Association of Height with Elevated Mortality Risk in ESRD: Variation by Race and Gender

Abstract

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.

Keywords: epidemiology and outcomes; kidney failure; mortality; renal dialysis.

Figure 1.

Selection process of the study population from merging of the USRDS standard analysis files.

Figure 2.

Age-adjusted mortality rates for (A) men and (B) women by race group across height quintiles in the United States ESRD population. P<0.001 for all group comparisons.

Figure 3.

Association of height with hazard ratio of death by race group for men and for women. Height mortality relationships for (A) whites, (B) blacks, (C) Asians, and (D) American Indians/Alaska natives. Height was modeled by a restricted cubic spline with four knots placed at the 20th, 40th, 60th and 80th percentiles of height for men and women, respectively. Models are adjusted for age, cause of ESRD, comorbid conditions at time of dialysis (coronary artery disease, peripheral vascular disease, heart failure, stroke, hypertension, diabetes, chronic lung disease, and malignancy), lifestyle factors (smoking status, drug and alcohol addiction), functional status indicators (inability to ambulate, inability to transfer independently), socioeconomic factors (employment status, insurance status at time of dialysis), baseline eGFR (from the CKD-EPI equation), albumin, use of erythropoietin prior to dialysis initiation, and incident year of cohort. HRs with 95% CI in dotted lines. CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration.