Phenotypes influencing low physical activity in maintenance dialysis.

Objective: The "Pas à Pas" initiative aimed at evaluating the weekly physical activity (PA) and its determinants in a large cohort of dialysis patients.

Setting: Physical inactivity is a risk factor for mortality in maintenance dialysis patients and is still poorly documented in this population.

Design: A prospective national epidemiological study was performed.

Subjects: A total of 1,163 patients on maintenance dialysis (hemodialysis and peritoneal dialysis) were included.

Intervention And Main Outcome Measure: PA was recorded during seven consecutive days using a pedometer to measure daily step numbers.

Results: Median age was 63 years (Q1 51-Q3 75). Sixty-three percent were sedentary (<5000 steps/day) with a median of 3,688 steps/day (1,866-6,271)]. PA level was similar between hemodialysis patients and those on peritoneal dialysis (3,693 steps [1,896-6,307] vs. 3,320 [1,478-5,926], P = .33). In hemodialysis patients, PA was lower on dialysis days compared with nondialysis days (2,912 [1,439-5,232] vs. 4,054 [2,136-7,108], respectively, P < .01). PA gradually decreased with age, 57% being sedentary between 50 and 65 years and 83% of patients after 80 years. Beyond this age effect, we identified, for the first time, specific phenotypes of patients with lower PA, such as inflammation, cardiovascular disease, protein energy wasting, obesity, and diabetes. By contrast, previous kidney transplantation and a higher muscle mass were associated with higher PA.

Conclusions: Dialysis patients present a very low level of PA with high sedentary. Acting on patient's modifiable phenotypes may help to increase PA to improve morbidity, mortality, and quality of life.