The conundrum of increased burden of end-stage renal disease in Asians

Racial Disparities in End-Stage Kidney Disease Outcomes among Asians and Native Hawaiians and Other Pacific Islanders across Geographic Residence

INTRODUCTION

While Asian and Native Hawaiian and other Pacific Islander (NHOPI) patients have a high prevalence of kidney disease risk factors, there are sparse data examining their end-stage kidney disease (ESKD) outcomes. As Hawaii has high representation of Asian and NHOPI individuals, we compared their ESKD outcomes based on residence in the mainland USA versus Hawaii/Pacific Islands (PIs).

MATERIALS AND METHODS

Using United States Renal Data System data, we examined the impact of geographic residence in the mainland versus Hawaii/PIs on race-mortality associations among incident ESKD patients transitioning to dialysis over January 1, 2000-December 31, 2016 using Cox regression. We examined likelihood of post-dialysis kidney transplantation using Cox models and cumulative incidence curves.

RESULTS

Compared with White patients in the mainland, Asian and NHOPI patients in the mainland had lower mortality: adjusted HRs (95% CIs) 0.67 (0.66-0.67) and 0.72 (0.70-0.73), respectively. When examining Asian and NHOPI patients in Hawaii/PIs, survival benefit was attenuated in Asian and diminished to the null in NHOPI patients (ref: mainland White patients). Cumulative incidence curves comparing Asian, NHOPI, and White patients showed Asian and NHOPI patients in the mainland had the highest likelihood of transplantation, whereas NHOPI and Asian patients in Hawaii/PIs had the lowest likelihood.

CONCLUSION

In the mainland, Asian and NHOPI patients had lower mortality versus White patients, whereas in Hawaii/PIs, this survival benefit was diminished in Asian and mitigated in NHOPI patients. NHOPI and Asian patients in Hawaii/PIs had less transplantation versus those in the mainland. Further research is needed to uncover factors contributing to differential ESKD outcomes among Asian and NHOPI patients across geographic residence.

Racial and Ethnic Differences in Chronic Kidney Disease and Its Risk Factors among Asian-Americans and Pacific Islanders in Hawaii

BACKGROUND

Several studies suggest that Asian-American and Native Hawaiian and Other Pacific Islander (NHOPI) racial/ethnic groups have a heightened risk of chronic kidney disease (CKD), but provide limited inference due to the aggregation of these groups into a single racial/ethnic category. We thus examined the association of granularly defined racial/ethnic groups with specific CKD indicators among a diverse group of participants from the National Kidney Foundation of Hawaii's Kidney Early Detection Screening (KEDS) Program.

METHODS

Among 1,243 participants enrolled in 19 KEDS screening events over 2006-2009, we examined the association between Asian-American and NHOPI groups and specific CKD indicators, defined as self-reported CKD, microalbuminuria, and macroalbuminuria, using multivariable logistic regression. We then examined associations of race/ethnicity with various CKD risk factors.

RESULTS

The most predominant racial/ethnic groups were White (22.0%), Multiracial (18.9%), Japanese (19.2%), Filipino (13.4%), NHOPI (8.4%), and Chinese (4.5%) participants. NHOPI and Chinese participants had a higher risk of microalbuminuria (adjusted ORs [aORs] [95% CIs] 2.48 [1.25-4.91] and 2.37 [1.07-5.27], respectively), while point estimates for all other minority groups suggested higher risk (reference: Whites). NHOPI participants also had a higher risk of macroalbuminuria and self-reported CKD. While most minorities had a higher risk of diabetes and hypertension, NHOPI and Multiracial participants had a higher risk of obesity, whereas the East Asian groups had a lower risk.

CONCLUSIONS

In this community-based cohort, compared with Whites, Asian-Americans had a higher risk of early CKD indicators, whereas NHOPIs had a higher risk of more severe CKD indicators. Further studies are needed to elucidate the distinct pathways leading to CKD across diverse racial/ethnic groups in Hawaii.

Identifying Genetic Variants and Metabolites Associated with Rapid Estimated Glomerular Filtration Rate Decline in Korea Based on Genome-Metabolomic Integrative Analysis

Identifying the predisposing factors to chronic or end-stage kidney disease is essential to preventing or slowing kidney function decline. Therefore, here, we investigated the genetic variants related to a rapid decline in the estimated glomerular filtration rate (eGFR) (i.e., a loss of >5 mL/min/1.73 m2 per year) and verified the relationships between variant-related diseases and metabolic pathway signaling in patients with chronic kidney disease. We conducted a genome-wide association study that included participants with diabetes, hypertension, and rapid eGFR decline from two Korean data sources (N = 115 and 69 for the discovery and the validation cohorts, respectively). We identified a novel susceptibility locus: 4q32.3 (rs10009742 in the MARCHF1 gene, beta = −3.540, P = 4.11 × 10−8). Fine-mapping revealed 19 credible, causal single-nucleotide polymorphisms, including rs10009742. The pimelylcarnitine and octadecenoyl carnitine serum concentrations were associated with rs10009742 (beta = 0.030, P = 7.10 × 10−5, false discovery rate (FDR) = 0.01; beta = 0.167, P = 8.11 × 10−4, FDR = 0.08). Our results suggest that MARCHF1 is associated with a rapid eGFR decline in patients with hypertension and diabetes. Furthermore, MARCHF1 affects the pimelylcarnitine metabolite concentration, which may mediate chronic kidney disease progression by inducing oxidative stress in the endoplasmic reticulum.

Comparative Risks of Nonsteroidal Anti-Inflammatory Drugs on CKD

BACKGROUND AND OBJECTIVES

There have been doubts about the association between nonsteroidal anti-inflammatory drug use and worsening kidney function, and whether there is a difference between risks of individual nonsteroidal anti-inflammatory drugs is presently unclear. Therefore, this study aimed to evaluate the association between nonsteroidal anti-inflammatory drug exposure and the risk of incident eGFR <60 ml/min per 1.73 m² and compare the risks between nonsteroidal anti-inflammatory drug subtypes in the Chinese population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From 2008 to 2017, a total of 1,982,488 subjects aged 18 years or older with baseline eGFR ≥60 ml/min per 1.73 m² were enrolled in this retrospective cohort study. Multivariable Cox proportional hazards regression adjusted for each patient's baseline characteristics was adopted to examine the association between nonsteroidal anti-inflammatory drug and incident eGFR <60 ml/min per 1.73 m² or eGFR decline ≥30% with reference to baseline.

RESULTS

After a median follow-up duration of 6.3 (interquartile range, 3.3-9.4) years, 271,848 cases (14%) of incident eGFR <60 ml/min per 1.73 m² and 388,386 (21%) events of eGFR decline ≥30% were recorded. After adjusting for each patient's baseline characteristics, nonsteroidal anti-inflammatory drug treatment was shown to be associated with a significantly higher risk of incident eGFR <60 ml/min per 1.73 m² (hazard ratio, 1.71; 95% confidence interval, 1.67 to 1.75) and eGFR decline ≥30% (hazard ratio, 1.93; 95% confidence interval, 1.89 to 1.96) when compared with no nonsteroidal anti-inflammatory drug, with etoricoxib exhibiting the highest risk of eGFR<60 ml/min per 1.73 m² (hazard ratio, 3.12; 95% confidence interval, 2.69 to 3.62) and eGFR decline ≥30% (hazard ratio, 3.11; 95% confidence interval, 2.78 to 3.48) and ibuprofen displaying the lowest risk of eGFR<60 ml/min per 1.73 m² (hazard ratio, 1.12; 95% confidence interval, 1.02 to 1.23) and eGFR decline ≥30% (hazard ratio, 1.32; 95% confidence interval, 1.23 to 1.41).

CONCLUSIONS

Nonsteroidal anti-inflammatory drug exposure was associated with higher risks of incident eGFR <60 ml/min per 1.73 m² and eGFR decline ≥30%. Highest risk was observed in etoricoxib users, and lowest risk was with ibuprofen.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_04_28_CJN18501120.mp3.

Lifetime risk of stroke stratified by chronic kidney disease and hypertension in the general Asian population: the Ohasama study

Lifetime risk (LTR) evaluates the absolute risk of developing a disease during the remainder of one's life. It can be a useful tool, enabling the general public to easily understand their risk of stroke. No study has been performed to determine the LTR of cardiovascular disease in patients with chronic kidney disease (CKD) with or without hypertension; therefore, we performed this study in an Asian population. We followed 1525 participants (66.0% women; age 63.1 years) in the general population of Ohasama, Japan. We defined CKD as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² and/or proteinuria. Hypertension was defined as a systolic/diastolic blood pressure ≥140/≥90 mmHg and/or the use of antihypertensive medication. We calculated the sex-specific LTR of stroke adjusted for the competing risk of death. During the mean follow-up period of 16.5 years, a first stroke occurred in 238 participants. The 10-year risk of stroke at the age of 45 years was 0.0% for men and women. The LTRs of stroke at the index age of 45 years (men/women) were 20.9%/14.5% for participants without CKD and hypertension, 34.1%/29.8% for those with CKD but not hypertension, 37.9%/27.3% for those with hypertension but not CKD, and 38.4%/36.4% for those with CKD and hypertension. The LTRs of stroke tended to be higher in younger participants than in older participants with CKD and/or hypertension. CKD contributed to the LTR of stroke, as did hypertension. The prevention of CKD and hypertension can reduce the LTR of stroke, especially in young populations.

N-Terminal Pro-B-Type Natriuretic Peptide Is a Predictor of Chronic Kidney Disease in an Asian General Population - The Ohasama Study

Background: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is known to increase in heart failure patients. Given that no reports have described the association between NT-proBNP and chronic kidney disease (CKD) incidence in Asian populations, we investigated this association in the Japanese population. Methods and Results: We followed up 867 participants without CKD from the general population of Ohasama, Japan. We defined CKD as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² and/or proteinuria. In accordance with previous studies, the participants were classified into 4 groups according to NT-proBNP level (<30.0, 30.0-54.9, 55.0-124.9, and ≥125.0 pg/mL). The Cox model was applied to assess adjusted hazard ratios (HR) for CKD incidence after full adjustment including baseline eGFR. Participant mean age was 59.1 years, and 587 (67.7%) were women. During the mean follow-up period of 9.7 years, 177 participants developed CKD. When the group with NT-proBNP <30.0 pg/mL was used as the reference, adjusted HR for CKD incidence in the 30.0-54.9, 55.0-124.9, and ≥125.0 pg/mL groups were 1.34 (95% CI: 0.90-2.01), 1.25 (95% CI: 0.81-1.92), and 1.83 (95% CI: 1.05-3.18), respectively. Conclusions: NT-proBNP can be significantly predictive for CKD incidence in Asian populations.

Association Between APOL1 Genotypes and Risk of Cardiovascular Disease in MESA (Multi-Ethnic Study of Atherosclerosis)

Background

APOL1 genetic variants confer an increased risk for kidney disease. Their associations with cardiovascular disease (CVD) are less certain. We aimed to compare the prevalence of subclinical CVD and incidence of atherosclerotic CVD and heart failure by APOL1 genotypes among self‐identified black participants of MESA (Multi‐Ethnic Study of Atherosclerosis).

Methods and Results

Cross‐sectional associations of APOL1 genotypes (high‐risk=2 alleles; low‐risk=0 or 1 allele) with coronary artery calcification, carotid‐intimal media thickness, and left ventricular mass were evaluated using logistic and linear regression. Longitudinal associations of APOL1 genotypes with incident myocardial infarction, stroke, coronary heart disease, and congestive heart failure were examined using Cox regression. We adjusted for African ancestry, age, and sex. We also evaluated whether hypertension or kidney function markers explained the observed associations. Among 1746 participants with APOL1 genotyping (mean age 62 years, 55% women, mean cystatin C–based estimated glomerular filtration rate 89 mL/min per 1.73 m², 12% with albuminuria), 12% had the high‐risk genotypes. We found no difference in prevalence or severity of coronary artery calcification, carotid‐intimal media thickness, or left ventricular mass by APOL1 genotypes. The APOL1 high‐risk group was 82% more likely to develop incident heart failure compared with the low‐risk group (95% confidence interval, 1.01–3.28). Adjusting for hypertension (hazard ratio, 1.80; 95% confidence interval, 1.00–3.24) but not markers of kidney function (hazard ratio, 1.86; 95% confidence interval, 1.03–3.35) slightly attenuated this association. The APOL1 high‐risk genotypes were not significantly associated with other clinical CVD outcomes.

Conclusions

Among blacks without baseline CVD, the APOL1 high‐risk variants may be associated with increased risk for incident heart failure but not subclinical CVD or incident clinical atherosclerotic CVD.

Strict blood pressure control associates with decreased mortality risk by APOL1 genotype

Although APOL1 high-risk genotype partially accounts for the increased susceptibility of blacks to chronic kidney disease (CKD), whether APOL1 associates differentially with mortality risk remains controversial. Here we evaluate the association between APOL1 genotype and risk of death and determine whether APOL1 status modifies the association between strict versus usual blood pressure control and mortality risk. We performed a retrospective analysis of the African American Study of Kidney Disease and Hypertension trial that randomized black participants with CKD to strict versus usual blood pressure control from 1995 to 2001. This included 682 participants with known APOL1 genotype (157 with high-risk genotype) previously assigned to either strict (mean arterial pressure [MAP] 92 mm Hg or less) versus usual blood pressure control (MAP 102-107 mm Hg) during the trial. During a median follow-up of 14.5 years, risk of death did not differ between individuals with high- versus low-risk APOL1 genotypes (unadjusted hazard ratio 1.00 [95% confidence interval 0.76-1.33]). However, a significant interaction was detected between the APOL1 risk group and blood pressure control strategy. In the APOL1 high-risk group, the risk of death was 42% lower comparing strict versus usual blood pressure control (0.58 [0.35-0.97]). In the APOL1 low-risk group, the risk of death comparing strict versus usual blood pressure control was not significantly different (1.09 [0.84-1.43]). Thus, strict blood pressure control during CKD associates with a lower risk of death in blacks with the high-risk CKD APOL1 genotype. Knowledge of APOL1 status could inform selection of blood pressure treatment targets in black CKD patients.

Insights from Screening a Racially and Ethnically Diverse Population for Chronic Kidney Disease

BACKGROUND

The value of chronic kidney disease (CKD) screening in the general population remains unclear but may be beneficial in populations with high disease prevalence. We examined risk factors for albuminuria among participants in a state-wide CKD screening program in Hawaii.

METHODS

The National Kidney Foundation of Hawaii Kidney Early Detection Screening (NKFH-KEDS) program held 19 CKD screening events from 2006 to 2012. Participants rotated through 5 stations during which sociodemographic, blood glucose, urine albumin-to-creatinine ratio (ACR), and spot urine albumin data were collected. Multivariate logistic regression analyses (adjusted for age, sex, race/ethnicity, body mass index [BMI]) were used to identify clinical predictors of abnormal ACR (≥30 μg/mg) and abnormal spot urine albumin (>20 mg/L) levels.

RESULTS

Among 1,190 NKFH-KEDS participants who met eligibility criteria, 13 and 49% had abnormal ACR and urine albumin levels, respectively. In multivariate logistic regression analyses, participants of older age (>65 years), Asian and Pacific Islander race/ethnicity, BMI ≥30 kg/m2, and with hypertension had higher risk of abnormal ACR. Being of older age; Asian, Pacific Islander, and Mixed race/ethnicity; and having diabetes was associated with higher risk of abnormal urine albumin levels in adjusted analyses.

CONCLUSIONS

NKFH-KEDS participants of older age; Asian and Pacific Islander race/ethnicity; and with obesity, hypertension, and diabetes had higher risk of kidney damage defined by elevated ACR and urine albumin levels. Further studies are needed to determine whether targeted screening programs can result in timely identification of CKD and implementation of interventions that reduce cardiovascular disease, death, and progression to end-stage renal disease.

Risk of end-stage renal disease in Japanese patients with chronic kidney disease increases proportionately to decline in estimated glomerular filtration rate

Predominantly based on North American and European studies, 30% to 40% declines in estimated glomerular filtration rate (eGFR) over a few years are strongly associated with the risk of end-stage renal disease (ESRD) and have been proposed as surrogate endpoints of ESRD for clinical research. However, this association has not been systematically quantified in Asian populations. To do this we studied adult Japanese patients with baseline eGFR 10-59 ml/min/1.73m². Changes in eGFR from baseline measured by centrally assessed serum creatinine were linked to subsequent ESRD in 2410 patients after one year and in 2079 patients after year 2. After year 1, 1.4% experienced a 53% decrease in eGFR (equivalent to doubling of serum creatinine), whereas 4.3% and 9.7% had eGFR decrease of 40% or 30% or more, respectively. The corresponding numbers after 2 years were 4.2%, 10.9%, and 19.3%, respectively. After year 1 baseline period, 498 patients developed ESRD over a median follow-up of 2.9 years (365 ESRD cases over a median follow-up of 2 years after year 2). In year 1, after accounting for potential confounders, a strong linear association was found between eGFR declines and subsequent ESRD, with adjusted hazard ratios of 20.7 (95% confidence interval 14.3-30.1) for a 53% decrease, 9.6 (7.4-12.5) for a 40% decrease, and 5.3 (4.1-6.9) for a 30% decrease compared to no change. Corresponding hazard ratios for year two analysis were 17.3 (11.8-25.3), 6.5 (4.7-9.1), and 3.1 (2.2-4.4), respectively. The associations were consistent across demographics and kidney diseases. Thus, 30% to 40% declines in eGFR are strongly associated with the risk of ESRD in Japanese patients with reduced eGFR, broadening global implications as a surrogate endpoint in clinical research.

A Meta-Analysis on Prehypertension and Chronic Kidney Disease

Background

Recent studies have demonstrated that there is an association between prehypertension and an increased risk of end-stage renal disease. However, there is conflicting evidence regarding the relationship between prehypertension and chronic kidney disease (CKD). This meta-analysis aimed to demonstrate the association between prehypertension and the incidence of CKD and identify the impacts of gender and ethnic differences.

Methods

MEDLINE, EMBASE, Cochrane Library (from inception through March 2016) and article reference lists were searched for relevant studies regarding blood pressure and CKD. Blood pressure (BP) measurements were classified as follows: optimal BP (less than 120/80 mmHg), prehypertension (120-139/80-89 mmHg) and hypertension (over 140/90 mmHg). CKD was defined by estimated glomerular filtration rate (eGFR)<60 ml/min/1.73 m² or proteinuria. Two investigators independently extracted the data and assessed the quality of studies enrolled in this meta-analysis using the Newcastle-Ottawa Scale (NOS). We performed the meta-analysis using Stata/SE 12.0 (StataCorp LP). The random-effect models were used in the heterogeneous analyses.

Results

After retrieving data from 4,537 potentially relevant articles, we identified 7 cohort studies including 261,264 subjects, according to the predefined selection criteria. Five studies were conducted in Mongolians from East Asia, and the other two studies were performed in Indo-Europeans from Austria and Iran. The participants ranged in age from 20 to 89 years, and the proportion of females ranged from 27.2% to 63.8%. The follow-up period ranged from 2 to 11 years. Compared with the optimal BP values, prehypertension showed an increased risk of CKD (pooled RR = 1.28; 95% CI = 1.13–1.44; P = 0.000; I² = 77.9%). In the sex-stratified analysis, we found a similar trend in women (pooled RR = 1.29; 95% CI = 1.01–1.63; P = 0.039; I² = 76.1%) but not in men. This effect was observed only in Mongolians from East Asia (pooled RR = 1.37; 95% CI = 1.18–1.59; P = 0.000; I² = 81.3%) and not in Indo-Europeans.

Conclusions

Prehypertension is considered a potential cause of CKD. Gender and ethnic differences are exhibited in this association.

A competing risk analysis of sequential complication development in Asian type 2 diabetes mellitus patients

This retrospective cohort study investigated the progression risk of sequential complication in Asian type 2 diabetes (T2D) patients using the Taiwan Pay-for-Performance Diabetes Registry and claim data from November 2003 to February 2009. 226,310 adult T2D patients without complication were followed from diagnosis to complications, including myocardial infarction (MI), other ischemic heart disease (IHD), congestive heart failure (CHF), stroke, chronic kidney disease (CKD), retinopathy, amputation, death or to the end of study. Cumulative incidences (CIs) of first and second complications were analyzed in 30 and 4 years using the cumulative incidence competing risk method. IHD (29.8%), CKD (24.5%) and stroke (16.0%) are the most common first complications. The further development of T2D complications depends on a patient’s existing complication profiles. Patients who initially developed cardiovascular complications had a higher risk (9.2% to 24.4%) of developing IHD or CKD, respectively. All-cause mortality was the most likely consequence for patients with a prior MI (12.0%), so as stroke in patients with a prior MI (10.8%) or IHD (8.9%). Patients with CKD had higher risk of developing IHD (16.3%), stroke (8.9%) and all-cause mortality (8.7%) than end-stage renal disease (4.0%). Following an amputation, patients had a considerable risk of all-cause mortality (42.1%).

Hemodialysis versus Peritoneal Dialysis: A Comparison of Survival Outcomes in South-East Asian Patients with End-Stage Renal Disease

Background

Studies comparing patient survival of hemodialysis (HD) and peritoneal dialysis (PD) have yielded conflicting results and no such study was from South-East Asia. This study aimed to compare the survival outcomes of patients with end-stage renal disease (ESRD) who started dialysis with HD and PD in Singapore.

Methods

Survival data for a maximum of 5 years from a single-center cohort of 871 ESRD patients starting dialysis with HD (n = 641) or PD (n = 230) from 2005–2010 was analyzed using the flexible Royston-Parmar (RP) model. The model was also applied to a subsample of 225 propensity-score-matched patient pairs and subgroups defined by age, diabetes mellitus, and cardiovascular disease.

Results

After adjusting for the effect of socio-demographic and clinical characteristics, the risk of death was higher in patients initiating dialysis with PD than those initiating dialysis with HD (hazard ratio [HR]: 2.08; 95% confidence interval [CI]: 1.67–2.59; p<0.001), although there was no significant difference in mortality between the two modalities in the first 12 months of treatment. Consistently, in the matched subsample, patients starting PD had a higher risk of death than those starting HD (HR: 1.73, 95% CI: 1.30–2.28, p<0.001). Subgroup analysis showed that PD may be similar to or better than HD in survival outcomes among young patients (≤65 years old) without diabetes or cardiovascular disease.

Conclusion

ESRD patients who initiated dialysis with HD experienced better survival outcomes than those who initiated dialysis with PD in Singapore, although survival outcomes may not differ between the two dialysis modalities in young and healthier patients. These findings are potentially confounded by selection bias, as patients were not randomized to the two dialysis modalities in this cohort study.

Evaluating risk of ESRD in the urban poor

The capacity of risk prediction to guide management of CKD in underserved health settings is unknown. We conducted a retrospective cohort study of 28,779 adults with nondialysis-requiring CKD who received health care in two large safety net health systems during 1996-2009 and were followed for ESRD through September of 2011. We developed and evaluated the performance of ESRD risk prediction models using recently proposed criteria designed to inform population health approaches to disease management: proportion of cases followed and proportion that needs to be followed. Overall, 1730 persons progressed to ESRD during follow-up (median follow-up=6.6 years). ESRD risk for time frames up to 5 years was highly concentrated among relatively few individuals. A predictive model using five common variables (age, sex, race, eGFR, and dipstick proteinuria) performed similarly to more complex models incorporating extensive sociodemographic and clinical data. Using this model, 80% of individuals who eventually developed ESRD were among the 5% of cohort members at the highest estimated risk for ESRD at 1 year. Similarly, a program that followed 8% and 13% of individuals at the highest ESRD risk would have included 80% of those who eventually progressed to ESRD at 3 and 5 years, respectively. In this underserved health setting, a simple five-variable model accurately predicts most cases of ESRD that develop within 5 years. Applying risk prediction using a population health approach may improve CKD surveillance and management of vulnerable groups by directing resources to a small subpopulation at highest risk for progressing to ESRD.

Incidence of end stage renal disease among type 1 diabetes: a nationwide cohort study in Taiwan

The aim of our study was to estimate the risk of end-stage renal disease (ESRD) in type 1 diabetes mellitus (T1DM) in Taiwanese people; in addition, our goal was to determine how the age, year, and sex at registration of T1DM affects the risk. Population-based cohort study. A nationwide cohort study of 7203 Taiwanese patients with T1DM registered in 1999 to 2010 was followed up until ESRD, death, or the end of follow-up on December 31, 2010. Annual age-, sex-, and calendar year-specific incidence rates of ESRD of the general population were used to calculate the standardized incidence ratio (SIR) of ESRD in relation to T1DM. The SIR of ESRD for male and female patients with T1DM was significantly increased at 25.85 (95% CI 23.40-28.29) and 28.08 (95% 25.45-30.71), respectively; the peak was at age 15 to 29 years for both genders. The cumulative incidence of ESRD was similar in male and female patients but was significantly higher in patients≥ 30 years old than in patients<30 years old (10.25% vs. 3.57%, P<0.001). Patients aged <15 years had a significantly lower risk of ESRD as compared to those aged 15 to 29 years; patients aged 30 to 44 (adjusted HR, 1.491) and 45 to 60 years (adjusted HR, 2.111) showed significantly increased hazards. Our data also demonstrated a lower risk of ESRD in patients who were registered in later years than in earlier years. The risk of ESRD is substantially increased in T1DM in the ethnic Chinese population. The continuously declining risk of ESRD in T1DM may advocate the use of a multidisciplinary chronic kidney disease care system in Taiwan.

APOL1 risk variants, race, and progression of chronic kidney disease

BACKGROUND

Among patients in the United States with chronic kidney disease, black patients are at increased risk for end-stage renal disease, as compared with white patients.

METHODS

In two studies, we examined the effects of variants in the gene encoding apolipoprotein L1 (APOL1) on the progression of chronic kidney disease. In the African American Study of Kidney Disease and Hypertension (AASK), we evaluated 693 black patients with chronic kidney disease attributed to hypertension. In the Chronic Renal Insufficiency Cohort (CRIC) study, we evaluated 2955 white patients and black patients with chronic kidney disease (46% of whom had diabetes) according to whether they had 2 copies of high-risk APOL1 variants (APOL1 high-risk group) or 0 or 1 copy (APOL1 low-risk group). In the AASK study, the primary outcome was a composite of end-stage renal disease or a doubling of the serum creatinine level. In the CRIC study, the primary outcomes were the slope in the estimated glomerular filtration rate (eGFR) and the composite of end-stage renal disease or a reduction of 50% in the eGFR from baseline.

RESULTS

In the AASK study, the primary outcome occurred in 58.1% of the patients in the APOL1 high-risk group and in 36.6% of those in the APOL1 low-risk group (hazard ratio in the high-risk group, 1.88; P<0.001). There was no interaction between APOL1 status and trial interventions or the presence of baseline proteinuria. In the CRIC study, black patients in the APOL1 high-risk group had a more rapid decline in the eGFR and a higher risk of the composite renal outcome than did white patients, among those with diabetes and those without diabetes (P<0.001 for all comparisons).

CONCLUSIONS

Renal risk variants in APOL1 were associated with the higher rates of end-stage renal disease and progression of chronic kidney disease that were observed in black patients as compared with white patients, regardless of diabetes status. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Predictors of end-stage renal disease in the urban poor

We sought to examine the influence of social and clinical factors on risk of progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD) in the urban poor. We studied 15,353 individuals with moderate-to-advanced CKD who received ambulatory care within a large public health system during 1996-2005. The primary outcome was progression to ESRD. Overall, 559 cases of ESRD occurred over a median follow-up of 2.8 years. Among traditional predictors of ESRD, younger age, male sex, non-White race/ethnicity, public health insurance coverage, diabetes, lower kidney function, higher proteinuria, lower hemoglobin level, and lower serum albumin concentration were significantly associated with a higher adjusted ESRD risk (p<.001 for all). There was no significant association between HIV/AIDS (p=.07), viral hepatitis (p=.11), or non-English language (p=.27) and ESRD risk. Our results highlight the importance of addressing traditional risk factors for progressive CKD to reduce the disproportionate burden of ESRD among disadvantaged populations.

Prehypertension and Incidence of ESRD: a systematic review and meta-analysis

BACKGROUND

Studies of the association of prehypertension with the incidence of end-stage renal disease (ESRD) after adjusting for other cardiovascular risk factors have shown controversial results.

STUDY DESIGN

Systematic review and meta-analysis of prospective cohort studies.

SETTING & POPULATION

Adults with prehypertension.

SELECTION CRITERIA FOR STUDIES

Studies evaluating the association of prehypertension with the incidence of ESRD identified by searches in PubMed, EMBASE, and Cochrane Library databases and conference proceedings, without language restriction.

PREDICTOR

Prehypertension.

OUTCOMES

The relative risks (RRs) of ESRD were calculated and reported with 95% CIs. Subgroup analyses were conducted according to blood pressure (BP), age, sex, ethnicity, and study characteristics.

RESULTS

Data from 1,003,793 participants were derived from 6 prospective cohort studies. Compared with optimal BP, prehypertension significantly increased the risk of ESRD (RR, 1.59; 95% CI, 1.39-1.91). In subgroup analyses, prehypertension significantly predicted higher ESRD risk across age, sex, ethnicity, and study characteristics. Even low-range (BP, 120-129/80-84 mm Hg) prehypertension increased the risk of ESRD compared with optimal BP (RR, 1.44; 95% CI, 1.19-1.74), and the risk increased further with high-range (BP, 130-139/85-89 mm Hg) prehypertension (RR, 2.02; 95% CI, 1.70-2.40). The RR was significantly higher in the high-range compared with the low-range prehypertensive population (P = 0.01).

LIMITATIONS

No access to individual patient-level data.

CONCLUSIONS

Prehypertension is associated with incident ESRD. The increased risk is driven largely by high-range prehypertension.

Differences in progression to ESRD between black and white patients receiving predialysis care in a universal health care system

BACKGROUND AND OBJECTIVES

Studies performed in the United States showed that blacks progress from CKD to ESRD faster than do whites. Possible explanations are differences in health care system factors. This study investigated whether progression is also faster in a universal health care system, where all patients receive comparable care.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from the PREdialysis PAtient REcord study, a multicenter follow-up study of patients with CKD who started predialysis care in The Netherlands (1999-2011), were analyzed. Time-dependent Cox proportional hazards models were used to estimate the hazard ratio (HR) for starting renal replacement therapy (RRT), and linear mixed models were used to compare renal function decline (RFD) between blacks and whites. To explore possible mechanisms, analyses were adjusted for patient characteristics.

RESULTS

At initiation of predialysis care, blacks (n=49) were younger and had more diabetes mellitus, higher proteinuria levels, and a higher estimated GFR than whites (n=946). Median follow-up time in months was similar (blacks: 13.9 [boundaries of interquartile range (IQR), 5.3 to 19.5]; whites: 13.1 [IQR, 5.1 to 24.0]). For blacks compared with whites, the crude HR for starting RRT within the first 15 months was 0.86 (95% confidence interval [CI], 0.55 to 1.34) and from 15 months onward, 1.93 (95% CI, 1.02 to 3.68), which increased after adjustment. RFD was faster by 0.18 (95% CI, 0.05 to 0.32) ml/min per 1.73 m(2) per month in blacks compared with whites.

CONCLUSION

Blacks receiving predialysis care in a universal health care system have faster disease progression than whites, suggesting that health care system factors have a less influential role than had been thought in explaining black-white differences.

Ethnic differences in the association between blood pressure components and chronic kidney disease in middle aged and older Asian adults

Background

Chronic kidney disease (CKD) is an emerging public health problem worldwide. Previous studies have shown an association between blood pressure (BP) and CKD. However, it is not clear if there are ethnic differences in this association. We examined the association between BP and CKD in a multi-ethnic Asian population in Singapore.

Methods

We analysed data from three large population-based studies conducted between 2004–2011, (n=3,167 Chinese, 3,082 Malays and 3,228 Indians) aged 40–80 years. CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73m² from serum creatinine. Hypertension was defined as a self-reported current use of antihypertensive medication or systolic BP ≥140 mm Hg or diastolic BP ≥90 mm Hg. We also analysed the association of CKD with individual BP components.

Results

The prevalence of both hypertension and CKD was higher among Malays (68.6, 21%) compared to Chinese (57.9, 5.9%) and Indians (56.0, 7.4%), but treatment for hypertension was lower among Malays (53.4%) compared to Chinese (89.8%) and Indians (83.1%). Hypertension was associated with CKD in all three ethnic groups (OR [95% CI] = 2.71 [1.59-4.63], 2.08 [1.62-2.68], 2.43 [1.66-3.57] in Chinese, Malays and Indians). Among the BP components, both systolic and diastolic BP were associated with CKD in Malays whereas, systolic BP was not significantly associated with CKD, and diastolic BP showed an inverse association which was explained by anti-hypertensive medication use in Chinese and Indians.

Conclusions

Hypertension was associated with CKD in Chinese, Malays and Indians. However, the BP components were associated with CKD only in Malays.

Risk of end-stage renal disease associated with gout: a nationwide population study

Introduction

We explored the risk of end-stage renal disease (ESRD) among gout patients in a representative cohort in Taiwan.

Methods

The primary database used was the Taiwan National Health Insurance Research Database. Subjects older than 20 years without ESRD, coronary heart disease, or stroke were included in the study. The case definition of gout in the present study was gout diagnosis and medical treatment for gout. An ESRD case was defined by the presence of chronic renal failure necessitating long-term renal replacement therapy. Multivariate Cox proportional hazards models were used to evaluate the risk of ESRD among gout patients.

Results

The analysis included data of 656,108 patients who were followed up for a mean of 8.0 years. Among them, 19,963 (3.0%) patients had gout. At the end of 2008, 2,377 individuals (gout, n = 276; non-gout, n = 2,101) had ESRD, and 861 individuals (gout, n = 77, 27.9%; non-gout, n = 521, 24.8%) died due to ESRD. The rates of incidence of ESRD were 1.73 and 0.41 cases per 1,000 patient-years in the gout and non-gout groups. After adjustment for age, sex, and history of diabetes mellitus and/or hypertension, gout was associated with a hazard ratio (HR) of 1.57 for ESRD (95% confidence interval [CI], 1.38-1.79; P < 0.001). In patients with ESRD, the adjusted HR for death in patients with gout was 0.95 (0.74-1.23, P = 0.71), which was similar to the HR obtained in patients without gout.

Conclusions

Gout is associated with an increased hazard for development of ESRD.

Chronic kidney disease and use of dental services in a United States public healthcare system: a retrospective cohort study

Background

As several studies have shown an association between periodontal disease and chronic kidney disease (CKD), regular dental care may be an important strategy for reducing the burden of CKD. Access to dental care may be limited in the US public health system.

Methods

In this retrospective cohort study of 6,498 adult patients with (n = 2,235) and without (n = 4,263) CKD and at least 12 months of follow-up within the San Francisco Department of Public Health Community Health Network clinical databases, we examined the likelihood of having a dental visit within the observation period (2005-2010) using Cox proportional hazards models. To determine whether dental visits reflected a uniform approach to preventive service use in this setting, we similarly examined the likelihood of having an eye visit among those with diabetes, for whom regular retinopathy screening is recommended. We defined CKD status by average estimated glomerular filtration rate based on two or more creatinine measurements ≥ 3 months apart (no CKD, ≥ 60 ml/min/1.73 m²; CKD, < 60 ml/min/1.73 m²).

Results

Only 11.0% and 17.4% of patients with and without CKD, respectively, had at least one dental visit. Those with CKD had a 25% lower likelihood of having a dental visit [HR = 0.75, 95% CI (0.64-0.88)] than those without CKD after adjustment for confounders. Among the subgroup of patients with diabetes, 11.8% vs. 17.2% of those with and without CKD had a dental visit, while 58.8% vs. 57.8% had an eye visit.

Conclusions

Dental visits, but not eye visits, in a US public healthcare setting are extremely low, particularly among patients with CKD. Given the emerging association between oral health and CKD, addressing factors that impede dental access may be important for reducing the disparate burden of CKD in this population.

Association between GFR, proteinuria, and adverse outcomes among White, Chinese, and South Asian individuals in Canada

BACKGROUND

We investigated the association between proteinuria, estimated glomerular filtration rate (eGFR), and risk of mortality and kidney failure in white, Chinese, and South Asian populations.

STUDY DESIGN

Population-based cohort study.

SETTING & PARTICIPANTS

Participants from Alberta, Canada, with a serum creatinine and urine protein dipstick measurement from January 1, 2005, to December 31, 2005.

PREDICTOR

White, Chinese, or South Asian ethnicity.

OUTCOMES

Prevalence of proteinuria by level of eGFR (estimated using the MDRD [Modification of Diet in Renal Disease] Study equation) and the association between eGFR, proteinuria, and all-cause mortality and kidney failure.

MEASUREMENTS

Rates of all-cause mortality and kidney failure per 1,000 person-years were calculated using Poisson regression by ethnicity, eGFR level, and proteinuria level while adjusting for sociodemographic variables and comorbid conditions.

RESULTS

Of 491,729 participants, 5.3% were Chinese and 4.7% were South Asian. For participants with eGFR <60 mL/min/1.73 m(2), the prevalence of heavy proteinuria was higher in Chinese and South Asians compared with whites. Compared with whites, adjusted rates of death were significantly lower for Chinese and South Asian populations (rate ratios, 0.67 [95% CI, 0.56-0.80] and 0.73 [95% CI, 0.59-0.88], respectively); these rate ratios did not vary by eGFR and proteinuria levels.

LIMITATIONS

Using surname to identify ethnicity has the potential for misclassification due to name changes and identical last names from different ethnic groups. Also, to be eligible for inclusion, participants had to have a measurement of serum creatinine and urine dipstick proteinuria.

CONCLUSIONS

Although increasing proteinuria and lower eGFR predicted mortality and progression to kidney failure in all 3 ethnic groups, both Chinese and South Asian populations experienced a lower risk of death and similar risk of kidney failure compared with whites at all eGFR and proteinuria levels. Studies exploring this association further are required.

Level and determinants of kidney function in a South Asian population in Pakistan

BACKGROUND

People of South Asian origin are at high risk of chronic kidney disease. Some have suggested that the usual level of glomerular filtration rate (GFR) in South Asians may be lower than in populations of European origin. However, measured GFR in a general adult population of South Asian origin has not been studied.

DESIGN

Cross-sectional observational study.

SETTING & PARTICIPANTS

530 patients 40 years or older randomly selected from communities in Karachi, Pakistan, using multistage cluster sampling. Patients with both diabetes and hypertension were excluded.

PREDICTOR

Age, sex, diabetes, and hypertension.

OUTCOME

Measured GFR using urinary clearance of inulin.

RESULTS

Mean age of participants was 49.7 ± 9.5 (standard deviation [SD]) years, 51% were men, 34.9% had hypertension, and 30.5% had diabetes. Mean measured GFR was 94.1 ± 28.6 mL/min/1.73 m(2). GFR was lower by 0.79 ± 0.11 mL/min/1.73 m(2) for each 1-year older age. The 5-year age- and sex-specific mean GFR of the study population generally was within 1 SD of the mean of previously reported values for US adults. Factors independently associated with GFR were younger age (β coefficient, -3.84 [95% CI, -5.46 to -2.21] mL/min/1.73 m(2) per 5 years older), higher serum albumin level (4.58 [95% CI, 0.74-8.42] mL/min/1.73 m(2) per 0.5-g/dL increase), higher fasting plasma glucose level (0.81 [95% CI, 0.44-1.18] mL/min/1.73 m(2) per 10-mg/dL increase), high versus low meat intake (7.81 [95% CI, 1.14-14.48] mL/min/1.73 m(2) for ≥11 vs ≤5 servings/wk), and higher estimated protein intake (1.46 [95% CI, 0.41-2.51] mL/min/1.73 m(2) per 1.0-g/d increase) from urine urea nitrogen.

LIMITATIONS

Moderate sample size, lack of validation of some items in the dietary assessment for this study population.

CONCLUSIONS

Mean measured GFR in South Asian adults from the general population in Karachi, Pakistan, is only modestly lower than in European-origin counterparts, with similar age association. This may reflect lower dietary protein intake in South Asians.

Racial and ethnic differences in kidney function decline among persons without chronic kidney disease

Whether the rate of kidney function decline before the onset of CKD differs among racial and ethnic groups remains unclear. Here, we evaluated kidney function decline and incident CKD among white, black, Hispanic, and Chinese participants in the Multi-Ethnic Study of Atherosclerosis (MESA) during 5 years of follow-up. We estimated GFR using both cystatin C (eGFRcys) and creatinine (eGFRcreat). The definition of incident CKD required eGFRcys <60 ml/min per 1.73 m(2) and a decline in eGFRcys ≥1 ml/min per year. Among participants with eGFRcreat >60 ml/min per 1.73 m(2) at baseline, blacks had a significantly higher rate of kidney function decline than whites (0.31 ml/min per 1.73 m(2)/yr faster on average, P=0.001), even after adjusting for multiple potential confounders. Among Hispanics, Dominicans and Puerto Ricans had faster rates of decline than whites (0.55 and 0.47 ml/min per 1.73 m(2)/yr faster, respectively). Mexicans, South Americans, or other Hispanics had similar rates of decline compared to whites. We did not detect significant differences in the rates of kidney function decline among Chinese and white participants. Among those with normal or near-normal kidney function at baseline, blacks and Hispanics had the highest rates of incident CKD during follow-up. Adjustment for comorbidities attenuated some of these differences. In conclusion, the average rate of kidney function decline before the onset of CKD differs among racial and ethnic groups. Traditional risk factors do not explain these differences fully, highlighting the need to explore these disparities.

High normal levels of albuminuria and risk of hypertension in Indo-Asian population

BACKGROUND

Urine albumin excretion in the high normal range [urine albumin to creatinine ratio (UACR) 10-29 mg/g)] predicts hypertension in European-origin populations. However, the prognostic significance of UACR in the high normal range for incident hypertension is unclear in Indo-Asians. The objective of this study was to examine the relationship of normal to high normal levels of UACR and incident hypertension.

METHODS

We conducted a nested cohort study within a cluster randomized controlled trial in Pakistan on 1272 normotensive non-diabetic adults aged ≥ 40 years with UACR <30 mg/g. Incident hypertension was defined as new onset of systolic blood pressure (SBP) ≥ 140 mmHg or diastolic ≥ 90 mmHg or initiation of antihypertensive therapy.

RESULTS

A total of 920 (72.3%) participants completed the 2-year final follow-up. During this time, 105 (11.4%) developed incident hypertension. In the multivariable model, the odds [95% confidence interval (CI)] for incident hypertension were 2.45(1.21-4.98) for those in the fourth (top) quartile (≥ 6.1 mg/g) and 2.12 (1.04-4.35) in the third quartile (3.8-6.1 mg/g) compared to those in the lowest quartile (<2.8 mg/g). In addition, a significant interaction between UACR and baseline SBP was observed suggesting that the odds (95% CI) of incident hypertension with UACR were greater at lower baseline SBP (interaction P = 0.044).

CONCLUSIONS

High normal levels of albuminuria as measured by UACR predict hypertension in non-diabetic Indo-Asians, and this relationship may be enhanced in individuals with low baseline SBP. Further research is needed to assess the clinical applicability of these findings.

Year-long antihypertensive therapy with candesartan completely prevents development of cardiovascular organ injuries in spontaneously hypertensive rats

Most previous studies have examined the effects of antihypertensive drugs in hypertensive animals for only a few months, and little information has been provided as to the protective effects of lifetime antihypertensive medication against cardiovascular organ injury. In this study, spontaneously hypertensive rats (SHR) were treated for 1 year with an angiotensin-II receptor antagonist (ARB) and the development of hypertensive organ injury was evaluated. Male 15-week-old SHR (n = 9) were given 25 mg/L candesartan (CS) in their drinking water for 1 year. Twelve SHR and 9 normotensive Wistar-Kyoto rats (WKY) were given normal tap water. Tail-cuff blood pressure was almost normalized by CS throughout 1 year (at 12-months: WKY 132 ± 3, SHR 229 ± 3, CS 137 ± 4 mmHg). After 1 year, cardiac ventricular weight (SHR +33%, CS -2% versus WKY) and aortic thickness (SHR +34%, CS +4% versus WKY) in the CS-treated SHR rats were not different than those of WKY. Echocardiographic midwall fractional shortening (SHR -18%, CS -1% versus WKY) and left ventricular hydroxyproline content (SHR +47%, CS +11% versus WKY) were also improved by CS to the WKY level. With respect to kidney function, GFR (SHR -24%, CS +9% versus WKY) was preserved, proteinuria (SHR +312%, CS +12% versus WKY) was reduced, and the histological glomerular injury rate (SHR +186%, CS +6% versus WKY) was reduced by CS. These results suggest that long-term antihypertensive therapy with CS can completely prevent hypertensive cardiovascular and renal injuries in SHR.

Associations of acculturation and kidney dysfunction among Hispanics and Chinese from the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Acculturation affects health, but it has never been studied with kidney disease.

METHODS

We studied the association of language spoken at home, generation and birth place with kidney function among Hispanics and Chinese in the Multi-Ethnic Study of Atherosclerosis (n = 2999). Kidney function was determined by cystatin C (eGFRcys) and albumin/creatinine ratio (ACR). We evaluated mediators in models: Model 1 = age, sex, income, education; Model 2 = Model 1 + behaviors; and Model 3 = Model 1 + comorbidities.

RESULTS

Among Hispanics, speaking mixed Spanish/English was significantly associated with lower eGFRcys (- 2.83 mL/min/1.73 m(2), - 5.69-0.04) and higher ACR (RD 40%, 17-68%) compared with speaking Spanish only; this was mildly attenuated by behaviors (- 2.29, - 5.33-0.75; RD 42%, 18-72%) but not comorbidities (- 3.04, - 5.83 to - 0.23); RD 35%, 14-59%). US-born Hispanics had lower eGFRcys compared with foreign-born Hispanics [1.83 mL/min/1.73 m(2) lower (0.97-1.31) for Generation 1; 1.37 mL/min/1.73 m(2) lower (0.75-1.57) for Generation ≥ 2]. In contrast, Chinese who spoke any English had higher eGFRcys (2.53, 95% CI: - 1.70-6.78), but similar ACR (RD - 5%, 95% CI: - 26-23%) compared with those speaking Chinese only, but associations were not statistically significant.

CONCLUSION

Higher acculturation was associated with worse kidney function in Hispanics, mediated perhaps by behavioral factors but not comorbidities. Associations may be in the opposite direction among Chinese. Future studies are needed to elucidate these mechanisms.

Differences in progression of CKD and mortality amongst Caucasian, Oriental Asian and South Asian CKD patients

BACKGROUND

Ethnic differences in chronic kidney disease (CKD) progression are not well characterized but are of interest across and within countries.

METHODS

We followed up a large CKD cohort of patients of three different ethnic origins [Caucasian, Oriental Asian (OA) and South Asian (SA)] from time of nephrology referral in a universal health care system. Key outcomes were time to death and/or renal replacement therapy (RRT) and rate of decline in estimated GFR (eGFR). The effects of known predictors (blood pressure, proteinuria, age, sex, diabetes, cardiovascular disease and medications) and of other laboratory abnormalities were assessed using multivariate modelling techniques, including both Cox proportional hazards and competing risk approach.

RESULTS

The cohort comprised 3444 patients (2626 Caucasians, 397 OA and 421 SA). All-cause mortality rates are higher in Caucasians than SA or OA [hazard ratio (HR) 0.693 and 0.803, P < 0.05]. OA and SA have higher risks of progressing to RRT (HR 1.281 and 1.349, P < 0.05) and lower risks of death before RRT (HR 0.718 and 0.520, P < 0.05) compared to Caucasians after adjustment for usual risk factors. However, when adjusted for additional laboratory abnormalities, differences did not persist for progression, but did for survival advantage of Asians. The median rate of decline in eGFR (in millilitres per minute per 1.73 m(2)) was significantly slower in Caucasians (-2.11) than in OA (-2.93) or SA (-3.56), P = 0.027.

CONCLUSIONS

Asians appear to have faster CKD progression and lower mortality rates compared to Caucasians. This effect is not explained by the usual variables, but rates of progression may be related to differences in severity of laboratory abnormalities at different CKD stages. Further research is needed to understand the implications of these findings.

Chronic kidney disease in the urban poor

BACKGROUND AND OBJECTIVES

In the United States, relatively little is known about clinical outcomes of chronic kidney disease (CKD) in vulnerable populations utilizing public health systems. The primary study objectives were to describe patient characteristics, incident ESRD, and mortality in adults with nondialysis-dependent CKD receiving care in the health care safety net.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Time to ESRD and time to death were examined among a cohort of 15,353 ambulatory adults with nondialysis-dependent CKD from the Community Health Network of San Francisco.

RESULTS

The mean age of the CKD cohort was 59.0 +/- 13.8 years; 50% of the cohort was younger than 60 years and 26% was younger than 50 years. Most (72%) were members of nonwhite racial-ethnic groups, 73% were indigent (annual income <$15,000) and 18% were uninsured. In adjusted analyses, blacks [hazard ratio (95% confidence interval), 4.00 (2.99 to 5.35)], Hispanics [2.20 (1.46 to 3.30)], and Asians/Pacific Islanders [3.84 (2.73 to 5.40)] had higher risks of progression to ESRD than non-Hispanic whites. The higher risk of progression to ESRD among nonwhite compared with white persons with CKD was not explained by lower relative mortality.

CONCLUSIONS

Adults with CKD stages 3 to 5 cared for within an urban public health system were relatively young and predominantly nonwhite-both factors associated with a higher risk of progression to ESRD. These findings call for targeted efforts to assess the burden and progression of CKD within other public and safety-net health systems in this country.

Ethnic disparities in prevalence and impact of risk factors of chronic kidney disease

BACKGROUND

There is substantial heterogeneity in literature regarding the epidemiology for chronic kidney disease (CKD) in different Asian populations. We aimed to assess the prevalence and risk factors of CKD in a multi-ethnic Asian population in Singapore.

METHODS

We examined 4499 participants of Chinese, Malay and Indian ethnicity, aged 24-95 years, who participated in the Singapore Prospective Study Program. CKD was defined as an estimated glomerular filtration rate <60 ml/min/1.73 m(2) or the presence of micro/macroalbuminuria.

RESULTS

The age, sex-standardized prevalence of CKD was 12.8% (11.4%, 18.6% and 17.6% in Chinese, Malays and Indians). Older age and the presence of diabetes, hypertension and dyslipidaemia were significantly associated with CKD in all ethnic groups. Clinical, metabolic, socioeconomic and behavioral factors accounted for 68% and 78% of excess risk of CKD in Malays and in Indians, respectively. Diabetes (45%) and dyslipidaemia (16%) among Malays and hypertension among Indians (23%) had greater population-attributable risk of CKD.

CONCLUSIONS

The prevalence of CKD is high in all three major Asian ethnic groups, in particular Malays and Indians, but risk factors are similar to those reported from previous studies in Western populations. The association of modifiable risk factors with CKD emphasizes the need to screen and treat high-risk populations for early detection and prevention of CKD.

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

BACKGROUND

Diabetes and hypertension are potent risk factors for end-stage renal disease (ESRD). Previous studies suggest that other cardiovascular risk factors also may increase the risk of ESRD; however, risk associated with a comprehensive cardiovascular risk-factor assessment has not been quantified in a population-based sample.

STUDY DESIGN

The Atherosclerosis Risk in Communities (ARIC) Study, a prospective observational cohort.

SETTING & PARTICIPANTS

15,324 white and African American participants aged 45-64 years from 4 US communities were followed up after a baseline visit that occurred in 1987-1989.

PREDICTOR

A comprehensive collection of cardiovascular risk factors were examined.

OUTCOMES & MEASUREMENTS

Incidence of ESRD (transplant, dialysis, catheter placement or kidney failure, and death) exclusive of acute kidney failure was ascertained through active surveillance of hospitalizations through 2004.

RESULTS

During a median 16-year follow-up, 241 cases of ESRD developed (incidence rate, 1.04 cases/1,000 person-years). Male sex, African American race, diabetes, hypertension, history of coronary heart disease, smoking, older age, body mass index, and triglyceride concentration were associated with increased risk of ESRD after adjustment for baseline estimated glomerular filtration rate (eGFR) and each other. There was a graded curvilinear association between risk of ESRD and lower baseline eGFR at levels < 90 mL/min/1.73 m(2) and moderately increased levels > 120 mL/min/1.73 m(2). The relative risk of eGFR on ESRD risk generally was greater in women and individuals with diabetes than in their counterparts.

LIMITATIONS

Only events occurring in acute-care hospitals were investigated (but there was long-term continuous active surveillance of events).

CONCLUSIONS

We quantify the relative risk of ESRD in a community-based African American and white population associated with established cardiovascular risk factors (diabetes, hypertension, male sex, and African American race) and report prospective data identifying greater risk of ESRD associated with other cardiovascular risk factors: moderately decreased eGFR, increased eGFR, higher body mass index, smoking, and increased triglyceride level.

Characteristics of uninsured Americans with chronic kidney disease

BACKGROUND

In the United States, public health insurance is available for nearly all persons with end-stage renal disease (ESRD). Little is known about the extent of health insurance coverage for persons with non-dialysis dependent chronic kidney disease (CKD).

OBJECTIVE

To describe patterns of health insurance coverage for adults with non-dialysis dependent CKD and to examine risk factors for progression of CKD to ESRD and management of hypertension among those lacking insurance.

DESIGN AND PARTICIPANTS

Cross-sectional analysis of data from a nationally representative sample of 16,148 US adults aged 20 years or older who participated in the National Health and Nutrition Examination Survey 1999-2006.

MEASUREMENTS

National prevalence estimates of health insurance coverage, ESRD risk factors, and treatment of hypertension.

MAIN RESULTS

An estimated 10.0% (95% CI, 8.3%-12.0%) of US adults with non-dialysis dependent CKD were uninsured, 60.9% (95% CI, 58.2%-63.7%) had private insurance and 28.7% (95% CI, 26.4%-31.1%) had public insurance alone. Uninsured persons with non-dialysis dependent CKD were more likely to be under the age of 50 (62.8% vs. 23.0%, P < 0.001) and nonwhite (58.7%, vs. 21.8%, P < 0.001) compared with their insured counterparts. Approximately two-thirds of uninsured adults with non-dialysis dependent CKD had at least one modifiable risk factor for CKD progression, including 57% with hypertension, 40% who were obese, 22% with diabetes, and 13% with overt albuminuria. In adjusted analyses, uninsured persons with non-dialysis dependent CKD were less likely to be treated for their hypertension (OR, 0.59; 95% CI, 0.40-0.85) and less likely to be receiving recommended therapy with angiotensin inhibitors (OR, 0.45; 95% CI, 0.26-0.77) compared with those with insurance coverage.

CONCLUSIONS

Uninsured persons with non-dialysis dependent CKD are at higher risk for progression to ESRD than their insured counterparts but are less likely to receive recommended interventions to slow disease progression. Lack of public health insurance for patients with non-dialysis dependent CKD may result in missed opportunities to slow disease progression and thereby reduce the public burden of ESRD.

How do communities want their information? Designing educational outreach on organ donation for Asian Americans

CONTEXT

Support of organ donation among Asian Americans has been limited, but lack of access to information and prevalence of misinformation are 2 barriers that might be counteracted by public education.

OBJECTIVE

To solicit advice from 4 Asian American communities on the design of a culturally appropriate educational campaign on organ donation and transplantation.

DESIGN AND SETTING

Cross-sectional, multilingual survey administered at community festivals and supermarkets.

PARTICIPANTS

201 Asian American respondents.

MAIN OUTCOME MEASURES

The components of an effective public education outreach campaign on organ donation were defined for 4 Asian American communities.

RESULTS

Media venues ranked highest for information dissemination on organ donation/transplantation were, in descending order, mainstream television, ethnic newspapers, mainstream newspapers, and ethnic television. Most respondents preferred a spokesperson of Asian American descent, but opinions differed by ethnicity as to whether an effective spokesperson needed to be of the same Asian ethnicity as the respondents. Respondents were further divided by ethnicity on their preference for a locally or nationally well-known spokesperson. The most compelling scenario to promote organ donation was an Asian American waiting for a transplant, followed by an organ donor family or individual, and, last, a transplant recipient. Different advertisements for organ donation appealed to different Asian ethnic groups.

CONCLUSIONS

Community-based research gives communities the opportunity to collaborate with health professionals in designing health education programs that target their own populations. Because key aspects influencing campaign efficacy can vary by ethnicity, these important differences need to be taken into account in outreach planning.

How Do Communities Want Their Information? Designing Educational Outreach on Organ Donation for Asian Americans

Context

Support of organ donation among Asian Americans has been limited, but lack of access to information and prevalence of misinformation are 2 barriers that might be counteracted by public education.

Objective

To solicit advice from 4 Asian American communities on the design of a culturally appropriate educational campaign on organ donation and transplantation.

Design and Setting

Cross-sectional, multilingual survey administered at community festivals and supermarkets.

Participants

201 Asian American respondents.

Main Outcome Measures

The components of an effective public education outreach campaign on organ donation were defined for 4 Asian American communities.

Results

Media venues ranked highest for information dissemination on organ donation/transplantation were, in descending order, mainstream television, ethnic newspapers, mainstream newspapers, and ethnic television. Most respondents preferred a spokesperson of Asian American descent, but opinions differed by ethnicity as to whether an effective spokesperson needed to be of the same Asian ethnicity as the respondents. Respondents were further divided by ethnicity on their preference for a locally or nationally well-known spokesperson. The most compelling scenario to promote organ donation was an Asian American waiting for a transplant, followed by an organ donor family or individual, and, last, a transplant recipient. Different advertisements for organ donation appealed to different Asian ethnic groups.

Conclusions

Community-based research gives communities the opportunity to collaborate with health professionals in designing health education programs that target their own populations. Because key aspects influencing campaign efficacy can vary by ethnicity, these important differences need to be taken into account in outreach planning.

Asian leadership in chronic kidney disease

Asian Pacific countries include those with the highest incidence of renal failure in the world, the richest and poorest economies and unparalleled diversity of economy, culture and geography. From this come many challenges, but also a strong basis for the introduction of strategies to combat renal diseases. With a rapidly developing scientific community, Asia needs to accept the challenge of becoming a global leader in nephrology in the near future.

Neighborhood poverty and kidney transplantation among US Asians and Pacific Islanders with end-stage renal disease

The degree to which low transplant rates among Asians and Pacific Islanders in the United States are confounded by poverty and reduced access to care is unknown. We examined the relationship between neighborhood poverty and kidney transplant rates among 22 152 patients initiating dialysis during 1995-2003 within 1800 ZIP codes in California, Hawaii and the US-Pacific Islands. Asians and whites on dialysis were distributed across the spectrum of poverty, while Pacific Islanders were clustered in the poorest areas. Overall, worsening neighborhood poverty was associated with lower relative rates of transplant (adjusted HR [95% CI] for areas with > or =20% vs. <5% residents living in poverty, 0.41 [0.32-0.53], p < 0.001). At every level of poverty, Asians and Pacific Islanders experienced lower transplant rates compared with whites. The degree of disparity increased with worsening neighborhood poverty (adjusted HR [95% CI] for Asians-Pacific Islanders vs. whites, 0.64 [0.51-0.80], p < 0.001 for areas with <5% and 0.30 [0.21-0.44], p < 0.001 for areas with > or =20% residents living in poverty; race-poverty level interaction, p = 0.039). High levels of neighborhood poverty are associated with lower transplant rates among Asians and Pacific Islanders compared with whites. Our findings call for studies to identify cultural and local barriers to transplant among Asians and Pacific Islanders, particularly those residing in resource-poor neighborhoods.

Age affects outcomes in chronic kidney disease

Chronic kidney disease (CKD) is common among the elderly. However, little is known about how the clinical implications of CKD vary with age. We examined the age-specific incidence of death, treated end-stage renal disease (ESRD), and change in estimated glomerular filtration rate (eGFR) among 209,622 US veterans with CKD stages 3 to 5 followed for a mean of 3.2 years. Patients aged 75 years or older at baseline comprised 47% of the overall cohort and accounted for 28% of the 9227 cases of ESRD that occurred during follow-up. Among patients of all ages, rates of both death and ESRD were inversely related to eGFR at baseline. However, among those with comparable levels of eGFR, older patients had higher rates of death and lower rates of ESRD than younger patients. Consequently, the level of eGFR below which the risk of ESRD exceeded the risk of death varied by age, ranging from 45 ml/min per 1.73 m(2) for 18 to 44 year old patients to 15 ml/min per 1.73 m(2) for 65 to 84 year old patients. Among those 85 years or older, the risk of death always exceeded the risk of ESRD in this cohort. Among patients with eGFR levels <45 ml/min per 1.73 m(2) at baseline, older patients were less likely than their younger counterparts to experience an annual decline in eGFR of >3 ml/min per 1.73 m(2). In conclusion, age is a major effect modifier among patients with an eGFR of <60 ml/min per 1.73 m(2), challenging us to move beyond a uniform stage-based approach to managing CKD.

Superiority of the Modification of Diet in Renal Disease equation over the Cockcroft-Gault equation in screening for impaired kidney function in Japanese Americans

The Cockcroft-Gault and the Modification of Diet in Renal Disease (MDRD) Study equations have not been validated in Asian Americans with varying degrees of glucose tolerance. We compared both equations to 24-h urinary creatinine clearance, the latter as a standard measurement of glomerular filtration rate (GFR), in 398 Japanese Americans (62.1+/-5.8 years, mean+/-S.D.) who had normal glucose tolerance (NGT) (n=138), impaired glucose tolerance (IGT) (n=136) and diabetes (n=124). Although both the Cockcroft-Gault (r=0.65, P<0.001) and the MDRD (r=0.74, P<0.001) equations correlated well with creatinine clearance, the latter was significantly superior (P=0.013 between r values). Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) for the MDRD equation was significantly greater than for the Cockcroft-Gault equation (AUC 0.86 versus 0.80, P=0.015) in classifying subjects as having mildly reduced GFR (<90ml/min per 1.73m(2)). However, both equations overestimated the number of individuals with decreased GFR. We conclude therefore that while the MDRD equation more accurately identifies Asians who are in the early stages of kidney disease, as for other groups, a correction term appears necessary in order to reduce the number of Asian subjects being falsely diagnosed with CKD.

Epidemiologic and clinical factors associated with chronic kidney disease among Asian Americans and Native Hawaiians

OBJECTIVE

To examine the association between key susceptibility factors and measures of chronic kidney disease in Asian American and Native Hawaiian participants enrolled in the Hawai'i site of the national Kidney Early Evaluation Program (KEEP-2) study community screening program.

DESIGN

In 2001-2003, 793 participants from five ethnic groups (Japanese, Native Hawaii an, Chinese, Filipino and Caucasian) were enrolled in the Hawai'i KEEP-2 program. Odds ratios were used as the measure of association and were computed using unconditional logistic regression. Renal susceptibility factors for chronic kidney disease were included in a multivariable model if found to be statistically significant in univariate analysis. The proportion of Hawai'i KEEP-2 study participants manifesting various clinical characteristics were compared by ethnicity with Japanese as the referent group.

RESULTS

Significant ethnic differences in the occurrence of chronic kidney disease were found, with Japanese having the lowest occurrence of chronic kidney disease (18%) and Native Hawaiians the highest (40%). Within each ethnic group, the occurrence of chronic kidney disease was associated with a different ethnic-specific clustering of susceptibility factors. Hypertension was associated with chronic kidney disease among four of the five ethnic groups: Japanese, Caucasian, Native Hawaiian and Filipino. Overweight was associated with a decreased occurrence of chronic kidney disease among Caucasians, while diabetes and lower educational attainment were associated with increased occurrence of chronic kidney disease among Native Hawaiians. For Filipinos, diabetes and age 65 years and older were both associated with an increased occurrence for chronic kidney disease while lower educational attainment was associated with a reduced occurrence of chronic kidney disease. Among Chinese, no factors were significantly associated with chronic kidney disease, although trends for all factors paralleled those of the overall study group.

CONCLUSIONS

The occurrence of chronic kidney disease in the Hawai'i KEEP-2 study was nearly fourfold greater compared with the general US population. The clustering of susceptibility factors for chronic kidney disease occurrence was found to differ for all five ethnic groups.

Longitudinal study of racial and ethnic differences in developing end-stage renal disease among aged medicare beneficiaries

Diabetes and hypertension are the leading causes of renal failure. This study investigated racial differences in developing ESRD by participants' diabetes and hypertension status. This longitudinal study included 1,306,825 Medicare beneficiaries who were aged > or =66 yr at the study start and followed up to 10 yr from January 1, 1993, for the development of ESRD or death. During the 10 yr, 0.93 patients per 100 received ESRD treatment. After adjustment for age and gender, among patients with diabetes, black patients were 2.4 to 2.7 times and other races/ethnicities 1.6 to 1.7 times more likely than white patients to develop ESRD. Among hypertensive patients, black patients were 2.5 to 2.9 and others 1.7 to 1.8 times more likely than white patients to develop ESRD. Among patients with neither diabetes nor hypertension, black patients were 3.5 and others 2.0 times more likely. Black men with diabetes were 1.9 to 2.1 and women 2.5 to 3.4 times more likely than their white counterparts to develop ESRD. Hypertensive black men were 2.1 to 2.2 and women 2.8 to 3.6 times more likely to develop ESRD. The same findings were noted in women of other races/ethnicities. Compared with white counterparts, mortality was higher for black patients in all cohorts but lower among patients with ESRD. Although they are leading causes for renal failure, diabetes and hypertension do not cause racial differences in developing ESRD. Minority women especially are at greater risk for ESRD than white women. Further studies are needed to determine whether earlier initiation of dialysis is a factor in higher ESRD incidence among minorities.

Exploring Secular Trends in the Likelihood of Receiving Treatment for End-Stage Renal Disease

There is a limited understanding of the forces that drive the steady rise in the number of patients who receive treatment for ESRD. It was hypothesized that this is not simply due to increasing prevalence of chronic kidney disease (CKD) or changes in renal failure risk factors in the population from which ESRD cases develop. A noncurrent cohort study was conducted to quantify the change over time (per year) in the likelihood of receiving ESRD therapy in a cohort of 320,252 individuals who volunteered for health check-ups between 1964 and 1985. Initiation of ESRD treatment was ascertained using the US Renal Data System registry through 2000. A total of 1471 cases of ESRD were observed during 8,347,955 person-years of observation, with ESRD cases developing between 1973 and 2000. In unadjusted Cox proportional hazards analysis, individuals who were examined later in time had an 8% per year higher risk for progressing to receive treatment for ESRD (relative risk 1.08; 95% confidence interval 1.05 to 1.11). This temporal trend in risk for future ESRD associated with year of cohort entry (baseline examination) was not explained by increases over time in the prevalence of CKD or risk factors for renal failure. After adjustment for age, gender, race, diabetes, BP, body mass index, education level, smoking status, history of myocardial infarction, serum cholesterol, proteinuria, hematuria, and serum creatinine level, there remained an 8% per year increase in risk (relative risk 1.08; 95% confidence interval 1.06 to 1.11). Among individuals who were examined from the 1960s through the 1980s, those who were examined later were more likely to receive treatment for ESRD. This trend was not accounted for by increasing prevalence of baseline CKD or risk factors for renal failure. These findings should spur further research into other forces that drive the rise in treated ESRD.