Racial and ethnic disparities in end-stage kidney failure-survival paradoxes in African-Americans

Incidence of end-stage renal disease in the Turkish-Cypriot population of Northern Cyprus: a population based study

BACKGROUND

This is the first report of the incidence and causes of end-stage renal disease (ESRD) of the Turkish-Cypriot population in Northern Cyprus.

METHODS

Data were collected over eight consecutive years (2004-2011) from all those starting renal replacement therapy (RRT) in this population. Crude and age-standardised incidence at 90 days was calculated and comparisons made with other national registries. We collected DNA from the entire prevalent population. As an initial experiment we looked for two genetic causes of ESRD that have been reported in Greek Cypriots.

RESULTS

Crude and age-standardised incidence at 90 days was 234 and 327 per million population (pmp) per year, respectively. The mean age was 63, and 62% were male. The age-adjusted prevalence of RRT in Turkish-Cypriots was 1543 pmp on 01/01/2011. The incidence of RRT is higher than other countries reporting to the European Renal Association - European Dialysis and Transplant Association, with the exception of Turkey. Diabetes is a major cause of ESRD in those under 65, accounting for 36% of incident cases followed by 30% with uncertain aetiology. 18% of the incident population had a family history of ESRD. We identified two families with thin basement membrane nephropathy caused by a mutation in COL4A3, but no new cases of CFHR5 nephropathy.

CONCLUSIONS

This study provides the first estimate of RRT incidence in the Turkish-Cypriot population, describes the contribution of different underlying diagnoses to ESRD, and provides a basis for healthcare policy planning.

The effect of race and chronic obstructive pulmonary disease on long-term survival after coronary artery bypass grafting

Background: Chronic obstructive pulmonary disease (COPD) is a known predictor of decreased long-term survival after coronary artery bypass grafting (CABG). Differences in survival by race have not been examined.

Methods: A retrospective cohort study was conducted of CABG patients between 2002 and 2011. Long-term survival was compared in patients with and without COPD and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model.

Results: A total of 984 (20%) patients had COPD (black n = 182; white n = 802) at the time of CABG (N = 4,801). The median follow-up for study participants was 4.4 years. COPD was observed to be a statistically significant predictor of decreased survival independent of race following CABG (no COPD: HR = 1.0; white COPD: adjusted HR = 1.9, 95% CI = 1.7–2.3; black COPD: adjusted HR = 1.6, 95% CI = 1.1–2.2).

Conclusion: Contrary to the expected increased risk of mortality among black COPD patients in the general population, a similar survival disadvantage was not observed in our CABG population.

The impact of cardiovascular disease and risk factor treatment on ethnic disparities in kidney transplant

There is limited data on the use of cardiovascular disease (CVD) risk factor medications following renal transplant, especially when comparing use across ethnicities. The aim of this study was to compare the incidence, treatment, and impact of CVD between ethnicities in kidney transplant recipients. This was a retrospective cohort study of adults who underwent transplant between 2000 and 2008 within our academic medical transplant center. Pediatrics, multiorgan transplants, and those lost to follow-up were excluded. Data collection included all transplant and sociodemographic characteristics, medication use, CVD risk factor management, and follow-up events, including acute rejection, graft loss, and death. A total of 987 patients were included and followed for a mean of 6.7 ± 3.0 years. The baseline demographics revealed black patients were equally likely to have preexisting CVD (24% vs 25%, P = .651), but more likely to have preexisting diabetes (35% vs 23%, P < .001) or hypertension (97% vs 94%, P = .029). Black patients had poorer treatment of CVD risk factors, with lower rates of control of diabetes (35% vs 51%, P < .05) and dyslipidemia (37% vs 42%, P < .05). Black renal transplant recipients who had preexisting CVD had reduced graft survival rates compared to white patients (10-year rate 50% vs 60%, P = .033), but similar rates of graft survival were found in those without CVD (10-year rate 70% vs 71% in white patients, P = .483). CVD is common in transplant recipients, with black patients having higher rates and poorer control of diabetes and dyslipidemia.

Religiosity and social support: implications for the health-related quality of life of African American hemodialysis patients

The purpose of this study was to determine whether sociocultural differences have any effect on the health-related quality of life among African American hemodialysis patients. This study examined relationships between religiosity, social support, and the health-related quality of life of African American hemodialysis patients. Four hemodialysis units were selected for the study. The study population consisted of 176 African American hemodialysis patients who had been receiving hemodialysis treatments for at least 1 month. The religiosity variable was measured by the Measure of Religious Involvement. Social Support was measured by the Medical Outcomes Study Social Support Survey, and health-related quality of life was measured by the Medical Outcomes Study 36 Short Form Health Survey (SF-36v2). The investigators found that social support contributed to the emotional and physical health of African American hemodialysis patients in the sample, whereas religiosity was inversely related to the physical health of these patients.

Trends in the incidence of atrial fibrillation in older patients initiating dialysis in the United States

BACKGROUND

One sixth of US dialysis patients 65 years of age have been diagnosed with atrial fibrillation/flutter (AF). Little is known, however, about the incidence of AF in this population.

METHODS AND RESULTS

We identified 258 605 older patients (≥67 years of age) with fee-for-service Medicare initiating dialysis in 1995 to 2007, who had not been diagnosed with AF within the previous 2 years. Patients were followed for newly diagnosed AF. Multivariable proportional hazard regression was used to examine temporal trends and associations of race and ethnicity with incident AF. We also studied temporal trends in the mortality and risk of ischemic stroke after new AF. Over 514 395 person-years of follow-up, 76 252 patients experienced incident AF for a crude AF incidence rate of 148/1000 person-years. Incidence of AF increased by 11% (95% confidence interval, 5-16) from 1995 to 2007. Compared with non-Hispanic whites, blacks (-30%), Asians (-19%), Native Americans (-42%), and Hispanics (-29%) all had lower rates of incident AF. Mortality after incident AF decreased by 22% from 1995 to 2008. Even more pronounced reductions were seen for incident ischemic stroke during these years.

CONCLUSIONS

The incidence of AF is high in older patients initiating dialysis in the United States and has been increasing over the 13 years of study. Mortality declined during that time but remained >50% during the first year after newly diagnosed AF. Because data on warfarin use were not available, we were unable to study whether trends toward better outcomes could be explained by higher rates of oral anticoagulation.

Influence of vascular access type on sex and ethnicity-related mortality in hemodialysis-dependent patients

OBJECTIVES

To determine whether sex- and ethnicity-based mortality differences in patients dependent on hemodialysis (hemodialysis patients) are because of prevalence of vascular access type.

METHODS

Southern California Permanente Medical Group Renal Database, which contained 5821 chronic hemodialysis patients between 2000 and 2008, was studied.

RESULTS

Mean age of the patients was 62 years, and 59% were male. Of the population, 33% were white; 32%, Hispanic; 23%, African American; 9%, Asian/Pacific Islander; and 3%, other race or ethnicity. Predominant access type over the course of the study was arteriovenous fistula (AVF) in 73%, arteriovenous graft (AVG) in 12%, and tunneled catheter in 14%. There was a higher percentage of AVF in whites (71%) than in African Americans (63%). Risk of death was independently increased by age (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.04-1.05), male sex (HR, 1.33; 95% CI, 1.22-1.45), diabetes (HR, 1.22; 95% CI, 1.12-1.33), use of an AVG (HR, 1.51; 95% CI, 1.34-1.71) or a tunneled catheter (HR, 6.45; 95% CI, 5.78-7.20). Compared with whites, African-American race decreased the risk of death (HR, 0.63; 95% CI, 0.56-0.70), as did Asian/Pacific Islander (HR, 0.58; 95% CI, 0.49-0.69), Hispanic (HR, 0.58; 95% CI, 0.51-0.65), and other race (HR, 0.67; 95% CI, 0.52-0.86).

CONCLUSION

Age, sex, race or ethnicity, access type, and diabetes are independent risk factors for mortality in hemodialysis patients. After controlling for potential confounders, when compared with whites, minorities all demonstrate significantly decreased risk of mortality. African Americans had reduced mortality risk despite a lower prevalence of arteriovenous fistula compared with whites. Male sex increased mortality. Differences in mortality between sexes and ethnicities in this population cannot be accounted for by differences in type of dialysis access.

Perceived discrimination predicts longer time to be accepted for kidney transplant

BACKGROUND

Although end-stage kidney disease in African Americans (AAs) is four times greater than in whites, AAs are less than one half as likely to undergo kidney transplantation (KT). This racial disparity has been found even after controlling for clinical factors such as comorbid conditions, dialysis vintage and type, and availability of potential living donors. Therefore, studying nonmedical factors is critical to understanding disparities in KT.

METHODS

We conducted a longitudinal cohort study with 127 AA and white patients with end-stage kidney disease undergoing evaluation for KT (December 2006 to July 2007) to determine whether, after controlling for medical factors, differences in time to acceptance for transplant is explained by patients' cultural factors (e.g., perceived racism and discrimination, medical mistrust, religious objections to living donor KT), psychosocial characteristics (e.g., social support, anxiety, depression), or transplant knowledge. Participants completed two telephone interviews (shortly after initiation of transplant evaluation and after being accepted or found ineligible for transplant).

RESULTS

Results indicated that AA patients reported higher levels of the cultural factors than did whites. We found no differences in comorbidity or availability of potential living donors. AAs took significantly longer to get accepted for transplant than did whites (hazard ratio=1.49, P=0.005). After adjustment for demographic, psychosocial, and cultural factors, the association of race with longer time for listing was no longer significant.

CONCLUSIONS

We suggest that interventions to address racial disparities in KT incorporate key nonmedical risk factors in patients.

APOL1 allelic variants are associated with lower age of dialysis initiation and thereby increased dialysis vintage in African and Hispanic Americans with non-diabetic end-stage kidney disease

BACKGROUND

The APOL1 G1 and G2 genetic variants make a major contribution to the African ancestry risk for a number of common forms of non-diabetic end-stage kidney disease (ESKD). We sought to clarify the relationship of APOL1 variants with age of dialysis initiation and dialysis vintage (defined by the time between dialysis initiation and sample collection) in African and Hispanic Americans, diabetic and non-diabetic ESKD.

METHODS

We examined APOL1 genotypes in 995 African and Hispanic American dialysis patients with diabetic and non-diabetic ESKD.

RESULTS

The mean age of dialysis initiation for non-diabetic African-American patients with two APOL1 risk alleles was 48.1 years, >9 years earlier than those without APOL1 risk alleles (t-test, P=0.0003). Similar results were found in the non-diabetic Hispanic American cohort, but not in the diabetic cohorts. G1 heterozygotes showed a 5.3-year lower mean age of dialysis initiation (t-test, P=0.0452), but G2 heterozygotes did not show such an effect. At the age of 70, 92% of individuals with two APOL1 risk alleles had already initiated dialysis, compared with 76% of the patients without APOL1 risk alleles. Although two APOL1 risk alleles are also associated with ∼2 years increased in dialysis vintage, further analysis showed that this increase is fully explained by earlier age of dialysis initiation.

CONCLUSIONS

Two APOL1 risk alleles significantly predict lower age of dialysis initiation and thereby increased dialysis vintage in non-diabetic ESKD African and Hispanic Americans, but not in diabetic ESKD. A single APOL1 G1, but not G2, risk allele also lowers the age of dialysis initiation, apparently consistent with gain of injury or loss of function mechanisms. Hence, APOL1 mutations produce a distinct category of kidney disease that manifests at younger ages in African ancestry populations.

Roma ethnicity and clinical outcomes in kidney transplant recipients

BACKGROUND

Racial and ethnic disparities among North American patients with chronic kidney disease have received significant attention. In contrast, little is known about health-related outcomes of patients with end-stage renal disease among the Roma minority, also known as gypsies, compared to Caucasian individuals. We prospectively assessed the association between Roma ethnicity and long-term clinical outcomes in kidney transplant recipients.

METHODS

In a prevalent cohort of renal transplant recipients, followed up over a median of 94 months, we prospectively collected socio-demographic, medical (and transplant related) characteristics and laboratory data at baseline from 60 Roma and 1,003 Caucasian patients (mean age 45 (SD = 11) and 49 (SD = 13) years, 33 and 41% women, 18 and 17% with diabetes mellitus, respectively). Survival analyses examined the associations between Roma ethnicity and all-cause mortality and death-censored graft loss or death with functioning renal allograft.

RESULTS

During the follow-up period, 341 patients (32%) died. Two-hundred eighty (26%) patients died with a functioning graft and 201 patients (19%) returned to dialysis. After multivariable adjustments, Roma ethnicity was associated with 77% higher risk of all-cause mortality (Hazard Ratio (HR): 1.77; 95% confidence interval (CI): 1.02, 3.07), two times higher risk of mortality with functioning graft (2.04 [1.17-3.55]) and 77% higher risk of graft loss (1.77 [1.01-3.13]), respectively.

CONCLUSIONS

Roma ethnicity is independently associated with increased mortality risk and worse graft outcome in kidney transplant recipients. Further studies should identify the factors contributing to worse outcomes among Roma patients.

Racial and ethnic differences in the association of body mass index and survival in maintenance hemodialysis patients

BACKGROUND

In maintenance hemodialysis (HD) patients, overweight and obesity are associated with survival advantages. Given the greater survival of maintenance HD patients who are minorities, we hypothesized that increased body mass index (BMI) is associated more strongly with lower mortality in blacks and Hispanics relative to non-Hispanic whites.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

We examined a 6-year (2001-2007) cohort of 109,605 maintenance HD patients including 39,090 blacks, 17,417 Hispanics, and 53,098 non-Hispanic white maintenance HD outpatients from DaVita dialysis clinics. Cox proportional hazards models examined the association between BMI and survival.

PREDICTORS

Race and BMI.

OUTCOMES

All-cause mortality.

RESULTS

Patients had a mean age of 62 ± 15 (standard deviation) years and included 45% women and 45% patients with diabetes. Across 10 a priori-selected BMI categories (<18-≥40 kg/m(2)), higher BMI was associated with greater survival in all 3 racial/ethnic groups. However, Hispanic and black patients experienced higher survival gains compared with non-Hispanic whites across higher BMI categories. Hispanics and blacks in the ≥40-kg/m(2) category had the largest adjusted decrease in death HR with increasing BMI (0.57 [95% CI, 0.49-0.68] and 0.63 [95% CI, 0.58-0.70], respectively) compared with non-Hispanic whites in the 23- to 25-kg/m(2) group (reference category). In linear models, although the inverse BMI-mortality association was observed for all subgroups, overall black maintenance HD patients showed the largest consistent decrease in death HR with increasing BMI.

LIMITATIONS

Race and ethnicity categories were based on self-identified data.

CONCLUSIONS

Whereas the survival advantage of high BMI is consistent across all racial/ethnic groups, black maintenance HD patients had the strongest and most consistent association of higher BMI with improved survival.

Association of race and age with survival among patients undergoing dialysis

CONTEXT

Many studies have reported that black individuals undergoing dialysis survive longer than those who are white. This observation is paradoxical given racial disparities in access to and quality of care, and is inconsistent with observed lower survival among black patients with chronic kidney disease. We hypothesized that age and the competing risk of transplantation modify survival differences by race.

OBJECTIVE

To estimate death among dialysis patients by race, accounting for age as an effect modifier and kidney transplantation as a competing risk.

DESIGN, SETTING, AND PARTICIPANTS

An observational cohort study of 1,330,007 incident end-stage renal disease patients as captured in the United States Renal Data System between January 1, 1995, and September 28, 2009 (median potential follow-up time, 6.7 years; range, 1 day-14.8 years). Multivariate age-stratified Cox proportional hazards and competing risk models were constructed to examine death in patients who receive dialysis.

MAIN OUTCOME MEASURES

Death in black vs white patients who receive dialysis.

RESULTS

Similar to previous studies, black patients undergoing dialysis had a lower death rate compared with white patients (232,361 deaths [57.1% mortality] vs 585,792 deaths [63.5% mortality], respectively; adjusted hazard ratio [aHR], 0.84; 95% confidence interval [CI], 0.83-0.84; P <.001). However, when stratifying by age and treating kidney transplantation as a competing risk, black patients had significantly higher mortality than their white counterparts at ages 18 to 30 years (27.6% mortality vs 14.2%; aHR, 1.93; 95% CI, 1.84-2.03), 31 to 40 years (37.4% mortality vs 26.8%; aHR, 1.46; 95% CI, 1.41-1.50), and 41 to 50 years (44.8% mortality vs 38.0%; aHR, 1.12; 95% CI, 1.10-1.14; P <.001 for interaction terms between race and each aforementioned age category), as opposed to patients aged 51 to 60 years (51.5% vs 50.9%; aHR, 0.93; 95% CI, 0.92-0.94), 61 to 70 years (64.9% vs 67.2%; aHR, 0.87; 95% CI, 0.86-0.88), 71 to 80 years (76.1% vs 79.7%; aHR, 0.85; 95% CI, 0.84-0.86), and older than 80 years (82.4% vs 83.6%; aHR, 0.87; 95% CI, 0.85-0.88).

CONCLUSIONS

Overall, among dialysis patients in the United States, there was a lower risk of death for black patients compared with their white counterparts. However, the commonly cited survival advantage for black dialysis patients applies only to older adults, and those younger than 50 years have a higher risk of death.

Survival disparities within American and Israeli dialysis populations: learning from similarities and distinctions across race and ethnicity

There are counterintuitive but consistent observations that African American maintenance dialysis patients have greater survival despite their less favorable socioeconomic status, high burden of cardiovascular risks including hypertension and diabetes, and excessively high chronic kidney disease prevalence. The fact that such individuals have a number of risk factors for lower survival and yet live longer when undergoing dialysis treatment is puzzling. Similar findings have been made among Israeli maintenance dialysis patients, in that those who are ethnically Arab have higher end-stage renal disease but exhibit greater survival than Jewish Israelis. The juxtaposition of these two situations may provide valuable insights into racial/ethnic-based mechanisms of survival in chronic diseases. Survival advantages of African American dialysis patients may be explained by differences in nutritional status, inflammatory profile, dietary intake habits, body composition, bone and mineral disorders, mental health and coping status, dialysis treatment differences, and genetic differences among other factors. Prospective studies are needed to examine similar models in other countries and to investigate the potential causes of these paradoxes in these societies. Better understanding the roots of racial/ethnic survival differences may help improve outcomes in both patients with chronic kidney disease and other individuals with chronic disease states.

Quality-of-life and mortality in hemodialysis patients: roles of race and nutritional status

BACKGROUND AND OBJECTIVES

Maintenance hemodialysis (MHD) patients often have protein-energy wasting, poor health-related quality of life (QoL), and high premature death rates, whereas African-American MHD patients have greater survival than non-African-American patients. We hypothesized that poor QoL scores and their nutritional correlates have a bearing on racial survival disparities of MHD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined associations between baseline self-administered SF36 questionnaire-derived QoL scores with nutritional markers by multivariate linear regression and with survival by Cox models and cubic splines in the 6-year cohort of 705 MHD patients, including 223 African Americans.

RESULTS

Worse SF36 mental and physical health scores were associated with lower serum albumin and creatinine levels but higher total body fat percentage. Spline analyses confirmed mortality predictability of worse QoL, with an almost strictly linear association for mental health score in African Americans, although the race-QoL interaction was not statistically significant. In fully adjusted analyses, the mental health score showed a more robust and linear association with mortality than the physical health score in all MHD patients and both races: death hazard ratios for (95% confidence interval) each 10 unit lower mental health score were 1.12 (1.05-1.19) and 1.10 (1.03-1.18) for all and African American patients, respectively.

CONCLUSIONS

MHD patients with higher percentage body fat or lower serum albumin or creatinine concentration perceive a poorer QoL. Poor mental health in all and poor physical health in non-African American patients correlate with mortality. Improving QoL by interventions that can improve the nutritional status without increasing body fat warrants clinical trials.

Association of decreased glomerular filtration rate with racial differences in survival after acute myocardial infarction

BACKGROUND AND OBJECTIVES

African-American race and decreased kidney function have been associated with higher mortality after acute myocardial infarction (AMI). However, whether there are racial differences in the prevalence or prognostic importance of renal insufficiency in AMI is unknown.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Among 1847 AMI patients enrolled in the multicenter Prospective Registry Evaluating Myocardial Infarction Event and Recovery (PREMIER) study, estimated glomerular filtration rate (eGFR) was used to stratify prognosis and to examine potential interactions among eGFR, race, and mortality. Multivariable proportional hazards regression was used to examine the effect of race and eGFR on 3.5-year all-cause mortality.

RESULTS

Race and eGFR were significantly associated with mortality. After adjustment for eGFR alone, differences in mortality by race were substantially attenuated (unadjusted hazard ratio [HR] for African Americans=1.56 [95% confidence interval {CI}=1.2 to 2.1]; eGFR-adjusted HR=1.32 [95% CI=0.99 to 1.75]). A similar magnitude of attenuation in racial differences in survival was observed after adjustment for all covariates except eGFR (HR=1.29 [95% CI=0.96 to 1.72]). A final model adjusting for all covariates only slightly attenuated the association further. No interaction between race and eGFR was detected.

CONCLUSIONS

Renal insufficiency, which may represent chronic kidney disease, is a prognostically important comorbidity in African Americans after AMI. However, the effect of decreased eGFR on mortality is comparable between races, suggesting that preventing renal insufficiency in African Americans could be an important target to reduce racial disparities in post-AMI survival.

Racial and ethnic differences in mortality of hemodialysis patients: role of dietary and nutritional status and inflammation

BACKGROUND

Racial/ethnic disparities prevail among hemodialysis patients. We hypothesized that significant differences exist between Black and non-Hispanic and Hispanic White hemodialysis patients in nutritional status, dietary intake and inflammation, and that they account for racial survival disparities.

METHODS

In a 6-year (2001-2007) cohort of 799 hemodialysis patients, we compared diet and surrogates of nutritional-inflammatory status and their mortality-predictabilities between 279 Blacks and 520 Whites using matched and regression analyses and Cox with cubic splines.

RESULTS

In age-, gender- and diabetes-matched analyses, Blacks had higher lean body mass and serum prealbumin, creatinine and homocysteine levels than Whites. In case-mix-adjusted analyses, dietary intakes in Blacks versus Whites were higher in energy (+293 ± 119 cal/day) and fat (+18 ± 5 g/day), but lower in fiber (-2.9 ± 1.3 g/day) than Whites. In both races, higher serum albumin, prealbumin and creatinine were associated with greater survival, whereas CRP and IL-6, but not TNF-α, were associated with increased mortality. The highest (vs. lowest) quartile of IL-6 was associated with a 2.4-fold (95% CI: 1.3-3.8) and 4.1-fold (2.2-7.2) higher death risk in Blacks and Whites, respectively.

CONCLUSIONS

Significant racial disparities exist in dietary, nutritional and inflammatory measures, which may contribute to hemodialysis outcome disparities. Testing race-specific dietary and/or anti-inflammatory interventions is indicated.

Role of nutritional status and inflammation in higher survival of African American and Hispanic hemodialysis patients

BACKGROUND

Observational studies indicate greater survival in African American and Hispanic maintenance hemodialysis patients compared with their non-Hispanic white counterparts, although African Americans have shorter life expectancy than whites in the general population. We hypothesized that this apparent survival advantage is due to a more favorable nutritional/inflammatory profile in minority hemodialysis patients.

STUDY DESIGN

We examined the association between race/ethnicity and 5-year survival before and after adjustment for case-mix and surrogates of the malnutrition-inflammation complex syndrome (MICS) using Cox regression with or without matched sampling in a large cohort of adult hemodialysis patients.

SETTING & PARTICIPANTS

124,029 adult hemodialysis patients, including 16% Hispanics, 49% non-Hispanic whites, and 35% African Americans.

PREDICTORS

Race/ethnicity before and after adjustment for MICS, including values for body mass index, serum albumin, total iron-binding capacity, ferritin, creatinine, phosphorus, calcium, bicarbonate, white blood cell count, lymphocyte percentage, hemoglobin, and protein intake.

OUTCOMES

5-year (July 2001 to June 2006) survival.

RESULTS

In dialysis patients, blacks and Hispanics had lower mortality overall than non-Hispanic whites after traditional case-mix adjustment. However, after additional control for MICS, Hispanics had mortality similar to non-Hispanic whites, and African Americans had even higher mortality. Unadjusted, case-mix-, and MICS-adjusted HRs for African Americans versus whites were 0.68 (95% CI, 0.66-0.69), 0.89 (95% CI, 0.86-0.91), and 1.06 (95% CI, 1.03-1.09) in the unmatched cohort and, 0.95 (95% CI, 0.90-0.99), 0.89 (95% CI, 0.84-0.94), and 1.16 (95% CI, 1.07-1.26) in the matched cohort, and for Hispanics versus whites, 0.66 (95% CI, 0.64-0.69), 0.84 (95% CI, 0.81-0.87), and 0.97 (95% CI, 0.94-1.00) in the unmatched cohort and 0.89 (95% CI, 0.84-0.95), 0.88 (95% CI, 0.83-0.95), and 0.98 (95% CI, 0.91-1.06) in the matched cohort, respectively.

LIMITATIONS

Adjustment cannot be made for unmeasured confounders.

CONCLUSIONS

Survival advantages of African American and Hispanic hemodialysis patients may be related to differences in nutritional and inflammatory status. Further studies are required to explore these differences.

The increasing prevalence of atrial fibrillation among hemodialysis patients

A half million Americans have ESRD, which puts them at high risk for cardiovascular disease and poor outcomes. Little is known about the epidemiology of atrial fibrillation among patients with ESRD. We analyzed data from annual cohorts (1992 to 2006) of prevalent hemodialysis patients from the United States Renal Data System. In each cohort, we searched 1 year of medical claims for relevant diagnosis codes to determine the prevalence of atrial fibrillation. Among 2.5 million patient observations, 7.7% had atrial fibrillation, with the prevalence increasing 3-fold from 3.5% (1992) to 10.7% (2006). The number of affected patients increased from 3620 to 23,893 (6.6-fold) during this period. Older age, male gender, and several comorbid conditions were associated with increased risk for atrial fibrillation. Compared with otherwise similar Caucasians, the prevalence of atrial fibrillation rates was substantially lower for blacks, Asians, and Native Americans. One-year mortality was twice as high among hemodialysis patients with atrial fibrillation compared with those without (39% versus 19%), and this increased risk was constant during the 15 years of the study. In conclusion, the prevalence of diagnosed atrial fibrillation among patients receiving hemodialysis in the United States is increasing, varies by race, and remains associated with substantially increased mortality. Identifying potentially modifiable risk factors for incident atrial fibrillation requires further investigation.

Impact of race on hyperparathyroidism, mineral disarrays, administered vitamin D mimetic, and survival in hemodialysis patients

Blacks have high rates of chronic kidney disease, are overrepresented among the US dialysis patients, have higher parathyroid hormone levels, but greater survival compared to nonblacks. We hypothesized that mineral and bone disorders (MBDs) have a bearing on survival advantages of black hemodialysis patients. In 139,328 thrice-weekly treated hemodialysis patients, including 32% blacks, in a large dialysis organization, where most laboratory values were measured monthly for up to 60 months (July 2001 to June 2006), we examined differences across races in measures of MBDs and survival predictabilities of these markers and administered the active vitamin D medication paricalcitol. Across each age increment, blacks had higher serum calcium and parathyroid hormone (PTH) levels and almost the same serum phosphorus and alkaline phosphatase levels and were more likely to receive injectable active vitamin D in the dialysis clinic, mostly paricalcitol, at higher doses than nonblacks. Racial differences existed in mortality predictabilities of different ranges of serum calcium, phosphorus, and PTH but not alkaline phosphatase. Blacks who received the highest dose of paricalcitol (>10 µg/week) had a demonstrable survival advantage over nonblacks (case-mix-adjusted death hazard ratio = 0.87, 95% confidence level 0.83-0.91) compared with those who received lower doses (<10 µg/week) or no active vitamin D. Hence, in black hemodialysis patients, hyperparathyroidism and hypercalcemia are more prevalent than in nonblacks, whereas hyperphosphatemia or hyperphosphatasemia are not. Survival advantages of blacks appear restricted to those receiving higher doses of active vitamin D. Examining the effect of MBD modulation on racial survival disparities of hemodialysis patients is warranted.

Age, race, diabetes, blood pressure, and mortality among hemodialysis patients

Observational studies involving hemodialysis patients suggest a U-shaped relationship between BP and mortality, but the majority of these studies followed large, heterogeneous cohorts. To examine whether age, race, and diabetes status affect the association between systolic BP (SBP; predialysis) and mortality, we studied a cohort of 16,283 incident hemodialysis patients. We constructed a series of multivariate proportional hazards models, adding age and BP to the analyses as cubic polynomial splines to model potential nonlinear relationships with mortality. Overall, low SBP associated with increased mortality, and the association was more pronounced among older patients and those with diabetes. Higher SBP associated with increased mortality among younger patients, regardless of race or diabetes status. We observed a survival advantage for black patients primarily among older patients. Diabetes associated with increased mortality mainly among older patients with low BP. In conclusion, the design of randomized clinical trials to identify optimal BP targets for patients with ESRD should take age and diabetes status into consideration.

Rate of ESRD exceeds mortality among African Americans with hypertensive nephrosclerosis

In several studies, patients with CKD seemed to be at greater risk for dying from cardiovascular disease (CVD) than reaching ESRD. The purpose of this study was to compare incident ESRD rates with rates of total mortality, CVD death, and a CVD composite (CVD mortality and CVD hospitalization) among participants who had hypertensive nephrosclerosis and were enrolled in the African American Study of Kidney Disease and Hypertension (AASK). The study period included the AASK trial phase (1996 through 2001) and a subsequent cohort phase (2002 through 2007). The AASK enrolled 1094 participants. Of the 764 participants who completed the trial phase without an event, 691 (90%) enrolled in the cohort phase. During 11 years of follow-up, there were 59 CVD-related deaths and 118 non-CVD-related deaths. The rate of ESRD (3.9/100 patient-years) was significantly higher than the rates of total mortality (2.2/100 patient-years), CVD mortality (0.8/100 patient-years), and the CVD composite (3.2/100 patient-years). The incidence rate ratio of ESRD to CVD mortality was 5.0. The rate of ESRD consistently exceeded the various mortality rates across most of the subgroups defined by age, gender, income, education, previous CVD, baseline urine protein excretion, and baseline estimated GFR. In conclusion, AASK participants were more likely to reach ESRD than to die.

Reappraisal of the impact of race on survival in patients on dialysis

Racial differences in the cause, natural history, and effects of chronic kidney disease have long been the subject of investigation. Dialysis-dependent kidney failure occurs nearly 4 times more often in African Americans than European Americans. Despite this observation, studies repeatedly show that African Americans have a significant survival advantage after initiating dialysis therapy. Although this phenomenon has been attributed to environmental and socioeconomic factors, recent studies show that inherited factors strongly influence racial differences in the development of diverse kidney diseases and may affect the risk of nephropathy-associated cardiovascular disease. We review relevant studies and propose the hypothesis that inherited factors leading to organ-limited kidney diseases and a lower burden of systemic atherosclerosis contribute in part to the improved survival rates in African American patients on dialysis therapy.

Inpatient hemodialysis initiation: reasons, risk factors and outcomes

BACKGROUND/AIMS

Inpatient initiation of chronic hemodialysis is considered undesirable because of cost and possible harms of hospitalization. We examined the patient characteristics and outcomes associated with inpatient initiation.

METHODS

In a prospective cohort study of incident dialysis patients, the independent association of inpatient hemodialysis initiation with patient outcomes was assessed in multivariable analyses with adjustment for patient characteristics and propensity for inpatient initiation.

RESULTS

A total of 410 of 652 (63%) hemodialysis patients began as inpatients; uremia and volume overload were the most commonly documented reasons. Compared to outpatients, inpatients were more likely to be unmarried, report less social support, have multiple comorbidities and be referred to a nephrologist 4 months or less prior to initiation. Inpatient initiation was protective for subsequent all-cause hospitalization (incidence rate ratio (IRR) = 0.92, confidence interval (CI) 0.89-0.94); this was most pronounced among those who had the highest propensity for inpatient initiation (IRR = 0.66, CI 0.56-0.78), including those referred late to nephrology. Similar results were found for infectious hospitalization. Mortality [hazard ratio = 1.03, CI 0.82-1.30] and cardiovascular events were not significantly different for inpatients versus outpatients.

CONCLUSION

Inpatient hemodialysis initiation has a protective association with hospitalization among those patients referred late to nephrology, with multiple comorbidities and/or little social support.

Race, gender, and socioeconomic disparities in CKD in the United States

Chronic kidney disease (CKD) is a national public health problem beset by inequities in incidence, prevalence, and complications across gender, race/ethnicity, and socioeconomic status. As health care providers, we can directly address some factors crucial for closing the disparities gap. Other factors are seemingly beyond our reach, entrenched within the fabric of our society, such as social injustice and human indifference. Paradoxically, the existence of health inequities provides unique, unrecognized opportunities for understanding biologic, environmental, sociocultural, and health care system factors that can lead to improved clinical outcomes. Several recent reports documented that structured medical care systems can reduce many CKD-related disparities and improve patient outcomes. Can the moral imperative to eliminate CKD inequities inspire the nephrology community not only to advocate for but also to demand high-quality, structured health care delivery systems for all Americans in the context of social reform that improves the ecology, health, and well-being of our communities? If so, then perhaps we can eliminate the unacceptable premature morbidity and mortality associated with CKD and the tragedy of health inequities. By so doing, we could become global leaders not only in medical technology, as we currently are, but also in health promotion and disease prevention, truly leaving no patient behind.