Impact of Physical Activity on Dialysis and Nondialysis Days and Clinical Outcomes Among Patients on Hemodialysis

Abstract

Objective: Patients undergoing hemodialysis (HD) have different physical activity (PA) patterns on HD and non-HD days. Nonetheless, whether these differences are associated with clinical outcomes remains unclear. We examined the association of PA levels on HD and non-HD days with cardiovascular (CV) hospitalizations and mortality.

Methods: Outpatients undergoing HD from 2002 to 2019 were retrospectively enrolled. The number of steps performed over 3 HD days and 4 non-HD days was recorded via accelerometry. Outcomes were all-cause mortality and a composite of CV hospitalizations and mortality. Patients were divided into two groups, each according to the median number of steps performed on HD (2371 steps/day) and non-HD days (3752 steps/day). Further, we categorized them into 4 groups according to each median values: "more active on HD/more active on non-HD (MM)," "more active on HD/less active on non-HD (ML)," "less active on HD/more active on non-HD (LM)," and "less active on HD/less active on non-HD (LL)." Cox and mixed-effects Poisson regression models were used for these outcomes.

Results: We analyzed 512 patients (median follow-up, 3.4 years). Higher PA on HD (hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.54-0.65), and non-HD (HR, 0.84; 95% CI, 0.80-0.88) was associated with lower mortality risk, respectively. Further, the ML group (HR, 1.20; 95% CI, 1.13-1.28), LM group (HR, 1.82; 95% CI, 1.53-2.17), and LL group (HR, 1.83; 95% CI, 1.65-2.02) had higher mortality risks than the MM group. Associations of PA with multiple CV hospitalizations and mortality were similar to those between PA and mortality.

Conclusions: Higher PA on HD and non-HD days was associated with lower risks of CV hospitalizations and mortality. However, higher PA levels on either HD or non-HD days alone did not improve clinical outcomes.