Low Serum Phosphate Levels Research Articles

7582 Genetic Profiling of Phosphaturic Mesenchymal Tumors Unravels Osterix's Significance in Tumor-Induced Osteomalacia

Abstract Disclosure: Y. Imanishi: None. Y. Nagata: None. M. Ohara: None. T. Maeda-Tateishi: None. T. Shoji: None. M. Emoto: None. Background & Purpose: Tumor-induced osteomalacia (TIO) is a rare condition caused by tumors releasing too much fibroblast growth factor 23 (FGF23). These tumors, specifically called phosphaturic mesenchymal tumors, mixed connective tissue variant (PMTMCT), lead to osteomalacia due to low serum phosphate levels. However, a detailed study regarding the genetic makeup of these tumors and their similarity to bone cells (osteoblasts/osteocytes) has been lacking. Methods: Nineteen PMTMCTs were analyzed and compared their gene expressions to 6 non-TIO tumors. Our focus was on genes usually found in bone cells. Additionally, we examined the relationship between FGF23 and these genes in PMTMCTs. One gene, Osterix, showing significant correlation was further studied using UMR106 osteoblast cells. Results: Fourteen genes related to bone cells expressed significantly higher in PMTMCTs compared to non-TIO tumors. Immunoblotting and Immunohistochemical examinations confirmed the presence of FGF23, Runx2, and Osterix in PMTMCTs. Particularly, Osterix showed the strongest link with FGF23 in PMTMCTs. Immunohistochemical tests revealed similar patterns of distribution for Osterix and FGF23, even co-localizing in some instances. However, the distribution of another gene, DMP1, differed from that of FGF23. In UMR106 cells, silencing Osterix expression led to decreased FGF23 expression, irrespective of DMP1 levels. Conclusions: PMTMCTs exhibit higher levels of genes associated with bone cell functions compared to other tumors. These tumors likely originated from mesenchymal stem cells and transformed into bone cells. Furthermore, Osterix might play a crucial role in the excessive release of FGF23 in PMTMCTs. Presentation: 6/1/2024

Pharmacodynamic Exposure-Response Analysis of Fracture Count Data Following Treatment with Burosumab in Patients with XLH.

X-linked hypophosphatemia (XLH) is a rare genetic disorder caused by excessive fibroblast growth factor 23 (FGF23), leading to low serum phosphate levels resulting in increased risk of fractures and pseudofractures. Burosumab is indicated for the treatment of XLH. In this work, we aimed to understand the quantitative relationship between burosumab-treatment-induced improvements in serum phosphate and reduction in fracture and pseudofracture counts in adults with XLH. Burosumab pharmacokinetic pharmacodynamic data from nine clinical studies were first utilized to update a prior population pharmacokinetic pharmacodynamic (PPKPD) model. The updated PPKPD model predictions for serum phosphate exposures along with other factors (i.e., time and treatment) were utilized to evaluate the relationship on fracture counts using Poisson model. The updated PPKPD model suggested that burosumab concentrations required for 50% of maximal effect decreased with increasing baseline serum phosphate levels. A Poisson model with time from baseline, average serum phosphate, and burosumab treatment described the time-varying fracture and pseudofracture count data appropriately. The model suggested a baseline rate of fracture and pseudofracture of 1.87 counts. The model predicted that fracture counts decrease by 1% each week, and by 23% with each unit increase (1.0 mg/dL) in average serum phosphate from lower limit of normal (2.5 mg/dL). An additional 1% decrease in fracture count each week was attributed to burosumab treatment that could not be explained by improvements in serum phosphate. Overall, the model quantified the relationship between burosumab-treatment-induced serum phosphate improvements and reduction in fracture and pseudofracture counts in patients with XLH over time.

Identification of a novel BAAT frameshift mutation in a female child diagnosed with skeletal dysplasia: A case report.

Skeletal dysplasias are a complex series of rare genetic disorders that cause irregular development of bones, joints, and cartilages in children. A total of 770 disorders associated with 41 groups of skeletal dysplasia have been documented, demonstrating a wide range of clinical manifestations and varying levels of severity. In addition to conventional methods, whole genome sequencing has emerged as a useful approach to pinpointing the underlying etiology of skeletal dysplasias. A 13-month-old female was admitted to the hospital due to the symptoms of jaundice and failure to thrive. The child was subjected to blood tests and a radiographic assessment. The blood chemistries revealed elevated levels of total bilirubin (178 µmol/L), bile acids (198 µmol/L), and low levels of serum calcium (1.69 mmol/L) and phosphate (0.8 mmol/L), along with irregular skeletal development in the forearms and legs, considering rickets and cholestasis. Whole exome sequencing data of the proband revealed a homozygous mutation of c.388dupA in the BAAT (bile acid-CoA: amino acid N-acyltransferase) gene sequence. This mutation caused a frameshift in the amino acid of the BAAT protein, resulting in the pR130Kfs*12 variant. This mutation has been identified as the underlying cause of skeletal dysplasia in the proband. A novel frameshift mutation in the BAAT gene of a Vietnamese female child diagnosed with skeletal dysplasia has been studied by whole exome sequencing analysis. This research reported a case of skeletal dysplasia caused by a frameshift mutation in the BAAT gene. The results of this study contribute to our understanding of the diverse factors that influence irregular skeletal development in children and provide genetic data to support clinical practice.

Comparing early and delayed [99mTc]Tc-MIBI SPECT/CT parathyroid scans: agreement, confidence levels, and clinical predictive factors

BackgroundParathyroid scan is an important imaging modality for localizing hyperfunctioning parathyroid tissue in patients with hyperparathyroidism. Unfortunately, whether early or delayed timing is the optimal protocol for [99mTc]Tc-MIBI SPECT/CT parathyroid remains under debate. This study aimed to evaluate the agreement and compare the confidence levels of physicians when interpreting early and delayed [99mTc]Tc-MIBI SPECT/CT parathyroid scans. Additionally, it sought to identify clinical factors that related to positive scan result. We conducted a prospective study where the early and delayed [99mTc]Tc-MIBI SPECT/CT was separately interpreted as either positive or negative. Furthermore, these interpretations were categorized based on whether they fell within more or less confidence levels of the readers and were correlated with clinical information.ResultsWe enrolled 39 patients with hyperparathyroidism with 158 possible locations of parathyroid glands. The per-location agreement between the early and delayed scans was moderate (concordant rate: 80.3%, Kappa = 0.558), and the per-patient agreement was slight (concordant rate: 71.8%, Kappa = 0.093). The confidence of interpretation was significantly higher for the delayed scans. Calcium supplementation, low serum parathyroid hormone levels, and low serum phosphate levels were associated with positive early scans. High calcium level and high parathyroid hormone levels were associated with positive delayed scans.ConclusionsOur study highlights the impact of the timing of SPECT/CT in [99mTc]Tc-MIBI parathyroid scans. The different confidence levels between early and delayed scans, along with clinical factors, imply that various factors affect parathyroid scan interpretation, and individualized scanning protocols adjusted for specific settings may be needed to optimize the successful localization of hyperfunctioning parathyroid tissue.

Prevalence and risk factors predisposing low bone mineral density in patients with thalassemia.

A common complication of thalassemia is secondary osteoporosis. This study aimed to assess the prevalence and factors associated with low BMD in thalassemic patients. This is a cross-sectional study. Eligible patients were males aged within 18-49 years or premenopausal women diagnosed with thalassemia in Chiang Mai University Hospital between July 2021 and July 2022. The diagnosis of low BMD by dual-energy x-ray absorptiometry (DXA) was defined as a Z-score of -2.0 SD or lower in either the lumbar spine or femoral neck. Clinical factors associated with low BMD were analyzed using a logistic regression model. Prevalence of low BMD was 62.4% from 210 patients with a mean age of 29.7 ± 7.6 years. The predominant clinical characteristics of low BMD thalassemia patients were being female, transfusion-dependent (TDT) and a history of splenectomy. From multivariable analysis, the independent variables associated with low BMD were transfusion dependency (odds ratio, OR 2.36; 95%CI 1.28 to 4.38; p=0.006) and body mass index (BMI) (OR 0.71; 95%CI 0.61 to 0.82; p<0.001). Among patients with low BMD, we observed a correlation between a Z-score with low IGF-1 levels (β=-0.42; 95% CI -0.83 to -0.01; p=0.040), serum phosphate levels (β=0.40; 95% CI 0.07 to 0.73; p=0.016) and hypogonadism (β=-0.48, 95% CI -0.91 to -0.04, p=0.031). This study found a prevalence of low BMD in 62.4% of subjects. Factors associated with low BMD were TDT and BMI. Within the low BMD subgroup, hypogonadism, serum phosphate and low serum IGF-1 levels were associated with a lower Z-score.

#2524 Impact of sevelamer hydrochloride on fibroblast growth factor-23 levels in patients undergoing hemodialysis

Abstract Background and Aims Serum intact fibroblast growth factor 23 (FGF23) levels are progressively increased in relation to the severity of kidney dysfunction. High serum intact FGF23 concentration is associated with the increased cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD). Clinically, phosphate binders are commonly used to reduce serum intact FGF23 levels in CKD patients by lowering serum phosphate levels. Reduction of high intact FGF23 concentration is a strategy, possibly improving the consequences of CKD. We aimed to Assessing the Impact of Sevelamer Carbonate on Fibroblast Growth Factor-23 Levels. Method This case-control study enrolled 100 pre-existing hemodialysis patients, evenly divided into two groups of 50. Group I received a specific sevelamer hydrochloride (Renagel)® dose (2 tablets every 8 hrs), while Group II served as the control group and did not receive (Renagel)®. All patients received the same modality of dialysis with a consistent dialysate calcium concentration. Additionally, they received comprehensive dietary phosphate counseling as part of the standard dietary education provided to our dialysis patients. The levels of phosphorus, calcium, alkaline phosphatase, and FGF23 were assessed in all individuals at the beginning of the study (baseline) and again following 3 months of sevelamer therapy. Results While baseline FGF-23 levels were not statistically different, a highly significant divergence emerged after 3 months of treatment. The sevelamer group experienced a remarkable 38.4% decrease in FGF-23, compared to a mere 0.5% change in the control group, highlighting the pronounced effect of sevelamer on this key protein. Analysis of PO4 levels revealed a remarkable difference between the groups following treatment. While initial PO4 measurements were statistically comparable, the sevelamer group experienced a significantly larger decrease compared to the control group (p &amp;lt; 0.001). Both baseline and follow-up FGF-23 levels displayed highly statistically significant positive correlations with PO4, PTH, alkaline phosphatase, and hsCRP. Conclusion This study found that non-calcium-based phosphate binders were associated with a substantial reduction in FGF-23 in hemodialysis patients. This finding suggests that utilizing such binders may offer protection against the adverse effects of high FGF-23 levels, which are prevalent in this population.

Hypophosphatemia in Chronic Obstructive Pulmonary Disease Patients Requiring Mechanical Ventilation and Its Impact on Weaning in an Intensive Care Unit of a Tertiary Care Hospital in Eastern India.

Background Hypophosphatemia, defined as a serum phosphate level less than 2.5 mg/dL, is a frequent finding in patients with chronic obstructive pulmonary disease (COPD) and has been speculated to negatively affect weaning outcomes. This study aimed to determine the incidence of hypophosphatemia in COPD patients requiring mechanical ventilation and evaluate the predictive role of hypophosphatemia as an indicator of successful weaning from mechanical ventilation in such patients admitted to the intensive care unit (ICU) in a tertiary care hospital in eastern India. Methodology This prospective observational study included 60 adult patients aged 18 to 75 years with acute exacerbations of COPD on mechanical ventilation in the ICU who were planned to undergo a weaning trial. Serum phosphate levels were assessed at the time of admission and before each weaning attempt. Weaning outcomes at each attempt, length of ventilator and ICU stay, and mortality were recorded. Data collection was initiated after approval of the Institutional Ethics Committee. Receiver operating curve (ROC) analysis was done to identify the cut-off value of serum phosphate which predicted successful weaning. Results Of 60 participants, hypophosphatemia on admission was present in 15 (25%) patients. Despite the correction, 13 (21.7%) patients had hypophosphatemia before the first weaning attempt. Only 22 patients out of 60 were successfully weaned off from mechanical ventilation in the first trial, accounting for a success rate of 36.7%, of whom 20 were normophosphatemic (90.9%). In the second and third weaning trials, hypophosphatemia was significantly associated with weaning failure. Overall differences in mean serum phosphate levels among those who failed to wean in each weaning trial and the successful attempt were statistically significant (p < 0.001). On ROC analysis of serum phosphate level before the first weaning trial, a cut-off value of ≥3.0 mg/dL was identified to have 86.4% sensitivity, 55.3% specificity, 52.8% positive predictive value, 87.5% negative predictive value, and 66.7% diagnostic accuracy in predicting weaning success. Five patients died, accounting for a mortality rate of 8.3%. Lower mean serum phosphate levels before the first weaning trial, higher mean age, and longer ventilator and ICU days were significantly associated with mortality among our study participants (p < 0.05). Conclusions Our findings suggest that maintaining normal serum phosphate levels is critical to successfully weaning off patients with COPD from ventilator support.

The Association Between Low Preoperative Phosphate Levels and Postliver Surgery Outcomes–A Single Center Experience

IntroductionPrevious research has demonstrated the impact of postoperative phosphate levels on liver regeneration and outcomes after liver resection surgeries, a potential predictor for regenerative success and liver failure. However, little is known about the association between low preoperative serum phosphate levels and outcomes in liver resections. MethodsWe performed a retrospective analysis of liver resections performed at our institution. Patients were categorized based on preoperative phosphate levels (low versus normal). Our primary outcome measure was posthepatectomy liver failure. ResultsA total of 265 cases met the study criteria. 71 patients (26.7%) had low preoperative phosphate levels. The incidence of posthepatectomy liver failure was higher in the low preoperative phosphate group (19.2% versus 12.4%). However, after propensity score matching, rates of posthepatectomy liver failure were similar between low and normal preoperative phosphate cohorts (13% versus 14%, P = 0.83). ConclusionsLow preoperative phosphate levels were not associated with worse postoperative outcomes in this study. Further studies are warranted to investigate this association and its relevance as a clinical prognostic factor for postoperative liver failure.

The Effect of Unadjusted Mineral Supplementation on Bone Health of Preterm Infants Fed Fortified Human Milk: An Exploratory Analysis

Background: In standard fortification of human milk (HM), the HM macronutrient content is assumed, and a fixed amount of a multinutrient fortifier is added to achieve recommended nutrient intakes. In target fortification, the HM macronutrient content is regularly measured, guiding the addition of modular macronutrient supplements to the fortified HM, to achieve the nutritional targets more precisely. Objective: The study aimed to investigate whether this addition of modular supplements, unaccompanied by mineral supplementation, predispose to metabolic bone disease (MBD). Methods: This is a secondary analysis of a larger study of infants born with &lt;33 weeks gestational age. Fortifications based on the assumed (Group 1) or measured (Group 2) of the HM macronutrient content were compared, using low serum phosphate levels as an indicator of MBD, and length growth as a surrogate of bone growth. Results: Eighty-four infants were included, 35 in Group 1 and 49 in Group 2. During the exposure period, infants of Group 2 received higher mean fat (6.1 vs. 5.3 g/kg/day, P &lt; 0.001) and carbohydrate (13.0 vs. 11.7 g/kg/day, P &lt; 0.001) intakes; in addition, they exhibited lower mean serum phosphate (5.5 vs. 6.0 mg/dL, P = 0.022) and faster mean length velocity (1.06 vs. 0.89 cm/week, P = 0.003). Conclusions: These findings suggest that feeding fortified HM with extra fat and carbohydrate content, unaccompanied by mineral supplementation, promotes increased bone growth, as indicated by accelerated length growth, but with insufficiently mineralized osteoid, indicated by low serum phosphate levels. Intervention studies using direct biomarkers of bone mass content and mineral density are necessary to corroborate our findings.

Hypophosphatemia and Type-2 Diabetes Mellitus: A Review

Type-2 diabetes is a global public health crisis that threatens the economies of all nations, particularly developing countries. Type-2 diabetes mellitus has been suggested to be the most common endocrine disorder associated with several metabolic disturbances including changes in serum calcium, zinc, magnesium, or phosphate. Moreover, those who have poor glycemic control and longtime diabetes mellitus are more likely to decrease the blood phosphate level. Low serum phosphate level may be associated with morbidity and mortality from cardiovascular disease in these patients. So, the findings of this study may suggest that serum phosphate is an important screening parameter in type-2 diabetic patients especially who have poor glycemic control and longtime diabetes mellitus. Eastern Med Coll J. July 2023; 8 (2): 45-50

Assessment of the Correlation Between Serum Phosphate Level and Muscle Strength as Measured by Handgrip Strength in Patients Treated With Hemodialysis.

Sarcopenia, commonly observed in patients treated with hemodialysis, correlates with low serum phosphate levels. Although normophosphatemia is desired, dietary phosphate restriction is difficult to achieve and may result in undesirable protein restriction. We aimed to evaluate whether hyperphosphatemia is associated with higher muscle strength in patients receiving hemodialysis treatment. A single-center prospective observational study. Ambulatory prevalent patients undergoing hemodialysis treatments in a dialysis unit of a tertiary hospital. Participants included prevalent patients treated with hemodialysis. All patients were above 18 years. Only patients with residual kidney function below 200 mL/24 hours were included to avoid bias. Muscle strength was measured by handgrip strength (HGS). Each patient repeated 3 measurements, and the highest value was recorded. Handgrip strength cutoffs for low muscle strength were defined as <27 kg in men and <16 kg in women. Biochemical parameters, including serum phosphate level, were driven from routine monthly blood tests. Hyperphosphatemia was defined as serum phosphate above 4.5 mg/dL. Handgrip strength results were compared to nutritional, anthropometric, and biochemical parameters-in particular phosphate level. Long-term mortality was recorded. Seventy-four patients were included in the final analysis. Handgrip strength was abnormally low in 33 patients (44.5%). Patients with abnormal HGS were older and more likely to have diabetes mellitus and lower albumin and creatinine levels. There was no correlation between HGS and phosphate level (r = 0.008, P = .945). On multivariable analysis, predictors of higher HGS were body mass index and creatinine. Diabetes mellitus and female sex predicted lower HGS. Hyperphosphatemia correlated with protein catabolic rate, blood urea nitrogen, and creatinine. On multivariable analysis, predictors of hyperphosphatemia were higher creatinine level, normal albumin level, and heart failure. During mean follow-up time of 7.66 ± 3.9 months, 11 patients died. Mortality was significantly higher in patients with abnormally low HGS compared with normal HGS (odds ratio = 9.32, P = .02). A single-center study. All measurements were performed at one time point without repeated assessments. Direct dietary intake, degree of physical activity, and medication compliance were not assessed. Hyperphosphatemia correlated with increased protein intake as assessed by protein catabolic rate in patients treated with hemodialysis; however, neither correlated with higher muscle strength as measured by HGS.Trial registration: MOH 202125213.

Prognostic value of serum phosphate levels in sepsis: a systematic review and meta-analysis.

There remain controversies over the conclusion of different serum phosphate levels as prognostic predictors of sepsis patients. As such, this study investigated the association between different serum phosphate and the prognosis of sepsis. Data from PubMed, Embase, Cochrane Library, and Web of Science were systematically retrieved from the inception of databases to June 1, 2023 and independently screened and extracted by two authors. Binary variables in the study were estimated as relative risk ratio (RR) and 95% confidence interval (CI), and continuous variables were estimated as mean and standard deviation. The Newcastle-Ottawa Scale (NOS) was employed to evaluate the quality of the included studies, and subgroup analysis and sensitivity analysis were performed for all outcomes to explore the sources of heterogeneity. Ten studies were included in this study including 38,320 patients with sepsis or septic shock. Against normal serum phosphate levels, a high serum phosphate level was associated with an elevated all-cause mortality risk (RR = 1.46; 95% CI [1.22-1.74]; P = 0.000) and prolonged Intensive Care Unit (ICU) length of stay (LOS) (WMD = 0.63; 95% CI [0.27-0.98]; P = 0.001). However, there was no significant difference in the in-hospital LOS (WMD = 0.22; 95% CI [-0.61-1.05]; P = 0.609). A low serum phosphate level was not significantly associated with the all-cause mortality risk (RR = 0.97; 95% CI [0.86-1.09]; P = 0.588), ICU LOS (WMD = -0.23; 95% CI [-0.75-0.29]; P = 0.394) and in-hospital LOS (WMD = -0.62; 95% CI [-1.72-0.49]; P = 0.274). Sepsis patients with high serum phosphate levels before therapeutic interventions were associated with a significant increase in the all-cause mortality risk, prolonged ICU LOS, and no significant difference in in-hospital LOS. Sepsis patients with low serum phosphate levels before interventions may have a reduced risk of all-cause mortality, shorter ICU LOS, and in-hospital LOS, but the results were not statistically significant.

Surgical and biochemical outcomes of phosphaturic mesenchymal tumors causing tumor-induced osteomalacia in the head and neck region

ObjectivesWe aimed to report the surgical outcomes of phosphaturic mesenchymal tumors causing tumor-induced osteomalacia in the head and neck. MethodsThis study analyzed nine patients who underwent surgical excision of phosphaturic mesenchymal tumors in the head and neck region. The primary sites were two in the maxilla and ethmoid sinus, and one in the intracranial, skull, parotid gland, maxillary sinus, and nasal cavity in each patient. Outcomes were compared with those in the extremities and trunk (n = 32). ResultsFive of nine patients (56%) developed residual disease/local recurrence associated with low serum phosphate level after initial surgical excision. At the last follow-up, the biochemical parameters were normalized in four of the five patients after re-excision without any medication. The local recurrence/residual disease risk was significantly higher for the head and neck compared with the extremities and trunk (56% vs. 25%, p = 0.048). The rate of remission (normalized serum phosphate without medication) at final follow-up was similar in both groups after re-excision (head and neck vs. extremities and trunk, 86% vs. 73%, p = 0.827). ConclusionsPhosphaturic mesenchymal tumor resection in the head and neck region was challenging because of its complex anatomy and proximity to the brain or other crucial organs, which was associated with high local recurrence/residual disease rate. However, biological remission was achieved in the majority of the patients after re-excision.

The impact of severe depression on the survival of older patients with end-stage kidney disease.

Incidence of depression increases in patients with end-stage kidney disease (ESKD). We evaluated the association between depression and mortality among older patients with ESKD, which has not been studied previously. This nationwide prospective cohort study included 487 patients with ESKD aged >65 years, who were categorized into minimal, mild-to-moderate, and severe depression groups based on their Beck Depression Inventory-II (BDI-II) scores. Predisposing factors for high BDI-II scores and the association between the scores and survival were analyzed. The severe depression group showed a higher modified Charlson comorbidity index value and lower serum albumin, phosphate, and uric acid levels than the other depression groups. The Kaplan-Meier curve revealed a significantly lower survival in the severe depression group than in the minimal and mild-to-moderate depression groups (p = 0.011). Multivariate Cox regression analysis confirmed that severe depression was an independent risk factor for mortality in the study cohort (hazard ratio, 1.39; 95% confidence interval, 1.01-1.91; p = 0.041). Additionally, BDI-II scores were associated with modified Charlson comorbidity index (p = 0.009) and serum albumin level (p = 0.004) in multivariate linear regression. Among the three depressive symptoms, higher somatic symptom scores were associated with increased mortality. Severe depression among older patients with ESKD increases mortality compared with minimal or mild-to-moderate depression, and patients with concomitant somatic symptoms require careful management of their comorbidities and nutritional status.

The altered composition of gut microbiota and biochemical features as well as dietary patterns in a southern Chinese population with recurrent renal calcium oxalate stones.

The correlation among gut microbiota, biochemical features, and dietary patterns in recurrent stone formers has been inadequately investigated in the Chinese population. Forty-two patients with calcium oxalate stones (CaOxS group), including 34 recurrent stone formers (RS group), and 40 nonstone healthy subjects (NS group) from Changshu Hospital Affiliated with Soochow University, were prospectively recruited. Food frequency questionnaires were completed by participants, fasting vein blood was extracted, 24-h urine was collected for biochemical detection, and fecal samples were gathered for 16S ribosomal RNA (rRNA) gene sequencing. BMI; serum levels of triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), magnesium, and creatinine; and urine levels of magnesium in stone formers were significantly different from those of controls, and RS patients showed significantly low serum phosphate and high urine phosphate levels. Celery, bamboo shoots, and pickled food were the favored foods of local stone formers. Patients with recurrent stones had altered microbiota composition, with Escherichia, Fusobacterium, and Epulopiscium being the predominant pathogenic genera. The gut microbiota in RS patients had stronger functions in fatty acid and amino acid degradation but weaker functions in their biosynthesis. The pathogenic genera were positively correlated with BMI; serum levels of TGs and creatinine; urine levels of calcium, phosphate, and uric acid (UA); and celery, bamboo shoots, and pickled food intake. The abundance of Escherichia and Fusobacterium and the levels of serum magnesium and creatinine were the most relevant factors associated with stone recurrence and could be validated as biomarkers of recurrence. Our research provides a novel prevention strategy for the recurrence of renal calcium oxalate stones in the Han Chinese population of southern China.

#5293 THE IMPACT OF SEVERE DEPRESSION ON THE SURVIVAL OF OLDER PATIENTS WITH END-STAGE KIDNEY DISEASE

Abstract Background and Aims Incidence of depression increases in patients with end-stage kidney disease (ESKD). We evaluated the association between depression and mortality among older patients with ESKD, which has not been studied previously. Method This nationwide prospective cohort study included 487 patients with ESKD aged &amp;gt; 65 years, who were categorized into minimal, mild-to-moderate, and severe depression groups based on their Beck Depression Inventory-II (BDI-II) scores. BDI-II scores were separated into three symptom domains: affective, cognitive, and somatic depressive symptoms. The association between the depression groups and survival were analyzed using multivariate Cox proportional hazard regression models. Predisposing factors for high BDI-II scores were evaluated using logistic regression analysis. The associations among the three depressive-symptom domains and survival were also analyzed. Results The severe depression group showed a higher modified Charlson comorbidity index value and lower serum albumin, phosphate, and uric acid levels than the other depression groups. The Kaplan–Meier curve revealed a significantly lower survival in the severe depression group than in the minimal and mild-to-moderate depression groups (P = 0.011). Multivariate Cox regression analysis confirmed that severe depression was an independent risk factor for mortality in the study cohort [hazard ratio (HR), 1.39; 95% confidence interval (CI), 1.01–1.91; P = 0.041). BDI-II scores were associated with modified Charlson comorbidity index (P = 0.009) and serum albumin level (P = 0.004) in multivariate linear regression. Among the three depressive symptoms, higher somatic symptom scores were associated with increased mortality (HR, 2.45; 95% CI, 1.25–4.79; P = 0.009). Conclusion Among older patients with ESKD, severe depression increases mortality compared with minimal or mild-to-moderate depression. And patients with concomitant somatic symptoms require careful management of their comorbidities and nutritional status.

Tumor-induced Osteomalacia Secondary to Phosphaturic Mesenchymal Tumor.

HomeRadiology: Imaging CancerVol. 5, No. 2 PreviousNext Images in CancerFree AccessTumor-induced Osteomalacia Secondary to Phosphaturic Mesenchymal TumorAmit Agarwal , Girish Bathla, Vivek GuptaAmit Agarwal , Girish Bathla, Vivek GuptaAuthor AffiliationsFrom the Departments of Radiology (A.A.) and Neuroradiology (V.G.), Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224; and Department of Radiology, Mayo Clinic, Rochester, Minn (G.B.).Address correspondence to A.A. (email: [email protected]).Amit Agarwal Girish BathlaVivek GuptaPublished Online:Mar 10 2023https://doi.org/10.1148/rycan.220170MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Tumor-induced osteomalacia (TIO), or oncogenic osteomalacia, is an uncommon paraneoplastic syndrome characterized by urinary phosphate wasting due to an increased production of fibroblast growth factor 23 (FGF23), secondary to an underlying phosphaturic mesenchymal tumor (PMT). Patients usually present with bone pain and pathologic fractures caused by hypophosphatemic hyperphosphaturic osteomalacia (Fig 1), characterized by high serum FGF23 levels (Fig 2) and low serum calcitriol levels. Given the rarity of this entity and nonspecific clinical and imaging features, these tumors are challenging to diagnose and can go undetected for many years (1). Tumors can be found in any osseous or soft-tissue location, however, and are typically observed in the extremities, most commonly the femur, of middle-aged adults. TIO is also associated with other mesenchymal tumors, including solitary fibrous tumors and giant cell tumors, primarily due to FGF23 secretion. A combination of nuclear scans using somatostatin analogs, such as gallium-68 tetraazacyclododecane tetraacetic acid octreotate (68Ga-DOTATATE) and indium-111 (111In)-pentetreotide (OctreoScan), provides the highest sensitivity for detecting tumors, which are usually small in size and not evident at clinical examination. These lesions appear to be moderately fluorodeoxyglucose avid, potentially aiding in diagnosis, but have wide variability in uptake and limited specificity. CT and MRI are noncontributory for initial location but are usually needed later to evaluate anatomic extent. Surgical resection of PMTs is typically curative, resulting in complete resolution of the syndrome (2,3). While few cases of PMT have been reported, it is important to consider this diagnosis in all patients with hypophosphatemic osteomalacia.Figure 1: (A) Methylene diphosphonate bone scan in a 65-year-old female patient with bone pain reveals multiple foci of increased uptake (arrowheads) over bilateral femur and sternum, along with prominent costochondral beadings (rosary), suggesting metabolic bone disease (osteomalacia). Serologic workup revealed a high serum fibroblast growth factor 23 (FGF23) level of 1155 reference unit (RU)/mL (reference range, ≤180 RU/mL) with low serum phosphate level and elevated alkaline phosphatase level. (B) Coronal noncontrast CT image of the lumbar spine reveals a lytic lesion in the right transverse process of L3 (arrow) with (C) increased fluorodeoxyglucose uptake (standardized uptake value, 9.8) (arrow) on the axial PET/CT image.Figure 1:Download as PowerPointOpen in Image Viewer Figure 2: Histopathologic features of phosphaturic mesenchymal tumors, with predominantly spindled cells on hematoxylin-eosin (H&E) stains and strong expression of fibroblast growth factor 23 (FGF-23) mRNA on in situ hybridization (ISH).Figure 2:Download as PowerPointOpen in Image Viewer Disclosures of conflicts of interest: A.A. Consulted for and expert testimony for Authnetic4D in 2020; institutional CME fund (attending meetings/travel); stocks in Gilead Pharma. G.B. Grant from Foundation of Sarcoidosis Research, unrelated to current work. V.G. No relevant relationships.Keywords: Osteomalacia, Phosphaturic, Spine, Tumor MicroenvironmentAuthors declared no funding for this work.

Serum 25-Hydroxyvitamin D Level Is Negatively Associated with Fatigue in Elderly Maintenance Hemodialysis Patients

Introduction: Chronic kidney disease-mineral and bone disorder (CKD-MBD) is frequently observed in maintenance hemodialysis (MHD) patients and is associated with fracture, muscle weakness, malnutrition, etc.; however, relationships of CKD-MBD markers and fatigue are not well established. Methods: This was a cross-sectional study including 244 MHD patients (89 elders) from July to September 2021 in the First Affiliated Hospital of Shandong First Medical University. CKD-MBD markers and other clinical data were collected from medical records. Fatigue in the past week was measured by Standardized Outcomes in Nephrology-Hemodialysis (SONG-HD) fatigue measure; fatigue at the end of hemodialysis was measured by numeric rating scale (NRS). Spearman correlation, linear regression, and robust linear regression were. Results: In all MHD patients, lg[25(OH)D] (nmol/L) was negatively correlated with SONG-HD score (β = −1.503, 95% CI: −2.826 to 0.18, p = 0.026) and NRS score (β = −1.532, p = 0.04) in multiple regression models adjusting for sex, age, and all CKD-MBD characters; but no correlations were found on univariate regression or in other multiple regression models. Interaction effects between age ≥65 years and lg(25[OH]D [nmol/L]) in terms of fatigue scores were significant based on multiple linear regressions (SONG-HD score β = −3.613, p for interaction = 0.006; NRS score β = −3.943, p for interaction = 0.008). Compared with non-elderly patients, elderly patients were with higher ACCI scores (7 [6, 8] vs. 4 [3, 5], p < 0.001), higher SONG-HD scores (3 [2, 6] vs. 2 [1, 3], p < 0.001), higher NRS score (4 [2, 7] vs. 3 [1, 5], p < 0.001), lower serum phosphate levels (1.65 [1.29, 2.10] vs. 1.87 [1.55, 2.26] mmol/L, p = 0.002), and lower serum iPTH levels (160.6 [90.46, 306.45] vs. 282.2 [139, 445.7] pg/mL, p < 0.001). There were no differences in serum calcium, alkaline serum, or 25(OH)D levels between the two groups. In elderly patients, lg[25(OH)D] was negatively correlated with SONG-HD score (β = −3.323, p = 0.010) and NRS score (β = −3.521, p = 0.006) on univariate linear regressions. Following adjustment for sex, age, and all CKD-MBD characters, lg[25(OH)D] was negatively correlated with SONG-HD scores (multiple linear regression β = −4.012, p = 0.004; multiple robust regression β = −4.012, p = 0.003) or NRS scores (multiple linear regression β = −4.104, p = 0.002; multiple robust regression β = −4.104, p = 0.001). There were no significant correlations between fatigue scores and other CKD-MBD markers (calcium, phosphate, lgiPTH, alkaline phosphatase) in elderly MHD patients, on either univariate linear regressions or multiple regressions. Conclusion: Serum 25(OH)D level is negatively associated with fatigue in elderly MHD patients.

Mild Hypophosphatemia-Associated Conditions in Children: The Need for a Comprehensive Approach.

To better understand the causes of hypophosphatemia in children, we evaluated all serum phosphate tests performed in a tertiary hospital with unexpected but persistent temporary or isolated hypophosphatemia over an 18 year period. We collected 29,279 phosphate tests from 21,398 patients, of which 268 (1.2%) had at least one result showing hypophosphatemia. We found that endocrinopathies (n = 60), tumors (n = 10), and vitamin D deficiency (n = 3) were the medical conditions most commonly associated with mild hypophosphatemia, but in many patients the cause was unclear. Among patients with endocrinopathies, those with diabetes mellitus were found to have lower mean serum phosphate levels (mean 3.4 mg/dL) than those with short stature (3.7 mg/dL) or thyroid disorders (3.7 mg/dL). In addition, we found a correlation between glycemia and phosphatemia in patients with diabetes. However, despite the potential relevance of monitoring phosphate homeostasis and the underlying etiologic mechanisms, renal phosphate losses were estimated in less than 5% of patients with hypophosphatemia. In the pediatric age group, malignancies, hypovitaminosis D, and endocrine disorders, mostly diabetes, were the most common causes of hypophosphatemia. This real-world study also shows that hypophosphatemia is frequently neglected and inadequately evaluated by pediatricians, which emphasizes the need for more education and awareness about this condition to prevent its potentially deleterious consequences.

Impact of X-Linked Hypophosphatemia on Muscle Symptoms

X-linked hypophosphatemia (XLH) is the most common hereditary form of rickets and deficiency of renal tubular phosphate transport in humans. XLH is caused by the inactivation of mutations within the phosphate-regulating endopeptidase homolog X-linked (PHEX) gene and follows an X-dominant transmission. It has an estimated frequency of 1 case per 20,000, and over 300 distinct pathogenic variations have been reported that result in an excess of fibroblast growth factor 23 (FGF23) in the serum. Increased levels of FGF23 lead to renal phosphate loss, decreased serum 1,25-dihydroxyvitamin D, and increased metabolism of 1,25-dihydoxyvitamin D, resulting in hypophosphatemia. Major clinical manifestations include rickets, bone deformities, and growth retardation that develop during childhood, and osteomalacia-related fractures or pseudo-fractures, degenerative osteoarthritis, enthesopathy, dental anomalies, and hearing loss during adulthood, which can affect quality of life. In addition, fatigue is also a common symptom in patients with XLH, who experience decreased motion, muscle weakness, and pain, contributing to altered quality of life. The clinical and biomedical characteristics of XLH are extensively defined in bone tissue since skeletal deformations and mineralization defects are the most evident effects of high FGF23 and low serum phosphate levels. However, despite the muscular symptoms that XLH causes, very few reports are available on the effects of FGF23 and phosphate in muscle tissue. Given the close relationship between bones and skeletal muscles, studying the effects of FGF23 and phosphate on muscle could provide additional opportunities to understand the interactions between these two important compartments of the body. By describing the current literature on XLH and skeletal muscle dysfunctions, the purpose of this review is to highlight future areas of research that could contribute to a better understanding of XLH muscular disability and its management.