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.