Risk of incident ESRD: a comprehensive look at cardiovascular risk factors and 17 years of follow-up in the Atherosclerosis Risk in Communities (ARIC) Study

Genetic association study of TERT gene variants with chronic kidney disease susceptibility in the Chinese population

The incidence and mortality of chronic kidney disease (CKD) are increasing globally. Studies have demonstrated the significance of genetic risk factors in the progression of CKD. Telomerase reverse transcriptase (TERT) may be implicated in the development of CKD. This study aimed to investigate the correlation between TERT gene variants and susceptibility to CKD in the Chinese population. A total of 507 patients with CKD and 510 healthy controls were recruited for this case-control study. Four candidate loci were identified using the MassARRAY platform. Logistic regression analysis was employed to assess the association between TERT gene variants and the risk of CKD. The false positive reporting probability (FPRP) method was utilized to evaluate the validity of statistically significant associations. The multifactorial dimensionality reduction (MDR) method was used to evaluate the interaction between SNPs and the risk of CKD. Furthermore, discrepancies in the clinical features of subjects with diverse genotypes were evaluated using one-way analysis of variance (ANOVA). Our findings revealed a correlation between rs2735940 and rs4635969 and an increased risk of CKD. Stratification analysis indicated that rs4635969 was related to an increased risk of CKD in different subgroups (age ≤ 50 years and male). MDR analysis indicated that the two-site model (rs2735940 and rs4635969) was the best prediction model. Furthermore, the rs2735940 GG genotype was found to be linked to an increased level of microalbuminuria (MAU) in patients with CKD. Our study is the first to reveal a connection between TERT gene variants and susceptibility to CKD, providing new insights into the field of nephrology.

Associations between the Serum Triglyceride Level and Kidney Outcome in Patients with Chronic Kidney Disease: The Fukuoka Kidney disease Registry Study

AIMS

Hypertriglyceridemia is a risk factor for chronic kidney disease (CKD). However, whether or not it predicts the risk of CKD progression is unknown. This study evaluated the association between serum triglyceride (TG) levels and kidney disease progression in patients with non-dialysis-dependent CKD.

METHODS

The Fukuoka Kidney disease Registry (FKR) study was a multicenter, prospective longitudinal cohort study. In total, 4,100 patients with CKD were followed up for 5 years. The primary outcome was the incidence of CKD progression, defined as a ≥ 1.5-fold increase in serum creatinine level or the development of end-stage kidney disease. The patients were divided into quartiles according to baseline serum TG levels under non-fasting conditions: Q1 ＜87 mg/dL; Q2, 87-120 mg/dL; Q3, 121-170 mg/dL, and Q4 ＞170 mg/dL.

RESULTS

During the 5-year observation period, 1,410 patients met the criteria for CKD progression. The multivariable-adjusted Cox proportional hazards model showed a significant association between high serum TG level and the risk of CKD progression in the model without macroalbuminuria as a covariate (multivariable hazard ratio[HR] for Q4 versus Q1, 1.20; 95% CI, 1.03-1.41; P=0.022), but the significance disappeared after adjusting for macroalbuminuria (HR for Q4 versus Q1, 1.06; 95% CI, 0.90-1.24; P=0.507).

CONCLUSIONS

The present findings suggest that individuals with high serum TG levels are more likely to develop CKD progression than those without; however, whether or not higher serum TG levels reflect elevated macroalbuminuria or lead to CKD progression via elevated macroalbuminuria is unclear.

Role of Age and Competing Risk of Death in the Racial Disparity of Kidney Failure Incidence after Onset of CKD

SIGNIFICANCE STATEMENT

Black adults in the United States have 2-4 times higher incidence of kidney failure than White adults. Yet, the reasons underlying this disparity remain poorly understood. Among 547,188 US veterans with new-onset CKD, according to a new race-free GFR equation, Black veterans had a 2.5-fold higher cumulative incidence of kidney failure, compared with White veterans, in any follow-up period from CKD onset. This disparity resulted from a combination of higher hazards of progression to kidney failure and lower hazards of competing-risk death in Black veterans. Both, in turn, were largely explained by the younger age at CKD onset in Black veterans, underscoring an urgent need to prevent early onset and slow progression of CKD in younger Black adults.

BACKGROUND

The Black adult population is well known to have higher incidence of kidney failure than their White counterpart in the United States, but the reasons underlying this disparity are unclear. We assessed the racial differences in kidney failure and death from onset of CKD on the basis of the race-free 2021 CKD Epidemiology Collaboration equation and examined the extent to which these differences could be explained by factors at the time of CKD onset.

METHODS

We analyzed a national cohort consisting of 547,188 US veterans (103,821 non-Hispanic Black and 443,367 non-Hispanic White), aged 18-85 years, with new-onset CKD between 2005 and 2016 who were followed through 10 years or May 2018 for incident kidney failure with replacement therapy (KFRT) and pre-KFRT death.

RESULTS

At CKD onset, Black veterans were, on average, 7.8 years younger than White veterans. In any time period from CKD onset, the cumulative incidence of KFRT was 2.5-fold higher for Black versus White veterans. Meanwhile, Black veterans had persistently >2-fold higher hazards of KFRT throughout follow-up (overall hazard ratio [95% confidence interval], 2.38 [2.31 to 2.45]) and conversely had 17%-48% decreased hazards of pre-KFRT death. These differences were reduced after accounting for the racial difference in age at CKD onset.

CONCLUSIONS

The 2.5-fold higher cumulative incidence of kidney failure in Black adults resulted from a combination of higher hazards of progression to kidney failure and lower hazards of the competing risk of death, both of which can be largely explained by the younger age at CKD onset in Black compared with White adults.

Joint modeling on serum creatinine and time to end stage of renal disease for chronic kidney disease patients under treatment at the University of Gondar Referral Hospital

Background and Aims

Chronic kidney disease (CKD) is a major health problem worldwide. The general objective of this study is to identify the joint factors of serum creatinine (SCr) and time to end stage of renal disease (ESRD) for CKD patients under treatment at University of Gondar Referral Hospital (UOGRH).

Methods

A retrospective cohort study was conducted. The collected information was secondary data type obtained from 311 CKD patient's medical charts in the UOGRH from September 2019 to January 2022 G.C. Joint modeling analysis contained a linear mixed model for SCr and the Cox-PH model for time to ESRD of CKD patients under treatment was used.

Result

From the total of 311 patients, 104 (33.4%) patients were developed the ESRD, while the other 207 (66.6%) were censored patients. In the longitudinal submodel, the variable sex, age, electrolyte, visit time, anemia, diabetes mellitus, chronic heart disease, hypertension, and hepatitis have a significant effect on the variable SCr. In survival process, anemia (HR = 2.53, p = < 0.001), diabetes mellitus (HR = 2.206, p = < 0.0047), chronic heart disease (HR = 2.83, p = < 0.0011), HIV (HR = 2.778, p = < 0.0045), hypertension (HR = 2.616, p = < 0.001), and hepatitis (HR = 4.4, p = < 0.0074) have a significant effect on the variable ESRD. On the basis of the result of the joint model, the variable anemia, diabetes mellitus, chronic heart disease, hypertension, and hepatitis were common significant factors.

Conclusion

The majority of patients 207 (66.6%) of CKD patients were censored. On the basis of the smaller information criteria value and the significance association value, the joint model better fits the data. In the joint model, the variable anemia, diabetes mellitus, chronic heart disease, hypertension, and hepatitis were common factors of two responses, and also concluded that the rate of progression of longitudinal measure SCr decreased over time.

Ambulatory blood pressure as risk factor for long-term kidney function decline in the general population: a distributional regression approach

The results of randomized controlled trials are unclear about the long-term effect of blood pressure (BP) on kidney function assessed as the glomerular filtration rate (GFR) in persons without chronic kidney disease or diabetes. The limited duration of follow-up and use of imprecise methods for assessing BP and GFR are important reasons why this issue has not been settled. Since a long-term randomized trial is unlikely, we investigated the association between 24-h ambulatory BP (ABP) and measured GFR in a cohort study with a median follow-up of 11 years. The Renal Iohexol Clearance Survey (RENIS) cohort is a representative sample of persons aged 50 to 62 years without baseline cardiovascular disease, diabetes, or kidney disease from the general population of Tromsø in northern Norway. ABP was measured at baseline, and iohexol clearance at baseline and twice during follow-up. The study population comprised 1589 persons with 4127 GFR measurements. Baseline ABP or office BP components were not associated with the GFR change rate in multivariable adjusted conventional regression models. In generalized additive models for location, scale, and shape (GAMLSS), higher daytime systolic, diastolic, and mean arterial ABP were associated with a slight shift of the central part of the GFR distribution toward lower GFR and with higher probability of GFR < 60 mL/min/1.73 m2 during follow-up (p < 0.05). The use of a distributional regression method and precise methods for measuring exposure and outcome were necessary to detect an unfavorable association between BP and GFR in this study of the general population.

CHA2DS2VASc score predicts risk of end stage renal disease in patients with atrial fibrillation: Long-term follow-up study

Background

End stage renal disease (ESRD) is an increasing worldwide epidemic disease. CHA2DS2-VASc score is a well-established predictor of cardiovascular outcome among atrial fibrillation (AF) patients.

Objective

The aim of this study was to test whether CHA2DS2-VASc score is a good predictor for incident ESRD events.

Methods

This is a retrospective cohort study (from January 2010 to December 2020) with median follow-up of 61.7 months. Clinical parameters and baseline characteristics were recorded. The endpoint was defined as ESRD with dialysis dependent.

Results

The study cohort comprised 29,341 participants. Their median age was 71.0 years, 43.2% were male, 21.5% had diabetes mellitus, 46.1% had hypertension, and mean CHA2DS2-VASc score was 2.89. CHA2DS2-VASc score was incrementally associated with the risk of ESRD status during follow-up. Using the univariate Cox model, we found a 26% increase in ESRD risk with an increase of one point in the CHA2DS2-VASc score (HR 1.26 [1.23-1.29], P < 0.001). And using the multi-variate Cox model adjusted by initial CKD stage, we still observed a 5.9% increase in risk of ESRD with a one-point increase in the CHA2DS2-VASc score (HR 1.059 [1.037-1.082], P < 0.001). The CHA2DS2-VASC score and the initial stage of CKD were associated with the risk of ESRD development in patients with AF.

Conclusions

Our results first confirmed the utility of CHA2DS2-VASC score in predicting progression to ESRD in AF patients. The efficiency is best in CKD stage 1.

Echocardiography-Based Cardiac Structure Parameters for the Long-term Risk of End-Stage Kidney Disease in Black Individuals: The Atherosclerosis Risk in Communities Study

OBJECTIVE

To assess whether echocardiographic parameters of left ventricular (LV) structure and function relate to the long-term risk of incident end-stage kidney disease (ESKD).

PATIENTS AND METHODS

We conducted a prospective cohort study analyzing 2137 Black participants from the Jackson site of the Atherosclerosis Risk in Communities Study from January 1, 1993, through July 31, 2017. Echocardiographic parameters of LV structure and function were obtained from 1993 to 1995. The primary outcome incident ESKD was identified through the linkage to the United States Renal Data System. Cox proportional hazards models were used to estimate the hazard ratios (HRs) according to each echocardiographic parameter.

RESULTS

There were 117 incident ESKD cases during a median follow-up of 22.2 (interquartile range, 15.0-23.3) years. Multivariable Cox models revealed that a higher LV mass index was significantly associated with the risk of ESKD (HR, 2.38; 95% CI, 1.21 to 4.68 for highest vs lowest quartile, P = 0.012). The HRs were significant and even higher for LV posterior wall thickness, with slightly higher HRs when their measures in end-systole (HR for highest vs lowest quartile, 4.38; 95% CI, 1.94 to 9.92, P < 0.001) vs end-diastole (HR, 3.50; 95% CI, 1.53 to 8.01, P = 0.003) were used. The associations were not significant for LV function parameters.

CONCLUSION

In Black individuals residing in the community, echocardiographic parameters of LV structure, including LV wall thickness, were robustly associated with the risk of subsequently incident ESKD. These results have potential implications for novel prevention and management strategies for persons with abnormal LV structure.

Etiology of Persistent Microalbuminuria in Nigeria (P_MICRO study): protocol and study design

BACKGROUND

Microalbuminuria is an independent risk factor for cardiovascular and kidney disease and a predictor of end organ damage, both in the general population and in persons with HIV (PWH). Microalbuminuria is also an important risk factor for mortality in PWH treated with antiretroviral therapy (ART). In the ongoing Renal Risk Reduction (R3) study in Nigeria, we identified a high prevalence of microalbuminuria confirmed by two measurements 4-8 weeks apart in ART-experienced, virologically suppressed PWH. Although Stage 1 or 2 hypertension and exposure to potentially nephrotoxic antiretroviral medications were common in R3 participants, other traditional risk factors for albuminuria and kidney disease, including diabetes, APOL1 high-risk genotype, and smoking were rare. Co-infection with endemic pathogens may also be significant contributors to albuminuria, but co-infections were not evaluated in the R3 study population.

METHODS

In Aim 1, we will cross-sectionally compare the prevalence of albuminuria and established kidney disease risk factors in a cohort of PWH to age- and sex-matched HIV-negative adults presenting for routine care at the Aminu Kano Teaching Hospital in Kano, Nigeria. We will leverage stored specimens from 2500 R3 participants and enroll an additional 500 PLWH recently initiated on ART (≤ 24 months) and 750 age- and sex-matched HIV-negative adults to determine the contribution of HIV, hypertension, and other comorbid medical conditions to prevalent albuminuria. In Aim 2, we will follow a cohort of 1000 HIV-positive, ART-treated and 500 HIV-negative normoalbuminuric adults for 30 months to evaluate the incidence and predictors of albuminuria.

DISCUSSION

The findings from this study will support the development of interventions to prevent or address microalbuminuria in PWH to reduce kidney and cardiovascular morbidity and mortality. Such interventions might include more intensive monitoring and treatment of traditional risk factors, the provision of renin-angiotensin aldosterone system or sodium-glucose cotransporter-2 inhibitors, consideration of changes in ART regimen, and screening and treatment for relevant co-infections.

Developing and validating a prognostic prediction model for patients with chronic kidney disease stages 3-5 based on disease conditions and intervention methods: a retrospective cohort study in China

OBJECTIVES

To develop and validate a nomogram model to predict chronic kidney disease (CKD) stages 3-5 prognosis.

DESIGN

A retrospective cohort study. We used univariate and multivariate Cox regression analysis to select the relevant predictors. To select the best model, we evaluated the prediction models' accuracy by concordance index (C-index), calibration curve, net reclassification index (NRI) and integrated discrimination improvement (IDI). We evaluated the clinical utility by decision curve analysis.

SETTING

Chronic Disease Management (CDM) Clinic in the Nephrology Department at the Guangdong Provincial Hospital of Chinese Medicine.

PARTICIPANTS

Patients with CKD stages 3-5 in the derivation and validation cohorts were 459 and 326, respectively.

PRIMARY OUTCOME MEASURE

Renal replacement therapy (haemodialysis, peritoneal dialysis, renal transplantation) or death.

RESULTS

We built four models. Age, estimated glomerular filtration rate and urine protein constituted the most basic model A. Haemoglobin, serum uric acid, cardiovascular disease, primary disease, CDM adherence and predictors in model A constituted model B. Oral medications and predictors in model A constituted model C. All the predictors constituted model D. Model B performed well in both discrimination and calibration (C-index: derivation cohort: 0.881, validation cohort: 0.886). Compared with model A, model B showed significant improvement in the net reclassification and integrated discrimination (model A vs model B: NRI: 1 year: 0.339 (-0.011 to 0.672) and 2 years: 0.314 (0.079 to 0.574); IDI: 1 year: 0.066 (0.010 to 0.127), p<0.001 and 2 years: 0.063 (0.008 to 0.106), p<0.001). There was no significant improvement between NRI and IDI among models B, C and D. Therefore, we selected model B as the optimal model.

CONCLUSIONS

We constructed a prediction model to predict the prognosis of patients with CKD stages 3-5 in the first and second year. Applying this model to clinical practice may guide clinical decision-making. Also, this model needs to be externally validated in the future.

TRIAL REGISTRATION NUMBER

ChiCTR1900024633 (http://www.chictr.org.cn).

Association of Serum Triglycerides and Renal Outcomes among 1.6 Million US Veterans

Background

Previous studies have suggested that metabolic syndrome (MetS) components are associated with renal outcomes, defined as a decline in kidney function or reaching end-stage renal disease (ESRD). Elevated triglycerides (TGs) are a component of MetS that have been reported to be associated with renal outcomes. However, the association of TGs with renal outcomes in chronic kidney disease (CKD) patients independent of the other components of the MetS remains understudied.

Methods

We examined 1,657,387 patients with data on TGs and other components of MetS in 2004–2006 and followed up until 2014. Patients with ESRD on renal replacement therapy were excluded. We examined time to ESRD, estimated glomerular filtration rate (eGFR) slope (renal function decline), and time to incident CKD (eGFR <60 mL/min/1.73 m²) among baseline normal kidney function (non-CKD) patients, using Cox or logistic regression, adjusted for clinical characteristics and MetS components. We also stratified analyses by the number of MetS components.

Results

The cohort was on average 64 years old and comprised 5% females, 15% African Americans, and 24% with nondialysis-dependent CKD. Among non-CKD patients, the adjusted relationship of TGs with time to incident CKD was strong and linear. Compared to TGs 120–<160 mg/dL, higher TGs were associated with a faster renal function decline across all CKD stages. Elevated TGs ≥240 mg/dL were associated with a faster time to ESRD among non-CKD and CKD stages 3A–3B, while the risk gradually declined to null or lower in CKD stages 4–5. Models were robust after MetS component adjustment and stratification.

Conclusion

Independent of MetS components, high TGs levels were associated with a higher incidence of CKD and a faster renal function decline, yet showed no or inverse associations with time to ESRD in CKD stages 4–5. Examining the effects of TGs-lowering interventions on incident CKD and kidney preserving therapy warrants further studies including clinical trials.

Association of Blood Pressure Genetic Risk Score with Cardiovascular Disease and CKD Progression: Findings from the CRIC Study

Background

In the general population, genetic risk for high BP has been associated with cardiovascular disease, but not kidney function or incident CKD. These relationships have not been studied longitudinally in participants with CKD. We examined whether BP genetic risk predicts cardiovascular disease and kidney disease progression in patients with CKD.

Methods

We included 1493 African- and 1581 European-ancestry participants from the Chronic Renal Insufficiency Cohort who were followed for 12 years. We examined associations of BP genetic risk scores with development of cardiovascular disease (myocardial infarction, congestive heart failure, or stroke) and CKD progression (incident ESKD or halving of eGFR) using Cox proportional hazards models. Analyses were stratified by race and included adjustment for age, sex, study site, and ancestry principal components.

Results

Among European-ancestry participants, each SD increase in systolic BP and pulse pressure genetic risk score conferred a 15% (95% CI, 4% to 27%) and 11% (95% CI, 1% to 23%), respectively, higher risk of cardiovascular disease, with a similar, marginally significant trend for diastolic BP. Among African-ancestry participants, each SD increase in systolic and diastolic BP genetic risk score conferred a 10% (95% CI, 1% to 20%) and 9% (95% CI, 0% to 18%), respectively, higher risk of cardiovascular disease. Higher genetic risk was not associated with CKD progression.

Conclusions

Genetic risk for elevation in BP was associated with increased risk of cardiovascular disease, but not CKD progression.

Modifiable Lifestyle Factors for Primary Prevention of CKD: A Systematic Review and Meta-Analysis

BACKGROUND

Despite increasing incidence of CKD, no evidence-based lifestyle recommendations for CKD primary prevention apparently exist.

METHODS

To evaluate the consistency of evidence associating modifiable lifestyle factors and CKD incidence, we searched MEDLINE, Embase, CINAHL, and references from eligible studies from database inception through June 2019. We included cohort studies of adults without CKD at baseline that reported lifestyle exposures (diet, physical activity, alcohol consumption, and tobacco smoking). The primary outcome was incident CKD (eGFR<60 ml/min per 1.73 m²). Secondary outcomes included other CKD surrogate measures (RRT, GFR decline, and albuminuria).

RESULTS

We identified 104 studies of 2,755,719 participants with generally a low risk of bias. Higher dietary potassium intake associated with significantly decreased odds of CKD (odds ratio [OR], 0.78; 95% confidence interval [95% CI], 0.65 to 0.94), as did higher vegetable intake (OR, 0.79; 95% CI, 0.70 to 0.90); higher salt intake associated with significantly increased odds of CKD (OR, 1.21; 95% CI, 1.06 to 1.38). Being physically active versus sedentary associated with lower odds of CKD (OR, 0.82; 95% CI, 0.69 to 0.98). Current and former smokers had significantly increased odds of CKD compared with never smokers (OR, 1.18; 95% CI, 1.10 to 1.27). Compared with no consumption, moderate consumption of alcohol associated with reduced risk of CKD (relative risk, 0.86; 95% CI, 0.79 to 0.93). These associations were consistent, but evidence was predominantly of low to very low certainty. Results for secondary outcomes were consistent with the primary finding.

CONCLUSIONS

These findings identify modifiable lifestyle factors that consistently predict the incidence of CKD in the community and may inform both public health recommendations and clinical practice.

When ESKD complicates the management of diabetes mellitus

Given the increased incidence and prevalence of ESKD (end-stage kidney disease) attributed to diabetes mellitus, it is important to consider the physiological and global sociodemographic factors that give rise to unique challenges in providing excellent care to this population. The individual with diabetes and ESKD faces alterations of glucose homeostasis that require close therapeutic attention, as well as the consideration of safe and effective means of maintaining glycemic control. Implementation of routine monitoring of blood glucose and thoughtful alteration of the individual's hypoglycemic drug regimen must be employed to reduce the risk of neurological, cardiovascular, and diabetes-specific complications that may arise as a result of ESKD. Titration of insulin therapy may become quite challenging, as kidney replacement therapy often significantly impacts insulin requirements. New medications have significantly improved the ability of the clinician to provide effective therapies for the management of diabetes, but have also raised an equal amount of uncertainty with respect to their safety and efficacy in the ESKD population. Additionally, the clinician must consider the challenges related to the delivery of kidney replacement therapy, and how inter-modality differences may impact glycemic control, diabetes, and ESKD-related complications, and issues surrounding dialysis vascular access creation.

Rate of kidney function decline and factors predicting progression of kidney disease in type 2 diabetes mellitus patients with reduced kidney function: A nationwide retrospective cohort study

Currently, the data on independent risk factors for the progression of kidney disease in type 2 diabetes mellitus (T2DM) patients with CKD are limited. This study aimed to investigate CKD progression in T2DM patients who have reduced kidney function with baseline estimated glomerular filtration rate (eGFRs) between 15 and 59 mL/min/1.73 m² . This study was composed of a nationwide retrospective cohort of adult T2DM patients from 831 public hospitals in Thailand during the year 2015. T2DM patients with CKD stages 3 and 4 were followed up, until development of CKD stage 5, requirement of chronic dialysis, loss to follow-up, death, or 31 May 2018, whichever came first. Cox proportional hazard regression was utilized for analysis. A total of 8464 participants were included; 30.4% were male. The mean age was 69 ± 10 years. The mean eGFR was 45 ± 11 mL/min/1.73 m² . The incidence of CKD stage 5 or the need for chronic dialysis was 16.4 per 1000 person-years. The annual rate of eGFR decline during a mean follow-up of 29 months was -2.3 mL/min/1.73 m² ; 14.4% had a rapid decline in eGFR. The risk factors associated with progression to CKD stage 5 or the need for chronic dialysis were diabetes duration, systolic blood pressure, serum uric acid, albuminuria, and baseline eGFR. Conversely, older age and the use of renin-angiotensin aldosterone system blockade were associated with decreased risks for rapid CKD progression and incidence CKD stage 5 or dialysis. This study identifies multiple predictive risk factors that support a multifaceted approach to prevent progression of advanced CKD.

Smoking and risk of incident end-stage kidney disease in general population: A Nationwide Population-based Cohort Study from Korea

We analyzed data from the Korean National Health Insurance Service (NHIS) to investigate whether smoking increases the risk of end-stage kidney disease (ESKD). This retrospective nationwide population-based cohort study included the data of 23,232,091 participants who underwent at least one health examination between 2009 and 2012. Smoking status was recorded at baseline. The incidence of ESKD was identified via ICD-10 codes and special medical aid codes from the Korean National Health Insurance Service database till December 2016. A Cox proportional-hazards model with multivariable adjustment was used to evaluate the association between smoking and ESKD incidence. Overall, 24.6% of participants were current smokers; 13.5% and 61.9%, were ex- and non-smokers, respectively. Overall, 45,143 cases of ESKD developed during the follow-up period. Current smokers (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.35-1.43) and ex-smokers (HR, 1.09; 95% CI, 1.06-1.12) demonstrated a significant increase in the adjusted risk of ESKD compared to non-smokers. The risk of ESKD was directly proportional to the smoking duration, number of cigarettes smoked daily, and pack-years. In conclusion, smoking is associated with a greater risk of ESKD in the general Korean population; the risk increases with an increase in the smoking duration, number of cigarettes smoked daily, and pack-years.

Racial disparities in end-stage renal disease in a high-risk population: the Southern Community Cohort Study

INTRODUCTION

The Southern Community Cohort Study is a prospective study of low socioeconomic status (SES) blacks and whites from the southeastern US, where the burden of end-stage renal disease (ESRD) and its risk factors are high. We tested whether the 2.4-fold elevated risk of ESRD we previously observed in blacks compared to whites was explained by differences in baseline kidney function.

METHODS

We conducted a case-cohort study of incident ESRD cases (n = 737) with stored blood and a probability sampled subcohort (n = 4238) and calculated estimated glomerular filtration rate (eGFR) from serum creatinine. 86% of participants were enrolled from community health centers in medically underserved areas and 14% from the general population in 12 states in the southeastern United States. Incident ESRD after entry into the cohort was ascertained by linkage of the cohort with the US Renal Data System (USRDS).

RESULTS

Median (25th, 75th percentile) eGFR at baseline was 63.3 (36.0, 98.2) ml/min/1.73m2 for ESRD cases and 103.2 (86.0, 117.9) for subcohort. Black ESRD cases had higher median (25th, 75th) eGFR [63.3 (35.9, 95.9)] compared to whites [59.1 (39.4, 99.2)]. In multivariable Cox models accounting for sampling weights, baseline eGFR was a strong predictor of ESRD risk, and an interaction with race was detected (P = 0.029). The higher ESRD risk among blacks relative to whites persisted (hazard ratio: 2.58; 95% confidence interval: 1.65, 4.03) after adjustment for eGFR.

CONCLUSION

In this predominantly lower SES cohort, the racial disparity in ESRD risk is not explained by differences in baseline kidney function.

Influence of Sex on the Progression of Chronic Kidney Disease

The role that sex plays in the development and progression of chronic kidney disease remains a subject of controversy. The lack of clarity in this important area reflects complex interactions between biological factors and cultural and socioeconomic influences that impact the relationship between sex and renal disease. Certainly, additional observational studies are indicated; however, innovative approaches are required to isolate biological processes from cultural influences. Despite these limitations, available data suggest that the progression of renal disease is slower in women than in men and that this sexual dimorphism is primarily due to direct actions of sex hormones on cellular metabolism. The extent to which differences in lifestyle factors between the sexes influence sexual dimorphism in the progression of chronic kidney disease remains to be elucidated.

Incremental hemodialysis, a valuable option for the frail elderly patient

Management of older people on dialysis requires focus on the wider aspects of aging as well as dialysis. Recognition and assessment of frailty is vital in changing our approach in elderly patients. Current guidelines in dialysis have a limited evidence base across all age group, but particularly the elderly. We need to focus on new priorities of care when we design guidelines "for people not diseases". Patient-centered goal-directed therapy, arising from shared decision-making between physician and patient, should allow adaption of the dialysis regime. Hemodialysis (HD) in the older age group can be complicated by intradialytic hypotension, prolonged time to recovery, and access-related problems. There is increasing evidence relating to the harm associated with the delivery of standard thrice-weekly HD. Incremental HD has a lower burden of treatment. There appears to be no adverse clinical effects during the first years of dialysis in presence of a significant residual kidney function. The advantages of incremental HD might be particularly important for elderly patients with short life expectancy. There is a need for more research into specific topics such as the assessment of the course of frailty with progression of chronic kidney disease and after dialysis initiation, the choice of dialysis modality impacting on the trajectory of frailty, the timing of dialysis initiation impacting on frailty or on other outcomes. In conclusion, understanding each individual's goals of care in the context of his or her life experience is particularly important in the elderly, when overall life expectancy is relatively short, and life experience or quality of life may be the priority.

Increased carotid intima-media thickness in African American pediatric kidney transplant recipients

Early signs of subclinical CV dysfunction can be detected by ultrasound for CIMT. Although A-A are at high risk for CV disease, CIMT of A-A kidney transplant recipients has not been previously investigated. The aim of this prospective, controlled, longitudinal study was to investigate determinants of CIMT in a multiracial pediatric kidney transplant population, with a focus on A-A. Transplant recipients (n = 42) had BMI, waist-to-height ratio, fasting glucose, lipid panel, HbA1c%, and CIMT measured at 1, 18, and 30 months post-transplant. Twenty-four healthy children (14 A-A) served as controls. CIMT of A-A transplant (0.49, 0.49, and 0.48 mm) was higher than non-AA transplant (0.43, 0.44, and 0.44 mm) at 1, 18, and 30 months and higher than A-A controls (0.47 mm). Hyperparathyroidism prior to transplant predicted high CIMT-for-race. A-A race was associated with 10% higher CIMT vs non-A-A transplant. Metabolic syndrome was associated with 0.03 ± 0.01 mm increase in CIMT among A-A transplant recipients only. In conclusion, A-A kidney transplant recipients have increased CIMT. Metabolic syndrome disproportionately affects CIMT of A-A children post-transplant. Identification of subclinical CV damage, detected by CIMT, may provide an opportunity for early detection of CV risk in this vulnerable population.

Marijuana Use and Renal Function Among US Adults

BACKGROUND

In recent years, the number of states that have legalized medical marijuana or retail sales has increased, bringing potential changes of marijuana use pattern among the general population. However, health effects of acute and chronic marijuana use on many relevant health outcomes, including renal function, remain largely unexamined. In this study, we aimed to assess the association between recent and past marijuana use and renal function.

METHODS

We conducted a cross-sectional study among 13,995 US adults aged 18 to 59 years in the National Health and Nutrition Examination Survey from 2007 to 2014. We examined associations between marijuana use and serum creatinine concentration, estimated glomerular filtration rate (eGFR), and odds of having stage 2 or greater chronic kidney disease using weighted multivariable linear regression.

RESULTS

In the study population, 6483 were never users, 5499 were past users, and 2013 were current users. Marijuana use did not have a significant association with serum creatinine, eGFR, or odds of having stage 2 or greater chronic kidney disease. Serum creatinine and eGFR had an increasing trend comparing past and current users with never users that did not reach statistical significance. All associations remained unchanged in the sensitivity analysis restricted to people without cardiovascular disease.

CONCLUSIONS

We did not observe any clinically significant association between current or past self-reported marijuana use and measures of kidney function.

Metabolically Healthy Obesity and Risk of Kidney Function Decline

OBJECTIVE

The aim of this study was to examine the association between BMI categories, stratified by metabolic health status, and the risk of kidney function decline (KFD).

METHODS

In this study, 42,128 adult patients with a stable BMI were classified over a 3-year baseline window by BMI and metabolic health status (assessed by Adult Treatment Panel-III criteria). KFD was defined as an estimated glomerular filtration rate (eGFR) decline ≥ 30%, eGFR < 15 mL/min/1.73 m² , or receipt of dialysis and/or transplant.

RESULTS

Over a median of 5.1 years (interquartile range 2.1-8.9), 6,533 (15.5%) individuals developed KFD. Compared with the normal weight, metabolically healthy category, metabolically healthy obesity was associated with a higher risk of KFD (adjusted hazard ratio [aHR] 1.52; 95% CI: 1.22-1.89). aHRs for KFD were 1.17 (95% CI: 0.89-1.53), 2.21 (95% CI: 1.59-3.08), and 2.20 (95% CI: 1.55-3.11) for metabolically healthy obesity with BMI 30 to 34.9, BMI 35 to 39.9, and BMI ≥ 40 kg/m² . These associations were consistent among men and women, patients with eGFR ≥ or < 90 mL/min/1.73 m² , and age ≥ or < 55 years. The risk of KFD was highest among metabolically unhealthy individuals with BMI ≥ 40 (aHR 4.02; 95% CI: 3.40-4.75 vs. metabolically healthy individuals with normal weight).

CONCLUSIONS

Obesity, whether in the presence or absence of metabolic health, is a risk factor for KFD.

Decreased DACH1 expression in glomerulopathy is associated with disease progression and severity

Cell fate determination factor dachshund1 (DACH1) is a chromosome-associated protein that regulates cellular differentiation throughout development. Recent genome-wide association studies have show that missense mutation in DACH1 leads to hereditary renal hypodysplasia. Renal DACH1 expression can be used to estimate glomerular filtration rate (eGFR). We firstly characterized the function of DACH1 in normal and diseased renal tissue using immunohistochemistry to assess DACH1 in human renal biopsy specimens from 40 immunoglobulin A nephropathy (IgAN) patients, 20 idiopathic membranous nephropathy (IMN) patients, and 15 minimal change disease (MCD) patients. We found that DACH1 expression was decreased in the nephropathy group relative to healthy controls. DACH1 staining in the glomerulus correlated positively with eGFR (r = 0.41, p < 0.001) but negatively with serum creatinine (r = −0.37, p < 0.01). In vitro, DACH1 overexpression in human podocytes or HK2 cells decreased expression of cyclin D1, but increased expression of p21 and p53, which suggested that DACH1 overexpression in human podocytes or HK2 cells increased the G1/S phase or G2/M cell arrest. Together, These findings indicate that DACH1 expression is decreased in glomerulopathy imply a potential role for DACH1 in the this development of human chornic glomerulopathy. These data suggest that DACH1 is a potential a marker of disease progression and severity for glomerular diseases.

Cardiovascular effects of metabolic syndrome after transplantation: convergence of obesity and transplant-related factors

Children are at increased risk of developing metabolic syndrome (MS) after kidney transplantation, which contributes to long-term cardiovascular (CV) morbidities and decline in allograft function. While MS in the general population occurs due to excess caloric intake and physical inactivity, additional chronic kidney disease and transplant-related factors contribute to the development of MS in transplant recipients. Despite its significant health consequences, the interplay of the individual components in CV morbidity in pediatric transplant recipients is not well understood. Additionally, the optimal methods to detect early CV dysfunction are not well defined in this unique population. The quest to establish clear guidelines for diagnosis is further complicated by genetic differences among ethnic groups that necessitate the development of race-specific criteria, particularly with regard to individuals of African descent who carry the apolipoprotein L1 variant. In children, since major CV events are rare and traditional echocardiographic measures of systolic function, such as ejection fraction, are typically well preserved, the presence of CV disease often goes undetected in the early stages. Recently, new noninvasive imaging techniques have become available that offer the opportunity for early detection. Carotid intima-media thickness and impaired myocardial strain detected by speckle tracking echocardiography or cardiac magnetic resonance are emerging as early and sensitive markers of subclinical CV dysfunction. These highly sensitive tools may offer the opportunity to elucidate subtle CV effects of MS in children after transplantation. Current knowledge and future directions are explored in this review.

Incidence of chronic kidney disease among people with diabetes: a systematic review of observational studies

AIMS

The aim was to systematically review published articles that reported the incidence of chronic kidney disease among people with diabetes.

METHODS

A systematic literature search was performed using MEDLINE, Embase and CINAHL databases. The titles and abstracts of all publications identified by the search were reviewed and 10 047 studies were retrieved.

RESULTS

A total of 71 studies from 30 different countries with sample sizes ranging from 505 to 211 132 met the inclusion criteria. The annual incidence of microalbuminuria and albuminuria ranged from 1.3% to 3.8% for Type 1 diabetes. For Type 2 diabetes and studies combining both diabetes types, the range was from 3.8% to 12.7%, with four of six studies reporting annual rates between 7.4% and 8.6%. In studies reporting the incidence of eGFR < 60 ml/min/1.73 m² using the Modification of Diet on Renal Disease (MDRD) equation, apart from one study which reported an annual incidence of 8.9%, the annual incidence ranged from 1.9% to 4.3%. The annual incidence of end-stage renal disease ranged from 0.04% to 1.8%.

CONCLUSIONS

The annual incidence of microalbuminuria and albuminuria is ~ 2-3% in Type 1 diabetes, and ~ 8% in Type 2 diabetes or mixed diabetes type. The incidence of developing eGFR < 60 ml/min/1.73 m² is ~ 2-4% per year. Despite the wide variation in methods and study design, within a particular category of kidney disease, there was only modest variation in incidence rates. These findings may be useful in clinical settings to help understand the risk of developing kidney disease among those with diabetes.

Blood pressure and age-related GFR decline in the general population

BACKGROUND

Hypertension is one of the most important causes of end-stage renal disease, but it is unclear whether elevated blood pressure (BP) also accelerates the gradual decline in the glomerular filtration rate (GFR) seen in the general population with increasing age. The reason may be that most studies have considered only baseline BP and not the effects of changes in BP, antihypertensive treatment and other determinants of GFR during follow-up. Additionally, the use of GFR estimated from creatinine or cystatin C instead of measurements of GFR may have biased the results because of influence from non-GFR related confounders. We studied the relationship between BP and GFR decline using time-varying variables in a cohort representative of the general population using measurements of GFR as iohexol clearance.

METHODS

We included 1594 subjects aged 50 to 62 years without baseline diabetes, kidney-, or cardiovascular disease in the Renal Iohexol-clearance Survey in Tromsø 6 (RENIS-T6). GFR, BP, antihypertensive medication and all adjustment variables were ascertained at baseline, and at follow-up after a median observation time of 5.6 years in 1299 persons (81%). The relationship between GFR decline and BP was analyzed in linear mixed models.

RESULTS

The mean (standard deviation) GFR decline rate was 0.95 (2.23) mL/min/year. The percentage of persons with hypertension (systolic BP ≥ 140 mmHg, diastolic BP ≥ 90 mmHg or antihypertensive medication) increased from 42 to 52% between baseline and follow-up. In multivariable adjusted linear mixed models using time-varying independent variables measured at baseline and follow-up, higher systolic and diastolic BP were associated with slower GFR decline rates by 0.10 and 0.20 mL/min/year/10 mmHg, respectively (p < 0.05). The association was stronger in persons on antihypertensive medication than in others (p < 0.05 for the interaction between BP and antihypertensive medication).

CONCLUSIONS

In the medium-term, elevated BP is not associated with accelerated GFR decline in the general middle-aged population. In persons using antihypertensive medication, elevated BP is associated with a paradoxical slower GFR decline. Studies with even longer observation periods are needed to evaluate the ultimate effect of BP on kidney function.

Increased Apoptosis in the Paraventricular Nucleus Mediated by AT1R/Ras/ERK1/2 Signaling Results in Sympathetic Hyperactivity and Renovascular Hypertension in Rats after Kidney Injury

Background: The central nervous system plays a vital role in the development of hypertension, but the molecular regulatory mechanisms are not fully understood. This study aimed to explore signaling in the paraventricular nucleus (PVN) which might contribute to renal hypertension.

Methods: Renal hypertension model was established by five-sixth nephrectomy operation (5/6Nx) in male Sprague Dawley rats. Ten weeks afterwards, they were random assigned to no treatment, or intracerebroventricular injection (ICV) with artificial cerebrospinal fluid, losartan [angiotensin II receptor type 1 (AT1R) antagonist], farnesylthiosalicylic acid (Ras inhibitor), PD98059 (MEK inhibitor), or SB203580 (p38 inhibitor) and Z-DEVD-FMK (caspase-3 inhibitor). Before and after treatment, physiological and biochemical indices were measured. Immunohistochemistry, western blot and RT-PCR were applied to quantify key components of renin-angiotensin system, apoptosis-related proteins, Ras-GTP, and MAPKs in the PVN samples. TUNEL assay was used to measure the situ apoptosis in PVN.

Results: The 5/6Nx rats showed significantly elevated systolic blood pressure, urinary protein excretion, serum creatinine, and plasma norepinephrine (p < 0.05) compared to sham rats. The expression of angiotensinogen, Ang II, AT1R, p-ERK1/2, or apoptosis-promoting protein Bax were 1.08-, 2.10-, 0.74-, 0.82-, 0.83-fold higher in the PVN of 5/6Nx rats, than that of sham rats, as indicated by immunohistochemistry. Western blot confirmed the increased levels of AT1R, p-ERK1/2 and Bax; meanwhile, Ras-GTP and p-p38 were also found higher in the PVN of 5/6Nx rats, as well as the apoptosis marker cleaved caspase-3 and TUNEL staining. In 5/6Nx rats, ICV infusion of AT1R antagonist, Ras inhibitor, MEK inhibitor or caspase-3 inhibitor could lower systolic blood pressure (20.8-, 20.8-, 18.9-, 14.3%-fold) together with plasma norepinephrine (53.9-, 57.8-,63.3-, 52.3%-fold). Western blot revealed that blocking the signaling of AT1R, Ras, or MEK/ERK1/2 would significantly reduce PVN apoptosis as indicated by changes of apoptosis-related proteins (p < 0.05). AT1R inhibition would cause reduction in Ras-GTP and p-ERK1/2, but not vice versa; such intervention with corresponding inhibitors also suggested the unidirectional regulation of Ras to ERK1/2.

Conclusion: These findings demonstrated that the activation of renin-angiotensin system in PVN could induce apoptosis through Ras/ERK1/2 pathway, which then led to increased sympathetic nerve activity and renal hypertension in 5/6Nx rats.

Ideal cardiovascular health score and incident end-stage renal disease in a community-based longitudinal cohort study: the Kailuan Study

OBJECTIVES

To investigate an association between ideal cardiovascular health metrics (CVH) and the risk of developing end-stage renal disease (ESRD).

SETTING

Community of Kailuan in Tangshan/China.

PARTICIPANTS

We examined in a community-based longitudinal cohort study 91 443 participants without history of stroke or myocardial infarction at baseline in 2006-2007, with a glomerular filtration rate (GFR) ≥15 mL/min at baseline, and who participated in at least 1 of 3 follow-up examinations in 2008-2009, 2010-2011 and 2012-2013.

INTERVENTIONS

CVH was measured by 7 key health factors (smoking, body mass index, physical activity, healthy dietary score, total cholesterol blood concentration, blood pressure, fasting blood glucose) each of which ranged between 'ideal' (2) and 'poor' (0). With a maximal CVH score of 14, the study participants were divided into categories of <5, 5-9 and 10-14 points.

PRIMARY AND SECONDARY OUTCOME MEASURES

CHV, incidence of ESRD.

RESULTS

Incidence of ESRD ranged from 7.06‰ in the lowest CVH category to 2.34‰ in the highest CVH category. After adjusting for age, sex, educational level, income, alcohol consumption and GFR, the lowest CVH category as compared with the highest CVH category had a significantly higher risk of incident ESRD (adjusted HR 2.87; 95% CI 1.53 to 5.39). For every decrease in group number of the cum-CVH score, the risk of ESRD increased by 20% (HR 1.20; 95% CI 1.13 to 1.28). The effect was consistent across sex and all age groups.

CONCLUSIONS

A low CVH score significantly increased the risk of incident ESRD. Risk factors for cardiovascular events may also be associated with an increased risk for kidney failure.

Relationship of proximal tubular injury to chronic kidney disease as assessed by urinary kidney injury molecule-1 in five cohort studies

BACKGROUND

The primary biomarkers used to define CKD are serum creatinine and albuminuria. These biomarkers have directed focus on the filtration and barrier functions of the kidney glomerulus even though albuminuria results from tubule dysfunction as well. Given that proximal tubules make up ∼90% of kidney cortical mass, we evaluated whether a sensitive and specific marker of proximal tubule injury, urinary kidney injury molecule-1 (KIM-1), is elevated in individuals with CKD or with risk factors for CKD.

METHODS

We measured urinary KIM-1 in participants of five cohort studies from the USA and Sweden. Participants had a wide range of kidney function and were racially and ethnically diverse. Multivariable linear regression models were used to test the association of urinary KIM-1 with demographic, clinical and laboratory values.

RESULTS

In pooled, multivariable-adjusted analyses, log-transformed, creatinine-normalized urinary KIM-1 levels were higher in those with lower eGFR {β = -0.03 per 10 mL/min/1.73 m(2) [95% confidence interval (CI) -0.05 to -0.02]} and greater albuminuria [β = 0.16 per unit of log albumin:creatinine ratio (95% CI 0.15-0.17)]. Urinary KIM-1 levels were higher in current smokers, lower in blacks than nonblacks and lower in users versus nonusers of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers.

CONCLUSION

Proximal tubule injury appears to be an integral and measurable element of multiple stages of CKD.

Smoking patterns and chronic kidney disease in US Hispanics: Hispanic Community Health Study/Study of Latinos

BACKGROUND

Intermittent smoking is prevalent among Hispanics, but little is known about whether this smoking pattern associates with increased chronic kidney disease (CKD) risk in this population. The objective of the present study is to identify patterns of exposure associated with CKD in US Hispanics.

METHODS

We used cross-sectional data on 15 410 participants of the Hispanics Community Health Study/the Study of Latinos, a population-based study of individuals aged 18-74 years, recruited in 2008 to 2011 from four US field centers (Bronx, NY; Chicago, IL; Miami, FL; San Diego, CA). Smoking exposure was obtained through a questionnaire. CKD was defined by an estimated glomerular filtration rate of <60 mL/min/1.73 m(2) or a urine albumin-to-creatinine ratio of ≥30 mg/g.

RESULTS

Approximately 14% of individuals were daily and 7% were intermittent smokers, and 16% were past smokers. There was a significant interaction between smoking status and pack-years of exposure (P = 0.0003). In adjusted models, there was an increased odds of CKD among daily, intermittent and past smokers by pack-years compared with never smokers. The association of intermittent smokers was significant at 10 pack-years [odds ratio (OR) = 1.38, 95% confidence intervals (CI) 1.06, 1.81], whereas for daily smokers this association was observed at 40 pack-years (OR = 1.43, 95% CI 1.09, 1.89).

CONCLUSIONS

Our findings of increased risk of CKD among Hispanics who are intermittent smokers support screening and smoking cessation interventions targeted to this population for the prevention of CKD. It also suggests novel mechanistic pathways for kidney toxicity that should be further explored in future studies.

Troponin T as a Predictor of End-Stage Renal Disease and All-Cause Death in African Americans and Whites From Hypertensive Families

OBJECTIVE

To evaluate cardiac troponin T (cTnT) as a predictor of end-stage renal disease (ESRD) and death in a cohort of African American and white community-dwelling adults with hypertensive families.

PATIENTS AND METHODS

A total of 3050 participants (whites from Rochester, Minnesota; African Americans from Jackson, Mississippi) of the Genetic Epidemiology Network of Arteriopathy study were followed from baseline examination (June 1, 1996, through August 31, 2000) through January 22, 2010. Cox proportional hazards regression models were used to examine the association of cTnT with ESRD and death after adjusting for traditional risk factors.

RESULTS

Cohort demographic characteristics and measurements included 1395 whites (45.7%), 2174 hypertensive (71.3%), 992 estimated glomerular filtration rate of less than 60 mL/min per 1.73 m(2) (32.5%), 1574 high-sensitivity C-reactive protein level of greater than 3 mg/L (51.6%), and 66 abnormal cTnT level of 0.01 ng/mL or higher (2.2%). The estimated cumulative incidence of ESRD at 10 years was 27.4% among those with abnormal cTnT levels compared with 1.3% for those with normal levels. Similarly, the estimated cumulative incidence of death at 10 years was 47% among those with abnormal cTnT compared with 7.3% among those with normal cTnT. Abnormal cTnT levels were strongly associated with ESRD and death. This effect was attenuated but was still highly significant after adjustment for demographic characteristics, estimated glomerular filtration rate, and traditional risk factors for ESRD (unadjusted hazard ratio [HR], 23.91; 95% CI, 12.9-44.2; adjusted HR, 2.81; 95% CI, 1.3-5.9) and death (unadjusted HR, 8.43; 95% CI, 6.0-11.9; adjusted HR, 3.46; 95% CI, 2.3-5.1).

CONCLUSION

Cardiac troponin T makes an independent contribution to the prediction of ESRD and all-cause death in community-dwelling individuals beyond traditional risk markers. Further studies may be needed to determine whether cTnT screening in individuals with hypertension or in a subset of hypertensive individuals would help identify those at risk of ESRD and all-cause death.

Biomarkers of Vitamin D Status and Risk of ESRD

BACKGROUND

Disordered mineral metabolism is characteristic of decreased kidney function. However, the prospective associations between circulating levels of vitamin D binding protein, vitamin D, and end-stage renal disease (ESRD) have not been extensively evaluated in epidemiologic studies.

STUDY DESIGN

Nested case-control study.

SETTING & PARTICIPANTS

Middle-aged black and white men and women from 4 US communities.

PREDICTORS

Baseline levels of vitamin D binding protein, 25-hydroxyvitamin D (25[OH]D), and 1,25-dihydroxyvitamin D (1,25[OH]2D) were measured in blood samples collected at study visit 4 (1996-1998) of the ARIC (Atherosclerosis Risk in Communities) Study.

OUTCOME

ESRD cases (n=184) were identified through hospitalization diagnostic codes from 1996 to 2008 and were frequency matched to controls (n=251) on categories of estimated glomerular filtration rate, albuminuria, diabetes mellitus, sex, and race.

MEASUREMENTS

Logistic regression was used to estimate the association between mineral metabolism biomarkers (vitamin D binding protein, 25(OH)D, and 1,25(OH)2D) and incident ESRD, adjusting for age, sex, race, estimated glomerular filtration rate, albuminuria, diabetes mellitus, hypertension, education, specimen type, and serum levels of calcium, phosphate, and parathyroid hormone.

RESULTS

Higher vitamin D binding protein levels were associated with elevated risk for incident ESRD (OR, 1.76; 95% CI, 1.22-2.54; P=0.003). Higher free and bioavailable 25(OH)D levels were associated with reduced risk for incident ESRD (ORs of 0.65 [95% CI, 0.46-0.92; P=0.02] and 0.63 [95% CI, 0.43-0.91; P=0.02] for free and bioavailable 25[OH]D, respectively). There was no association between ESRD and overall levels of 25(OH)D (OR, 0.83; 95% CI, 0.58-1.19; P=0.3) or 1,25(OH)2D (OR, 0.73; 95% CI, 0.48-1.13; P=0.2).

LIMITATIONS

Lack of direct measurement of free and bioavailable vitamin D.

CONCLUSIONS

In the general population, blood levels of vitamin D binding protein were positively associated and blood levels of free and bioavailable 25(OH)D were inversely associated with new-onset ESRD during follow-up.

Urinary Biomarkers and Risk of ESRD in the Atherosclerosis Risk in Communities Study

BACKGROUND AND OBJECTIVES

Liver fatty acid binding protein (L-FABP), kidney injury molecule 1 (KIM-1), N-acetyl-β-d-glucosaminidase (NAG), and neutrophil gelatinase-associated lipocalin (NGAL) are urinary markers of tubular injury that may also be markers of chronic kidney damage. We evaluated the association of these markers with incident ESRD in a community-based sample from the Atherosclerosis Risk in Communities Study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a matched case-control study of 135 patients with ESRD and 186 controls who were matched on sex, race, kidney function, and diabetes status at baseline (Atherosclerosis Risk in Communities Study visit 4, 1996-1998). Urinary KIM-1 indexed to creatinine (Cr), NAG/Cr, NGAL/Cr, and L-FABP/Cr were measured in stored spot urine samples from the baseline examination. Associations of KIM-1/Cr, NAG/Cr, and NGAL/Cr with patients with incident ESRD through 2008 were modeled continuously and categorically (quartiles) using conditional logistic regression. L-FABP/Cr was modeled only categorically because of a large number of measurements below the lower limit of detection for the assay (2.4 ng/ml).

RESULTS

No significant associations were observed for NAG/Cr, NGAL/Cr, or L-FABP/Cr with ESRD. Those in the highest category for KIM-1/Cr had a higher risk of ESRD compared with those with undetectable biomarker levels (reference group) in unadjusted models (odds ratio, 2.24; 95% confidence interval, 1.97 to 4.69; P=0.03) or adjustment for age (odds ratio, 2.23; 95% confidence interval, 1.06 to 4.67; P=0.03). This association was attenuated with additional adjustment for baseline kidney function (odds ratio, 2.02; 95% confidence interval, 0.95 to 4.31; P=0.07 after additional adjustment for eGFR and natural log of the urinary albumin-to-creatinine ratio). No association between KIM-1/Cr and ESRD was found when KIM-1/Cr was analyzed as a continuous variable.

CONCLUSIONS

Elevated urinary KIM-1/Cr may be associated with a higher risk of incident ESRD, but it does not add to risk prediction after accounting for traditional markers of kidney function in this population.

Pesticide use and risk of end-stage renal disease among licensed pesticide applicators in the Agricultural Health Study

OBJECTIVES

Experimental studies suggest a relationship between pesticide exposure and renal impairment, but epidemiological evidence is limited. We evaluated the association between exposure to 39 specific pesticides and end-stage renal disease (ESRD) incidence in the Agricultural Health Study, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina.

METHODS

Via linkage to the US Renal Data System, we identified 320 ESRD cases diagnosed between enrolment (1993-1997) and December 2011 among 55 580 male licensed pesticide applicators. Participants provided information on use of pesticides via self-administered questionnaires. Lifetime pesticide use was defined as the product of duration and frequency of use and then modified by an intensity factor to account for differences in pesticide application practices. Cox proportional hazards models, adjusted for age and state, were used to estimate associations between ESRD and: (1) ordinal categories of intensity-weighted lifetime use of 39 pesticides, (2) poisoning and high-level pesticide exposures and (3) pesticide exposure resulting in a medical visit or hospitalisation.

RESULTS

Positive exposure-response trends were observed for the herbicides alachlor, atrazine, metolachlor, paraquat, and pendimethalin, and the insecticide permethrin. More than one medical visit due to pesticide use (HR=2.13; 95% CI 1.17 to 3.89) and hospitalisation due to pesticide use (HR=3.05; 95% CI 1.67 to 5.58) were significantly associated with ESRD.

CONCLUSIONS

Our findings support an association between ESRD and chronic exposure to specific pesticides, and suggest pesticide exposures resulting in medical visits may increase the risk of ESRD.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov NCT00352924.

Association Between Chronic Osteomyelitis and Risk of End-Stage Renal Disease: A Nationwide Population-Based Cohort Study

Inflammation, which initiates endothelial dysfunction, vascular atherosclerosis, and oxidative stress, may negatively influence renal function and accelerate the development of end-stage renal disease (ESRD). The role of chronic osteomyelitis (COM), a chronic inflammatory disease, in the development of ESRD has not been investigated. This study explored whether patients with COM have a higher risk of ESRD than that of patients without COM.Taiwan National Health Insurance claims from 1997 to 2010 were used to identify 24,267 newly diagnosed patients with COM and 97,068 age- and sex-matched non-COM controls for comparison. The risks of ESRD among COM patients, with adjustment for comorbidities, namely, hypertension, diabetes, coronary artery disease, congestive heart failure, and hyperlipidemia, were assessed until the end of 2010.ESRD risk was 2.01-fold higher (95% confidence interval [CI]: 1.81-2.25) in the COM cohort than in the non-COM cohort. Regarding the joint effect of COM with comorbidity, the ESRD risk was 1.57-fold higher (95% CI: 1.23-2.00) for the COM cohort without comorbidities and increased to 2.25 (95% CI: 1.97-2.57) for the COM cohort with at least 1 comorbidity. Age-specific analysis revealed that the adjusted ESRD risk for the COM cohort increased as age decreased, with the highest hazard ratio being 17.8 (95% CI: 5.18-61.4) for patients aged 20-34 years.This was the first study to report that COM is associated with an increased risk of ESRD, particularly among patients with comorbidities and younger patients.

Renal cell cancer histological subtype distribution differs by race and sex

OBJECTIVES

To examine racial differences in the distribution of histological subtypes of renal cell carcinoma (RCC) and associations with established RCC risk factors by subtype.

MATERIALS AND METHODS

Tumours from 1532 consecutive patients with RCC who underwent nephrectomy at Vanderbilt University Medical Center (1998-2012) were classified as clear-cell, papillary, chromophobe and other subtypes. In pairwise comparisons, we used multivariate logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between race, sex, age, end-stage renal disease (ESRD) and body mass index at diagnosis according to histological subtype.

RESULTS

The RCC subtype distribution was significantly different in black people from that in white people (P < 0.001), with a substantially higher proportion of patients with papillary RCC among black people than white people (35.7 vs 13.8%). In multivariate analyses, compared with clear-cell RCC, people with papillary RCC were significantly more likely to be black (OR 4.15; 95% CI 2.64-6.52) and less likely to be female (OR 0.60; 95% CI 0.43-0.83). People with chromophobe RCC were significantly more likely to be female (OR 2.32; 95% CI 1.44-3.74). Both people with papillary RCC (OR 6.26; 95% CI 2.75-14.24) and those with chromophobe RCC (OR 7.07; 95% CI 2.13-23.46) were strongly and significantly more likely to have ESRD, compared with those with clear-cell RCC.

CONCLUSION

We observed marked racial differences in the proportional subtype distribution of RCCs diagnosed at a large tertiary care academic centre. To our knowledge, no previous study has examined racial differences in the distribution of RCC histologies while adjusting for ESRD, which was the factor most strongly associated with papillary and chromophobe RCC compared with clear-cell RCC.

Kidney Failure and ESRD in the Atherosclerosis Risk in Communities (ARIC) Study: Comparing Ascertainment of Treated and Untreated Kidney Failure in a Cohort Study

BACKGROUND

Linkage to the US Renal Data System (USRDS) registry commonly is used to identify end-stage renal disease (ESRD) cases, or kidney failure treated with dialysis or transplantation, but it underestimates the total burden of kidney failure. This study validates a kidney failure definition that includes both kidney failure treated and not treated by dialysis or transplantation. It compares kidney failure risk factors and outcomes using this broader definition with USRDS-identified ESRD risk factors and outcomes.

STUDY DESIGN

Diagnostic test study with stratified random sampling of hospitalizations for chart review.

SETTING & PARTICIPANTS

Atherosclerosis Risk in Communities Study (n=11,530; chart review, n=546).

INDEX TEST

USRDS-identified ESRD; treated or untreated kidney failure defined by USRDS-identified ESRD or International Classification of Diseases, Ninth or Tenth Revision, Clinical Modification (ICD-9-CM/ICD-10-CM) code for hospitalization or death.

REFERENCE TEST

For ESRD, determination of permanent dialysis therapy or transplantation; for kidney failure, determination of permanent dialysis therapy, transplantation, or estimated glomerular filtration rate < 15 mL/min/1.73 m(2).

RESULTS

During 13 years' median follow-up, 508 kidney failure cases were identified, including 173 (34.1%) from the USRDS registry. ESRD and kidney failure incidence were 1.23 and 3.66 cases per 1,000 person-years in the overall population and 1.35 and 6.59 cases per 1,000 person-years among participants older than 70 years, respectively. Other risk-factor associations were similar between ESRD and kidney failure, except diabetes and albuminuria, which were stronger for ESRD. Survivals at 1 and 5 years were 74.0% and 24.0% for ESRD and 59.8% and 31.6% for kidney failure, respectively. Sensitivity and specificity were 88.0% and 97.3% comparing the kidney failure ICD-9-CM/ICD-10-CM code algorithm to chart review; for USRDS-identified ESRD, sensitivity and specificity were 94.9% and 100.0%.

LIMITATIONS

Some medical charts were incomplete.

CONCLUSIONS

A kidney failure definition including treated and untreated disease identifies more cases than linkage to the USRDS registry alone, particularly among older adults. Future studies might consider reporting both USRDS-identified ESRD and a more inclusive kidney failure definition.

Adiposity patterns and the risk for ESRD in postmenopausal women

BACKGROUND AND OBJECTIVES

Body mass index and waist circumference associate with adverse health outcomes, including CKD. Studies of the association of body mass index and ESRD have been inconsistent; these adiposity measures have not been previously assessed together for ESRD risk or among postmenopausal women.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

This was prospective cohort study of 20,117 postmenopausal women enrolled in the multiethnic cohort of the Women's Health Initiative. Body mass index and waist circumference were obtained at baseline, incident ESRD was obtained from the US Renal Data System, and all-cause death was obtained from surveillance data. A competing-risk framework was used to account for the effect of mortality before ESRD while adjusting for significant predictors and baseline kidney function. Associations of adiposity with mortality were also studied.

RESULTS

Events included 212 patients with incident ESRD and 3104 deaths for a mean follow-up of 11.6 years. Increased waist circumference and body mass index were associated with 2.59- (95% confidence interval, 1.89 to 3.53) and 1.97-fold (95% confidence interval, 1.30 to 2.98) higher hazards of ESRD as well as 1.42- (95% confidence interval, 1.32 to 1.53) and 1.21-fold (95% confidence interval, 1.11 to 1.33) higher hazards of death, respectively, compared with the lower categories in adjusted analyses. The associations of waist circumference with ESRD varied by baseline renal function (P for interaction=0.01) and were significant only among women without baseline eGFR-defined CKD (hazard ratio, 1.93; 95% confidence interval, 1.23 to 3.03).

CONCLUSIONS

Central obesity was associated with an increased risk of ESRD in postmenopausal women, even among women with normal body mass index but not among women with reduced baseline kidney function, and an increased risk of death. Body mass index was associated with ESRD, and the association is likely mediated through hypertension and diabetes.

Epidemiological study of chronic kidney disease progression: a large-scale population-based cohort study

The prognostic information about CKD progression, particularly for GFR categories 1 and 2, is still limited. This cohort was therefore conducted to determine the CKD progression using a competing risk approach. We conducted a retrospective cohort study linking community health screening with hospitals and death registry data in a province of Thailand, from 1997 to 2011. A competing risk model was applied by treating death as a competing risk factor to estimate 2-, 5-, and 10-year probability of kidney failure and median time for CKD progression from lower to higher GFR category. There were 17,074 non-diabetic and 15,032 diabetic CKD subjects. Diabetic subjects progressed more rapidly through GFR categories with the median times for CKD progression from GFR categories G1 to G2, G2 to G3a, G3a to G3b, G3b to G4, and G4 to G5 of 4.4, 6.1, 4.9, 6.3, and 9.0 years, respectively. Non-diabetic subjects took longer to progress with the corresponding median time of 9.4, 14.0, 11.0, 13.8, and >14.3 years. After adjusting for confounders, diabetic subjects were 49% (cause-specific hazard ratio ((c)HR) = 1.49, 95% CI: 1.37, 1.62) more likely to develop kidney failure than non-diabetic subjects. Albuminuria categories A3 and A2 were, respectively, 3.40 (95% CI: 3.07, 3.76) and 1.71 (95% CI: 1.53, 1.92) higher risk of kidney failure when compared to A1. For each albumin category, death rate increased as albuminuria increased particularly in diabetic subjects, which was approximately 2 times higher in A3 compared to A1. Considering GFR category, it gradually increased from G1 to G4 and sharply increased from G4 to G5 in both non-diabetic and diabetic subjects. This study has quantified CKD progression in an Asian population within ordinary practice. Diabetic subjects progress through GFR and albuminuria categories and reach kidney failure about twice as rapidly as non-diabetic subjects.

The association of adiposity with kidney function decline among HIV-infected adults: findings from the Fat Redistribution and Metabolic Changes in HIV Infection (FRAM) study

OBJECTIVES

The aim of the study was to investigate the association of adiposity with longitudinal kidney function change in 544 HIV-infected persons in the Study of Fat Redistribution and Metabolic Change in HIV infection (FRAM) cohort over 5 years of follow-up.

METHODS

The regional distribution of muscle and adipose tissue was quantified by whole-body magnetic resonance imaging (MRI), and total adiponectin and leptin levels were measured in serum. Kidney function was assessed using the estimated glomerular filtration rate from serum cystatin C (eGFRCys), obtained at baseline and follow-up. Rapid kidney function decline was defined as annual loss of eGFRCys ≥ 3 mL/min/1.73 m(2) , and incident chronic kidney disease (CKD) was defined as eGFRCys <60 mL/min/1.73 m(2) . Multivariate regression analysis was adjusted for age, race, gender, glucose, antihypertensive use, serum albumin, baseline and change in HIV viral load.

RESULTS

At baseline, mean age was 43 years, mean eGFRCys was 86 mL/min/1.73 m(2) , and 21% of patients had albuminuria. The mean (± standard deviation) eGFRCys decline was -0.11 ± 4.87 mL/min/1.73 m(2) per year; 23% of participants had rapid kidney function decline, and 10% developed incident CKD. The lowest tertile of visceral adipose tissue and the highest tertile of adiponectin were both marginally associated with annual kidney function decline of -0.5 mL/min/1.73 m(2) each, but these associations were not statistically significant after adjustment. We found no statistically significant associations of MRI-measured regional adiposity or serum adipokines with rapid kidney function decline or incident CKD (all P-values>0.1 in adjusted models).

CONCLUSIONS

Contrary to findings in the general population, adiposity did not have a substantial association with longitudinal change in kidney function among HIV-infected persons.

Predictors of advanced chronic kidney disease and end-stage renal disease in HIV-positive persons

OBJECTIVES

Whilst several antiretroviral drugs have been associated with moderate chronic kidney disease (CKD), their contribution to advanced CKD and end-stage renal disease (ESRD) remain unknown.

DESIGN

D:A:D participants with at least three estimated glomerular filtration rates (eGFR) after February 2004 were followed until the first of advanced CKD (confirmed eGFR ≤ 30 ml/min, ≥3 months apart), ESRD (dialysis ≥3 months/ transplantation), 6 months after last visit or February 2012.

METHODS

Poisson regression was used to assess risk factors for advanced CKD/ESRD including exposure to potential nephrotoxic antiretroviral drugs and antiretroviral drug discontinuation rates according to latest eGFR.

RESULTS

Among 35 192 persons contributing 200 119 person years of follow-up (PYFU), 135 (0.4%) developed advanced CKD (n = 114)/ESRD (n = 21); incidence rate = 0.67 [95% confidence interval (CI), 0.56-0.79]/1000 PYFU. Tenofovir (TDF) was particularly frequently discontinued as eGFR declined. After adjustment, those previously exposed but currently off TDF had similar advanced CKD/ESRD rate ratios compared with those unexposed [1.00 (95% CI, 0.66-1.51)], while those currently on TDF had reduced rates [0.23 (95% CI, 0.13-0.41)]. No consistent associations with other antiretroviral drugs were seen. Results were robust after time-lagging antiretroviral drug exposure, stratifying by baseline eGFR, and allowing for competing risks. Other predictors were diabetes, hypertension, baseline eGFR, smoking and current CD4 cell count. The incidence rate in nonsmokers with baseline eGFR > 60 and no diabetes or hypertension was 0.16 (95% CI 0.09-0.26)/1000 PYFU.

CONCLUSION

Neither current nor recent antiretroviral drug use predicted advanced CKD/ESRD during 6 years median follow-up in a large, heterogenenous and primarily white cohort. TDF discontinuation rates increased with decreasing eGFR, leaving a selected group still on TDF at lower advanced CKD/ESRD risk. Traditional renal risk factors and current CD4 cell count were the strongest advanced CKD/ESRD predictors.

No racial differences in the association of glycated hemoglobin with kidney disease and cardiovascular outcomes

OBJECTIVE

There is debate regarding the clinical significance of well-established racial differences in HbA1c. We compared the associations of diabetes diagnostic categories for HbA1c and fasting glucose with clinical outcomes in black and white persons in the community.

RESEARCH DESIGN AND METHODS

We conducted a prospective cohort analysis of participants without diabetes or cardiovascular disease from the Atherosclerosis Risk in Communities study. We examined the associations of clinical categories of HbA1c (<5.7%, 5.7-6.4%, ≥6.5%) and fasting glucose (<100, 100-125, ≥126 mg/dL) with outcomes separately among 2,484 black and 8,593 white participants and tested for race interactions.

RESULTS

Baseline characteristics differed significantly in blacks compared with whites, including HbA1c (5.8 vs. 5.4%; P<0.001). During 18 years of follow-up, there were trends of increased risk of kidney disease, fatal and nonfatal coronary heart disease, and stroke across categories of HbA1c in both blacks and whites. The adjusted hazard ratios for each outcome across categories of HbA1c were similar in blacks and whites (P for interaction>0.05) except for all-cause mortality. Patterns of association were similar, but weaker, for fasting glucose. HbA1c and fasting glucose both were more strongly associated with all-cause mortality in whites compared with blacks, largely explained by racial differences in the rate of cardiovascular deaths.

CONCLUSIONS

HbA1c is a risk factor for vascular outcomes and mortality in both black and white adults. Patterns of association for HbA1c were similar to or stronger than those for fasting glucose. With respect to long-term outcomes, our findings support a similar interpretation of HbA1c in blacks and whites for diagnosis and treatment of diabetes mellitus.

APOL1 variants associate with increased risk of CKD among African Americans

Although case-control studies suggest that African Americans with common coding variants in the APOL1 gene are 5-29 times more likely than those individuals without such variants to have focal segmental glomerulosclerosis, HIV-associated nephropathy, or ESRD, prospective studies have not yet evaluated the impact of these variants on CKD in a community-based sample of African Americans. Here, we studied whether the APOL1 G1 and G2 risk alleles associate with the development of CKD and progression to ESRD by analyzing data from 3067 African Americans in the Atherosclerosis Risk in Communities Study who did not have CKD at baseline. Carrying two risk alleles associated with a 1.49-fold increased risk of CKD (95% CI=1.02 to 2.17) and a 1.88-fold increased risk of ESRD (95% CI=1.20 to 2.93) compared with zero or one risk allele; associations persisted after adjusting for European ancestry. Among participants who developed CKD, those participants with two risk alleles were more likely to progress to ESRD than their counterparts with zero or one risk allele (HR=2.22, 95% CI=1.01 to 4.84). In conclusion, APOL1 risk variants are risk factors for the development of CKD and progression from CKD to ESRD among African Americans in the general population.

Lifetime incidence of CKD stages 3-5 in the United States

BACKGROUND

Lifetime risk estimates of chronic kidney disease (CKD) can motivate preventative behaviors at the individual level and forecast disease burden and health care use at the population level.

STUDY DESIGN

Markov Monte Carlo model simulation study.

SETTING & POPULATION

Current US black and white population.

MODEL, PERSPECTIVE, & TIMEFRAME

Markov models simulating kidney disease development, using an individual perspective and lifetime horizon.

OUTCOMES

Age-, sex-, and race-specific residual lifetime risks of CKD stages 3a+ (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m²), 3b+ (eGFR <45 mL/min/1.73 m²), 4+ (eGFR <30 mL/min/1.73 m²), and end-stage renal disease (ESRD).

MEASUREMENTS

State transition probabilities of developing CKD and of dying prior to its development were modeled using: (1) mortality rates from the National Vital Statistics Report, (2) mortality risk estimates from a 2-million person meta-analysis, and (3) CKD prevalence from National Health and Nutrition Examination Surveys. Incidence, prevalence, and mortality related to ESRD were supplied by the US Renal Data System.

RESULTS

At birth, the overall lifetime risks of CKD stages 3a+, 3b+, 4+, and ESRD were 59.1%, 33.6%, 11.5%, and 3.6%, respectively. Women experienced greater CKD risk yet lower ESRD risk than men; blacks of both sexes had markedly higher CKD stage 4+ and ESRD risks (lifetime risks for white men, white women, black men, and black women, respectively: CKD stage 3a+, 53.6%, 64.9%, 51.8%, and 63.6%; CKD stage 3b+, 29.0%, 36.7%, 33.7%, and 40.2%; CKD stage 4+, 9.3%, 11.4%, 15.8%, and 18.5%; and ESRD, 3.3%, 2.2%, 8.5%, and 7.8%). Risk of CKD increased with age, with approximately one-half the CKD stage 3a+ cases developing after 70 years of age.

LIMITATIONS

CKD incidence was modeled from prevalence estimates in the US population.

CONCLUSIONS

In the United States, the lifetime risk of developing CKD stage 3a+ is high, emphasizing the importance of primary prevention and effective therapy to reduce CKD-related morbidity and mortality.

Risk factors for ESRD in individuals with preserved estimated GFR with and without albuminuria: results from the Kidney Early Evaluation Program (KEEP)

BACKGROUND

Given the increasing costs and poor outcomes of end-stage renal disease (ESRD), we sought to identify risk factors for ESRD in people with preserved estimated glomerular filtration rate (eGFR), with or without albuminuria, who were at high risk of ESRD.

METHODS

This cohort study included participants in the National Kidney Foundation's Kidney Early Evaluation Program (KEEP) with eGFR ≥ 60 mL/min/1.73 m(2) at baseline stratified by the presence or absence of albuminuria. The Chronic Kidney Disease Epidemiology Collaboration equation was used to calculate eGFR. Urine was tested for albuminuria by semiquantitative dipstick. The outcome was the development of treated chronic kidney failure, defined as initiation of maintenance dialysis therapy or kidney transplantation, determined by linkage to the US Renal Data System. We used a Cox model with the Fine-Gray method to assess risk factors for treated chronic kidney failure while accounting for the competing risk of death.

RESULTS

During a median follow-up of 4.8 years, 126 of 13,923 participants with albuminuria (16/10,000 patient-years) and 56 of 109,135 participants without albuminuria (1.1/10,000 patient-years) developed treated chronic kidney failure. Diabetes was a strong risk factor for developing treated chronic kidney failure in participants with and without albuminuria (adjusted HRs of 9.3 [95% CI, 5.7-15.3] and 7.8 [95% CI, 4.1-14.8], respectively). Black race, lower eGFR, and higher systolic blood pressure also were associated with higher adjusted risks of developing treated chronic kidney failure.

CONCLUSIONS

In a diverse high-risk cohort of KEEP participants with preserved eGFR, we showed that diabetes, higher systolic blood pressure, lower eGFR, and black race were risk factors for developing treated chronic kidney failure irrespective of albuminuria status, although the absolute risk of kidney failure in participants without albuminuria was very low. Our findings support testing for kidney disease in high-risk populations, which often have otherwise unrecognized kidney disease.

Lifestyle-related factors, obesity, and incident microalbuminuria: the CARDIA (Coronary Artery Risk Development in Young Adults) study

BACKGROUND

Modifiable lifestyle-related factors are associated with risk of coronary heart disease and may also influence kidney disease risk.

STUDY DESIGN

Community-based prospective cohort study.

SETTING & PARTICIPANTS

2,354 African American and white participants aged 28-40 years without baseline microalbuminuria or estimated glomerular filtration rate <60 mL/min/1.73 m² recruited from 4 US centers: Birmingham, AL; Chicago, IL; Minneapolis, MN; and Oakland, CA.

FACTORS

Current smoking, physical activity, fast food habits, obesity, and diet quality, which was based on 8 fundamental components of the Dietary Approaches to Stop Hypertension (DASH) diet, including increased intake of fruits, vegetables, low-fat dairy products, whole grains, and nuts and legumes and reduced intake of sodium, sugar-sweetened beverages, and red and processed meats.

OUTCOMES & MEASUREMENTS

Spot urine albumin-creatinine ratios were obtained at baseline (1995-1996) and three 5-year follow-up examinations (5, 10, and 15 years' follow-up). Incident microalbuminuria was defined as the presence of age- and sex-adjusted albumin-creatinine ratio ≥25 mg/g at 2 or more of the successive follow-up examinations.

RESULTS

During the 15-year follow-up, 77 (3.3%) individuals developed incident microalbuminuria. After multivariable adjustment, poor diet quality (OR, 2.0; 95% CI, 1.1-3.4) and obesity (OR, 1.9; 95% CI, 1.1-3.3) were associated significantly with microalbuminuria; current smoking (OR, 1.6; 95% CI, 0.9-2.8) was associated with microalbuminuria, although the CI crossed 1.0. Neither low physical activity (OR, 1.0; 95% CI, 0.5-1.8) nor fast food consumption (OR, 1.2; 95% CI, 0.7-2.3) was associated with microalbuminuria. Compared with individuals with no unhealthy lifestyle-related factors (poor diet quality, current smoking, and obesity), adjusted odds of incident microalbuminuria were 131%, 273%, and 634% higher for the presence of 1 (OR, 2.3; 95% CI, 1.3-4.3), 2 (OR, 3.7; 95% CI, 1.8-7.7), and 3 (OR, 7.3; 95% CI, 2.1-26.1) unhealthy lifestyle-related factors.

LIMITATIONS

Self-reported dietary history and physical activity, low number of outcomes.

CONCLUSIONS

Consuming an unhealthy diet and obesity are associated with incident microalbuminuria.

Advanced chronic kidney disease, end-stage renal disease and renal death among HIV-positive individuals in Europe

OBJECTIVES

Knowledge about advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD) in HIV-positive persons is limited. The aim of this study was to investigate incidence, predictors and outcomes for advanced CKD/ESRD and renal death.

METHODS

Advanced CKD was defined as confirmed (two consecutive measurements ≥ 3 months apart) estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m(2) using Cockcroft-Gault, and ESRD as haemodialysis or peritoneal dialysis for ≥ 1 month or renal transplant. Renal death was death with renal disease as the underlying cause, using Coding Causes of Death in HIV (CoDe) methodology. Follow-up was from 1 January 2004 until last eGFR measurement, advanced CKD, ESRD or renal death, whichever occurred first. Poisson regression was used to identify predictors.

RESULTS

Of 9044 individuals included in the study, 58 (0.64%) experienced advanced CKD/ESRD/renal death [incidence rate 1.32/1000 person-years of follow-up (PYFU); 95% confidence interval (CI) 0.98-1.66]; 52% of those who experienced the endpoint had a baseline eGFR ≤ 60 mL/min/1.73 m(2) compared with 3% of those who did not. Using Kaplan-Meier methods, at 6 years from baseline, 0.83% (95% CI 0.59-1.07%) were estimated to have experienced the endpoint overall and 11.26% (95% CI 6.75-15.78%) among those with baseline eGFR ≤ 60 mL/min/1.73 m(2) . Independent predictors of the endpoint included any cardiovascular event [incidence rate ratio (IRR) 2.16; 95% CI 1.24-3.77], lower eGFR (IRR 0.64 per 5 mL/min/1.73 m(2) ; 95% CI 0.59-0.70) and lower CD4 count (IRR 0.77 per doubling; 95% CI 0.62-0.95). One year after experiencing advanced CKD or ESRD, an estimated 19.21% (95% CI 7.84-30.58%) of patients had died, mostly from extra-renal causes.

CONCLUSIONS

The incidence of advanced CKD/ESRD/renal death was low and predictors included traditional renal risk factors, HIV-related factors and pre-existing renal impairment. The prognosis following advanced CKD/ESRD was poor. Larger studies should address possible contributions of specific antiretrovirals.