Changes in Excess Mortality from End Stage Renal Disease in the United States from 1995 to 2013

Abstract

Background and objectives: Individuals with ESRD have a very high risk of death. Although mortality rates have decreased over time in ESRD, it is unknown if improvements merely reflect parallel increases in general population survival. We, therefore, examined changes in the excess risk of all-cause mortality-over and above the risk in the general population-among people treated for ESRD in the United States from 1995 to 2013. We hypothesized that the magnitude of change in the excess risk of death would differ by age and RRT modality.

Design, setting, participants, & measurements: We used time-dependent relative survival models including data from persons with incident ESRD as recorded in the US Renal Data System and age-, sex-, race-, and calendar year-specific general population mortality rates from the Centers for Disease Control and Prevention. We calculated relative excess risks (analogous to hazard ratios) to examine the association between advancing calendar time and the primary outcome of all-cause mortality.

Results: We included 1,938,148 children and adults with incident ESRD from 1995 to 2013. Adjusted relative excess risk per 5-year increment in calendar time ranged from 0.73 (95% confidence interval, 0.69 to 0.77) for 0-14 year olds to 0.88 (95% confidence interval, 0.88 to 0.88) for ≥65 year olds, meaning that the excess risk of ESRD-related death decreased by 12%-27% over any 5-year interval between 1995 and 2013. Decreases in excess mortality over time were observed for all ages and both during treatment with dialysis and during time with a functioning kidney transplant (year by age and year by renal replacement modality interactions were both P<0.001), with the largest relative improvements observed for the youngest persons with a functioning kidney transplant. Absolute decreases in excess ESRD-related mortality were greatest for the oldest persons.

Conclusions: The excess risk of all-cause mortality among people with ESRD, over and above the risk in the general population, decreased significantly between 1995 and 2013 in the United States.

Keywords: Adult; Centers for Disease Control and Prevention (U.S.); Child; Confidence Intervals; Humans; Kidney Failure, Chronic; Renal Replacement Therapy; Risk; United States; kidney; kidney transplantation; renal dialysis.

Graphical abstract

Figure 1.

Flow chart describing the study cohort. The numbers of persons in the cohort who died or were censored at each stage in the trajectory of ESRD care are illustrated.

Figure 2.

Crude excess mortality rates decreased over calendar time, for all ages, in people with ESRD. Crude excess ESRD-attributable mortality rates by calendar year are shown within each current age category. Excess mortality rates were calculated by subtracting age-, sex-, race- (white, black, or other), and calendar year–specific United States general population mortality rates (expected) from the observed ESRD mortality rates. Observed mortality rates were compared with general population rates in the following age intervals: <1, 1–4, and 5–9 years and 5-year intervals thereafter. The years 1995 and 1996 are excluded from the plot, because these years include primarily the observation of patients with incident ESRD. Because mortality rates are highest in the initial months after ESRD onset, calendar years in which observation is mainly from incident patients will overestimate excess mortality compared with years in which observation represents a mix of incident and prevalent patients. Fitted excess mortality rates on the basis of the relative excess risks determined by the models and the observed excess mortality rates in 2005, when the proportion of incident and prevalent patients became stable, are shown in Supplemental Figure 4.