Project description:Hypokalemia and hyperkalemia are often noted in chronic kidney disease (CKD) patients, but their impact on mortality and end-stage renal disease (ESRD) is less well understood. We aimed at studying the associations between potassium disorders, and mortality and progression to ESRD in a CKD population.Using our electronic health record-based CKD registry, 36,359 patients with eGFR <60 ml/min/1.73 m(2) and potassium levels measured from January 1, 2005 to September 15, 2009 were identified. We examined factors associated with hypokalemia (<3.5 mmol/l) and hyperkalemia (>5.0 mmol/l) using logistic regression models and associations between serum potassium levels (both as continuous and categorical variables) and all-cause mortality or ESRD using Cox-proportional hazards models.Serum potassium <3.5 mmol/l was noted among 3% and >5.0 mmol/l among 11% of the study population. In the multivariable logistic regression analysis, lower eGFR, diabetes and use of ACE inhibitors or Angiotensin-Receptor Blockers were associated with higher odds of having hyperkalemia. Heart failure and African American race were factors associated with higher odds of hypokalemia. After adjustment for covariates including kidney function, serum potassium <4.0 and >5.0 mmol/l were significantly associated with increased mortality risk, but there was no increased risk for progression to ESRD. Time-dependent repeated measures analysis confirmed these findings. When potassium was examined as a continuous variable, there was a U-shaped association between serum potassium levels and mortality.In patients with stage 3-4 CKD, serum potassium levels <4.0 and >5.0 mmol/l are associated with higher mortality but not with ESRD.
Project description:Some suggest race-specific cutpoints for kidney measures to define and stage chronic kidney disease (CKD), but evidence for race-specific clinical impact is limited. To address this issue, we compared hazard ratios of estimated glomerular filtration rates (eGFR) and albuminuria across races using meta-regression in 1.1 million adults (75% Asians, 21% Whites, and 4% Blacks) from 45 cohorts. Results came mainly from 25 general population cohorts comprising 0.9 million individuals. The associations of lower eGFR and higher albuminuria with mortality and end-stage renal disease (ESRD) were largely similar across races. For example, in Asians, Whites, and Blacks, the adjusted hazard ratios (95% confidence interval) for eGFR 45-59 versus 90-104 ml/min per 1.73 m(2) were 1.3 (1.2-1.3), 1.1 (1.0-1.2), and 1.3 (1.1-1.7) for all-cause mortality, 1.6 (1.5-1.7), 1.4 (1.2-1.7), and 1.4 (0.7-2.9) for cardiovascular mortality, and 27.6 (11.1-68.7), 11.2 (6.0-20.9), and 4.1 (2.2-7.5) for ESRD, respectively. The corresponding hazard ratios for urine albumin-to-creatinine ratio 30-299 mg/g or dipstick 1+ versus an albumin-to-creatinine ratio under 10 or dipstick negative were 1.6 (1.4-1.8), 1.7 (1.5-1.9), and 1.8 (1.7-2.1) for all-cause mortality, 1.7 (1.4-2.0), 1.8 (1.5-2.1), and 2.8 (2.2-3.6) for cardiovascular mortality, and 7.4 (2.0-27.6), 4.0 (2.8-5.9), and 5.6 (3.4-9.2) for ESRD, respectively. Thus, the relative mortality or ESRD risks of lower eGFR and higher albuminuria were largely similar among three major races, supporting similar clinical approach to CKD definition and staging, across races.
Project description:A high level of the phosphate-regulating hormone fibroblast growth factor 23 (FGF-23) is associated with mortality in patients with end-stage renal disease, but little is known about its relationship with adverse outcomes in the much larger population of patients with earlier stages of chronic kidney disease.To evaluate FGF-23 as a risk factor for adverse outcomes in patients with chronic kidney disease.A prospective study of 3879 participants with chronic kidney disease stages 2 through 4 who enrolled in the Chronic Renal Insufficiency Cohort between June 2003 and September 2008.All-cause mortality and end-stage renal disease.At study enrollment, the mean (SD) estimated glomerular filtration rate (GFR) was 42.8 (13.5) mL/min/1.73 m(2), and the median FGF-23 level was 145.5 RU/mL (interquartile range [IQR], 96-239 reference unit [RU]/mL). During a median follow-up of 3.5 years (IQR, 2.5-4.4 years), 266 participants died (20.3/1000 person-years) and 410 reached end-stage renal disease (33.0/1000 person-years). In adjusted analyses, higher levels of FGF-23 were independently associated with a greater risk of death (hazard ratio [HR], per SD of natural log-transformed FGF-23, 1.5; 95% confidence interval [CI], 1.3-1.7). Mortality risk increased by quartile of FGF-23: the HR was 1.3 (95% CI, 0.8-2.2) for the second quartile, 2.0 (95% CI, 1.2-3.3) for the third quartile, and 3.0 (95% CI, 1.8-5.1) for the fourth quartile. Elevated fibroblast growth factor 23 was independently associated with significantly higher risk of end-stage renal disease among participants with an estimated GFR between 30 and 44 mL/min/1.73 m(2) (HR, 1.3 per SD of FGF-23 natural log-transformed FGF-23; 95% CI, 1.04-1.6) and 45 mL/min/1.73 m(2) or higher (HR, 1.7; 95% CI, 1.1-2.4), but not less than 30 mL/min/1.73 m(2).Elevated FGF-23 is an independent risk factor for end-stage renal disease in patients with relatively preserved kidney function and for mortality across the spectrum of chronic kidney disease.
Project description:Mounting evidence indicates that sclerostin, a well-known inhibitor of bone formation, may qualify as a clinically relevant biomarker of chronic kidney disease-related mineral and bone disorder (CKD-MBD), including abnormal mineral and bone metabolism and extraskeletal calcification. For this purpose, in this study we investigate the extent to which circulating sclerostin, skeletal sclerostin expression, bone histomorphometric parameters, and serum markers of bone metabolism associate with each other. Bone biopsies and serum samples were collected in a cohort of 68 end-stage kidney disease (ESKD) patients. Serum sclerostin levels were measured using 4 different commercially available assays. Skeletal sclerostin expression was evaluated on immunohistochemically stained bone sections. Quantitative bone histomorphometry was performed on Goldner stained tissue sections. Different serum markers of bone metabolism were analyzed using in-house techniques or commercially available assays. Despite large inter-assay differences for circulating sclerostin, results obtained with the 4 assays under study closely correlated with each other, whilst moderate significant correlations with skeletal sclerostin expression were also found. Both skeletal and circulating sclerostin negatively correlated with histomorphometric bone and serum parameters reflecting bone formation and turnover. In this study, the unique combined evaluation of bone sclerostin expression, bone histomorphometry, bone biomarkers, and serum sclerostin levels, as assessed by 4 different assays, demonstrated that sclerostin may qualify as a clinically relevant marker of disturbed bone metabolism in ESKD patients.
Project description:BackgroundHigher serum alkaline phosphatase (ALP) levels have been associated with excess mortality in patients with non-dialysis-dependent chronic kidney disease (NDD-CKD) and end-stage renal disease (ESRD). However, little is known about the impact of late-stage NDD-CKD ALP levels on outcomes after dialysis initiation.MethodsAmong 17 732?US veterans who transitioned to dialysis between October 2007 and September 2011, we examined the association of serum ALP levels averaged over the last 6 months of the pre-ESRD transition period ('prelude period') with all-cause, cardiovascular and infection-related mortality following dialysis initiation, using Cox (for all-cause mortality) and competing risk (for cause-specific mortality) regressions adjusted for demographics, comorbidities, medications, estimated glomerular filtration rate and serum albumin levels over the 6-month prelude period, and vascular access type at dialysis initiation.ResultsDuring a median follow-up of 2.0 (interquartile range, 1.1-3.2) years following dialysis initiation, a total of 9196 all-cause deaths occurred. Higher ALP levels were incrementally associated with higher all-cause, cardiovascular and infection-related mortality. Compared with patients in the lowest ALP quartile (<66.0?U/L), those in the highest quartile (?111.1?U/L) had multivariable-adjusted hazard/subhazard ratios (95% confidence interval) of 1.42 (1.34-1.51), 1.43 (1.09-1.88) and 1.39 (1.09-1.78) for all-cause, cardiovascular and infection-related mortality, respectively. The associations remained consistent in various subgroups and after further adjustment for liver enzymes, serum phosphorus and intact parathyroid hormone levels.ConclusionsHigher pre-ESRD serum ALP levels are independently associated with higher post-ESRD mortality risk. Further studies are warranted to determine if interventions that lower pre-ESRD ALP levels reduce mortality in incident dialysis patients.
Project description:ContextPrevious studies have shown that the endocannabinoid system plays a major role in energy metabolism through the actions of its main mediators, 2-arachidonoyl-sn-glycerol (2-AG) and anandamide (AEA).ObjectiveWe examined serum levels of major endocannabinoid mediators and their association with clinical parameters in patients with end-stage renal disease (ESRD).Design and settingSerum concentrations of 2-AG and AEA were measured in patients on maintenance hemodialysis (MHD) and controls, and correlations with various clinical and laboratory indices were examined. 2-AG was also measured in age and sex-matched healthy subjects for comparison of levels in patients undergoing MHD.Main outcome measureSerum 2-AG.ResultsSerum 2-AG levels were significantly elevated in patients with ESRD compared with healthy controls. Higher levels of 2-AG were found in patients on MHD compared to healthy subjects, and similar findings were seen in a second set of subjects in independent analyses. Among 96 patients on MHD, 2-AG levels correlated significantly and positively with serum triglycerides (ρ = 0.43; P < 0.0001), body mass index (ρ = 0.40; P < 0.0001), and body anthropometric measures and negatively with serum high-density lipoprotein cholesterol (ρ = -0.33; P = 0.001) following adjustment for demographic and clinical variables.ConclusionsIn patients on MHD, levels of serum 2-AG, a major endocannabinoid mediator, were increased. In addition, increasing serum 2-AG levels correlated with increased serum triglycerides and markers of body mass. Future studies will need to evaluate the potential mechanisms responsible for these findings.
Project description:ObjectivePrevious reports have demonstrated the association of serum bilirubin levels with the progression of diabetic nephropathy. The objective of this study is to assess the association of basal bilirubin levels with progressive renal decline (PRD) and end-stage kidney disease (ESKD).MethodsA total of 298 patients with diabetes who visited Kyushu University Hospital (Japan) were recruited and followed up for 10 years. PRD was defined as a negative change in estimated glomerular filtration ratio (eGFR) >3.7%/year, 2.5th percentile. Logistic regression analysis was performed to evaluate the association of total bilirubin levels with PRD and its cut-off point was determined by receiver operating characteristic (ROC) analysis. Kaplan-Meier method and Cox hazard regression analysis were used to evaluate the predictive ability of its cut-off point for ESKD.ResultsLogistic regression model showed that total bilirubin levels were significantly associated with PRD, and ROC analysis showed that its cut-off point was 0.5 mg/dL. Kaplan-Meier method showed that the percent of patients who reached two endpoints, composite endpoint (ESKD or doubling of creatinine level) or 30% eGFR decline, was significantly higher in the low bilirubin group than in the high bilirubin group (18.5% vs 11.0%, P = 0.045; 49.1% vs 42.1%, P = 0.045, respectively, log-rank test). Cox hazard regression models confirmed the independence of the predictive ability of its cut-off point.ConclusionsSerum total bilirubin levels were negatively associated with PRD in diabetic nephropathy and its cut-off point was 0.5 mg/dL. It may be clinically useful for identifying patients at high risk of ESKD.
Project description:The correlation of low serum albumin with mortality in patients with chronic kidney disease (CKD) is partly linked to its association with systemic inflammation. However, it is not clear to what extent albumin's correlation with mortality depends on concomitant systemic inflammation. Here we addressed this question in patients with CKD stage 5.Serum albumin (S-Alb), systemic inflammation (high-sensitive C-reactive protein, hsCRP), cardiovascular disease (CVD) and nutritional status (subjective global assessment, SGA) were assessed at baseline in 822 patients: 523 incident dialysis patients, 212 prevalent hemodialysis (HD) and 87 prevalent peritoneal dialysis (PD) patients. Patients were divided into four groups according to hsCRP and S-Alb in each cohort: Group 1 -normal S-Alb and normal hsCRP (reference); Group 2 -low S-Alb and normal hsCRP; Group 3-normal S-Alb and high hsCRP; Group 4-low S-Alb and high hsCRP. Survival over 60 months was analyzed.In Cox analysis, Group 4 had an increased mortality risk (adjusted Hazard ratio (95% confidence interval): 1.62 (1.06-2.47); p = 0.02) whereas the augmented mortality risks for Groups 2 and 3 in univariate analyses were not significant after adjustments for age, gender, blood pressure, diabetes mellitus, smoking, SGA, renal function and renal replacement technique.Whereas mortality risk was increased in CKD stage 5 patients with low S-Alb and high CRP, it was not increased in patients with low S-Alb and normal CRP. Our observation suggests that inflammatory status should be taken into account when using S-albumin for risk assessment in CKD stage 5 patients.
Project description:Background and objectivesThe mechanisms underlying erythropoietin resistance are not fully understood. Carbamylation is a post-translational protein modification that can alter the function of proteins, such as erythropoietin. The hypothesis of this study is that carbamylation burden is independently associated with erythropoietin resistance.Design, setting, participants, & measurementsIn a nonconcurrent prospective cohort study of incident hemodialysis patients in the United States, carbamylated albumin, a surrogate of overall carbamylation burden, in 158 individuals at day 90 of dialysis initiation and erythropoietin resistance index (defined as average weekly erythropoietin dose [U] per kg body weight per hemoglobin [g/dl]) over the subsequent 90 days were measured. Linear regression was used to describe the relationship between carbamylated albumin and erythropoietin resistance index. Logistic regression characterized the relationship between erythropoietin resistance index, 1-year mortality, and carbamylation.ResultsThe median percent carbamylated albumin was 0.77% (interquartile range=0.58%-0.93%). Median erythropoietin resistance index was 18.7 units/kg per gram per deciliter (interquartile range=8.1-35.6 units/kg per gram per deciliter). Multivariable adjusted analysis showed that the highest quartile of carbamylated albumin was associated with a 72% higher erythropoietin resistance index compared with the lowest carbamylation quartile (P=0.01). Increasing erythropoietin resistance index was associated with a higher risk of death (odds ratio per unit increase in log-erythropoietin resistance index, 1.69; 95% confidence interval, 1.06 to 2.70). However, the association between erythropoietin resistance index and mortality was no longer statistically significant when carbamylation was included in the analysis (odds ratio, 1.44; 95% confidence interval, 0.87 to 2.37), with carbamylation showing the dominant association with death (odds ratio for high versus low carbamylation quartile, 4.53; 95% confidence interval, 1.20 to 17.10).ConclusionCarbamylation was associated with higher erythropoietin resistance index in incident dialysis patients and a better predictor of mortality than erythropoietin resistance index.
Project description:The incidence and prevalence of metabolic acidosis increase with declining kidney function. We studied the associations of both low and high serum bicarbonate levels with all-cause mortality among stage 3 and 4 chronic kidney disease (CKD) patients.We examined factors associated with low (<23 mmol/L) and high (>32 mmol/L) serum bicarbonate levels using logistic regression models and associations between bicarbonate and all-cause mortality using Cox-proportional hazard models, Kaplan-Meier survival curves, and time-dependent analysis.Out of 41,749 patients, 13.9% (n = 5796) had low and 1.6% (n = 652) had high serum bicarbonate levels. After adjusting for relevant covariates, there was a significant association between low serum bicarbonate and all-cause mortality (hazard ratio [HR] 1.23, 95% CI 1.16, 1.31). This association was not statistically significant among patients with stage 4 CKD and diabetes. The time-dependent analysis demonstrated a significant mortality risk associated with a decline from normal to low bicarbonate level (HR 1.59, 95% CI 1.49, 1.69). High serum bicarbonate levels were associated with death irrespective of the level of kidney function (HR 1.74, 95% CI 1.52, 2.00). When serum bicarbonate was examined as a continuous variable, a J-shaped relationship was noted between serum bicarbonate and mortality.Low serum bicarbonate levels are associated with increased mortality among stage 3 CKD patients and patients without diabetes. High serum bicarbonate levels are associated with mortality in both stage 3 and stage 4 CKD patients.