Depression does not predict clinical outcome of Chinese peritoneal Dialysis patients after adjusting for the degree of frailty

BACKGROUND: Depression and frailty contribute to the adverse clinical outcome of peritoneal dialysis (PD) patients. However, the interaction between depression and frailty in PD patients remains uncertain. We determined the prevalence of depression and frailty in prevalent Chinese PD patients, dissected the internal relationship between depression and frailty, and determined their relative contribution to the adverse clinical outcome in PD patients. METHODS: In a prospective observational study, we recruited 267 prevalent PD patients. Depression was identified by Patient Health Questionnaire (PHQ-9). Frailty was identified by a validated Frailty Score. All cases were followed for one year. Outcome measures included number and duration of hospitalization, peritonitis rate, and all-cause mortality. RESULTS: Of the 267 patients, 197 patients (73.8%) were depressed, and 157 (58.8%) were frail. There was a substantial overlap between depression and frailty. Although depression and frailty were associated the number and duration of hospitalization by univariate analysis, the association became insignificant after adjusting for confounding factors by multivariate analysis. Both depression and frailty were associated with one-year mortality by univariate analysis. One-year patient survival was 95.9, 86.5, 82.4 and 71.0% for patients with nil, mild, moderate and severe frailty, respectively (p = 0.001). Frailty was an independent predictor of patient survival by multivariate analysis (adjusted hazard ratio 1.424, 95% confidence interval 1.011–2.005. p = 0.043), while the prognostic effect of depression disappears after adjusting for frailty score. CONCLUSION: Depression and frailty were common among Chinese PD patients. Frailty, but not depression, was an independent predictor of one-year mortality.