Self-reported health change in haemodialysis recipients modulates the effect of frailty upon mortality and hospital admissions: outcomes from a large prospective UK cohort

Background Frailty among haemodialysis patients is associated with hospitalization and mortality, but high frailty prevalence suggests further discrimination of risk is required. We hypothesized that incorporation of self-reported health with frailty measurement may aid risk stratification. Methods Prospective cohort study of 485 prevalent haemodialysis recipients linked to English national datasets. Frailty Phenotype (FP), Frailty Index (FI), Edmonton Frail Scale (EFS), Clinical Frailty Scale (CFS) and self-reported health change were assessed. Mortality was explored using Fine and Gray regression, and admissions by negative binomial regression. Results Over a median 678 (interquartile range 531-812) days, there were 111 deaths, and 1241 hospitalizations. Increasing frailty was associated with mortality on adjusted analyses for FP [subdistribution hazard ratio (SHR) 1.26, 95% confidence interval (CI) 1.05-1.53, P = .01], FI (SHR 1.21, 95% CI 1.09-1.35, P = .001) and CFS (SHR 1.32, 95% CI 1.11-1.58, P = .002), but not EFS (HR 1.08, 95% CI 0.99-1.18, P = .1). Health change interacted with frailty tools to modify association with mortality; only those who rated their health as the same or worse experienced increased mortality hazard associated with frailty by FP (P-interaction = .001 and 0.035, respectively), FI (P-interaction = .002 and .007, respectively) and CFS (P-interaction = .009 and 0.02, respectively). CFS was the only frailty tool associated with hospitalization (incidence rate ratio 1.12, 95% CI 1.02-1.23, P = .02). Conclusions We confirm the high burden of hospitalization and mortality associated with haemodialysis patients regardless of frailty tool utilized and introduce the discriminatory ability of self-reported health to identify the most at-risk frail individuals.