Chronic Renal Insufficiency Cohort Research Articles

Proteomics of CKD progression in the chronic renal insufficiency cohort

Progression of chronic kidney disease (CKD) portends myriad complications, including kidney failure. In this study, we analyze associations of 4638 plasma proteins among 3235 participants of the Chronic Renal Insufficiency Cohort Study with the primary outcome of 50% decline in estimated glomerular filtration rate or kidney failure over 10 years. We validate key findings in the Atherosclerosis Risk in the Communities study. We identify 100 circulating proteins that are associated with the primary outcome after multivariable adjustment, using a Bonferroni statistical threshold of significance. Individual protein associations and biological pathway analyses highlight the roles of bone morphogenetic proteins, ephrin signaling, and prothrombin activation. A 65-protein risk model for the primary outcome has excellent discrimination (C-statistic[95%CI] 0.862 [0.835, 0.889]), and 14/65 proteins are druggable targets. Potentially causal associations for five proteins, to our knowledge not previously reported, are supported by Mendelian randomization: EGFL9, LRP-11, MXRA7, IL-1 sRII and ILT-2. Modifiable protein risk markers can guide therapeutic drug development aimed at slowing CKD progression.

Plasma Tryptophan-Kynurenine Pathway Metabolites and Risk for Progression to End-Stage Kidney Disease in Patients With Type 2 Diabetes.

We sought to study the associations between plasma metabolites in the tryptophan-kynurenine pathway and the risk of progression to end-stage kidney disease (ESKD) in patients with type 2 diabetes. Plasma tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid, and xanthurenic acid concentrations were measured in discovery (n = 1,915) and replication (n = 346) cohorts. External validation was performed in Chronic Renal Insufficiency Cohort (CRIC) participants with diabetes (n = 1,312). The primary outcome was a composite of incident ESKD (progression to estimated glomerular filtration rate [eGFR] <15 mL/min/1.73 m2, sustained dialysis, or renal death). The secondary outcome was annual eGFR decline. In the discovery cohort, tryptophan was inversely associated with risk for ESKD, and kynurenine-to-tryptophan ratio (KTR) was positively associated with risk for ESKD after adjustment for clinical risk factors, including baseline eGFR and albuminuria (adjusted hazard ratios [HRs] 0.62 [95% CI 0.51, 0.75] and 1.48 [1.20, 1.84] per 1 SD). High levels of kynurenic acid and xanthurenic acid were associated with low risks of ESKD (0.74 [0.60, 0.91] and 0.74 [0.60, 0.91]). Consistently, high levels of tryptophan, kynurenic acid, and xanthurenic acid were independently associated with a slower eGFR decline, while a high KTR was predictive of a faster eGFR decline. Similar outcomes were obtained in the replication cohort. Furthermore, the inverse association between kynurenic acid and risk of ESKD was externally validated in CRIC participants with diabetes (adjusted HR 0.78 [0.65, 0.93]). Accelerated catabolism of tryptophan in the kynurenine pathway may be involved in progressive loss of kidney function. However, shunting the kynurenine pathway toward the kynurenic acid branch may potentially slow renal progression.

Isolated Diastolic Hypertension and Kidney and Cardiovascular Outcomes in CKD: The Chronic Renal Insufficiency Cohort (CRIC) Study

The clinical significance of isolated diastolic hypertension in patients with chronic kidney disease (CKD) is unclear. We assessed the prevalence of isolated diastolic hypertension and its association with adverse kidney and cardiovascular outcomes in participants in the Chronic Renal Insufficiency Cohort (CRIC) study. Prospective cohort study. CRIC study participants with complete baseline data on systolic blood pressure (SBP) and diastolic BP (DBP) (N=5,621). Isolated diastolic hypertension defined as SBP≤130mm Hg and DBP>80mm Hg. Normotension, defined as SBP≤130mm Hg and DBP≤80mm Hg. Composite kidney events (50% decline in estimated glomerular filtration rate or onset of kidney failure), composite cardiovascular events (myocardial infarction, heart failure, stroke, or peripheral arterial disease), and all-cause mortality. Cox proportional hazards models adjusted for demographic, health behavior, and clinical covariates. Of the 5,621 participants, 347 (6.2%) had isolated diastolic hypertension. Among the 347 participants with isolated diastolic hypertension, there was no association between isolated diastolic hypertension and the composite kidney outcome (HR, 1.17; 95% CI, 0.93-1.47; P=0.18), composite cardiovascular events (HR, 0.91; 95% CI, 0.65-1.27; P=0.58), or all-cause mortality (HR, 0.82; 95% CI, 0.57-1.19; P=0.30). Older age of cohort and low number of participants of Asian ethnicity limit generalizability of findings. A relatively small sample size is inadequate to detect modest associations with outcomes. Isolated diastolic hypertension wasnot associated with the risk of adverse kidneyand cardiovascular events in participants with CKD. Clinicians frequently encounter patients with kidney disease who have controlled systolic blood pressure (BP) but high diastolic BP and do not know whether they should intensify BP treatment in an attempt to control the diastolic BP. We examined whether having controlled systolic BP but uncontrolled diastolic BP leads to worse heart and kidney outcomes in patients with chronic kidney disease. We did not find any such association. However, our study was relatively small and had a number of limitations. Till larger studies confirm or refute this finding, we recommend not increasing blood pressure medications to improve the diastolic BP control if the systolic BP is already well controlled in patients with chronic kidney disease.

Fibroblast Growth Factor 23 and Risk of Heart Failure Subtype: The CRIC (Chronic Renal Insufficiency Cohort) Study

Heart failure (HF) is an important cause of morbidity and mortality among individuals with chronic kidney disease (CKD). A large body of evidence from preclinical and clinical studies implicates excess levels of fibroblast growth factor 23 (FGF23) in HF pathogenesis in CKD. It remains unclear whether the relationship between elevated FGF23 levels and HF risk among individuals with CKD varies by HF subtype. Prospective cohort study. A total of 3,502 participants were selected in the Chronic Renal Insufficiency Cohort study. Baseline plasma FGF23. Incident HF by subtype and total rate of HF hospitalization. HF was categorized as HF with preserved ejection fraction (HFpEF, ejection fraction [EF]≥ 50%), HF with reduced EF (HFrEF, EF<50%) and HF with unknown EF (HFuEF). Multivariable-adjusted cause-specific Cox proportional hazards models were used to investigate associations between FGF23 and incident hospitalizations for HF by subtype. The Lunn-McNeil method was used to compare hazard ratios across HF subtypes. Poisson regression models were used to evaluate the total rate of HF. During a median follow-up time of 10.8 years, 295 HFpEF, 242 HFrEF, and 156 HFuEF hospitalizations occurred. In multivariable-adjusted cause-specific Cox proportional hazards models, FGF23 was significantly associated with the incidence of HFpEF (HR, 1.41; 95% CI, 1.21-1.64), HFrEF (HR, 1.27; 95% CI, 1.05-1.53), and HFuEF (HR, 1.40; 95% CI, 1.13-1.73) per 1 standard deviation (SD) increase in the natural log of FGF23. The Lunn-McNeil method determined that the risk association was consistent across all subtypes. The rate ratio of total HF events increased with FGF23 quartile. In multivariable-adjusted models, compared with quartile 1, FGF23 quartile 4 had a rate ratio of 1.81 (95% CI, 1.28-2.57) for total HF events. Self-report of HF hospitalizations and possible lack of an echocardiogram at time of hospitalization. In this large multicenter prospective cohort study, elevated FGF23 levels were associated with increased risks for all HF subtypes. Heart failure (HF) is a prominent cause of morbidity and mortality in individuals with chronic kidney disease (CKD). Identifying potential pathways in the development of HF is essential in developing therapies to prevent and treat HF. In a large cohort of individuals with CKD, the Chronic Renal Insufficiency Cohort (N=3,502), baseline fibroblast growth factor-23 (FGF23), a hormone that regulates phosphorous, was evaluated in relation to the development of incident and recurrent HF with reduced, preserved, and unknown ejection fraction. In this large multicenter prospective cohort study, elevated FGF23 levels were associated with increased risk of all HF subtypes. These findings demonstrate the need for further research into FGF23 as a target in preventing the development of HF in individuals with CKD.

A 4-Variable Model to Predict Cardio-Kidney Events and Mortality in Chronic Kidney Disease: The Chronic Renal Insufficiency Cohort (CRIC) Study

Introduction: Current prognostic models for chronic kidney disease (CKD) are complex and were designed to predict a single outcome. We aimed to develop and validate a simple and parsimonious prognostic model to predict cardio-kidney events and mortality. Methods: Patients from the CRIC Study (n = 3,718) were randomly divided into derivation (n = 2,478) and validation (n = 1,240) cohorts. Twenty-nine candidate variables were preselected. Multivariable Cox regression models were developed using stepwise selection for various cardio-kidney endpoints, namely, (i) the primary composite outcome of 50% decline in estimated glomerular filtration rate (eGFR) from baseline, end-stage renal disease, or cardiovascular (CV) mortality; (ii) hospitalization for heart failure (HHF) or CV mortality; (iii) 3-point major CV endpoints (3P-MACE); (iv) all-cause death. Results: During a median follow-up of 9 years, the primary outcome occurred in 977 patients of the derivation cohort and 501 patients of the validation cohort. Log-transformed N-terminal pro-B-type natriuretic peptide (NT-proBNP), log-transformed high-sensitive cardiac troponin T (hs-cTnT), log-transformed albuminuria, and eGFR were the dominant predictors. The primary outcome risk score discriminated well (c-statistic = 0.83) with a proportion of events of 11.4% in the lowest tertile of risk and 91.5% in the highest tertile at 10 years. The risk model presented good discrimination for HHF or CV mortality, 3P-MACE, and all-cause death (c-statistics = 0.80, 0.75, and 0.75, respectively). The 4-variable risk model achieved similar c-statistics for all tested outcomes in the validation cohort. The discrimination of the 4-variable risk model was mostly superior to that of published models. Conclusion: The combination of NT-proBNP, hs-cTnT, albuminuria, and eGFR in a single 4-variable model provides a unique individual prognostic assessment of multiple cardio-kidney outcomes in CKD.

Effect of blood pressure index on clinical outcomes in patients with heart failure and chronic kidney disease.

This study aimed to assess the effect of blood pressure (BP) index, in terms of level and variability, on the progression of cardiovascular and renal diseases in patients with both heart failure (HF) and chronic kidney disease (CKD). The study involved patients with HF and CKD from the database of the Chronic Renal Insufficiency Cohort (CRIC) study. The study endpoint includes the following: (i) primary endpoint, including cardiovascular disease (CVD) events, renal events, and all-cause death; (ii) CVD events; (iii) renal events; and (iv) all-cause death. Among 3939 participants in the CRIC study, a total of 382 patients were included. The duration of the follow-up was 6.3±2.7years, the age was 60.2±8.9years, and 57.6% were male. BP index included 20 indicators in relation to BP level and variability, 4 of which were analysed including baseline systolic BP (SBP), standard deviation of SBP, coefficient of variation of diastolic BP (DBP CV), and average real variability of pulse pressure. In the Cox regression analysis after adjustment, baseline SBP was significant for the risk of primary endpoint [hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.03-1.44, P=0.02] and renal events (HR 1.54, 95% CI 1.22-1.95, P<0.001), and DBP CV was significant for the risk of primary endpoint (HR 1.03, 95% CI 1.01-1.06, P=0.02) and CVD events (HR 1.04, 95% CI 1.02-1.07, P<0.01). The result of the forest plot depicted that baseline SBP had a linear association with the risk of CVD and renal events (P=0.04 and 0.001, respectively) and DBP CV with CVD events (P=0.02). As the restricted cubic spline models displayed, DBP CV featured a J- or L-curved association with the primary endpoint, renal events, and all-cause death (P for nonlinearity=0.01, <0.001, and 0.01, respectively). The baseline SBP and DBP CV may remain significant for clinical outcomes in patients with both HF and CKD. The increase in baseline SBP is associated with a higher risk of primary endpoint, CVD events, and renal events,and the increase in DBP CV with a higher risk of CVD events. Concerning nonlinear association, DBP CV features a J- or L-curved relationship with the primary endpoint, renal events, and all-cause death, with a higher risk at both low and high values. https://www. gov; unique identifier: NCT00304148.

Factors Associated With Non-vaccination for Influenza Among Patients With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

Vaccination for influenza is strongly recommended for people with chronic kidney disease (CKD) due to their immunocompromised state. Identifying risk factors for not receiving an influenza vaccine (non-vaccination) could inform strategies for improving vaccine uptake in this high-risk population. Longitudinal observational study. 3,692 Chronic Renal Insufficiency Cohort Study (CRIC) participants. Demographic factors, social determinants of health, clinical conditions, and health behaviors. Influenza non-vaccination, which was assessed based on a receipt of influenza vaccine ascertained during annual clinic visits in a subset of participants who were under nephrology care. Mixed-effects Poisson models to estimate adjusted prevalence ratios (APRs). Between 2009 and 2020, the pooled mean vaccine uptake was 72% (mean age, 66 years; 44% female; 44% Black race). In multivariable models, factors significantly associated with influenza non-vaccination were younger age (APR, 2.16 [95% CI, 1.85-2.52] for<50 vs≥75 years), Black race (APR, 1.58 [95% CI, 1.43-1.75] vs White race), lower education (APR, 1.20 [95% CI, 1.04-1.39 for less than high school vs college graduate]), lower annual household income (APR, 1.26 [95% CI, 1.06-1.49] for<$20,000 vs >$100,000), formerly married status (APR, 1.22 [95% CI, 1.09-1.35] vs currently married), and nonemployed status (APR, 1.13 [95% CI, 1.02-1.24] vs employed). In contrast, participants with diabetes (APR, 0.80 [95% CI, 0.73-0.87] vs no diabetes), chronic obstructive pulmonary disease (COPD) (APR, 0.80 [95% CI, 0.70-0.92] vs no COPD), end-stage kidney disease (APR, 0.64 [0.56 to 0.76] vs estimated glomerular filtration rate≥60mL/min/1.73m2), frailty (APR, 0.86 [95% CI, 0.74-0.99] vs no frailty), and ideal physical activity (APR, 0.90 [95% CI, 0.82-0.99] vs. physically inactive) were less likely to have non-vaccination status. Possible residual confounding. Among adults with CKD receiving nephrology care, younger adults, Black individuals, and those with adverse social determinants of health were more likely to have the influenza non-vaccination status. Strategies are needed to address these disparities and reduce barriers to vaccination. Identifying risk factors for not receiving an influenza vaccine ("non-vaccination") in people living with kidney disease, who are at risk of influenza and its complications, could inform strategies for improving vaccine uptake. In this study, we examined whether demographic factors, social determinants of health, and clinical conditions were linked to the status of not receiving an influenza vaccine among people living with kidney disease and receiving nephrology care. We found that younger adults, Black individuals, and those with adverse social determinants of health were more likely to not receive the influenza vaccine. These findings suggest the need for strategies to address these disparities and reduce barriers to vaccination in people living with kidney disease.

Frailty and Cardiovascular Outcomes in Adults With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

Frailty is common in individuals with chronic kidney disease (CKD) and increases the risk of adverse outcomes in adults with kidney failure requiring dialysis. However, this relationship has not been thoroughly evaluated among those with non-dialysis-dependent CKD. Prospective cohort study. 2,539 adults in the Chronic Renal Insufficiency Cohort Study. Frailty status assessed using 5 criteria: slow gait speed, muscle weakness, low physical activity, exhaustion, and unintentional weight loss. Atherosclerotic events, incident heart failure, all-cause death, and cardiovascular death. Cause-specific hazards models. At study entry, the participants' mean age was 62 years, 46% were female, the mean estimated glomerular filtration rate was 45.4mL/min/1.73m2, and the median urine protein was 0.2mg/day. Frailty status was as follows: 12% frail, 51% prefrail, and 37% nonfrail. Over a median follow-up of 11.4 years, there were 393 atherosclerotic events, 413 heart failure events, 497 deaths, and 132 cardiovascular deaths. In multivariable regression analyses, compared with nonfrailty, both frailty and prefrailty status were each associated with higher risk of an atherosclerotic event (HR, 2.03 [95% CI, 1.41-2.91] and 1.77 [95% CI, 1.35-2.31], respectively) and incident heart failure (HR, 2.22 [95% CI, 1.59-3.10] and 1.39 [95% CI, 1.07-1.82], respectively), as well as higher risk of all-cause death (HR, 2.52 [95% CI, 1.84-3.45] and 1.76 [95% CI, 1.37-2.24], respectively) and cardiovascular death (HR, 3.01 [95% CI, 1.62-5.62] and 1.78 [95% 1.06-2.99], respectively). Self-report of aspects of the frailty assessment and comorbidities, which may have led to bias in some estimates. In adults with CKD, frailty status was associated with higher risk of cardiovascular events and mortality. Future studies are needed to evaluate the impact of interventions to reduce frailty on cardiovascular outcomes in this population. Frailty is common in individuals with chronic kidney disease (CKD) and increases the risk of adverse outcomes. We sought to evaluate the association of frailty status with cardiovascular events and death in adults with CKD. Frailty was assessed according to the 5 phenotypic criteria detailed by Fried and colleagues. Among 2,539 participants in the CRIC Study, we found that 12% were frail, 51% were prefrail, and 37% were nonfrail. Frailty status was associated with an increased risk of atherosclerotic events, incident heart failure, and death.

Plasma Serotonin and Cardiovascular Outcomes in Chronic Kidney Disease.

Background Platelet-poor plasma serotonin levels are associated with adverse cardiovascular outcomes. Although plasma serotonin levels increase in chronic kidney disease, the cardiovascular implications remain unknown. Methods and Results In 1114 participants from the prospective CRIC (Chronic Renal Insufficiency Cohort) Study, we evaluated the association between plasma serotonin, categorized as undetectable, intermediate, and high (≥20 ng/mL) levels, and cross-sectional findings on echocardiography, including left ventricular hypertrophy, left ventricular ejection fraction, and pulmonary hypertension. We also analyzed whether serotonin was associated with time-to-event cardiovascular outcomes, including heart failure hospitalization and atherosclerotic cardiovascular disease (ASCVD) events, in addition to mortality. Because selective serotonin reuptake inhibitors decrease plasma serotonin levels, we specifically evaluated the influence of selective serotonin reuptake inhibitor use in the relationship between serotonin and outcomes. Plasma serotonin level inversely correlated with estimated glomerular filtration rate and directly correlated with blood pressure. High plasma serotonin was associated with left ventricular hypertrophy (adjusted odds ratio, 2.74 [95% CI, 1.11-7.41]). In contrast, undetectable plasma serotonin level was associated with the highest risk of heart failure (adjusted hazard ratio [HR], 2.26 [95% CI, 1.40-3.66]) and ASCVD events (adjusted HR, 1.96 [95% CI, 1.15-3.32]). Conclusions In a large chronic kidney disease cohort, plasma serotonin levels correlated with blood pressure, and elevated serotonin levels were associated with left ventricular hypertrophy. In contrast, undetectable plasma serotonin was associated with the highest risk of heart failure and ASCVD events.

Depression and incident cardiovascular disease among patients with chronic kidney disease

BackgroundDepression is associated with an increased risk of cardiovascular disease (CVD) and is prevalent among patients with chronic kidney disease (CKD). We aimed to identify the association of depression with incident CVD. MethodsWe studied patients with CKD stages 2–4 enrolled in the Chronic Renal Insufficiency Cohort (CRIC) and excluded participants with preexisting CVD. The Cox proportional hazard model was used to examine the association between baseline depression [Beck's Depression Inventory (BDI) score ≥11] and incidence of CVD (cerebrovascular accident, myocardial infarction, heart failure, or peripheral artery disease). Models were adjusted for age, sex, race, estimated glomerular filtration rate (eGFR), urine albumin-creatinine ratio (UACR), systolic and diastolic blood pressure, and 10-year estimated CVD risk. ResultsAmong 2585 CRIC study participants, 640 (25%) patients had depression at study baseline. Compared to patients without depression, patients with depression were more likely to be women (56% vs. 46%), non-White (68% vs. 53%), with household income <$20,000 (53% vs. 26%), without a high school degree (31% vs. 15%), uninsured (13% vs. 7%), with lower eGFR (42 vs. 46 ml/min/1.73 m (Palmer et al., 2013 Jul)22), and with higher UACR (90 vs. 33 mg/g). In multivariate analyses, depression was associated with a 29% increased risk of developing CVD (adjusted hazard ratio 1.29, 95% confidence interval 1.03–1.62, p = 0.03). BDI (as a continuous variable) was associated with CVD (adjusted hazard ratio 1.017, 95% confidence interval 1.004–1.030, p = 0.012). ConclusionsAmong patients with CKD stages 2–4 enrolled in CRIC without preexisting CVD, depression was associated with a 29% increased risk of incident CVD.

Vitamin D Metabolites and Risk of Cardiovascular Disease in Chronic Kidney Disease: The CRIC Study.

Background The ratio of 24,25-dihydroxyvitamin D3/25-hydroxyvitamin D3 (vitamin D metabolite ratio [VDMR]) may reflect functional vitamin D activity. We examined associations of the VDMR, 25-hydroxyvitamin D (25[OH]D), and 1,25-dihydroxyvitamin D (1,25[OH]2D) with cardiovascular disease (CVD) in patients with chronic kidney disease. Methods and Results This study included longitudinal and cross-sectional analyses of 1786 participants from the CRIC (Chronic Renal Insufficiency Cohort) Study. Serum 24,25-dihydroxyvitamin D3, 25(OH)D, and 1,25(OH)2D were measured by liquid chromatography-tandem mass spectrometry 1 year after enrollment. The primary outcome was composite CVD (heart failure, myocardial infarction, stroke, and peripheral arterial disease). We used Cox regression with regression-calibrated weights to test associations of the VDMR, 25(OH)D, and 1,25(OH)2D with incident CVD. We examined cross-sectional associations of these metabolites with left ventricular mass index using linear regression. Analytic models adjusted for demographics, comorbidity, medications, estimated glomerular filtration rate, and proteinuria. The cohort was 42% non-Hispanic White race and ethnicity, 42% non-Hispanic Black race and ethnicity, and 12% Hispanic ethnicity. Mean age was 59 years, and 43% were women. Among 1066 participants without prevalent CVD, there were 298 composite first CVD events over a mean follow-up of 8.6 years. Lower VDMR and 1,25(OH)2D were associated with incident CVD before, but not after, adjustment for estimated glomerular filtration rate and proteinuria (hazard ratio, 1.11 per 1 SD lower VDMR [95% CI, 0.95-1.31]). Only 25(OH)D was associated with left ventricular mass index after full covariate adjustment (0.6 g/m2.7 per 10 ng/mL lower [95% CI, 0.0-1.3]). Conclusions Despite modest associations of 25(OH)D with left ventricular mass index, 25(OH)D, the VDMR, and 1,25(OH)2D were not associated with incident CVD in chronic kidney disease.

Blood Pressure, Incident Cognitive Impairment, and Severity of CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

Hypertension is a known risk factor for dementia and cognitive impairment. There are limited data on the relation of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with incident cognitive impairment in adults with chronic kidney disease. We sought to identify and characterize the relationship among blood pressure, cognitive impairment, and severity of decreased kidney function in adults with chronic kidney disease. Longitudinal cohort study. 3,768 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study. Baseline SBP and DBP were examined as exposure variables, using continuous (linear, per 10-mm Hg higher), categorical (SBP<120 [reference], 120 to 140,>140mm Hg; DBP<70 (reference), 70 to 80, > 80mm Hg) and nonlinear terms (splines). Incident cognitive impairment defined as a decline in Modified Mini-Mental State Examination (3MS) score to greater than 1 standard deviation below the cohort mean. Cox proportional hazard models adjusted for demographics as well as kidney disease and cardiovascular disease risk factors. The mean age of participants was 58±11 (SD) years, estimated glomerular filtration rate (eGFR) was 44mL/min/1.73m2 ± 15 (SD), and the median follow-up time was 11 (IQR, 7-13) years. In 3,048 participants without cognitive impairment at baseline and with at least 1 follow-up 3MS test, a higher baseline SBP was significantly associated with incident cognitive impairment only in the eGFR>45mL/min/1.73m2 subgroup (adjusted hazard ratio [AHR], 1.13 [95% CI, 1.05-1.22] per 10mm Hg higher SBP]. Spline analyses, aimed at exploring nonlinearity, showed that the relationship between baseline SBP and incident cognitive impairment was J-shaped and significant only in the eGFR>45mL/min/1.73m2 subgroup (P=0.02). Baseline DBP was not associated with incident cognitive impairment in any analyses. 3MS test as the primary measure of cognitive function. Among patients with chronic kidney disease, higher baseline SBP was associated with higher risk of incident cognitive impairment specifically in those individuals with eGFR>45mL/min/1.73m2. High blood pressure is a strong risk factor for dementia and cognitive impairment in studies of adults without kidney disease. High blood pressure and cognitive impairment are common in adults with chronic kidney disease (CKD). The impact of blood pressure on the development of future cognitive impairment in patients with CKD remains unclear. We identified the relationship between blood pressure and cognitive impairment in 3,076 adults with CKD. Baseline blood pressure was measured, after which serial cognitive testing was performed over 11 years. Fourteen percent of participants developed cognitive impairment. We found that a higher baseline systolic blood pressure was associated with an increased risk of cognitive impairment. We found that this association was stronger in adults with mild-to-moderate CKD compared with those with advanced CKD.

Association of urine and plasma ADMA with atherosclerotic risk in DKD cardiovascular disease risk in diabetic kidney disease: findings from the Chronic Renal Insufficiency Cohort (CRIC) study.

Chronic kidney disease (CKD) is associated with atherosclerotic cardiovascular disease (ASCVD) risk, especially among those with diabetes. Altered metabolism of solutes that accumulate in CKD [asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and trimethylamine N-oxide (TMAO)] may reflect pathways linking CKD with ASCVD. This case-cohort study included Chronic Renal Insufficiency Cohort participants with baseline diabetes, estimated glomerular filtration rate <60mL/min/1.73 m2, and without prior history for each outcome. The primary outcome was incident ASCVD (time to first myocardial infarction, stroke or peripheral artery disease event) and secondary outcome was incident heart failure. The subcohort comprised randomly selected participants meeting entry criteria. Plasma and urine ADMA, SDMA and TMAO concentrations were determined by liquid chromatography-tandem mass spectrometry. Associations of uremic solute plasma concentrations and urinary fractional excretions with outcomes were evaluated by weighted multivariable Cox regression models, adjusted for confounding covariables. Higher plasma ADMA concentrations (per standard deviation) were associated with ASCVD risk [hazard ratio (HR) 1.30, 95% confidence interval (CI) 1.01-1.68]. Lower fractional excretion of ADMA (per standard deviation) was associated with ASCVD risk (HR 1.42, 95% CI 1.07-1.89). The lowest quartile of ADMA fractional excretion was associated with greater ASCVD risk (HR 2.25, 95% CI 1.08-4.69) compared with the highest quartile. Plasma SDMA and TMAO concentration and fractional excretion were not associated with ASCVD. Neither plasma nor fractional excretion of ADMA, SDMA and TMAO were associated with incident heart failure. These data suggest that decreased kidney excretion of ADMA leads to increased plasma concentrations and ASCVD risk.

Lipoprotein(a) and the Risk for Recurrent Atherosclerotic Cardiovascular Events Among Adults With CKD: The Chronic Renal Insufficiency Cohort (CRIC) Study

Many adults with chronic kidney disease (CKD) and atherosclerotic cardiovascular disease (ASCVD) have high lipoprotein(a) levels. It is unclear whether high lipoprotein(a) levels confer an increased risk for recurrent ASCVD events in this population. We estimated the risk for recurrent ASCVD events associated with lipoprotein(a) in adults with CKD and prevalent ASCVD. Observational cohort study. We included 1,439 adults with CKD and prevalent ASCVD not on dialysis enrolled in the Chronic Renal Insufficiency Cohort study between 2003 and2008. Baseline lipoprotein(a) mass concentration, measured using a latex-enhanced immunoturbidimetric assay. Recurrent ASCVD events (primary outcome), kidney failure, and death (exploratory outcomes) through2019. We used Cox proportional-hazards regression models to estimate adjusted HR (aHRs) and 95% CIs. Among participants included in the current analysis (mean age 61.6 years, median lipoprotein(a) 29.4 mg/dL [25th-75th percentiles 9.9-70.9 mg/dL]), 641 had a recurrent ASCVD event, 510 developed kidney failure, and 845 died over a median follow-up of 6.6 years. The aHR for ASCVD events associated with 1 standard deviation (SD) higher log-transformed lipoprotein(a) was 1.04 (95% CI, 0.95-1.15). In subgroup analyses, 1 SD higher log-lipoprotein(a) was associated with an increased risk for ASCVD events in participants without diabetes (aHR, 1.23; 95% CI, 1.02-1.48), but there was no evidence of an association among those with diabetes (aHR, 0.99; 95% CI, 0.88-1.10, P comparing aHRs=0.031). The aHR associated with 1 SD higher log-lipoprotein(a) in the overall study population was 1.16 (95% CI, 1.04-1.28) for kidney failure and 1.02 (95% CI, 0.94-1.11) for death. Lipoprotein(a) was not available in molar concentration. Lipoprotein(a) was not associated with the risk for recurrent ASCVD events in adults with CKD, although it was associated with a risk for kidney failure.

Obesity Weight Loss Phenotypes in CKD: Findings From the Chronic Renal Insufficiency Cohort Study

Although people with chronic kidney disease (CKD) and obesity have important motivations to lose weight, weight loss is also associated with health risks. We examined whether patterns of change in systolic blood pressure (SBP), serum albumin level, and fat-free mass (FFM) can help to differentiate between healthy and high-risk weight loss in this population. Using data from the Chronic Renal Insufficiency Cohort Study (CRIC), we estimated a joint multivariate latent class model with 6 classes to identify distinct trajectories of body mass index (BMI), albumin, and SBP among participants with obesity (BMI≥30 kg/m2 at baseline), accounting for informative missingness from death. In a secondary analysis, we fit a 6-class model with BMI and FFM. Among 2831 participants (median baseline BMI 35.6, interquartile range [IQR] 32.4-40.0 kg/m2), median follow-up was 6.8 (IQR 4.8-12.9) years, median age was 61 (IQR 54-67) years, 53% were male, 50% were non-Hispanic Black, and 82% were trying to control or lose weight at baseline. Latent classes were associated with mortality risk (5-year cumulative incidence of mortality 6.8% and 1.5% in class 6 and 3, respectively). Class 6 had the highest mortality rate and was characterized by early, steep BMI loss, early serum albumin decline, and late SBP increase. In the secondary analysis, a class characterized by steep BMI and FFM loss was associated with the highest death risk. Among adults with CKD and obesity, BMI loss with concomitant serum albumin or FFM loss was associated with a high risk of death.

Identification of RhBG Mutations that Impair NH3/NH4+ Transport in Patients with Chronic Kidney Disease

Background: Acid-base disturbances are common in many illnesses, and metabolic acidosis is a major complication in patients with chronic kidney disease (CKD). The kidneys respond to acidosis by increasing urinary excretion of total ammonia (NH 3 /NH 4 + ) and to a lesser extent titratable acids. In the collecting duct, total ammonia is secreted by the NH 3 /NH 4 + transporters, RhBG and RhCG. RhBG transports NH 3 and NH 4 + at the basolateral membrane of intercalated cells. In CKD patients, the increase in ammonium excretion in response to acidosis is markedly impaired. Recent studies suggest that the reduced ability of the kidney to excrete ammonium is likely a cause of detrimental renal outcome in CKD and faster progression towards end-stage renal disease. Hypothesis: This study aims to identify loss of function mutations of RhBG (nsSNPs) that impair NH 3 /NH 4 + transport which may contribute to the deleterious effect of acidosis in CKD. Methods: We used Chronic Renal Insufficiency Cohort (CRIC) study to select SNPs of RhBG that are present in CKD patients but not in controls, or have a significant odds ratio (OR). Transport studies were conducted on Xenopus oocytes expressing Rh proteins or mutants. Wild-type RhBG (RhBG-WT) or RhBG-mutants were expressed by microinjecting oocytes with respective mRNA. H 2 O-injected oocytes served as negative controls. Each oocyte was perfused with solutions containing 5 mM NH 3 /NH 4 + or 5 mM MA/MA + (methylamine/methylammonium, a surrogate of NH 3 /NH 4 + ) to test RhBG function. Using ion-selective microelectrodes, we measured changes in intracellular pH, whole cell currents or surface pH to assess transport of NH 3 or NH 4 + . Results: Two RhBG mutations, G148R and G148W, which are only present in the patient group from CRIC cohort, significantly inhibited transport of NH 3 and NH 4 + (and MA/MA + ) compared with RhBG-WT (p&lt;0.05) in Xenopus oocytes. Two other mutations, G86S and G86C, positively associated with CKD patients (OR=4.65, p&lt;0.05), showed different inhibition patterns: G86S maintained the ability to transport NH 4 + , NH 3 and MA + while G86C inhibited NH 3 and NH 4 + transport but MA + transport was less affected compared with RhBG-WT. Both G86S and G86C showed a 50% decrease in MA transport (p&lt;0.05) that was still significantly higher than negative control. Conclusions: We discovered two RhBG mutations, G148R and G148W, in CKD patients that completely inhibited the transport of NH 3 /NH 4 + . The other two mutations, G86S and G86C, partially inhibited transport, and G86C was more deleterious than G86S in its inhibitory effect on NH 4 + and NH 3 transport. Significance: This study is the first to identify, in a cohort of CKD patients, 4 mutations with functional effects on NH 3 /NH 4 + transport. This work provides the foundation to further investigate whether naturally occurring genetic variations that impair ammonia secretion are associated with fast CKD progression under acidosis conditions. Funding grants: NIH-U54 GM104940, Paul Teschan Research, NIH-R01, Carol Lavin Bernick, Tulane institutional This is the full abstract presented at the American Physiology Summit 2023 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.

Probing the Association between Acute Kidney Injury and Cardiovascular Outcomes.

Patients hospitalized with AKI have higher subsequent risks of heart failure, atherosclerotic cardiovascular events, and mortality than their counterparts without AKI, but these higher risks may be due to differences in prehospitalization patient characteristics, including the baseline level of estimated glomerular filtration rate (eGFR), the rate of prior eGFR decline, and the proteinuria level, rather than AKI itself. Among 2177 adult participants in the Chronic Renal Insufficiency Cohort study who were hospitalized in 2013-2019, we compared subsequent risks of heart failure, atherosclerotic cardiovascular events, and mortality between those with serum creatinine-based AKI (495 patients) and those without AKI (1682 patients). We report both crude associations and associations sequentially adjusted for prehospitalization characteristics including eGFR, eGFR slope, and urine protein-creatinine ratio (UPCR). Compared with patients hospitalized without AKI, those with hospitalized AKI had lower eGFR prehospitalization (42 versus 49 ml/min per 1.73 m 2 ), faster chronic loss of eGFR prehospitalization (-0.84 versus -0.51 ml/min per 1.73 m 2 per year), and more proteinuria prehospitalization (UPCR 0.28 versus 0.16 g/g); they also had higher prehospitalization systolic BP (130 versus 127 mm Hg; P < 0.01 for all comparisons). Adjustment for prehospitalization patient characteristics attenuated associations between AKI and all three outcomes, but AKI remained an independent risk factor. Attenuation of risk was similar after adjustment for absolute eGFR, eGFR slope, or proteinuria, individually or in combination. Prehospitalization variables including eGFR, eGFR slope, and proteinuria confounded associations between AKI and adverse cardiovascular outcomes, but these associations remained significant after adjusting for prehospitalization variables.

Low concentrations of medium-sized HDL particles predict incident CVD in chronic kidney disease patients

Patients with chronic kidney disease (CKD) are at high risk for CVD. However, traditional CVD risk factors cannot completely explain the increased risk. Altered HDL proteome is linked with incident CVD in CKD patients, but it is unclear whether other HDL metrics are associated with incident CVD in this population. In the current study, we analyzed samples from two independent prospective case-control cohorts of CKD patients, the Clinical Phenotyping and Resource Biobank Core (CPROBE) and the Chronic Renal Insufficiency Cohort (CRIC). We measured HDL particle sizes and concentrations (HDL-P) by calibrated ion mobility analysis and HDL cholesterol efflux capacity (CEC) by cAMP-stimulated J774 macrophages in 92 subjects from the CPROBE cohort (46 CVD and 46 controls) and in 91 subjects from the CRIC cohort (34 CVD and 57 controls). We tested associations of HDL metrics with incident CVD using logistic regression analysis. No significant associations were found for HDL-C or HDL-CEC in either cohort. Total HDL-P was only negatively associated with incident CVD in the CRIC cohort in unadjusted analysis. Among the six sized HDL subspecies, only medium-sized HDL-P was significantly and negatively associated with incident CVD in both cohorts after adjusting for clinical confounders and lipid risk factors with odds ratios (per 1-SD) of 0.45 (0.22–0.93, P = 0.032) and 0.42 (0.20–0.87, P = 0.019) for CPROBE and CRIC cohorts, respectively. Our observations indicate that medium-sized HDL-P—but not other-sized HDL-P or total HDL-P, HDL-C, or HDL-CEC—may be a prognostic cardiovascular risk marker in CKD.

Ultraprocessed Foods and Kidney Disease Progression, Mortality, and Cardiovascular Disease Risk in the CRIC Study

Ultraprocessed foods are widely consumed in the United States and are associated with cardiovascular disease (CVD), mortality, and kidney function decline in the general population. We investigated associations between ultraprocessed food intake and chronic kidney disease (CKD) progression, all-cause mortality, and incident CVD in adults with chronic kidney disease (CKD). Prospective cohort study. Chronic Renal Insufficiency Cohort Study participants who completed baseline dietary questionnaires. Ultraprocessed food intake (in servings per day) classified according to the NOVA system. CKD progression (≥50% decrease in estimated glomerular filtration rate [eGFR] or initiation of kidney replacement therapy), all-cause mortality, and incident CVD (myocardial infarction, congestive heart failure, or stroke). Cox proportional hazards models adjusted for demographic, lifestyle, and health covariates. There were 1,047 CKD progression events observed during a median follow-up of 7 years. Greater ultraprocessed food intake was associated with higher risk of CKD progression (tertile 3 vs tertile 1, HR, 1.22; 95% CI, 1.04-1.42; P=0.01 for trend). The association differed by baseline kidney function, such that greater intake was associated with higher risk among people with CKD stages 1/2 (eGFR≥60mL/min/1.73m2; tertile 3 vs tertile 1, HR, 2.61; 95% CI, 1.32-5.18) but not stages 3a-5 (eGFR<60mL/min/1.73m2; P=0.003 forinteraction). There were 1,104 deaths observed during a median follow-up of 14 years. Greater ultraprocessed food intake was associated with higher risk of mortality (tertile 3 vs tertile 1, HR, 1.21; 95% CI, 1.04-1.40; P=0.004 for trend). Self-reported diet. Greater ultraprocessed food intake may be associated with CKD progression in earlier stages of CKD and is associated with higher risk of all-cause mortality in adults with CKD. Ultraprocessed foods are industrial formulations produced using ingredients and processes that are not commonly used in culinary preparations and contain few, if any, intact unprocessed foods. Ultraprocessed foods are widely consumed in the United States, and high intakes of such foods have been linked to cardiovascular disease, kidney disease, and mortality in the general population. In this study, we found that greater intake of ultraprocessed foods was associated with higher risk of kidney disease progression and mortality in adults with chronic kidney disease. Our findings suggest that patients with kidney disease may benefit from greater consumption of fresh, whole, and homemade or hand-prepared foods and fewer highly processed foods.

Proteomic cardiovascular risk assessment in chronic kidney disease.

Chronic kidney disease (CKD) is widely prevalent and independently increases cardiovascular risk. Cardiovascular risk prediction tools derived in the general population perform poorly in CKD. Through large-scale proteomics discovery, this study aimed to create more accurate cardiovascular risk models. Elastic net regression was used to derive a proteomic risk model for incident cardiovascular risk in 2182 participants from the Chronic Renal Insufficiency Cohort. The model was then validated in 485 participants from the Atherosclerosis Risk in Communities cohort. All participants had CKD and no history of cardiovascular disease at study baseline when ∼5000 proteins were measured. The proteomic risk model, which consisted of 32 proteins, was superior to both the 2013 ACC/AHA Pooled Cohort Equation and a modified Pooled Cohort Equation that included estimated glomerular filtrate rate. The Chronic Renal Insufficiency Cohort internal validation set demonstrated annualized receiver operating characteristic area under the curve values from 1 to 10 years ranging between 0.84 and 0.89 for the protein and 0.70 and 0.73 for the clinical models. Similar findings were observed in the Atherosclerosis Risk in Communities validation cohort. For nearly half of the individual proteins independently associated with cardiovascular risk, Mendelian randomization suggested a causal link to cardiovascular events or risk factors. Pathway analyses revealed enrichment of proteins involved in immunologic function, vascular and neuronal development, and hepatic fibrosis. In two sizeable populations with CKD, a proteomic risk model for incident cardiovascular disease surpassed clinical risk models recommended in clinical practice, even after including estimated glomerular filtration rate. New biological insights may prioritize the development of therapeutic strategies for cardiovascular risk reduction in the CKD population.