CKD: Exercise May Improve Pain, Physical Function

Beth Skwarecki

November 21, 2014

Patients with stage 3 and 4 chronic kidney disease (CKD) who completed a 12-week supervised exercise program improved significantly on exercise tests and in their health-related quality of life, according to results from a single-center randomized controlled trial published online November 20 in the Clinical Journal of the American Society of Nephrology.

"This study proves that [renal rehabilitation exercise] programs can be integrated into standard CKD clinic care," write Ana Rossi, MD, from the Division of Nephrology and Transplantation at Maine Medical Center in Portland, and colleagues. Kidney Disease: Improving Global Outcomes clinical practice guidelines recommend cardiovascular exercise for 30 minutes, 5 times a week, for patients with CKD.

"This study addresses an understudied problem of high clinical relevance in chronically ill CKD population," write Manisha Jhamb, MD, from the University of Pittsburgh School of Medicine, Pennsylvania, and Daniel Weiner, MD, from Tufts-New England Medical Center, Boston, Massachusetts, in an accompanying editorial. Previous studies of exercise in patients with CKD have mainly focused on patients who are already receiving dialysis, they note, but this study represents one of the largest clinical trials to date on the safety and efficacy of exercise programs for people with stage 3 or 4 CKD.

The trial involved 107 patients in the Portland, Maine, area who received either usual CKD clinic care or the same care in addition to a 24-session (approximately 12-week) supervised exercise program. Participants had stage 3 or 4 kidney disease and were given permission to participate by their primary care physician and primary nephrologist.

The exercise program was designed to include two sessions per week of strengthening and stretching activities and cardiovascular exercise, including treadmill walking and stationary cycling, at a Perceived Level of Exertion of no more than 11, which corresponds to 60% to 65% maximal heart rate. Participants were coached to increase the length of time they exercised until the cycling or walking sessions reached 60 minutes and to increase the exercise intensity by increasing the bicycle’s free wheel tension or the treadmill’s speed or incline. Staff members also encouraged participants to exercise on their own and to walk 5,000 to 10,000 steps per day, as measured by provided pedometers.

Patients who completed the exercise program were able to cover more ground in a 6-minute walk test (210 ± 266 feet more than baseline vs −10 ± 220 feet for the group that received usual care; P < .001). In addition to the 19% improvement in a 6-minute walk test over the usual care group, the participants who exercised also showed a 29% improvement over usual care in a sit-to-stand test, measured as time to get up from a chair 10 times in a row. The exercisers showed an improvement in the sit-to-stand test of 27% ± 27% of age-predicted score vs an improvement of 0.7% ±12% for the usual care group; P < .001). The investigators also tested gait speed, but there was no significant difference in improvement between the groups.

Health-related quality of life improved more in the exercisers than the control group, including physical functioning (mean change, −0.7 in the control group vs 11.1 in the exercise group; P = .004), energy/fatigue levels (mean change, 0.5 in the control group vs 9.8 in the exercise group; P = .01), and general health (mean change, −1.2 in the control group vs 4.9 in the exercise group; P = .03). The exercisers also reported a decrease in pain (mean change, −3.8 in the control group vs 5.7 in the exercise group; P = .04).

Only 72.9% of patients in the exercise group attended all 24 sessions, completing the program in a mean of 15.1 weeks. The other patients in the exercise group averaged 13 sessions, and 11 patients (18.6% of the exercise group) did not complete the program. Of the six patients who withdrew from the study early, chronic pain and time conflict were among the reasons given. Only two patients in the control group did not complete the study.

"While this may seem a high dropout rate over a relatively brief study, it is comparable to reported adherence rates in other lifestyle intervention studies in CKD and elderly patients," write Dr Jhamb and Dr Weiner. They note that difficulty traveling to the exercise sessions may have deterred sicker patients from participating, which could bias results.

There were no adverse events related to exercise, although the authors write that "[t]he exercise trainers required significant teaching and reassurance to allow them to confidently coach this patient population at increased risk for cardiovascular morbidity and mortality." Dr Jhamb and Dr Weiner write that future research is needed to reassure providers about safety, although this study "showed that moderate intensity supervised exercise was safe in these patients."

Clin J Am Soc Nephrol. Published online November 20, 2014. Abstract


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