Perceived mental health at the start of dialysis as a predictor of morbidity and mortality in patients with end-stage renal disease (CALVIDIA Study)

Background. Health-related quality of life may affect morbidity and survival in end-stage renal disease, but it is not clear whether coexisting comorbidity and other known prognostic variables could account for such an association. Methods. To study the relationship between health-related quality of life and morbidity and survival, we carried out an inception cohort study in patients starting chronic dialysis, mostly diabetics, with a follow-up of 1-3 years in 34 Spanish hospitals. Health-related quality of life was measured by the SF-36 Health Survey and Karnofsky scale. Charlson age-comorbidity index and other prognostic clinical variables were measured concurrently. The primary outcome variable was time until death and the secondary outcome was hospitalization days. Results. Of 318 patients enrolled (208 diabetics), with a median follow-up of 771 days, 80 died. In the unadjusted analysis, all-cause mortality was associated with lower SF-36 physical and mental component scores and Karnofsky scale. In the adjusted analysis, SF-36 mental component score predicted all-cause mortality (hazard ratio for a 10 point decrease: 1.28; 95% confidence interval: 1.05-1.56). The SF-36 mental component score also predicted more hospitalization days (adjusted risk ratio of each additional hospital day associated with every 10 point decrease: 1.25; 95% confidence interval: 1.08-1.45). Among diabetics, both the SF-36 physical and mental components predicted mortality and hospitalization days. Conclusions. In end-stage renal disease, perceived mental health is an independent predictor of mortality and morbidity, mainly among diabetics patients.