Associations of self-reported physical activity types and levels with quality of life, depression symptoms, and mortality in hemodialysis patients: the DOPPS

Abstract

Background and objectives: Physical activity has been associated with better health status in diverse populations, but the association in patients on maintenance hemodialysis is less established. Patient-reported physical activities and associations with mortality, health-related quality of life, and depression symptoms in patients on maintenance hemodialysis in 12 countries were examined.

Design, setting, participants, & measurements: In total, 5763 patients enrolled in phase 4 of the Dialysis Outcomes and Practice Patterns Study (2009-2011) were classified into five aerobic physical activity categories (never/rarely active to very active) and by muscle strength/flexibility activity using the Rapid Assessment of Physical Activity questionnaire. The Kidney Disease Quality of Life scale was used for health-related quality of life. The Center for Epidemiologic Studies Depression scale was used for depression symptoms. Linear regression was used for associations of physical activity with health-related quality of life and depression symptoms scores. Cox regression was used for association of physical activity with mortality.

Results: The median (interquartile range) of follow-up was 1.6 (0.9-2.5) years; 29% of patients were classified as never/rarely active, 20% of patients were classified as very active, and 20.5% of patients reported strength/flexibility activities. Percentages of very active patients were greater in clinics offering exercise programs. Aerobic activity, but not strength/flexibility activity, was associated positively with health-related quality of life and inversely with depression symptoms and mortality (adjusted hazard ratio of death for very active versus never/rarely active, 0.60; 95% confidence interval, 0.47 to 0.77). Similar associations with aerobic activity were observed in strata of age, sex, time on dialysis, and diabetes status.

Conclusions: The findings are consistent with the health benefits of aerobic physical activity for patients on maintenance hemodialysis. Greater physical activity was observed in facilities providing exercise programs, suggesting a possible opportunity for improving patient outcomes.

Keywords: depression; hemodialysis; mortality; outcomes.

Figure 1.

Patient subgroup comparisons regarding the association of mortality with greater aerobic physical activity (sometimes to very active versus infrequently or never/rarely active) after extensive covariate adjustment. The hazard ratios (HRs) for mortality were adjusted for geographic region, age, sex, number of years on dialysis, race, smoking, employment status, education, living conditions, assistance with walking, muscle strength/flexibility, body mass index, diabetes, hypertension, coronary disease, heart failure, other cardiovascular disease, peripheral vascular disease, cerebrovascular disease, recurrent cellulitis, gastrointestinal bleed, lung disease, neurologic disorder, psychiatric disorders, nonskin cancer, HIV, catheter use, blood hemoglobin, dialysis dose by Kt/V, systolic BP<120 mmHg, systolic BP>160 mmHg, serum creatinine, serum albumin, serum calcium, serum phosphorus, parathyroid hormone, and normalized protein catabolic rate. All models accounted for facility clustering effects. The dashed vertical line indicates the overall HR (0.80), and the solid vertical line indicates no effect (HR, 1.00). 95% CI, 95% confidence interval.