Self-reported physical activity and survival in adults treated with hemodialysis: a DIET-HD cohort study

Regular physical activity is associated with longevity in adults receiving hemodialysis, but it is uncertain whether this association varies by causal pathways (cardiovascular and noncardiovascular). Methods DIET-HD was a prospective, multinational study of adults undergoing hemodialysis across Europe and Argentina. We classified participants as physically inactive, occasionally active (irregularly to once a week), or frequently active (twice a week or more), using a self-reported questionnaire. Potential confounders were balanced across exposure groups using propensity scores. Weighted Cox proportional hazards models with double robust estimators assessed the association between physical activity and all-cause, cardiovascular, and non-cardiovascular mortality. Results Of 8043 participants in DIET-HD, 6147 (76%) had information on physical activity. 2940 (48%) were physically inactive, 1981 (32%) occasionally active and 1226 (20%) frequently active. During a median follow-up of 3.82 years (19 677 person-years), 2337 (38%) deaths occurred, including 1050 (45%) from cardiovascular causes. After propensity score-weighting, occasional physical activity was associated with lower all-cause (adjusted hazard ratio [aHR]=0.80, 95% CI 0.72 to 0.89), cardiovascular (aHR=0.82, 95% CI 0.70 to 0.96) and non-cardiovascular mortality (aHR=0.81 95% CI, 0.69 to 0.94) compared to inactivity. Frequent physical activity was associated with lower all-cause (aHR=0.82, 95% CI 0.71 to 0.95) and cardiovascular mortality (aHR=0.77, 95% CI 0.62 to 0.94), but not non-cardiovascular mortality (aHR=0.88, 95% CI 0.72to 1.08). A dose-dependent association of physical activity with cardiovascular death was observed (p trend=0.01). Conclusion Compared with self-reported physical inactivity, occasional and frequent physical activity was associated, dose-dependently, with lower cardiovascular mortality in adults receiving hemodialysis.