The association between mental health, physical function, and hemodialysis mortality

The association between mental health, physical function, and hemodialysis mortality. Mortality rates for individuals on chronic hemodialysis remain very high; therefore, strategies are needed to identify individuals at greatest risk for mortality so preventive strategies can be implemented. One such approach is to stratify individuals by self-reported mental health and physical function. Examining these parameters at baseline, and over time, may help identify individuals at greater risk for mortality. We enrolled 14,815 individuals with end-stage renal disease (ESRD) and followed these individuals for up to 2 years. The mean age was 61.0 ± 15.4 years (range, 20 to 96 years) and 31% were African Americans. The SF-36 Health Survey was administered 1 to 3 months after hemodialysis initiation and 6 months later. We examined the associations between the initial SF-36 Health Survey mental component summary (MCS) and physical component summary (PCS) scores and mortality during the follow-up period, and examined the associations between 6-month decline in PCS and MCS scores and subsequent mortality. We also examined the interactions between age and MCS and PCS scores. The general population-based mean of each of these scores was 50 with a standard deviation of 10. The main outcome measurement was death. Self-reported baseline mental health (MCS score) and physical function (PCS score) were both independently associated with increased mortality, and 6-month decline in these parameters was also associated with increased mortality. The multivariate hazard ratios for 1-year mortality for MCS scores of less than 30, 30 to 39, and 40 to 49 were 1.48 (95% CI, 1.32 to 1.64), 1.23 (95% CI, 1.14 to 1.32) and 1.18 (95% CI, 1.10 to 1.26) compared with a MCS score of 50 or more. The hazard ratios for PCS scores of less than 20, 20 to 29, and 30 to 39 were 1.97 (95% CI, 1.64 to 2.36), 1.62 (95% CI, 1.36 to 1.92), and 1.32 (95% CI, 1.11 to 1.57) compared with a PCS score of 50 or more. Six-month decline in self-reported mental health (hazard ratio, 1.07; 95% CI, 1.02 to 1.12, per 10-point decline in MCS score) and physical function (hazard ratio, 1.25; 95% CI, 1.18 to 1.33, per 10-point decline in PCS score) were also both significantly associated with an additional increase in mortality beyond baseline risk. We also found a significant interaction between age and physical function (P = 0.02). Specifically, there was a graded response between the PCS score category and mortalit