Mortality and morbidity following exercise-based renal rehabilitation in patients with chronic kidney disease: the effect of programme completion and change in exercise capacity.

BACKGROUND: Twelve weeks of renal rehabilitation (RR) have been shown to improve exercise capacity in patients with chronic kidney disease (CKD); however, survival following RR has not been examined.

METHODS: This study included a retrospective longitudinal analysis of clinical service outcomes. Programme completion and improvement in exercise capacity, characterised as change in incremental shuttle walk test (ISWT), were analysed with Kaplan-Meier survival analyses to predict risk of a combined event including death, cerebrovascular accident, myocardial infarction and hospitalisation for heart failure in a cohort of patients with CKD. Time to combined event was examined with Kaplan-Meier plots and log rank test between 'completers' (attended >50% planned sessions) and 'non-completers'. In completers, time to combined event was examined between 'improvers' (≥50 m increase ISWT) and 'non-improvers' (<50 m increase). Differences in time to combined event were investigated with Cox proportional hazards models (adjusted for baseline kidney function, body mass index, diabetes, age, gender, ethnicity, baseline ISWT and smoking status).

RESULTS: In all, 757 patients (male 54%) (242 haemodialysis patients, 221 kidney transplant recipients, 43 peritoneal dialysis patients, 251 non-dialysis CKD patients) were referred for RR between 2005 and 2017. There were 193 events (136 deaths) during the follow-up period (median 34 months). A total of 43% of referrals were classified as 'completers', and time to event was significantly greater when compared with 'non-completers' (P = 0.009). Responding to RR was associated with improved event-free survival time (P = 0.02) with Kaplan-Meier analyses and log rank test. On multivariate analysis, completing RR contributed significantly to the minimal explanatory model relating clinical variables to the combined event (overall χ2 = 38.0, P < 0.001). 'Non-completers' of RR had a 1.6-fold [hazard ratio = 1.6; 95% confidence interval (CI) 1.00-2.58] greater risk of a combined event (P = 0.048). Change in ISWT of >50 m contributed significantly to the minimal explanatory model relating clinical variables to mortality and morbidity (overall χ2 = 54.0, P < 0.001). 'Improvers' had a 40% (hazard ratio = 0.6; 95% CI 0.36-0.98) independent lower risk of a combined event (P = 0.041).

CONCLUSIONS: There is an association between completion of an RR programme, and also RR success, and a lower risk of a combined event in this observational study. RR interventions to improve exercise capacity in patients with CKD may reduce risk of morbidity and mortality, and a pragmatic randomised controlled intervention trial is warranted.