-occlusive complications, organ damage, and early death (Agrawal et al., 2014). We hypothesize that having a higher hemoglobin F (unaffected by sickle cell mutation), would confer some protection from hemolysis and would be inversely related to the incidence of thrombosis in sickle cell disease patients. Methods This study uses a descriptive and cross-sectional design to analyze existing, secondary medical record data of 496 SCD patients that received care from the Center for Blood Disorders in Augusta, Georgia. Data abstraction included history of thrombotic event (TE) and HbF values closest to the TE, along with, presence of SCD clinical complications, use of blood thinning medications, specific lab values, hemoglobin electrophoresis, and history of COVID-19. For those without a history of TE, the most recent data in these categories was collected. To test the association of HbF with a categorical variable such as medical history of thrombosis, we used a two-sample t-test. To test the association of HbF with a continuous variable such as D-dimer, we computed Pearson's correlation coefficient and used Fisher's z-test. Patients with SCD who developed thrombosis were further divided into quantiles based on HbF levels [Table 1]. We collected mean age at thrombosis and mean D-dimer for these quantiles and ANOVA was used for statistical analysis. All analyses were performed using R version 4.2.3. Results Of the 496 charts reviewed, 131 patients had a history of TE and 27 of those patients have more than one recorded TE (total=189). Twenty patients did not have HbF data close to TE and were not included in this analysis. The mean HbF for patients without history of TE was 8.89 (SD 10.0), whereas the mean HbF for patients with history of TE was 10.1 (SD 10.3). A two-sample t-test comparing these two groups produced a p-value of 0.2126. Mean age of thrombosis in each quantile were 31.6 (SD 14.6), 28.7 (SD 10.5), 34.8 (SD 11.7), and 37.1 (SD 11.9), respectively, with ANOVA producing a p-value of 0.008059. Mean D-dimer in each quantile were 1017 (SD 1408), 1417 (SD 1415), 1404 (SD 1493), and 2921 (SD 8898), respectively, with ANOVA producing a p-value of .6645. Conclusions While there is no significant relationship between mean HbF levels and development of thrombosis in this cohort of 496 SCD patients, the mean age of development of thrombosis was significantly higher in higher quantiles of HbF, compared to lower quantiles, suggesting that patients with higher HbF are protected longer from thrombosis. There was no relationship between mean D-dimer level and development of thrombosis in the patients we analyzed. In SCD patients with thrombosis, D-dimer was not significantly associated with thrombosis even between different quantiles of HbF. To our knowledge, this is the first study evaluating association between HbF level, D-dimer, and development of thrombosis in SCD patients. Current therapies for SCD focus on symptom management and disease modification. While the mechanism is still not completely understood, Hydroxyurea increases the number of red blood cells (RBCs) with detectable HbF, protecting RBCs from sickle hemoglobin polymerization, thus interrupting the natural disease pathophysiology (Steinberg, 2020). Some gene therapy for sickle cell disease aims at increasing HbF in SCD patients (Abraham & Tisdale, 2021). Would such therapy be protective against increased risk of thrombosis associated with SCD, remains to be determined. One limitation of this project is the restricted sample size of SCD patients with thromboembolism, and larger data size of sickle cell patients may better elucidate a relationship between Hemoglobin F and thrombosis in SCD patients.

Plasma Lipid Levels in Relation to Disease Severity in Sickle Cell Anaemia in Abakaliki, Southeast Nigeria

Background: Dyslipidaemia has been implicated in the pathophysiology of sickle cell disease (SCD) complications; hence its role requires further elucidation. Objectives: To investigate the relationship between disease severity and plasma lipid levels of patients with sickle cell anaemia. Methods: A cross-sectional study design was used for the survey. A total of 50 patients with sickle cell anaemia and 50 controls without SCD were recruited for the study. The clinical data and plasma lipid levels of lipids and haemoglobin parameters were analysed. Results: The majority of the participants were aged 18-25 years. Total plasma cholesterol and HDL-C were significantly lower in individuals with SCA compared with the controls (3.3±1.2 vs 4.2±1.2; p<0.001) and (1.3±0.5 vs 1.5±0.4; p = 0.038) respectively. Most patients with SCA had moderate disease severity (24; 48%). There was no statistically significant difference in the plasma levels of total cholesterol and HDL-C across the disease severity groups of SCA (p = 0.694 and 0.262). There was also no significant correlation between total cholesterol, HDL-C, and markers of haemolysis, haemoglobin F, and haemoglobin S levels. Conclusion: SCA is characterised by lower mean plasma TC and HDL than controls. However, no relationship was found between TC, HDL levels and SCD disease severity, markers of haemolysis, HbF and HbS levels. Further studies are required to ascertain the implications of plasma lipid levels in SCD.

Longitudinal Predictors of Pain in Pediatric Sickle Cell Disease.

Despite the identified pathophysiology of vaso-occlusive pain in sickle cell disease (SCD), predictors of pain in youth with SCD remain elusive. In this study, we measured changes in pain frequency, intensity, and interference over 1 year and examined biopsychosocial risk factors (SCD disease severity, age, female, depression, and sleep quality) as possible longitudinal predictors. Medical history was obtained from retrospective chart review for 79 children with SCD (ages 2-18 years; 48.1% female; 100% Black/African American; 83.5% SCD, SS genotype). As part of a clinical screening protocol, caregivers (n = 79) and youth 8-18 years (n = 43) completed psychosocial questionnaires approximately 1 year apart (M = 15.52 months, SD = 5.69). Zero-order correlations, paired t-tests, and hierarchical linear models examined longitudinal predictors of pain. The longitudinal bidirectional relationship between pain and sleep was also examined. The rate of severe SCD disease increased from 41.8% to 55.7% across the year, while most hematologic medical parameters remained stable. Increased depression and pain interference at survey 1 significantly predicted increased pain interference at survey 2. Poor sleep quality and increased pain frequency at survey 1 predicted increased pain frequency at survey 2. Finally, increased pain interference at survey 1 predicted poor sleep quality at survey 2. History of pain, depression, and sleep quality were longitudinal predictors of pain over 1 year in youth with SCD. Identifying longitudinal predictors of pain may lead to earlier identification of patients with a high-risk SCD pain phenotype and earlier medical, psychological, and behavioral interventions.

P-023: 2,3-DIPHOSPHOGLYCERATE DETECTION VIA DIRECT INFUSION HIGH RESOLUTION MASS SPECTROMETRY CORRELATES WITH QUANTITATIVE DETECTION IN BLOOD OF PATIENTS WITH SICKLE CELL DISEASE

Purpose: Sickle cell disease (SCD) is a hereditary and chronic life-threatening disorder, characterized by haemolytic anaemia. Increased 2,3-diphosphoglycerate (2,3-DPG) concentrations, along with decreased oxygen affinity of hemoglobin, may be related to the variability of clinical outcomes in SCD. Furthermore, genomic health data holds promise to improve the prediction of disease severity in SCD. Based on the integration of genomics, metabolomics and clinical data from 1000 SCD patients, to be included in 2022, GenoMED4all aims to develop Artificial Intelligence (AI) based deep learning algorithms to improve the prediction of disease severity and phenotype in SCD. This study aims to correlate non-quantitative metabolomics data obtained from dried blood spots (DBS), one of the inputs for GenoMED4all, to quantitative measurement of 2,3-DPG. Aiming to improve the potential of non-quantitative metabolomics from DBS to asses 2,3-DPG. Materials and methods: In snap frozen blood samples from 37 SCD patients and 29 healthy controls, 2,3-DPG was quantified by liquid chromatography mass spectrometry. 2,3-DPG was also detected in DBS from the same subjects by direct infusion high resolution mass spectrometry (DIHRMS). The oxygen tension at 50% Hb saturation (p50) was determined using a Hemox Analyzer (TCS). Statistical analysis were performed by Spearman’s correlation coefficients (SPSS v26.0.0.1) and Mann Whitney testing (GraphPad Prism v9.3.0). Results: After correcting for Hb, 2,3-DPG concentrations were higher in SCD patients than in controls (p<0.001) and Z-scores for 2,3-DPG, as assessed by DIHRMS, were similar in patients and controls. The Z-scores positively correlated with 2,3-DPG concentrations (Fig1A, 0.353, p=0.004). Because of the anaemia in SCD, red blood cells (RBCs) and plasma make up lower and higher volumes in the blood, respectively, compared to healthy controls. This affects the ratio of RBC and plasma metabolites on the DBS. DIHRMS detects a wide range of RBC and plasma metabolites, whereas the quantitative measurement is restricted to measuring 2,3-DPG of RBCs. To correct for those differences between methods, we applied a correction factor to the DIHRMS data using (1/Ht)*(1-Ht/1), correcting for the RBC volume (1/Ht) and the plasma volume (1-Ht/1). This resulted in a trend towards higher Z-scores in patients than controls (p=0.0597). Moreover, the positive correlation with 2,3-DPG concentrations increased to 0.526 (Fig1B, p<0.001). As 2,3-DPG affects the oxygen affinity of Hb, all measurements were correlated to p50. Expectedly, 2,3-DPG concentrations positively correlated with p50 (0.842, p<0.001). After applying the correction factor to the DIHRMS data, p50 correlations increased from 0.361 (p=0.003) to 0.529 (p<0.001). Conclusion: Strongest correlation between quantitative and non-quantitative methods for 2,3-DPG detection were observed after correcting for both RBC and plasma volumes in non-quantitative metabolomics. After correction, DIHRMS can be used to assess 2,3-DPG concentrations in DBS. This translation of non-quantitative to quantitative metabolomics for 2,3-DPG and potentially other RBC metabolites adds significant value to the use of DIHRMS, as DIHRMS is far more efficient in obtaining extensive information about the total metabolome than quantitative methods. The large population size and the AI based deep learning algorithms of GenoMED4all will enable to evaluate the potential of non-quantitative metabolomics in SCD. Funding: Horizon2020, GenoMED4all(https://genomed4all.eu/), Agios Pharmaceuticals Inc., ERN-EuroBloodNetFig 1. correlations between non-quantitative (Z-score) and quantitative 2,3-DPG detection A) non-quantitative and quantitative 2,3-DPG detection B) non-quantitative detection corrected for RBC and plasma volume and quantitative 2,3-DPG detection The authors do not declare any conflict of interest

P1500: 2,3-DIPHOSPHOGLYCERATE DETECTION VIA DIRECT INFUSION HIGH RESOLUTION MASS SPECTROMETRY CORRELATES WITH QUANTITATIVE DETECTION IN BLOOD OF PATIENTS WITH SICKLE CELL DISEASE

Background: Sickle cell disease (SCD) is a hereditary and chronic life-threatening disorder, characterized by haemolytic anaemia. Increased 2,3-diphosphoglycerate (2,3-DPG) concentrations, along with decreased oxygen affinity of hemoglobin, may be related to the variability of clinical outcomes in SCD. Furthermore, genomic health data holds promise to improve the prediction of disease severity in SCD. Based on the integration of genomics, metabolomics and clinical data from 1000 SCD patients, to be included in 2022, GenoMED4all aims to develop Artificial Intelligence (AI) based deep learning algorithms to improve the prediction of disease severity and phenotype in SCD. Aims: To correlate non-quantitative metabolomics data obtained from dried blood spots (DBS), one of the inputs for GenoMED4all, to quantitative measurement of 2,3-DPG. Aiming to improve the potential of non-quantitative metabolomics from DBS to asses 2,3-DPG. Methods: In snap frozen blood samples from 37 SCD patients and 29 healthy controls, 2,3-DPG was quantified by liquid chromatography mass spectrometry. 2,3-DPG was also detected in DBS from the same subjects by direct infusion high resolution mass spectrometry (DIHRMS). The oxygen tension at 50% Hb saturation (p50)was determined using a Hemox Analyzer (TCS). Statistical analysis were performed by Spearman’s correlation coefficients (SPSS v26.0.0.1) and Mann Whitney testing (GraphPad Prism v9.3.0). Results: After correcting for Hb, 2,3-DPG concentrations were higher in SCD patients than in controls (p<0.001) and Z-scores for 2,3-DPG, as assessed by DIHRMS, were similar in patients and controls. The Z-scores positively correlated with 2,3-DPG concentrations (Fig.1A, 0.353, p=0.004). Because of the anaemia in SCD, RBCs and plasma make up lower and higher volumes in the DBS, respectively, compared to healthy controls. DIHRMS detects a wide range of RBC and plasma metabolites, whereas the quantitative measurement is restricted to measuring 2,3-DPG of RBCs. To correct for those differences between methods, we applied a correction factor to the DIHRMS data using the formula (1/Ht)*(1-Ht/1), correcting for the RBC volume (1/Ht) and the plasma volume (1-Ht/1). This resulted in a trend towards higher Z-scores in patients than controls (p=0.0597). Moreover, the positive correlation with 2,3-DPG concentrations increased to 0.526 (Fig 1B, p<0.001). As 2,3-DPG affects the oxygen affinity of Hb, all measurements were correlated to p50. Expectedly, 2,3-DPG concentrations positively correlated with p50 (0.842, p<0.001). After applying the correction factor to the DIHRMS data, p50 correlations increased from 0.361 (p=0.003) to 0.529 (p<0.001). Image:Summary/Conclusion: Strongest correlation between quantitative and non-quantitative methods for 2,3-DPG detection were observed after correcting for both the RBC and plasma volume in non-quantitative metabolomics. After correction, DIHRMS can be used to assess 2,3-DPG concentrations in DBS. This translation of non-quantitative to quantitative metabolomics for 2,3-DPG and potentially other RBC metabolites adds significant value to the use of DIHRMS, as DIHRMS is far more efficient in obtaining extensive information about the total metabolome than quantitative methods. The large population size and the AI based deep learning algorithms of GenoMED4all will enable to evaluate the potential of non-quantitative metabolomics in SCD. Funding: Horizon2020, GenoMED4all (https://genomed4all.eu/), Agios Pharmaceuticals Inc., ERN-EuroBloodNet

Impact of Superoxide Dismutase Genetic Polymorphism (SOD2 Val16Ala) and Superoxide Dismutase Level on Disease Severity in a Cohort of Egyptian Sickle Cell Disease Patients.

BackgroundOxidative stress plays a pivotal role in the pathophysiology of sickle cell disease (SCD) and its associated disease complications. Superoxide Dismutases (SODs) are protective enzymes against oxidative stress. SOD2 deficiency results in the accumulation of oxidized red cell proteins, increased rate of hemoglobin oxidation, decreased red cell membrane deformability, and subsequently decreased red cells survival.ObjectiveThe current study was designed to determine the effect of SOD2 Val16Ala gene polymorphism (rs4880) on SOD2 level and their possible impact on SCD disease severity in a cohort of Egyptian SCD patients.MethodsGenotyping SOD2 Val16Ala polymorphism by TaqMan allelic discrimination assay for hundred SCD patients and a hundred age-sex matched healthy controls revealed the genotypic and allelic frequencies of the studied polymorphism in the SCD patients were close to that of the controls.ResultsSerum SOD2 level was significantly lower in those having the polymorphic genotypes (p=0.005). SOD2 level inversely correlates with the annual rate of hospitalization (r=−0.023, p= 0.038).ConclusionSOD2 Val16Ala polymorphism was associated with low serum SOD2 level that may predict disease severity.

Sleep Patterns and Associated Clinical Correlates Amongst Ghanaian Individuals with Sickle Cell Disease

▪Background: Sickle cell disease (SCD) is the most commonly inherited blood disorder that affects 1 in 500 individuals of African descent worldwide and 70,000-80,000 individuals in the United States. While the molecular basis and progression of this condition has been well established, the association between sleep, stress and frequency of complications such as pain crises has not been well studied. In this study, we investigate how sleep behavioral patterns are associated with the severity and incidence of sickle cell crises amongst patients with SCD.Methods: Adult individuals with SCD were recruited from the Korle Bu Teaching Hospital in Accra, Ghana as participants for this study. No compensation was provided. Participants completed a questionnaire that assessed SCD disease severity such as frequency of pain crises and need for hospitalization. Self-reported sleep habits, including average hours of sleep both at baseline and during pain crisis were also evaluated. Medical records for each participant were also obtained to establish demographic and genotype information.Results: A total of 308 individuals with SCD were enrolled in the study. Patients were classified according to SCD genotype with 68.6% of individuals with severe genotype (hemoglobin SS or sickle/beta thalassemia), and 31% had mild genotype (hemoglobin SC, sickle/beta plus thalassemia disease). Regarding average sleep per night, 2.4% reported 0-2 hours, 14.4% reported 3-4 hours, 38.8% reported 5-6 hours, 36.8 reported 7-9 hours, and 7.7% reported 10 hours or more. During pain crises, 48% reported 0-2 hours of sleep and 91.1% reported 0-4 hours of sleep per night. A paired sample t-test of average hours of sleep at baseline versus sleep during pain crisis showed a significant decrease in hours of sleep while in pain crisis (t=20.16, p < 0.001). Furthermore, female gender was associated with decreased sleep during pain crises (p = 0.008) compared to their male counterparts. An analysis of all SCD Genotypes revealed average sleep per night at baseline was not associated with frequency of crises per year, pain crises requiring ER/doctor visits nor per pain crises per year requiring hospitalizations. However, within the mild genotype group alone, average hours of sleep during a pain crisis was significantly associated with number of crises per year (r = 0.299, p = 0.04), number of crises/year requiring ER/doctor visit (r = 0.256, p = 0.013), and crises/year requiring hospitalization per year (r = 0.246, p = 0.018). Sleep patterns and pain crises/year measures did not correlate amongst patients with severe genotype.Discussion: Per patient self-report, individuals with SCD experience significant disruption with sleep due to pain crises. Most of the individuals report a significant reduction in average amount of sleep during a pain crisis, suggesting that pain crisis likely plays a crucial role in quality of life amongst patients with SCD. In patient with milder genotypes, worse outcomes (frequent ER/doctor visits, frequent crises, and frequent hospitalizations) are associated with less sleep during a pain crisis. This association suggests that amongst those with mild genotypes, sleep amount likely reflects SCD morbidity. The lack of associated pain crises patterns and sleep within the severe genotype suggests most adult patient regardless of severity report a severe lack of sleep during painful crises. Leg ulcer associated with less sleep during painful crises may reflect the impact of leg ulcers on sleep patterns. A limitation of this study was that data was obtained from a single site which may not reflective of sleep patterns amongst individuals with SCD elsewhere. Future areas of exploration could include evaluation of sleep habits with a validated sleep questionnaire and compared with end organ complications of sickle cell disease. DisclosuresWilson:American Society of Hematology: Research Funding. Asare:Office of Research Innovation and Development (ORID) Research Fund/8/LMG-008, University of Ghana; Doris Duke Charitable Foundation; Burroughs Wellcome Foundation; Phillips Family Donation; Aaron Ardoin Foundation for Sickle Cell Anemia; Vanderbilt Univer: Research Funding. Olayemi:Office of Research Innovation and Development (ORID) Research Fund/8/LMG-008, University of Ghana; Doris Duke Charitable Foundation; Burroughs Wellcome Foundation; Phillips Family Donation; Aaron Ardoin Foundation for Sickle Cell Anemia; Vanderbilt Univer: Research Funding.

Oxygen Gradient Ektacytometry-Derived Biomarkers Are Associated with the Occurrence of Cerebral Infarction, Acute Chest Syndrome and Vaso-Occlusive Crisis in Sickle Cell Disease

Background: In sickle cell disease (SCD), hemoglobin S (HbS) polymerizes upon deoxygenation, reducing red blood cell (RBC) deformability. RBC deformability can be measured over a gradient of oxygen tensions (pO2) with the Laser Optical Rotational Red Cell Analyzer (Lorrca) ektacytometer (RR Mechatronics). Oxygen gradient ektacytometry generates 3 key parameters: 1) EImax, RBC deformability at normoxia; 2) EImin, minimum RBC deformability upon deoxygenation; and 3) the point of sickling (PoS): the oxygen tension at which a 5% decrease in deformability is observed during deoxygenation, reflecting the patient-specific pO2 at which sickling begins (Figure 1A). Previously we showed that oxygen gradient ektacytometry-derived biomarkers correlate with measures of SCD disease severity and hemolytic rate (Rab et al. Blood 2018), and is associated with vaso-occlusive crisis (VOC) frequency (Rab et al, Blood 2019). In this study, we confirm these observations in 2 independent cohorts and extend it to occurrence of acute chest syndrome (ACS), stroke including silent cerebral infarction (SCI), and transcranial Doppler (TCD) outcome. Methods: We analyzed 2 cohorts of SCD patients; an adult patient cohort of 53 SCD patients, enrolled at either University Medical Center Utrecht, The Netherlands (UMCU, n=25) or Hospital Lyon France (LIBM, n=28), and a pediatric patient cohort of 190 SCD patients enrolled at Texas Children's Hospital, USA (TCH). Subjects were HbSS or HbS/β-thalassemia, with a substantial number of subjects on hydroxyurea (HU) therapy (adult cohort 66% and pediatric cohort 86%), and not on chronic transfusion therapy. Correlations between oxygen gradient ektacytometry-derived biomarkers and the clinical complications of stroke or silent infarcts (SCI), ACS, VOC were assessed in both pediatric and adult patients. Patient groups generally did not significantly differ significantly by age, gender or HU treatment in the adult cohort except for age, which was lower in the ACS+ group (25.3years (y) compared to 32.0y) and also lower in the VOC+ group (27.1y compared to 35.8y). In the pediatric cohort, patient groups differed significantly in the ACS+ group compared to the ACS- group by age (ACS- group 8.37, ACS+ group 10.9y) and HU treatment (ACS- group 76%, ACS+ group 93%). Similarly, age was significantly higher in the Stroke+ group compared to the Stroke- group (14.0y compared to 9.3y), which was also found when studying VOC (VOC+ group 11.6y, VOC- group 8.2y). Results: In the pediatric cohort, PoS was significantly higher in patients with ACS (mean 40.3 compared to 34.9 mmHg, p=0.0001, Figure 1B). In the adult cohort, PoS was also higher in those with ACS although this did not reach significance (p=0.053, Figure 1C). In the pediatric cohort, PoS was higher in patients with stroke or SI (mean 43.0 mmHg compared to mean 37.3 mmHg, p&amp;lt;0.05), Figure 1D). This finding was replicated in the adult cohort (p&amp;lt;0.05, Figure 1E). EImin and EImax in both cohorts were significantly lower in patients who experienced stroke or SCI (all p&amp;lt;0.05). PoS was higher and EImin and EImax lower in subjects with elevated TCD measurements (all p&amp;lt;0.01, Figure 1F and G). In the adult and pediatric patient cohort, PoS was higher in patients with recent VOC (both p&amp;lt;0.05, Figure 1H and I). Differences in mean PoS between pediatric and adult patient cohorts could be due to differences in treatment, age, genetic background or technical differences between Lorrca devices. Lower significance levels found in the adult patient cohort could be due to smaller sample size. Conclusion: We show that oxygen gradient ektacytometry provides functional, clinically relevant next generation biomarkers that are associated with ACS, stroke and VOC. This study therefore further validates the clinical usefulness of these biomarkers, in particular in relation to cerebral vasculopathy. Since our results merely describe an association and not causality further validation is warranted to establish how well oxygen gradient ektacytometry can assess disease severity. However, its parameters could already provide the clinician with information about patient RBC characteristics and sickling propensity that could aid in clinical decision making. Our results provide a rationale for further development of these biomarkers in the evaluation of novel therapies as part of clinical care, or clinical trial endpoints. Disclosures Rab: RR Mechatronics: Research Funding. Bos:RR Mechatronics: Research Funding. Cnossen:Takeda: Research Funding; Shire: Research Funding; Baxter: Research Funding; Bayer: Research Funding; Sobi: Research Funding; CSL behring: Research Funding; Nordic Pharma: Research Funding; Novo Nordisk: Research Funding; Pfizer: Research Funding. Wijk:Agios Pharmaceuticals Inc.: Research Funding; RR mechatronics: Research Funding. Sheehan:Emmaus: Research Funding; Global Blood Therapeutics: Research Funding; Novartis: Research Funding. van Beers:Pfizer: Research Funding; RR mechatronics: Research Funding; Agios: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding.

How Does Sickle Cell Disease Severity Affect Patient Collection of Disability Insurance and Income: An Analysis of US Survey Data

Introduction: Sickle cell disease (SCD) is a complex genetic disease with a multifactorial pathophysiology including multi-cell adhesion between red blood cells, white blood cells, platelets and endothelial cells, ultimately resulting in vaso-occlusive crises (VOCs). VOCs are the hallmark of SCD and are the primary cause for hospitalization. These recurrent episodes induce severe pain, decrease quality of life, can cause life-threatening complications, and are associated with increased risk of organ damage and mortality. While the clinical burden of SCD is well-documented, less evidence exists surrounding how the severity of SCD affects patients economically. The number of VOCs and other complications not only affect the likelihood of patients being able to work on a given day, but may also affect their long-term economic prospects. This analysis aims to better understand the association between SCD disease severity and its impact on the likelihood of collecting Supplemental Security Income (SSI) and patient income. Methods: A web-based survey was administered to adult patients (≥18 years) living in the United States with a self-reported diagnosis of SCD. The outcomes of interest for this analysis were Social Security Income (SSI) receipt and self-reported total household annual income. These outcomes were stratified by SCD disease severity. Our first measure of disease severity was the number of self-reported VOCs in the prior year. Our second measure of disease severity was developed through clinical expert opinion and relied on an algorithm for dividing patients into 3 disease severity classes. Severity Class I was defined as having no VOCs requiring treatment by health care providers in the past year; Severity Class II was defined as ≥1 emergency department visit or hospital admission for a VOC, or complication in the past year without any organ damage; and Severity Class III was defined as long-term organ damage (such as stroke or renal disease). Generalized linear models (GLM) with a binomial link function were used to analyze the association between SCD disease severity and SSI collection (one model used VOC frequency; a second model used severity classes). A linear regression model was used to analyze the relationship between VOC frequency and income level, while an ordered logistic regression model was used to analyze the association between SCD disease severity classes and income level. Results: The final sample was comprised of 303 individuals who completed the survey. The average age was 34.4 years (range 18 - 72) and 221 (72.9%) were female. The probability of SSI collection among patients with SCD varied across VOC frequency in the previous year. The probability of collecting SSI for patients having 0 and ≥4 VOCs in the past year, was 12% (95% confidence interval (CI): 4% to 31%) and 47% (39% to 55%), respectively. A chi-squared p-value of 0.002 indicated a statistically significant association between a greater number of VOCs and probability of SSI collection. The probability of SSI collection among SCD patients with Severity Class II and Severity Class III SCD was 16% (7.5% to 32%), and 39% (32.9% to 45%), respectively. A chi-squared p-value of 0.03 indicated a statistically significant association between SCD disease severity class and SSI collection. The predicted mean income for patients with SCD experiencing 0 and ≥4 VOCs in the past year was $47,488 and $34,569, respectively. A linear association test p-value of 0.06 indicated weak evidence of a lower mean income in relation to number of VOCs experienced. The predicted mean income among patients with class II and class III SCD was $42,443 and $36,842, respectively. There was no evidence of association between SCD severity class and mean income (p=0.29). Conclusion: Among patients with SCD, having more VOCs was strongly associated with the probability of collecting SSI and weakly associated with lower income. Disease severity class was strongly associated with the probability of collecting SSI. Disclosures Shafrin: Precision Health Economics, part of Precision Medicine Group: Employment, Equity Ownership. Thom:Bayer AG: Consultancy; Hoffman-La Roche: Consultancy; Pfizer: Consultancy; Novartis Pharma AG: Consultancy. Gaunt:Novartis Pharma AG: Consultancy. Zhao:Precision Health Economics, part of Precision Medicine Group: Employment. Joseph:Cigna: Equity Ownership; Pfizer: Equity Ownership; Amgen: Equity Ownership; Novartis: Employment, Equity Ownership. Bhor:Novartis: Employment, Equity Ownership. Rizio:Optum: Employment. Bronté-Hall:bluebird bio: Research Funding. Shah:GBT: Research Funding; Alexion: Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau.

The Oxygenscan Provides Clinically Relevant Biomarkers for Treatment Efficacy That Are Associated with Frequency of Vaso-Occlusive Crisis in Sickle Cell Disease

The Oxygenscan Provides Clinically Relevant Biomarkers for Treatment Efficacy That Are Associated with Frequency of Vaso-Occlusive Crisis in Sickle Cell Disease

Minireview: Clinical severity in sickle cell disease: the challenges of definition and prognostication.

Sickle cell disease (SCD) is a monogenic, yet highly phenotypically variable disease with multisystem pathology. This manuscript provides an overview of many of the known determinants, modifiers, and correlates of disease severity in SCD. Despite this wealth of data, modeling the variable and multisystem pathology of SCD continues to be difficult. The current status of prediction of specific adverse outcomes and global disease severity in SCD is also reviewed, highlighting recent successes and ongoing challenges.

Association between Duffy antigen receptor expression and disease severity in sickle cell disease patients

Objectives: Sickle cell disease (SCD) is associated with a pro-inflammatory state, characterized by an elevated baseline leukocyte count and inflammatory cytokines. Inflammation, white blood cell (WBC) adhesion to vascular endothelium with subsequent endothelial injury, and repeated ischemia–reperfusion injury contribute to disease pathogenesis. Identification of genetic polymorphisms that may modulate disease severity in SCD is becoming a field of interest. The Duffy blood group antigen has been identified as a receptor for various chemokines involved in neutrophil activation and trafficking. This study aimed at investigating the effect of RBCs’ Duffy antigen expression and its genetic polymorphisms on modulating disease severity and its complications among Egyptian sickle cell patients.MethodsWe analyzed the association of Duffy genotypes and phenotypes with clinical expression of SCD in 100 Egyptian patients. The Duffy phenotype expression was detected by indirect anti-globulin test while Duffy genotyping was conducted with polymerase chain reaction-restriction fragment length polymorphism-based assay.ResultsTotal WBC count was strongly associated with Duffy genotype. WBCs were significantly higher in Duffy-positive patients (P = 0.002). No statistical significance was evident between individual measures of disease severity (pulmonary dysfunction, avascular necrosis, central nervous system dysfunction, kidney dysfunction, and leg ulcers) and Duffy genotype.ConclusionOur study suggests that RBC Duffy expression increases levels of WBCs in SCD patients and that Duffy genotype may not be a potential biomarker for end-organ damage in SCD.

Nutrient Insufficiencies/Deficiencies in Children With Sickle Cell Disease and Its Association With Increased Disease Severity.

Sickle cell disease (SCD) is characteristically described as a disease of hemolytic anemia and vaso-occlusive crises (VOCs). However, patients suffer from a multitude of other problems including impaired development, chronic pain, and increased susceptibility to infection. Nutritional deficiency has been implicated as a contributor to these issues. We reported the nutrition status with respect to vitamin D, zinc, B6, B12, folate, and homocysteine serum levels in Canadian children with SCD (n = 91). We also tested for associations between nutrients and markers of disease severity and growth. Almost half the sample (42%) had multiple nutrient insufficiencies/deficiencies, and a further 27% had a single insufficiency/deficiency. The most common insufficiency/deficiency was zinc in 57% followed by calcidiol (25 dihydroxyvitamin D (25(OH)D)) (52%). Sixteen percent of patients had low vitamin B6 levels, while folate, calcitriol (1,25(OH)D), and homocysteine levels were normal. Increased number of vitamin insufficiencies/deficiencies was associated with increasing disease severity (P = 0.018). Zinc insufficiency/deficiency was significantly associated with an increased number of home pain crises (P = 0.001) and an increased incidence of hospitalizations for VOCs (P = 0.01). Our findings show that patients with SCD commonly have multiple nutrient insufficiencies/deficiencies and support the growing evidence for the link between low zinc and increased VOC. It also indicates that increased nutrient insufficiencies/deficiencies are associated with increased disease severity in SCD. Prospective studies with larger samples are needed to further elucidate the relationship between nutrient deficiencies and SCD, and to determine whether nutrient supplementation can improve the disease course.

Increased Prevalence of Autoimmunity and Connective Tissue Diseases in Sickle Cell Disease

Connective tissue disease (CTD) and sickle cell disease (SCD) are diverse group of disorders; however, both of these diseases are characterized by underlying chronic inflammation. CTD is perceived to have a higher incidence and to affect the disease severity in SCD. Objectives: We seek to describe prevalence of autoimmunity and CTD and itsimpact on SCD disease severity as this is not well described in the literature. Methods: We retrospectively reviewed the medical records of 722 patients with SCD, seen over an 11 year period followed at a tertiary care hospital in London, UK. During the last 2 years of the study, number of hospitalizations and length of hospital stay were compared in patients with SCD with and without CTD. Results: In the study cohort, hemoglobin SS was the most common genotype (n = 451; 62%) and 411 (57%) were female. Twenty-three patients (3.1% had documented evidence of CTD, with rheumatoid arthritis (n = 14; 2%) and systemic lupus erythematosus (n = 2; 0.3%) being the most common. Antinuclear antibody was present in 108 (15%) of the patients and anti-smooth muscle antibody was present in 60 (8%). The mean number of hospitalizations (1.9 ± 2.7 vs. 1.5 ± 2.7) and mean length of hospital stay (6 days ± 4.1 vs. 7 days ± 11.4) were not different between those with or without autoimmunity and/or CTD. Avascular necrosis was the most common non-CTD musculoskeletal complication, affecting 72 (10%) patients. Conclusion: Our study suggests that positive autoimmune serology and CTD were more common in SCD compared to non-SCD population of similar ethnic background; however, presence of CTD does not appear to affect the SCD severity. The high frequency of CTD and overlapping of clinical symptoms suggest a need for diagnostic vigilance in diagnosing CTD in patients with SCD.

Important clinical and laboratory correlates of glomerular filtration rate in sickle cell anemia

Renal impairment is routinely assessed using the estimated glomerular filtration rate (eGFR) and it may be helpful to obtain certain clinical or laboratory markers, which show relationship with glomerular filtration rate (GFR) in sickle cell disease (SCD). To assess the relationship between important clinical and laboratory parameters in SCD, and the eGFR. Steady state clinical and laboratory data were obtained from 228 homozygous SCD patients seen over a 7-year period. The GFR was estimated using (isotope dilution mass spectrometry) traceable modification of diet in renal disease (MDRD) and Cockroft-Gault methods. The correlation coefficient and independent t-test were done to assess the level of significance between the eGFR_MDRD and the known indicators of disease severity. The serum alkaline phosphatase (ALP) and serum direct bilirubin levels both showed significant inverse relationship with eGFR_MDRD P = 0.012 and P = 0.24, respectively. The patients' age, Hb, leukocyte count, platelet count, serum direct bilirubin and aspartate transaminase did not show a significant correlation. The eGFR_MDRD was more discriminatory revealing that 20.3% of the patients had suboptimal GFR. Proteinuria in steady state was observed in 20.3% of the patients. High serum direct bilirubin and ALP are associated with a deteriorating eGFR_MDRD. Other clinical and laboratory indicators of disease severity in SCD do not show the relationship with the GFR. MDRD_GFR estimation seemed to be a more appropriate method of estimating GFR in SCD.

Creatinine, Lactate Dehydrogenase, and C-Reactive Protein As Indicators of Acute Vaso-Occlusive Crisis and Sickle Cell Disease Severity in the Emergency Department

Sickle cell disease (SCD) patients often seek care in the Emergency Department (ED) due to vaso-occlusive crisis (VOC), the most common complication of SCD. Currently, no diagnostic test can determine if a SCD patient is having an acute VOC. This study analyzed the utility of creatinine (Cr), C-reactive protein (CRP), and lactate dehydrogenase (LDH) as indicators of acute VOC and increased disease severity. We hypothesized that increased levels of these markers correlated with acute VOC and increased SCD severity because they are suggestive of renal injury, accelerated hemolysis, and inflammation with VOC onset.Data was collected from a cohort of 171 patients followed at an adult sickle cell clinic from 2005 to 2012. Eligibility criteria included a minimum age of 18 with SCD genotypes Hb S/S, Hb S/C, Hb S/B+, or Hb S/B0. Marker values were collected prospectively, with baseline values obtained during non-crisis visits to the sickle cell clinic, and crisis values obtained during treatment for VOC in the ED. Patients were categorized as high or low ED users to approximate disease severity using two methods. Aggregate (AG) analysis assigned patients to the high user group, 65 patients (38%), if they had >3 VOC ED visits in any year. The low user group, 106 patients (62%), had 3 or less VOC ED visits in any year. Since disease severity fluctuates in individual patients over time, a second analysis divided the groups using an individual (IN) analysis where high user-years were defined as >3 VOC ED visits/year. IN analysis resulted in 226 (47%) high user-years and 259 (53%) low user-years. Statistical analysis using R Version 3.1.0 compared overall average baseline and crisis values to determine if biomarker levels increased in acute VOC. High and low user values were compared with respect to baseline and crisis averages to determine if biomarker levels correlated with SCD severity. Analysis of baseline and crisis values over the study period evaluated changes with age. Statistical significance was set to p<0.05.Table 1 summarizes the significant results of the statistical analysis. Changes in Cr and LDH between high and low users with respect to baseline, crisis, and difference between baseline and crisis were not statistically significant in both analyses. However, crisis CRP values between high and low user-years differed significantly. In both analyses, overall baseline and crisis Cr and LDH differed significantly. Crisis Cr and baseline LDH increased significantly over the 7-year time span.Table 1MarkerVariableMeanSDP-valueCr (mg/dL)AG overall baseline0.800.6870.0053AG overall crisis1.081.55IN overall baseline0.8170.9310.0178IN overall crisis1.001.48Overall crisis start1.021.590.0087Overall crisis end1.101.76LDH (U/L)AG overall baseline3871967.90E-5AG overall crisis463227IN overall baseline3952280.0194IN overall crisis445269Overall baseline start3731810.0015Overall baseline end417234CRP (mg/dL)IN high user crisis2.614.310.0247IN low user crisis1.051.02Creatinine, a urinary muscle metabolite, is a marker of kidney function. Dehydration, a potential cause of VOC, may explain the rise in Cr during crisis. LDH increase in crisis reflects increased intravascular hemolysis during VOC. The results support the utility of Cr and LDH as indicators of acute VOC in the ED. However, both AG and IN analyses reveal no distinction between high and low users of the ED. LDH and Cr increase with age, suggesting potential for monitoring SCD disease progression. Increased Cr crisis levels with age may reflect kidney dysfunction due to medullary ischemia from multiple VOCs. Increased non-crisis LDH levels with age suggest increased disease severity, progressive organ damage, and steady state pro-inflammatory conditions.CRP, an acute phase reactant indicative of systemic inflammation, was higher during crisis in high user-years than in low user-years. The correlation of increased crisis CRP to increased ED usage may represent a higher inflammatory state in these patients. Further studies are needed to determine the cause and effect relationship of this correlation.The data supports the utility of Cr and LDH as markers for acute VOC. LDH and Cr also demonstrate potential as indicators of SCD disease severity in a long-term context, while CRP demonstrates potential to monitor for short-term inflammatory states leading to increased severity in frequency and possibly intensity of VOC. DisclosuresNo relevant conflicts of interest to declare.