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The association of adult height with mortality has been extensively investigated in the general population, but little is known about this relationship among dialysis patients. We explored the relationship between height and mortality in a retrospective cohort study of 1,171,842 adults who began dialysis in the United States from 1995 to 2008 and were followed until December 31, 2010. We evaluated height-mortality associations in sex-specific quintiles of increasing height (Q1-Q5) using multivariable Cox regression models adjusted for demographics, comorbid conditions, lifestyle and disability indicators, socioeconomic status, and body weight. For men, compared with the referent quintile (Q1 <167 cm), successive height quintiles had significantly increased hazard ratios (HRs [95% confidence interval]) for mortality: 1.04 (1.02-1.06), 1.08 (1.06-1.10), 1.12 (1.11-1.14), and 1.18 (1.16-1.20) for Q2-Q5, respectively. For women (referent Q1 <155 cm), HRs for mortality were 1.00 (0.99-1.02), 1.05 (1.03-1.06), 1.05 (1.03-1.07), and 1.08 (1.06-1.10) for Q2-Q5, respectively. However, stratification by race showed the pattern of association differed significantly by race (P<0.001 for interaction). For black men, unlike other race groups, height only associated with mortality in Q5, with an HR of 1.06 (1.02-1.09). For black women, HRs for mortality were 0.94 (0.91-0.97), 0.98 (0.95-1.02), 0.96 (0.93-0.99), and 0.99 (0.96-1.02) for Q2-Q5, respectively. These results indicate tallness is associated with higher mortality risks for adults starting dialysis, but this association did not extend to black patients., (Copyright © 2016 by the American Society of Nephrology.)

Differences in coronary disease have been reported among ethnic minorities in the US population. Whether these persist in patients with chronic kidney disease is unknown. The prevalence of myocardial infarction (MI) and angina was compared by race and GFR in the Third National Health and Nutrition Examination Survey using the Modification of Diet in Renal Disease Study equation. Age-gender standardized estimates were computed for each GFR category (>or=90, 60 to 89, and <60 ml/min per 1.73 m2), and odds ratios were compared using weighted multivariable logistic regression for each race. The age-gender standardized prevalence of MI was 3.0, 3.1, and 4.9% in white individuals; 2.8, 3.8, and 9.9% in black individuals; and 1.9, 2.9, and 3.8% in Mexican-American individuals in each category: >or=90, 60 to 89, and <60 ml/min, respectively. Compared with the referent (Mexican-American; GFR>or=90 ml/min; odds ratio 1.00), Mexican-American individuals with GFR of 60 to 89 and <60 ml/min had more than four and nine times the odds for MI; black individuals at successively lower GFR levels had 1.6, 6.1, and 16.3 times the odds for MI, whereas white individuals had 1.9, 4.7, and 20.2 times that of the referent, respectively. After adjustment for traditional risk factors, the inverse association of GFR with MI was substantially attenuated in black and white individuals and completely abolished in Mexican-American individuals. The burden of coronary disease is lower in Mexican-American than in white or black individuals with reduced kidney function even accounting for differences in traditional risk factors.

Differences in survival have been reported among ethnic groups in the general population. Whether these extend to patients with ESRD is unclear. Using national data, mortality risks of ethnic groups who began dialysis treatment in the United States between May 1, 1995, and July 31, 1997, were compared over 2 yr. Patients were classified as Hispanic or non-Hispanic and then subclassified by race forming six race-specific subgroups: Hispanic white, black, and other and non-Hispanic white, black, and other. Mortality rates for Hispanics compared with non-Hispanics were 19.2 versus 26 per 100 patient-years at risk for those with diabetes and were 14.7 versus 22.7 per 100 patient-years at risk for those without diabetes. For those with diabetes, adjusted mortality risks for Hispanics versus non-Hispanics were 30% lower (95% confidence interval [CI], 26 to 34%). In subgroup analysis, mortality risks for Hispanic whites and Hispanic blacks were 35% (95% CI, 31 to 39%) and 33% (95% CI, 12 to 48%) lower than non-Hispanic whites and were similar in magnitude to those of non-Hispanic blacks (32% lower; 95% CI, 29 to 35%) and non-Hispanic other (33% lower; 95% CI, 28 to 39%). Interestingly, mortality risks for Hispanic others were not significantly different from non-Hispanic whites. For those without diabetes, adjusted mortality risks for Hispanics versus non-Hispanics were 17% lower (95% CI, 9 to 23%), and subgroup analysis yielded similar patterns to those of individuals with diabetes. The survival advantage of Hispanic over non-Hispanic patients who receive chronic dialysis treatment in the United States is not consistent across subgroups and is modified by race. Cultural and genetic differences as well as variation in the access and delivery of care before and while on dialysis may account for these differences.

It is unclear whether peritoneal dialysis (PD) compared with hemodialysis (HD) confers a survival advantage in end-stage renal disease (ESRD) patients with coronary artery disease (CAD). This hypothesis was tested in a national cohort of 107,922 patients starting dialysis therapy between May 1, 1995, and July 31, 1997. Data on patient characteristics were obtained from the Center for Medicare and Medicaid Services Medical Evidence Form (CMS) and linked to mortality data from the United States Renal Data System (USRDS). Patients were classified on the basis of CAD presence and followed until death or the end of 2 yr. Nonproportional Cox regression models estimated the relative risk (RR) of death for patients with and without CAD by dialysis modality using primarily the intent-to-treat but also the as-treated approach. Diabetic patients (DM) and nondiabetic patients (non-DM) were analyzed separately. Among DM, patients with CAD treated with PD had a 23% higher RR (95% CI, 1.12 to 1.34) compared with similar HD patients, whereas patients without CAD receiving PD had a 17% higher RR (CI, 1.08 to 1.26) compared with HD. Among non-DM, patients with CAD treated with PD had a 20% higher RR (CI. 1.10 to 1.32) compared with HD patients, whereas patients without CAD had similar survival on PD or HD (RR = 0.99; CI, 0.93 to 1.05). The mortality risk for new ESRD patients with CAD differed by treatment modality. In both DM and non-DM, patients with CAD treated with PD had significantly poorer survival compared with HD. Whether differences in solute clearance and/or cardiac risk profiles between PD and HD may explain these findings deserves further investigation.

Few studies have comprehensively addressed the association of social factors and elements of pre-end-stage renal disease (ESRD) care with the selection of dialysis modality. This study examines the relative contribution of demographic, medical, social, pre-ESRD, and geographic factors to modality assignment among new ESRD patients. Data were collected from the Dialysis Mortality and Morbidity Wave 2 Study, a national random sample of 4025 patients in 1996 and 1997. In multivariate analyses, the selection of peritoneal dialysis (PD) over hemodialysis (HD) was significantly associated with younger age, white race, fewer comorbid conditions, and lower serum albumin. Greater use of PD was seen in patients who were employed, married, and living with someone before the start of ESRD and in those who were more autonomous and more accomplished educationally. Patients referred earlier to a nephrologist (> 4 mo versus < or =4 mo) and seen more frequently by a nephrologist (> or =2 visits versus < 2 visits) in the pre-ESRD period had greater PD use. Of the factors listed, 25% of the variability (R(2)) in PD use was explained by demographic (4.1%), comorbid (1.2%), social/pre-ESRD (14.5%), and geographic (5.2%) factors. This study identifies several clinical, social, and pre-ESRD factors with the selection of PD, and it underscores the importance of patient education, autonomy, and a strong social support system in improving rates of PD use in the United States. As pre-ESRD patient care is an important contributor to PD use in the United States, greater efforts should be expended in improving its delivery earlier in the pre-ESRD period.

Hyperphosphatemia is highly prevalent among patients with end-stage renal disease (ESRD) and is associated with increased mortality risk in hemodialysis (HD) patients. The mechanism through which this mortality risk is mediated is unclear. Data from two national random samples of HD patients (n = 12,833) was used to test the hypothesis that elevated serum PO(4) contributes mainly to cardiac causes of death. During a 2-yr follow-up, the cause-specific relative risk (RR) of death for patients was analyzed separately for several categories of cause of death, including coronary artery disease (CAD), sudden death, and other cardiac causes, cerebrovascular and infection. Cox regression models were fit for each of the eight cause of death categories, adjusting for patient demographics and non-cardiovascular comorbid conditions. Time at risk for each cause-specific model was censored at death that resulted from any of the other causes. Higher mortality risk was seen for patients in the high PO(4) group (>6.5mg/dl) compared with the lower PO(4) group (< or =6.5mg/dl) for death resulting from CAD (RR 1.41; P < 0.0005), sudden death (RR 1.20; P < 0.01), infection (RR 1.20; P < 0.05), and unknown causes (RR 1.25; P < 0.05). Patients in the high PO(4) group also had non-significantly increased RR of death from other cardiac and cerebrovascular causes of death. The RR of sudden death was also strongly associated with elevated Ca x PO(4) product (RR 1.07 per 10 mg(2)/dl(2); P < 0.005) and serum parathyroid hormone levels greater than 495 pg/ml (RR 1.25; P < 0.05). This study identifies strong relationships between elevated serum PO(4), Ca x PO(4) product, and parathyroid hormone and cardiac causes of death in HD patients, especially deaths resulting from CAD and sudden death. More vigorous measures to reduce the prevalence of these factors in HD patients may result in improved survival.

Despite the high prevalence of coronary artery disease (CAD) among patients with end-stage renal disease (ESRD), few studies have identified clinical correlates using national data. The purpose of this study was to determine the prevalence and clinical associations of CAD in a national random sample of new ESRD in the United States in 1996/1997 (n = 4025). Data on demographic characteristics and comorbidities were obtained from the Dialysis Morbidity and Mortality Study, Wave 2. The principal outcome was CAD, defined as the presence of a previous history of CAD, myocardial infarction, or angina, coronary artery bypass surgery, coronary angioplasty, or abnormal coronary angiographic findings. Multivariate logistic regression analysis was used to assess the relationship of conventional factors and proposed uremic factors to the presence of CAD. CAD was present in 38% of patients. Of the total cohort, 17% had a history of myocardial infarction and 23% had angina. Several conventional risk factors, including advancing age, male gender, diabetes mellitus, and smoking, were significantly associated with CAD. Of the proposed uremic factors, lower serum albumin levels but higher residual renal function and higher hematocrit values were significantly associated with the presence of CAD. Vascular comorbid conditions, structural cardiac abnormalities, white race, and geographic location were also strongly correlated with the presence of CAD. This national study suggests that several conventional CAD risk factors may also be risk factors for CAD among the ESRD population. This study identifies nonconventional factors such as serum albumin levels, vascular comorbid conditions, and structural cardiac abnormalities as important disease correlates. Future logitudinal studies are required to explore the relative importance of the relationships observed here.