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Quality of life in chronic kidney disease (CKD) is impaired by a large burden of symptoms including some that overlap with the symptoms of heart failure (HF). We studied a group of individual with CKD to understand the patterns and trajectories of HF-type symptoms in this setting.Prospective cohort study.3,044 participants in the Chronic Renal Insufficiency Cohort (CRIC) without prior diagnosis of HF.Sociodemographics, medical history, medications, vital signs, laboratory values, echocardiographic and EKG parameters.Trajectory over 5.5 years of a HF-type symptom score (modified Kansas City Cardiomyopathy Questionnaire [KCCQ] Overall Summary Score with a range of 0-100 where75 reflects clinically significant symptoms).Latent class mixed models were used to model trajectories. Multinomial logistic regression was used to model relationships of predictors with trajectory group membership.Five trajectories of KCCQ score were identified in the cohort of 3,044 adults, 45% of whom were female, and whose median age was 61 years. Group 1 (41.7%) had a stable high score (minimal symptoms, average score of 96); Groups 2 (35.6%) and 3 (15.6%) had stable but lower scores (mild symptoms, average 81, and clinically significant symptoms, average 52, respectively). Group 4 (4.9%) had a substantial worsening in symptoms over time (mean 31-point decline) and Group 5 (2.2%) had a substantial improvement (mean 33-point increase) in KCCQ score. A majority of Group 1 was male, non-diabetic, non-obese, and had higher baseline kidney function. A majority of Groups 2 and 3 had diabetes and obesity. A majority of Group 4 was male and had substantial proteinuria. Group 5 had the highest proportion of baseline cardiovascular disease (CVD).No validation cohort available, CKD management changes in recent years may alter trajectories, and latent class models depend on the missing at random assumption.Distinct HF-type symptom burden trajectories were identified in the setting of CKD, corresponding to different baseline characteristics. These results highlight the diversity of HF-type symptom experiences in individuals with CKD.

Heart failure (HF) is common in chronic kidney disease (CKD); identifying patients with CKD at high risk for HF may guide clinical care. We assessed the prognostic value of cardiac biomarkers and echocardiographic variables for 10-year HF prediction compared with a published clinical HF prediction equation in a cohort of participants with CKD.We studied 2147 Chronic Renal Insufficiency Cohort (CRIC) participants without prior HF with complete clinical, cardiac biomarker (N-terminal brain natriuretic peptide [NT-proBNP] and high sensitivity troponin-T [hsTnT]), and echocardiographic data (left ventricular mass [LVM] and left ventricular ejection fraction [LVEF] data). We compared the discrimination of the 11-variable Atherosclerosis Risk in Communities (ARIC) HF prediction equation with LVM, LVEF, hsTnT, and NT-proBNP to predict 10-year risk of hospitalization for HF using a Fine and Gray modeling approach. We separately evaluated prediction of HF with preserved and reduced LVEF (LVEF ≥50% and 50%, respectively). We assessed discrimination with internally valid C-indices using 10-fold cross-validation.Participants' mean (SD) age was 59 (11) years, 53% were men, 43% were Black, and mean (SD) estimated glomerular filtration rate (eGFR) was 44 (16) ml/min per 1.73 mThe ARIC HF prediction model for 10-year HF risk had modest discrimination among adults with CKD. NT-proBNP and hsTnT discriminated better than the ARIC HF model and at least as well as a model with echocardiographic variables. HF clinical prediction models tailored to adults with CKD are needed. Until then, measurement of NT-proBNP and hsTnT may be a low-burden approach to predicting HF in this population, as they offer moderate discrimination.

Metabolomics genome wide association study (GWAS) help outline the genetic contribution to human metabolism. However, studies to date have focused on relatively healthy, population-based samples of White individuals. Here, we conducted a GWAS of 537 blood metabolites measured in the Chronic Renal Insufficiency Cohort (CRIC) Study, with separate analyses in 822 White and 687 Black study participants. Trans-ethnic meta-analysis was then applied to improve fine-mapping of potential causal variants. Mean estimated glomerular filtration rate was 44.4 and 41.5 mL/min/1.73m(2) in the White and Black participants, respectively. There were 45 significant metabolite associations at 19 loci, including novel associations at PYROXD2, PHYHD1, FADS1-3, ACOT2, MYRF, FAAH, and LIPC. The strength of associations were unchanged in models additionally adjusted for estimated glomerular filtration rate and proteinuria, consistent with a direct biochemical effect of gene products on associated metabolites. At several loci, trans-ethnic meta-analysis, which leverages differences in linkage disequilibrium across populations, reduced the number and/or genomic interval spanned by potentially causal single nucleotide polymorphisms compared to fine-mapping in the White participant cohort alone. Across all validated associations, we found strong concordance in effect sizes of the potentially causal single nucleotide polymorphisms between White and Black study participants. Thus, our study identifies novel genetic determinants of blood metabolites in chronic kidney disease, demonstrates the value of diverse cohorts to improve causal inference in metabolomics GWAS, and underscores the shared genetic basis of metabolism across race.

RATIONALE & OBJECTIVE: The utility of conventional upper reference limits (URL) for N-terminal pro brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hsTnT) in chronic kidney disease (CKD) remains debated. We analyzed the distribution of hsTnT and NT-proBNP in people with CKD in ambulatory settings to examine the diagnostic value of conventional URL in this population. STUDY DESIGN: Observational study. SETTING & PARTICIPANTS: We studied participants of the Chronic Renal Insufficiency Cohort with CKD and no self-reported history of cardiovascular disease (CVD). EXPOSURE: Estimated glomerular filtration rate (eGFR). OUTCOMES: NT-proBNP and hsTnT at baseline. ANALYTICAL APPROACH:. We described the proportion of participants above the conventional URL for NT-proBNP (125 pg/ml) and hsTnT (14 ng/L) overall, and by eGFR. We then estimated 99(th) percentile URL for NT-proBNP and hsTnT. Using quantile regression of the 99(th) percentile, we modeled the association of eGFR with NT-proBNP and hsTnT. RESULTS: Among 2,312 CKD participants, 40% and 43% had levels of NT-proBNP and hsTnT above conventional URL, respectively. In those with eGFR

Introduction: Recent studies have suggested a higher incidence of cardiovascular disease (CVD) among patients with chronic kidney disease (CKD) in the USA than in Japan. Hyperphosphatemia, a possible risk for CVD, may explain this difference; however, international differences in phosphate parameters in CKD have not been well elaborated. Methods: By using the baseline data from the USA and the Japanese nation-wide, multicenter, CKD cohort studies; the Chronic Renal Insufficiency Cohort Study (CRIC, N = 3,870) and the Chronic Kidney Disease-Japan Cohort Study (CKD-JAC, N = 2,632), we harmonized the measures and compared clinical parameters regarding phosphate metabolism or serum phosphate, fibroblast growth factor-23 (FGF23), and parathyroid hormone (PTH), in the cross-sectional model. Results: Multivariable linear regression analyses revealed that serum phosphate levels were significantly higher in CRIC across all levels of estimated glomerular filtration rate (eGFR) with the greatest difference being observed at lower levels of eGFR. Serum FGF23 and 25-hydroxy vitamin D (25OHD) levels were higher in CRIC, while PTH levels were higher in CKD-JAC at all levels of eGFR. Adjustments for demographics, 25OHD, medications, dietary intake or urinary excretion of phosphate, PTH, and FGF23 did not eliminate the difference in serum phosphate levels between the cohorts (0.43, 0.46, 0.54, 0.64, and 0.78 mg/dL higher in CRIC within eGFR strata of >50, 41–50, 31–40, 21–30, and ≤20 mL/min/1.73 m2, respectively). These findings were consistent when only Asian CRIC participants (N = 105) were included in the analysis. Conclusion: Serum phosphate levels in CRIC were significantly higher than those of CKD-JAC across all stages of CKD, which may shed light on the international variations in phosphate parameters and thus in cardiovascular risk among CKD patients. The key mechanisms for the substantial differences in phosphate parameters need to be elucidated.

Disordered iron and mineral homeostasis are interrelated complications of chronic kidney disease that may influence cardiovascular and kidney outcomes. In a prospective analysis of 3747 participants in the Chronic Renal Insufficiency Cohort Study, we investigated risks of mortality, heart failure, end-stage kidney disease (ESKD), and atherosclerotic cardiovascular disease according to iron status, and tested for mediation by C-terminal fibroblast growth factor 23 (FGF23), hemoglobin and parathyroid hormone. Study participants were agnostically categorized based on quartiles of transferrin saturation and ferritin as: “Iron Replete” (27.1% of participants; referent group for all outcomes analyses), “Iron Deficiency” (11.1%), “Functional Iron Deficiency” (7.6%), “Mixed Iron Deficiency” (iron indices between the Iron Deficiency and Functional Iron Deficiency groups; 6.3%), “High Iron” (9.2%), or “Non-Classified” (the remaining 38.8% of participants). In multivariable-adjusted Cox models, Iron Deficiency independently associated with mortality (hazard ratio 1.28, 95% confidence interval 1.04–1.58) and heart failure (1.34, 1.05–1.72). Mixed Iron Deficiency associated with mortality (1.61, 1.27–2.04) and ESKD (1.33, 1.02–1.73). High Iron associated with mortality (1.54, 1.24–1.91), heart failure (1.58, 1.21–2.05), and ESKD (1.41, 1.13–1.77). Functional Iron Deficiency did not significantly associate with any outcome, and no iron group significantly associated with atherosclerotic cardiovascular disease. Among the candidate facilitators, FGF23 most significantly mediated the risks of mortality and heart failure conferred by Iron Deficiency. Thus, alterations in iron homeostasis associated with adverse cardiovascular and kidney outcomes in patients with chronic kidney disease.

Introduction Self-management is an integral component of chronic kidney disease (CKD) treatment. Nevertheless, many patients with CKD do not adequately engage in self-management behaviors, and little is known on the underlying reasons. We aimed to identify and describe the factors that influence self-management behaviors from the perspective of adults with CKD. Methods We conducted 30 semistructured interviews with adults with CKD stage 3 or 4 from an academic nephrology clinic in the United States. Interviews were analyzed thematically. Results The following are the 3 key phases of CKD self-management behavior engagement identified: (i) prioritization, (ii) performance, and (iii) maintenance. Prioritization was favorably influenced by optimism, stress management, and patient-provider communication and hampered by fatalism and competing priorities. Behavior performance was facilitated by motivating factors, self-efficacy, and support resources and impeded by comorbid conditions that caused treatment burden and adverse symptoms. Behavior maintenance relied on effective routines, influenced by similar factors as behavior performance, and reinforced by memory aids, goal setting, self-monitoring, and proactive preparation. Conclusion We identified modifiable facilitators and barriers that influence the incorporation of CKD self-management into daily life. Our findings have important implications for the care of patients with CKD by providing a framework for providers to develop effective, tailored approaches to promote self-management engagement.

Background Novel urine biomarkers may improve identification of children at greater risk of rapid kidney function decline, and elucidate the pathophysiology of CKD progression. Methods We investigated the relationship between urine biomarkers of kidney tubular health (EGF and α-1 microglobulin), tubular injury (kidney injury molecule-1; KIM-1), and inflammation (monocyte chemoattractant protein-1 [MCP-1] and YKL-40) and CKD progression. The prospective CKD in Children Study enrolled children aged 6 months to 16 years with an eGFR of 30-90ml/min per 1.73m2. Urine biomarkers were assayed a median of 5 months [IQR: 4-7] after study enrollment. We indexed the biomarker to urine creatinine by dividing the urine biomarker concentration by the urine creatinine concentration to account for the concentration of the urine. The primary outcome was CKD progression (a composite of a 50% decline in eGFR or kidney failure) during the follow-up period. Results Overall, 252 of 665 children (38%) reached the composite outcome over a median follow-up of 6.5 years. After adjustment for covariates, children with urine EGF concentrations in the lowest quartile were at a seven-fold higher risk of CKD progression versus those with concentrations in the highest quartile (fully adjusted hazard ratio [aHR], 7.1; 95% confidence interval [95% CI], 3.9 to 20.0). Children with urine KIM-1, MCP-1, and α-1 microglobulin concentrations in the highest quartile were also at significantly higher risk of CKD progression versus those with biomarker concentrations in the lowest quartile. Addition of the five biomarkers to a clinical model increased the discrimination and reclassification for CKD progression. Conclusions After multivariable adjustment, a lower urine EGF concentration and higher urine KIM-1, MCP-1, and α-1 microglobulin concentrations were each associated with CKD progression in children.

Introduction Management of chronic kidney disease (CKD) entails high medical complexity and often results in high hospitalization burden. There are limited data on the associations of longitudinal hospital utilization patterns with adverse clinical outcomes in individuals with CKD. Methods We derived cumulative all-cause hospitalization trajectory groups using latent class trajectory analysis in 3012 participants of the Chronic Renal Insufficiency Cohort (CRIC) Study who were alive and did not reach end-stage kidney disease (ESKD) within 4 years of study entry. Cox proportional hazards models tested the associations between hospitalization trajectory groups and risks of ESKD and death prior to the onset of ESKD (ESKD-censored death). Results Within 4 years of study entry, there were 5658 hospitalizations among 3012 participants. We identified 3 distinct subgroups of individuals with CKD based on cumulative all-cause hospitalization trajectories over 4 years: low-utilizer (n = 1066), intermediate-utilizer (n = 1802), and high-utilizer (n = 144). High-utilizers represented a patient population of lower socioeconomic status who had a greater prevalence of comorbid conditions and lower kidney function compared with intermediate- and low-utilizers. After the 4-year ascertainment period to form the trajectory subgroups, there were 544 ESKD events and 437 ESKD-censored deaths during a median follow-up time of 5.1 years. Compared with low-utilizers, intermediate-utilizers and high-utilizers were at 1.49-fold (95% confidence interval [CI] 1.22–1.84) and 1.75-fold (95% CI 1.20–2.56) higher risk of ESKD in adjusted analyses, respectively. Compared with low-utilizers, intermediate-utilizers and high-utilizers were at 1.48-fold (95% CI 1.17–1.87) and 2.58-fold (95% CI 1.74–3.83) higher risk of ESKD-censored death in adjusted analyses, respectively. Conclusions Trajectories of cumulative all-cause hospitalization identify subgroups of individuals with CKD who are at high risk of ESKD and death., Graphical abstract

Rationale & Objective Circulating cardiac biomarkers may signal potential mechanistic pathways involved in heart failure (HF) and atrial fibrillation (AF). Single measures of circulating cardiac biomarkers are strongly associated with incident HF and AF in chronic kidney disease (CKD). We tested the associations of longitudinal changes in the N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP), high-sensitivity troponin T (hsTnT), galectin-3, growth differentiation factor 15 (GDF-15), and soluble ST-2 (sST-2) with incident HF and AF in patients with CKD. Study Design Observational, case-cohort study design. Setting & Participants Adults with CKD enrolled in the Chronic Renal Insufficiency Cohort study. Exposures Biomarkers were measured at baseline and 2 years later among those without kidney failure. We created 3 categories of absolute change in each biomarker: the lowest quartile, the middle 2 quartiles, and the top quartile. Outcomes The primary outcomes were incident HF and AF. Analytical Approach Cox proportional hazards regression models were used to test the associations of the change categories of each cardiac biomarker with each outcome (with the middle 2 quartiles of change as the referent group), adjusting for potential confounders and baseline concentrations of each biomarker. Results The incident HF analysis included 789 participants (which included 138 incident HF cases), and the incident AF analysis included 774 participants (123 incident AF cases). In multivariable models, the top quartile of NT-proBNP change (>232 pg/mL over 2 years) was associated with increased risk of incident HF (HR, 1.79 [95% CI, 1.06-3.04]) and AF (HR, 2.32 [95% CI, 1.37-3.93]) compared with the referent group. Participants in the top quartile of sST2 change (>3.37 ng/mL over 2 years) had significantly greater risk of incident HF (HR, 1.89 [95% CI, 1.13-3.16]), whereas those in the bottom quartile (≤−3.78 ng/mL over 2 years) had greater risk of incident AF (HR, 2.43 [95% CI, 1.39-4.22]) compared with the 2 middle quartiles. There was no association of changes in hsTnT, galectin-3, or GDF-15 with incident HF or AF. Limitations Observational study. Conclusions In CKD, increases in NT-proBNP were significantly associated with greater risk of incident HF and AF, and increases in sST2 were associated with HF. Further studies should investigate whether these markers of subclinical cardiovascular disease can be modified to reduce the risk of cardiovascular disease in CKD.

Genomic disorders (GDs) are associated with many comorbid outcomes, including CKD. Identification of GDs has diagnostic utility.We examined the prevalence of GDs among participants in the Chronic Kidney Disease in Children (CKiD) cohort II (We found nine out of 248 (3.6%) CKiD II participants carried a GD, replicating prior findings in pediatric CKD. We also identified GDs in 72 out of 6679 (1.1%) adult patients with CKD in the CRIC, CU-CKD, and FIND cohorts, compared with 199 out of 30,746 (0.65%) GDs in controls (OR, 1.7; 95% CI, 1.3 to 2.2). Among adults with CKD, we found recurrent GDs at the 1q21.1, 16p11.2, 17q12, and 22q11.2 loci. The 17q12 GD (diagnostic of renal cyst and diabetes syndrome) was most frequent, present in 1:252 patients with CKD and diabetes. In the PheWAS, dialysis and neuropsychiatric phenotypes were the top associations with GDs. In CRIC participants, GDs were associated with lower serum magnesium, lower educational achievement, and higher mortality risk.Undiagnosed GDs are detected both in children and adults with CKD. Identification of GDs in these patients can enable a precise genetic diagnosis, inform prognosis, and help stratify risk in clinical studies. GDs could also provide a molecular explanation for nephropathy and comorbidities, such as poorer neurocognition for a subset of patients.

RATIONALE & OBJECTIVE: Current dietary guidelines recommend that chronic kidney disease (CKD) patients restrict individual nutrients, such as sodium, potassium, phosphorus and protein. This approach can be difficult for patients to implement and ignores important nutrient interactions. Dietary patterns are an alternative method to intervene on diet. Our objective was to define the associations of four healthy dietary patterns with risk of CKD progression and all-cause mortality among people with CKD. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 2,403 participants aged 21–74 years with an estimated glomerular filtration rate (eGFR) of 20–70 mL/min/1.73 m(2) and dietary data in the Chronic Renal Insufficiency Cohort (CRIC) study. EXPOSURES: Healthy Eating Index-2015 (HEI-2015), Alternative Healthy Eating Index-2010 (AHEI-2010), alternate Mediterranean diet (aMed), and Dietary Approaches to Stop Hypertension (DASH) diet scores were calculated from food frequency questionnaires. OUTCOMES: 1) CKD progression defined as ≥50% eGFR decline, kidney transplantation, or dialysis and 2) all-cause mortality. ANALYTICAL APPROACH: Cox proportional hazards regression models adjusted for demographic, lifestyle, and clinical covariates to estimate hazard ratios (HR) and 95% confidence intervals (CI). RESULTS: There were 855 cases of CKD progression and 773 deaths over a maximum of 14 years. Compared with participants with the lowest adherence, the most highly adherent tertile of AHEI-2010, aMed, and DASH had lower adjusted risk of CKD progression with the strongest results for aMed (HR: 0.75, 95% CI: 0.62–0.90). Compared with participants with the lowest adherence, the highest adherence tertiles for all scores had lower adjusted risk of all-cause mortality for each index (24–31% lower risk). LIMITATIONS: Self-reported dietary intake. CONCLUSIONS: Greater adherence to several healthy dietary patterns is associated with a lower risk of CKD progression and all-cause mortality among people with CKD. Guidance to adopt healthy dietary patterns can be considered as a strategy for managing CKD. INDEX WORDS: dietary patterns, nutrition, kidney disease, renal, mortality

Background Studies in the general population suggest that atrial fibrillation (AF) is an independent risk factor for decline in cognitive function, but this relationship has not been examined in adults with chronic kidney disease (CKD). We investigated the association between incident AF and changes in cognitive function over time in this population. Methods and Results We studied a subgroup of 3254 adults participating in the Chronic Renal Insufficiency Cohort Study. Incident AF was ascertained by 12-lead electrocardiogram (ECG) obtained at a study visit and/or identification of a hospitalization with AF during follow-up. Cognitive function was assessed biennially using the Modified Mini-Mental State Exam. Linear mixed effects regression was used to evaluate the association between incident AF and longitudinal change in cognitive function. Compared with individuals without incident AF (n = 3158), those with incident AF (n = 96) were older, had a higher prevalence of cardiovascular disease and hypertension, and lower estimated glomerular filtration rate. After median follow-up of 6.8 years, we observed no significant multivariable association between incident AF and change in cognitive function test score. Conclusion In this cohort of adults with CKD, incident AF was not associated with a decline in cognitive function.

Background Patients with chronic kidney disease (CKD) face risks of not only end-stage kidney disease (ESKD), cardiovascular disease (CVD) and death, but also decline in kidney function, quality of life (QOL) and mental and physical well-being. This study describes the multidimensional trajectories of CKD using clinical events, kidney function and patient-reported outcome measures (PROMs). We hypothesized that more advanced CKD stages would associate with more rapid decline in each outcome. Methods Among 3939 participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study, we evaluated multidimensional disease trajectories by G- and A-stages of enrollment estimated glomerular filtration rate (eGFR) and albuminuria, respectively. These trajectories included clinical events (ESKD, CVD, heart failure and death), eGFR decline and PROMs [kidney disease QOL (KDQOL) burden, effects and symptoms questionnaires, as well as the 12-item short form mental and physical component summaries]. We also evaluated a group-based multitrajectory model to group participants on the basis of longitudinal PROMs and compared group assignments by enrollment G- and A-stage. Results The mean participant age was 58 years, 45% were women, mean baseline eGFR was 44 mL/min/1.73 m2 and median urine albumin:creatinine ratio was 52 mg/g. The incidence of all clinical events was greater and eGFR decline was faster with more advanced G- and A-stages. While baseline KDQOL and physical component measures were lower with more advanced G- and A-stage of CKD, changes in PROMs were inconsistently related to the baseline CKD stage. Groups formed on PROM trajectories were fairly distinct from existing CKD staging (observed agreement 60.6%) and were associated with the risk of ESKD, CVD, heart failure and death. Conclusions More advanced baseline CKD stage was associated with a higher risk of clinical events and faster eGFR decline, and was only weakly related to changes in patient-reported metrics over time.

Having a usual source of care increases use of preventive services and is associated with improved survival in the general population. We evaluated this association in adults with chronic kidney disease (CKD).Prospective, observational cohort study.Adults with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.Usual source of care was self-reported as: 1) clinic, 2) emergency department (ED)/urgent care, 3) other.Primary outcomes included incident end-stage kidney disease (ESKD), atherosclerotic events (myocardial infarction, stroke, or peripheral artery disease), incident heart failure, hospitalization events, and all-cause death.Multivariable regression analyses to evaluate the association between usual source of care (ED/urgent care vs clinic) and primary outcomes.Among 3,140 participants, mean age was 65 years, 44% female, 45% non-Hispanic White, 43% non-Hispanic Black, and 9% Hispanic, mean estimated glomerular filtration rate 50 mL/min/1.73 mCannot be generalized to all patients with CKD. Causal relationships cannot be established.In this large, diverse cohort of adults with moderate-to-severe CKD, those identifying ED/urgent care as usual source of care were at increased risk for death and hospitalizations. These findings highlight the need to develop strategies to improve health care access for this high-risk population.

Introduction Cardiovascular disease (CVD) is the leading cause of mortality among individuals with chronic kidney disease (CKD). Cardiac biomarkers of myocardial distention, injury, and inflammation may signal unique pathways underlying CVD in CKD. In this analysis, we studied the association of baseline levels and changes in 4 traditional and novel cardiac biomarkers with risk of all-cause, CV, and non-CV mortality in a large cohort of patients with CKD. Methods Among 3664 adults with CKD enrolled in the Chronic Renal Insufficiency Cohort Study, we conducted a cohort study to examine the associations of baseline levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP), cardiac high-sensitivity troponin T (hsTnT), growth differentiation factor−15 (GDF-15), and soluble ST-2 (sST-2) with risks of all-cause and cardiovascular (CV) mortality. Among a subcohort of 842 participants, we further examined the associations between change in biomarker levels over 2 years with risk of all-cause mortality. We used Cox proportional hazards regression models and adjusted for demographics, kidney function measures, cardiovascular risk factors, and medication use. Results After adjustment, elevated baseline levels of each cardiac biomarker were associated with increased risk of all-cause mortality: NT-proBNP (hazard ratio [HR] = 1.92, 95% confidence interval [CI] = 1.73−2.12); hsTnT (HR = 1.62, 95% CI = 1.48, 1.78]); GDF-15 (HR = 1.61, 95% CI = 1.46−1.78]); and sST-2 (HR = 1.26, CI = 1.16−1.37). Higher baseline levels of all 4 cardiac biomarkers were also associated with increased risk of CV. Declines in NT-proBNP (adjusted HR = 0.55, 95% CI = 0.36−0.86) and sST2 (HR = 0.55, 95% CI = 0.36−0.86]) over 2 years were associated with lower risk of all-cause mortality. Conclusion In a large cohort of CKD participants, elevations of NT-proBNP, hsTnT, GDF-15, and sST-2 were independently associated with greater risks of all-cause and CV mortality., Graphical abstract

Background: Chronic kidney disease (CKD) is associated with anxiety and depression. Though the Coronavirus 2019 (COVID-19) pandemic has increased stressors on patients with CKD, assessments of anxiety, its predictors and consequences, including on virus mitigation behaviors are lacking. Methods: From June to October 2020, we administered a survey about anxiety related to the COVID-19 pandemic to 1888 participants in CRIC. We examined associations of anxiety with demographics, clinical indices, health literacy, health-related behaviors and COVID-19 mitigation behaviors. Results: Four anxiety-related constructs were assessed: one composite overall global anxiety construct and three sub-constructs: general anxiety, worry, mood/feelings. Construct scores had moderate to strong correlations with each other (0.48-0.89) and high internal consistency (Cronbach's alpha ≥0.81). In adjusted analyses, younger age, female gender, Hispanic ethnicity, cardiovascular disease, household income

Rationale & Objective Studies using a single measurement of fibroblast growth factor 23 (FGF-23) suggest that elevated FGF-23 levels are associated with increased risk for requirement for kidney replacement therapy (KRT) in patients with chronic kidney disease. However, the data do not account for changes in FGF-23 levels as kidney disease progresses. Study Design Case-cohort study. Setting & Participants To evaluate the association between serial FGF-23 levels and risk for requiring KRT, our primary analysis included 1,597 individuals in the Chronic Renal Insufficiency Cohort Study who had up to 5 annual measurements of carboxy-terminal FGF-23. There were 1,135 randomly selected individuals, of whom 266 initiated KRT, and 462 individuals who initiated KRT outside the random subcohort. Exposure Serial FGF-23 measurements and FGF-23 trajectory group membership. Outcomes Incident KRT. Analytical Approach To handle time-dependent confounding, our primary analysis of time-updated FGF-23 levels used time-varying inverse probability weighting in a discrete time failure model. To compare our results with prior data, we used baseline and time-updated FGF-23 values in weighted Cox regression models. To examine the association of FGF-23 trajectory subgroups with risk for incident KRT, we used weighted Cox models with FGF-23 trajectory groups derived from group-based trajectory modeling as the exposure. Results In our primary analysis, the HR for the KRT outcome per 1 SD increase in the mean of natural log–transformed (ln)FGF-23 in the past was 1.94 (95% CI, 1.51-2.49). In weighted Cox models using baseline and time-updated values, elevated FGF-23 level was associated with increased risk for incident KRT (HRs per 1 SD ln[FGF-23] of 1.18 [95% CI, 1.02-1.37] for baseline and 1.66 [95% CI, 1.49-1.86] for time-updated). Membership in the slowly and rapidly increasing FGF-23 trajectory groups was associated with ∼3- and ∼21-fold higher risk for incident KRT compared to membership in the stable FGF-23 trajectory group. Limitations Residual confounding and lack of intact FGF-23 values. Conclusions Increasing FGF-23 levels are independently associated with increased risk for incident KRT.

The worldwide burden of kidney disease is rising, but public awareness remains limited, underscoring the need for more effective communication by stakeholders in the kidney health community. Despite this need for clarity, the nomenclature for describing kidney function and disease lacks uniformity. In June 2019, Kidney Disease: Improving Global Outcomes (KDIGO) convened a Consensus Conference with the goal of standardizing and refining the nomenclature used in the English language to describe kidney function and disease, and of developing a glossary that could be used in scientific publications. Guiding principles of the conference were that the revised nomenclature should be patient-centered, precise, and consistent with nomenclature used in the KDIGO guidelines. Conference attendees reached general consensus on the following recommendations: (i) to use "kidney" rather than "renal" or "nephro-" when referring to kidney disease and kidney function; (ii) to use "kidney failure" with appropriate descriptions of presence or absence of symptoms, signs, and treatment, rather than "end-stage kidney disease"; (iii) to use the KDIGO definition and classification of acute kidney diseases and disorders (AKD) and acute kidney injury (AKI), rather than alternative descriptions, to define and classify severity of AKD and AKI; (iv) to use the KDIGO definition and classification of chronic kidney disease (CKD) rather than alternative descriptions to define and classify severity of CKD; and (v) to use specific kidney measures, such as albuminuria or decreased glomerular filtration rate (GFR), rather than "abnormal" or "reduced" kidney function to describe alterations in kidney structure and function. A proposed 5-part glossary contains specific items for which there was general agreement. Conference attendees acknowledged limitations of the recommendations and glossary, but they considered standardization of scientific nomenclature to be essential for improving communication.

Background After accounting for known risk factors for CKD progression in children, clinical outcomes among children with CKD still vary substantially. Biomarkers of tubular injury (such as KIM-1), repair (such as YKL-40), or inflammation (such as MCP-1, suPAR, TNF receptor-1 [TNFR-1], and TNFR-2) may identify children with CKD at risk for GFR decline. Methods We investigated whether plasma KIM-1, YKL-40, MCP-1, suPAR, TNFR-1, and TNFR-2 are associated with GFR decline in children with CKD and in subgroups defined by glomerular versus nonglomerular cause of CKD. We studied participants of the prospective CKiD Cohort Study which enrolled children with an eGFR of 30-90 ml/min per 1.73 m2 and then assessed eGFR annually. Biomarkers were measured in plasma collected 5 months after study enrollment. The primary endpoint was CKD progression, defined as a composite of a 50% decline in eGFR or incident ESKD. Results Of the 651 children evaluated (median age 11 years; median baseline eGFR of 53 ml/min per 1.73 m2), 195 (30%) had a glomerular cause of CKD. Over a median follow-up of 5.7 years, 223 children (34%) experienced CKD progression to the composite endpoint. After multivariable adjustment, children with a plasma KIM-1, TNFR-1, or TNFR-2 concentration in the highest quartile were at significantly higher risk of CKD progression compared with children with a concentration for the respective biomarker in the lowest quartile (a 4-fold higher risk for KIM-1 and TNFR-1 and a 2-fold higher risk for TNFR-2). Plasma MCP-1, suPAR, and YKL-40 were not independently associated with progression. When stratified by glomerular versus nonglomerular etiology of CKD, effect estimates did not differ significantly. Conclusions Higher plasma KIM-1, TNFR-1, and TNFR-2 are independently associated with CKD progression in children.

Background The secretion of organic solutes by the proximal tubules is an essential intrinsic kidney function. However, the clinical significance of the kidney's clearance of tubular secretory solutes is uncertain. Methods In this prospective cohort study, we evaluated 3416 participants with CKD from the Chronic Renal Insufficiency Cohort (CRIC) study. We measured plasma and 24-hour urine concentrations of endogenous candidate secretory solutes at baseline, using targeted liquid chromatography-tandem mass spectrometry. The study defined CKD progression by a ≥50% decline in the eGFR, initiation of maintenance dialysis, or kidney transplantation. We used Cox proportional hazards regression to test associations of secretory-solute clearances with CKD progression and mortality, adjusting for eGFR, albuminuria, and other confounding characteristics. Results Participants in this ancillary study had a mean age of 58 years and 41% were black; the median eGFR was 43 ml/min per 1.73 m2. After adjustment, lower kidney clearances of six solutes-kynurenic acid, pyridoxic acid, indoxyl sulfate, xanthosine, isovalerylglycine, and cinnamoylglycine-were associated with significantly greater risks of CKD progression, with clearance of kynurenic acid, a highly protein-bound solute, having the strongest association. Lower clearances of isovalerylglycine, tiglylglycine, hippurate, and trimethyluric acid were significantly associated with all-cause mortality after adjustment. Conclusions We found lower kidney clearances of endogenous secretory solutes to be associated with CKD progression and all-cause mortality, independent of eGFR and albuminuria. This suggests that tubular clearance of secretory solutes provides additional information about kidney health beyond measurements of glomerular function alone.

Rationale & Objectives Few studies have investigated racial disparities in survival among dialysis patients in a manner that considers risk factors and mortality during the phase of kidney disease before maintenance dialysis. Our objective was to explore racial variations in survival among dialysis patients and relate them to racial differences in comorbid conditions and rates of death in the setting of kidney disease not yet requiring dialysis therapy. Study Design Retrospective cohort study. Settings & Participants 3,288 black and white participants in the Chronic Renal Insufficiency Cohort (CRIC), none of whom were receiving dialysis at enrollment. Exposure Race. Outcome Mortality. Analytic Approach Cox proportional hazards regression was used to examine the association between race and mortality starting at: (1) time of dialysis initiation and (2) entry into the CRIC. Results During 7.1 years of median follow-up, 678 CRIC participants started dialysis. Starting from the time of dialysis initiation, blacks had lower risk for death (unadjusted HR, 0.67; 95% CI, 0.51-0.87) compared with whites. Starting from baseline CRIC enrollment, the strength of the association between some risk factors and dialysis was notably stronger for whites than blacks. For example, the HR for dialysis onset in the presence (vs absence) of heart failure at CRIC enrollment was 1.30 (95% CI, 1.01-1.68) for blacks versus 2.78 (95% CI, 1.90-4.50) for whites, suggesting differential severity of these risk factors by race. When we included deaths occurring both before and after dialysis, risk for death was higher among blacks (vs whites) starting from CRIC enrollment (HR, 1.41; 95% CI, 1.22-1.64), but this finding was attenuated in adjusted models (HR, 1.08; 95% CI, 0.91-1.28). Limitations Residual confounding. Conclusions The apparent survival advantage among blacks over whites treated with dialysis may be attributed to selected transition of a subset of whites with more severe comorbid conditions onto dialysis.

Rationale & Objective The pathogenesis of disordered mineral metabolism in chronic kidney disease (CKD) is largely informed by cross-sectional studies of humans and longitudinal animal studies. We sought to characterize the longitudinal evolution of disordered mineral metabolism during the course of CKD. Study Design Retrospective analysis nested in a cohort study. Setting & Participants Participants in the Chronic Renal Insufficiency Cohort (CRIC) Study who had up to 5 serial annual measurements of estimated glomerular filtration rate, fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), serum phosphate, and serum calcium and who subsequently reached end-stage kidney disease (ESKD) during follow-up (n = 847). Exposure Years before ESKD. Outcomes Serial FGF-23, PTH, serum phosphate, and serum calcium levels. Analytical Approach To assess longitudinal dynamics of disordered mineral metabolism in human CKD, we used "ESKD-anchored longitudinal analyses" to express time as years before ESKD, enabling assessments of mineral metabolites spanning 8 years of CKD progression before ESKD. Results Mean FGF-23 levels increased markedly as time before ESKD decreased, while PTH and phosphate levels increased modestly and calcium levels declined minimally. Compared with other mineral metabolites, FGF-23 levels demonstrated the highest rate of change (velocity: first derivative of the function of concentration over time) and magnitude of acceleration (second derivative). These changes became evident approximately 5 years before ESKD and persisted without deceleration through ESKD onset. Rates of changes in PTH and phosphate levels increased modestly and without marked acceleration around the same time, with modest deceleration immediately before ESKD, when use of active vitamin D and phosphate binders increased. Limitations Individuals who entered the CRIC Study at early stages of CKD and who did not progress to ESKD were not studied. Conclusions Among patients with progressive CKD, FGF-23 levels begin to increase 5 years before ESKD and continue to rapidly accelerate until transition to ESKD.

In the general population, there is an association between higher levels of physical activity and lower risk for cardiovascular events and mortality, but this relationship has not been well evaluated in chronic kidney disease (CKD). We investigated the association between self-reported physical activity and outcomes in a CKD cohort.Prospective cohort study.3,926 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study.Time-updated self-reported physical activity assessed by (1) quartile of moderate-to-vigorous physical activity (MVPA) and (2) meeting guideline-recommended level of physical activity (categorized as active, meeting guidelines; active, not meeting guidelines; or inactive).Atherosclerotic events (myocardial infarction, stroke, or peripheral artery disease), incident heart failure, and all-cause and cardiovascular death.Cox proportional hazards regression.At baseline, compared with the lowest MVPA quartile, those in the highest quartile were more likely to be younger, male, not have prevalent cardiovascular disease, and have higher estimated glomerular filtration rate. Overall, 51% met the physical activity guidelines; of those who did not, 30% were inactive. During the median follow-up period of 13.4 years, there were 772 atherosclerotic events, 848 heart failure events, and 1,553 deaths, and 420 cardiovascular deaths. Compared with the participants in the lowest MVPA quartile, the highest quartile had a lower risk of atherosclerotic events (HR, 0.64 [95% CI, 0.51-0.79]), incident heart failure (HR, 0.71 [95% CI, 0.58-0.87]), and all-cause and cardiovascular death (HRs of 0.54 [95% CI, 0.46-0.63] and 0.47 [95% CI, 0.35-0.64], respectively). The findings were similar for analyses evaluating recommended level of physical activity.Self-reported physical activity may result in some degree of misclassification.Higher self-reported physical activity was associated with lower risk of cardiovascular events and mortality in CKD patients, which may have important implications for clinical practice and the design of interventional studies.In this long-term study of 3,926 adults with chronic kidney disease, we found that individuals with higher levels of physical activity were less likely to experience an atherosclerotic event (for example, a heart attack, stroke, or peripheral arterial disease), new-onset heart failure, and death as compared with those with lower levels of physical activity. The findings were similar for the analyses evaluating adherence to guideline-recommended level of physical activity (that is, for more than 150 minutes per week), and they strengthen the evidence supporting the current guideline recommendations.

Rationale and Objective: Glomerular filtration rate (GFR) estimation based on creatinine and cystatin C (eGFRcr-cys) is more accurate than estimated GFR (eGFR) based on creatinine or cystatin C alone (eGFRcr or eGFRcys, respectively), but the inclusion of creatinine in eGFRcr-cys requires specification of a person's race. beta 2-Microglobulin (B2M) and beta-trace protein (BTP) are alternative filtration markers that appear to be less influenced by race than creatinine is.Study Design: Study of diagnostic test accuracy.Setting and Participants: Development in a pooled population of 7 studies with 5,017 participants with and without chronic kidney disease. External validation in a pooled population of 7 other studies with 2,245 participants. Tests Compared: Panel eGFR using B2M and BTP in addition to cystatin C (3-marker panel) or creatinine and cystatin C (4-marker panel) with and without age and sex or race. Outcomes: GFRmeasured as the urinary clearance of iothalamate, plasmaclearanceof iohexol, orplasma clearance of [Cr-51]EDTA.Results: Mean measured GFRs were 58.1 and 83.2 mL/min/1.73 m(2), and the proportions of Black participants were 38.6% and 24.0%, in the development and validation populations, respectively. In development, addition of age and sex improved the performance of all equations compared with equations without age and sex, but addition of race did not further improve the performance. In validation, the 4-marker panels were more accurate than the 3-marker panels (P < 0.001). The 3-marker panel without race was more accurate than eGFRcys (percentage of estimates greater than 30% different from measured GFR [1-P30] of 15.6% vs 17.4%; P = 0.01), and the 4-marker panel without race was as accurate as eGFRcr-cys (1-P-30 of 8.6% vs 9.4%; P = 0.2). Results were generally consistent across subgroups.Limitations: No representation of participants with severe comorbid illness and from geographic areas outside of North America and Europe.Conclusions: The 4-marker panel eGFR is as accurate as eGFRcr-cys without requiring specification of race. A more accurate race-free eGFR could be an important advance.

Rationale & Objective Elevated levels of deoxycholic acid (DCA) are associated with adverse outcomes and may contribute to vascular calcification in patients with chronic kidney disease (CKD). We tested the hypothesis that elevated levels of DCA were associated with increased risks of cardiovascular disease, CKD progression, and death in patients with CKD. Study Design Prospective observational cohort study. Setting & Participants We included 3,147 Chronic Renal Insufficiency Cohort study participants who had fasting DCA levels. The average age was 59 ± 11 years, 45.3% were women, 40.6% were African American, and the mean estimated glomerular filtration rate was 42.5 ± 16.0 mL/min/1.73 m2. Predictor Fasting DCA levels in Chronic Renal Insufficiency Cohort study participants. Outcomes Risks of atherosclerotic and heart failure events, end-stage kidney disease (ESKD), and all-cause mortality. Analytical Approach We used Tobit regression to identify predictors of DCA levels. We used Cox regression to examine the association between fasting DCA levels and clinical outcomes. Results The strongest predictors of elevated DCA levels in adjusted models were increased age and nonuse of statins. The associations between log-transformed DCA levels and clinical outcomes were nonlinear. After adjustment, DCA levels above the median were independently associated with higher risks of ESKD (HR, 2.67; 95% CI, 1.51-4.74) and all-cause mortality (HR, 2.13; 95% CI, 1.25-3.64). DCA levels above the median were not associated with atherosclerotic and heart failure events, and DCA levels below the median were not associated with clinical outcomes. Limitations We were unable to measure DCA longitudinally or in urinary or fecal samples, and we were unable to measure other bile acids. We also could not measure many factors that affect DCA levels. Conclusions In 3,147 participants with CKD stages 2-4, DCA levels above the median were independently associated with ESKD and all-cause mortality., Graphical abstract

BACKGROUND: Proteomic profiling may allow identification of plasma proteins that associate with subsequent changesin kidney function, elucidating biologic processes underlying the development and progression of CKD. METHODS: We quantified the association between 4877 plasma proteins and a composite outcome of ESKD or decline in eGFR by ≥50% among 9406 participants in the Atherosclerosis Risk in Communities (ARIC) Study (visit 3; mean age, 60 years) who were followed for a median of 14.4 years. We performed separate analyses for these proteins in a subset of 4378 participants (visit 5), who were followed at a later time point, for a median of 4.4 years. For validation, we evaluated proteins with significant associations (false discovery rate

Few studies have investigated racial disparities in acute kidney injury (AKI), in contrast to the extensive literature on racial differences in the risk of kidney failure. We sought to study potential differences in risk in the setting of chronic kidney disease (CKD).Prospective cohort study.We studied 2,720 self-identified Black or White participants with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study from July 1, 2013, to December 31, 2017.Self-reported race (Black vs White).Hospitalized AKI (≥50% increase from nadir to peak serum creatinine).Cox regression models adjusting for demographics (age and sex), prehospitalization clinical risk factors (diabetes, blood pressure, cardiovascular disease, estimated glomerular filtration rate, proteinuria, receipt of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers), and socioeconomic status (insurance status and education level). In a subset of participants with genotype data, we adjusted for apolipoprotein L1 gene (APOL1) high-risk status and sickle cell trait.Black participants (n = 1,266) were younger but had a higher burden of prehospitalization clinical risk factors. The incidence rate of first AKI hospitalization among Black participants was 6.3 (95% CI, 5.5-7.2) per 100 person-years versus 5.3 (95% CI, 4.6-6.1) per 100 person-years among White participants. In an unadjusted Cox regression model, Black participants were at a modestly increased risk of incident AKI (HR, 1.22 [95% CI, 1.01-1.48]) compared with White participants. However, this risk was attenuated and no longer significant after adjusting for prehospitalization clinical risk factors (adjusted HR, 1.02 [95% CI, 0.83-1.25]). There were only 11 AKI hospitalizations among individuals with high-risk APOL1 risk status and 14 AKI hospitalizations among individuals with sickle cell trait.Participants were limited to research volunteers and potentially not fully representative of all CKD patients.In this multicenter prospective cohort of CKD patients, racial disparities in AKI incidence were modest and were explained by differences in prehospitalization clinical risk factors.

Cardiovascular disease (CVD) is a major cause of mortality among people with diabetic kidney disease (DKD). The pathophysiology is inadequately explained by traditional CVD risk factors. The uremic solutes trimethylamine-N-oxide (TMAO) and asymmetric and symmetric dimethylarginine (ADMA, SDMA) have been linked to CVD in kidney failure with replacement therapy (KFRT), but data are limited in populations with diabetes and less severe kidney disease.Observational cohort.Random subcohort of 555 REGARDS (Reasons for Geographic and Racial Differences in Stroke) study participants with diabetes and estimated glomerular filtration rate (eGFR) 60 mL/min/1.73 mADMA, SDMA, and TMAO assayed by liquid chromatography-mass spectrometry in plasma and urine.Cardiovascular mortality (primary outcome); all-cause mortality and incident KFRT (secondary outcomes).Plasma concentrations and ratios of urine to plasma concentrations of ADMA, SDMA, and TMAO were tested for association with outcomes. Adjusted Cox regression models were fitted and hazard ratios of outcomes calculated per standard deviation and per doubling, and as interquartile comparisons.The mean baseline eGFR was 44 mL/min/1.73 mSingle cohort, restricted to patients with diabetes and eGFR 60 mL/min/1.73 mHigher plasma concentrations and lower ratios of urine to plasma concentrations of uremic solutes were independently associated with cardiovascular and all-cause mortality in DKD. Associations of ratios of urine to plasma concentrations with mortality suggest a connection between renal uremic solute clearance and CVD pathogenesis.

Zelnick et al1 analyzed data from the Chronic Renal Insufficiency Cohort (CRIC) obtained from the National Institute of Diabetes and Digestive and Kidney Diseases central repository and reported that the Chronic Kidney Disease-Epidemiology (CKD-EPI) equation estimated glomerular filtration rates (eGFR) were higher than iothalamate clearance glomerular filtration rates (iGFR) among self-reported Black participants with iGFR less than 45 mL/min/1.73 m2. Using the CKD-EPI equation without a (Black vs non-Black) race coefficient appeared to attenuate the difference between eGFR and iGFR (eGFR − iGFR). The authors suggested that the latter approach should be used more widely in clinical practice. We believe that examining potential bias in eGFR values within subgroups defined by iGFR is problematic. An unbiased eGFR estimation aims to ensure that for the set of individuals who have the same eGFR value, the mean iGFR value is the same as the eGFR. The correlation between the difference between eGFR and iGFR (eGFR − iGFR) and iGFR is expected for an unbiased eGFR estimation.2 We offer an alternative view of the data here with different clinical implications.

BACKGROUND: Individuals with CKD may be at high risk for atherosclerotic cardiovascular disease (ASCVD). However, there are no ASCVD risk prediction models developed in CKD populations to inform clinical care and prevention. METHODS: We developed and validated 10-year ASCVD risk prediction models in patients with CKD that included participants without self-reported cardiovascular disease from the Chronic Renal Insufficiency Cohort (CRIC) study. ASCVD was defined as the first occurrence of adjudicated fatal and nonfatal stroke or myocardial infarction. Our models used clinically available variables and novel biomarkers. Model performance was evaluated based on discrimination, calibration, and net reclassification improvement. RESULTS: Of 2604 participants (mean age 55.8 years; 52.0% male) included in the analyses, 252 had incident ASCVD within 10 years of baseline. Compared with the American College of Cardiology/American Heart Association pooled cohort equations (area under the receiver operating characteristic curve [AUC]=0.730), a model with coefficients estimated within the CRIC sample had higher discrimination (P=0.03), achieving an AUC of 0.736 (95% confidence interval [CI], 0.649 to 0.826). The CRIC model developed using clinically available variables had an AUC of 0.760 (95% CI, 0.678 to 0.851). The CRIC biomarker-enriched model had an AUC of 0.771 (95% CI, 0.674 to 0.853), which was significantly higher than the clinical model (P=0.001). Both the clinical and biomarker-enriched models were well-calibrated and improved reclassification of nonevents compared with the pooled cohort equations (6.6%; 95% CI, 3.7% to 9.6% and 10.0%; 95% CI, 6.8% to 13.3%, respectively). CONCLUSIONS: The 10-year ASCVD risk prediction models developed in patients with CKD, including novel kidney and cardiac biomarkers, performed better than equations developed for the general population using only traditional risk factors.

For almost two decades, equations that use serum creatinine, age, sex, and race to eGFR have included “race” as Black or non-Black. Given considerable evidence of disparities in health and healthcare delivery in African American communities, some regard keeping a race term in GFR equations as a practice that differentially influences access to care and kidney transplantation. Others assert that race captures important non GFR determinants of serum creatinine and its removal from the calculation may perpetuate other disparities. The National Kidney Foundation (NKF) and American Society of Nephrology (ASN) established a task force in 2020 to reassess the inclusion of race in the estimation of GFR in the United States and its implications for diagnosis and subsequent management of patients with, or at risk for, kidney diseases. This interim report details the process, initial assessment of evidence, and values defined regarding the use of race to estimate GFR. We organized activities in phases: (1) clarify the problem and examine evidence, (2) evaluate different approaches to address use of race in GFR estimation, and (3) make recommendations. In phase one, we constructed statements about the evidence and defined values regarding equity and disparities; race and racism; GFR measurement, estimation, and equation performance; laboratory standardization; and patient perspectives. We also identified several approaches to estimate GFR and a set of attributes to evaluate these approaches. Building on evidence and values, the attributes of alternative approaches to estimate GFR will be evaluated in the next phases and recommendations will be made.

Contains fulltext : 215593.pdf (Publisher’s version ) (Closed access) Although blood pressure control is a major goal in chronic kidney disease, no worldwide overview of either its achievement or antihypertensive prescriptions is currently available. To evaluate this we compared crude prevalence of uncontrolled blood pressure among 17 cohort studies, including 34 602 individuals with estimated glomerular filtration rate under 60 ml/min/1.73 m(2) and treated hypertension across four continents, and estimated observed to expected prevalence ratios, adjusted for potential confounders. Crude prevalence of blood pressure of 140/90 mm Hg or more varied from 28% to 61% and of blood pressure of 130/80 or more from 54% to 84%. Adjusted prevalence ratios indicated poorer hypertension control than expected in cohorts from European countries, India, and Uruguay, and better control in patients from North American and high-income Asian countries. Four antihypertensive drug classes or more were prescribed to more than 30% of participants in North American and some European cohorts, but this practice was less common elsewhere. Renin angiotensin-aldosterone system inhibitors were the most common antihypertensive drugs, prescribed for 54% to 91% of cohort participants. Differences for other drug classes were much stronger, ranging from 11% to 79% for diuretics, 22% to 70% for beta-blockers, and 27% to 75% for calcium-channel blockers. The confounders studied explain only a part of the international variation in blood pressure control among individuals with chronic kidney disease. Thus, considerable heterogeneity in prescription patterns worldwide calls for further investigation into the impact of different approaches on patient outcomes.

Author(s): Hsu, Raymond K; Hsu, Chi-Yuan; McCulloch, Charles E; Yang, Jingrong; Anderson, Amanda H; Chen, Jing; Feldman, Harold I; He, Jiang; Liu, Kathleen D; Navaneethan, Sankar D; Porter, Anna C; Rahman, Mahboob; Tan, Thida C; Wilson, F Perry; Xie, Dawei; Zhang, Xiaoming; Go, Alan S; Chronic Renal Insufficiency Cohort (CRIC) Study Investigators | Abstract: Background:Observational studies relying on clinically obtained data have shown that acute kidney injury (AKI) is linked to accelerated chronic kidney disease (CKD) progression. However, prior reports lacked uniform collection of important confounders such as proteinuria and pre-AKI kidney function trajectory, and may be susceptible to ascertainment bias, as patients may be more likely to undergo kidney function testing after AKI. Methods:We studied 444 adults with CKD who participated in the prospective Chronic Renal Insufficiency Cohort (CRIC) Study and were concurrent members of a large integrated healthcare delivery system. We estimated glomerular filtration rate (eGFR) trajectories using serum creatinine measurements from (i) the CRIC research protocol (yearly) and (ii) routine clinical care. We used linear mixed effects models to evaluate the associations of AKI with acute absolute change in eGFR and post-AKI eGFR slope, and explored whether these varied by source of creatinine results. Models were adjusted for demographic characteristics, diabetes status and albuminuria. Results:During median follow-up of 8.5 years, mean rate of eGFR loss was -0.31 mL/min/1.73nm2/year overall, and 73 individuals experienced AKI (55% Stage 1). A significant interaction existed between AKI and source of serum creatinine for acute absolute change in eGFR level after discharge; in contrast, AKI was independently associated with a faster rate of eGFR decline (mean additional loss of -0.67 mL/min/1.73nm2/year), which was not impacted by source of serum creatinine. Conclusions:AKI is independently associated with subsequent steeper eGFR decline regardless of the serum creatinine source used, but the strength of association is smaller than observed in prior studies after taking into account key confounders such as pre-AKI eGFR slope and albuminuria.

RATIONALE & OBJECTIVE: Traditional risk estimates for atherosclerotic vascular disease (ASVD) and death may not perform optimally in the setting of CKD. We sought to determine whether the addition of measures of inflammation and kidney function to traditional estimation tools improves prediction of these events in a diverse cohort of patients with CKD. STUDY DESIGN: Observational cohort study SETTING & PARTICIPANTS: 2399 Chronic Renal Insufficiency Cohort (CRIC) study participants without history of cardiovascular disease at study entry. PREDICTORS: Baseline plasma levels of biomarkers of inflammation (interleukin (IL)-1β, IL-1RA (IL-1 receptor antagonist), IL-6, tumor necrosis factor (TNF)-α, transforming growth factor β (TGFβ), high sensitivity C-Reactive protein (hs-CRP), fibrinogen, and serum albumin), measures of kidney function (estimated glomerular filtration rate (eGFR) and albuminuria), and the Pooled Cohort Equation Probability (PCEP) estimate. OUTCOMES: Composite of ASVD events (incident myocardial infarction (MI), peripheral arterial disease (PAD), and stroke) and death. ANALYTICAL APPROACH: Cox proportional hazard models adjusted for PCEP estimates, albuminuria, and eGFR. RESULTS: During a median follow-up of 7.3 years, 86, 61, 48, and 323 participants experienced MI, PAD, stroke, or death, respectively. 1-decile greater levels of IL-6 (adjusted Hazard Ratio [aHR], 1.12; 95% CI, 1.08-1.16; p

Background Insulin resistance contributes to the metabolic syndrome, which is associated with the development of kidney disease. However, it is unclear if insulin resistance independently contributes to an increased risk of chronic kidney disease (CKD) progression or CKD complications. Additionally, predisposing factors responsible for insulin resistance in the absence of diabetes in CKD are not well described. This study aimed to describe factors associated with insulin resistance and characterize the relationship of insulin resistance to CKD progression, cardiovascular events and death among a cohort of non-diabetics with CKD. Methods Data was utilized from Chronic Renal Insufficiency Cohort Study participants without diabetes (N = 1883). Linear regression was used to assess associations with insulin resistance, defined using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). The relationship of HOMA-IR, fasting glucose, hemoglobin A1c (HbA1c), and C-peptide with CKD progression, cardiovascular events, and all-cause mortality was examined with Cox proportional hazards models. Results Novel positive associations with HOMA-IR included serum albumin, uric acid, and hemoglobin A1c. After adjustment, HOMA-IR was not associated with CKD progression, cardiovascular events, or all-cause mortality. There was a notable positive association of one standard deviation increase in HbA1c with the cardiovascular endpoint (HR 1.16, 95% CI: 1.00–1.34). Conclusion We describe potential determinants of HOMA-IR among a cohort of non-diabetics with mild-moderate CKD. HOMA-IR was not associated with renal or cardiovascular events, or all-cause mortality, which adds to the growing literature describing an inconsistent relationship of insulin resistance with CKD-related outcomes. Electronic supplementary material The online version of this article (10.1186/s12882-019-1220-6) contains supplementary material, which is available to authorized users.

The last two decades have witnessed an explosion in research focused on the development and assessment of novel biomarkers for improved prognosis of diseases. As a result, best practice standards guiding biomarker research have undergone extensive development. Currently, there is great interest in the promise of biomarkers to enhance research efforts and clinical practice in the setting of chronic kidney disease, acute kidney injury, and glomerular disease. However, some have questioned whether biomarkers currently add value to the clinical practice of nephrology. The current state of the art pertaining to statistical analyses regarding the use of such measures is critical. In December 2014, the National Institute of Diabetes and Digestive and Kidney Diseases convened a meeting, "Toward Building Better Biomarker Statistical Methodology," with the goals of summarizing the current best practice recommendations and articulating new directions for methodological research. This report summarizes its conclusions and describes areas that need attention. Suggestions are made regarding metrics that should be commonly reported. We outline the methodological issues related to traditional metrics and considerations in prognostic modeling, including discrimination and case mix, calibration, validation, and cost-benefit analysis. We highlight the approach to improved risk communication and the value of graphical displays. Finally, we address some "new frontiers" in prognostic biomarker research, including the competing risk framework, the use of longitudinal biomarkers, and analyses in distributed research networks.

Introduction: A cornerstone of kidney disease management is participation in guideline-recommended health behaviors. However, the relationship of these health behaviors with outcomes, and the identification of barriers to health behavior engagement, have not been described among younger and older adults with chronic kidney disease. Methods: Data from a cohort study of 5499 individuals with chronic kidney disease was used to identify health behavior patterns with latent class analysis stratified by age

RATIONALE & OBJECTIVE: Most circulating biomarkers of chronic kidney disease (CKD) progression focus on factors reflecting glomerular filtration. Few biomarkers capture non-glomerular pathways of kidney injury or damage, which may be particularly informative in populations at high risk for CKD progression such as individuals with diabetes. STUDY DESIGN: Cohort study. SETTING & PARTICIPANTS: 594 participants (mean age 70, 53% women) of the Reason for Geographic and Racial Differences in Stroke study who had diabetes and an estimated glomerular filtration rate (eGFR)

Rationale & Objective Adults with chronic kidney disease (CKD) may be at increased risk of adverse effects from use of potentially inappropriate medications (PIMs). Our objective was to assess whether PIM exposure has an independent association with CKD progression, hospitalizations, mortality, or falls. Study Design Retrospective observational study. Setting & Participants Chronic Renal Insufficiency Cohort (CRIC) study; 3,929 adults with CKD enrolled 2003-2008 and followed prospectively until December 2011. Exposure PIM exposure was defined as prescriptions for any medications to be avoided in older adults as defined by the 2015 American Geriatrics Society Beers Criteria. Outcome Hospitalization count, death, a composite kidney disease end point of CKD progression or initiation of kidney replacement therapy (KRT), KRT, and fall events assessed 1 year after PIM exposure. Analytical Approach Logistic regression and Poisson regression to estimate the associations of PIM exposure with each outcome. Results The most commonly prescribed PIMs were proton pump inhibitors and α-blockers. In unadjusted models, any PIM exposure (compared to none) was associated with hospitalizations, death, and fall events. After adjustment, exposure to 1, 2, or ≥3 PIMs had a graded association with a higher hospitalization rate (rate ratios of 1.09 [95% CI, 1.01-1.17], 1.18 [95% CI, 1.07-1.30], and 1.35 [95% CI, 1.19-1.53], respectively) and higher odds of mortality (odds ratios of 1.19 [95% CI, 0.91-1.54], 1.62 [95% CI, 1.21-2.17], and 1.65 [95% CI, 1.14-2.41], respectively). In a cohort subset reporting falls (n = 1,109), prescriptions for ≥3 PIMs were associated with an increased risk of falls (adjusted OR, 2.85 [95% CI, 1.54-5.26]). PIMs were not associated with CKD progression or KRT. Age did not modify the association between PIM count and outcomes. Limitations Measurement bias; confounding by indication. Conclusions Adults of any age with CKD who are prescribed PIMs have an increased risk of hospitalization, mortality, and falls with the greatest risk occurring after more than 1 PIM prescription.

BACKGROUND: Untargeted plasma metabolomic profiling combined with machine learning (ML) may lead to discovery of metabolic profiles that inform our understanding of pediatric CKD causes. We sought to identify metabolomic signatures in pediatric CKD based on diagnosis: FSGS, obstructive uropathy (OU), aplasia/dysplasia/hypoplasia (A/D/H), and reflux nephropathy (RN). METHODS: Untargeted metabolomic quantification (GC-MS/LC-MS, Metabolon) was performed on plasma from 702 Chronic Kidney Disease in Children study participants (n: FSGS=63, OU=122, A/D/H=109, and RN=86). Lasso regression was used for feature selection, adjusting for clinical covariates. Four methods were then applied to stratify significance: logistic regression, support vector machine, random forest, and extreme gradient boosting. ML training was performed on 80% total cohort subsets and validated on 20% holdout subsets. Important features were selected based on being significant in at least two of the four modeling approaches. We additionally performed pathway enrichment analysis to identify metabolic subpathways associated with CKD cause. RESULTS: ML models were evaluated on holdout subsets with receiver-operator and precision-recall area-under-the-curve, F1 score, and Matthews correlation coefficient. ML models outperformed no-skill prediction. Metabolomic profiles were identified based on cause. FSGS was associated with the sphingomyelin-ceramide axis. FSGS was also associated with individual plasmalogen metabolites and the subpathway. OU was associated with gut microbiome–derived histidine metabolites. CONCLUSION: ML models identified metabolomic signatures based on CKD cause. Using ML techniques in conjunction with traditional biostatistics, we demonstrated that sphingomyelin-ceramide and plasmalogen dysmetabolism are associated with FSGS and that gut microbiome–derived histidine metabolites are associated with OU.