CKD: Exercise Beneficial in Chronic Kidney Disease

Beth Skwarecki

October 23, 2014

Hemodialysis patients who exercised aerobically had greater health-related quality of life and lower rates of depression symptoms and mortality according to a prospective cohort study involving dialysis centers in 12 countries.

"Our findings provide further support to the promotion of physical activity programs in hemodialysis units," write Antonio Alberto Lopes, MD, PhD, from the Department of Internal Medicine, School of Medicine, Federal University of Bahia, Salvador, Brazil, and colleagues.

The work was published online October 2 and in the October 7 issue of the Clinical Journal of the American Society of Nephrology.

The Dialysis Outcomes and Practice Patterns study (DOPPS) is based on nationally representative samples of dialysis facilities and patients in Australia, Belgium, Canada, France, Germany, Italy, Japan, New Zealand, Spain, Sweden, the United Kingdom, and the United States. This analysis included 5763 patients (out of a total 11,733) who completed the physical activity questionnaires, could walk, and had data on outcomes available. These patients were younger, had more time on dialysis, and had a lower prevalence of comorbid conditions compared with the patients who were excluded from the analysis.

Patients self-reported their levels of aerobic exercise and indicated whether they did any flexibility or strength exercise, using the Rapid Assessment of Physical Activity questionnaire. For aerobic exercise, 28.6% reported that they were never or rarely active, and 20.4% were very active. In addition, 9.3% of the patients reported flexibility activities, 4.3% reported strength activities, and 6.8% reported both.

Some dialysis centers offer exercise programs, ranging from 14% in Japan to 37% in North America. Where these programs were available, 70% of patients reported being sometimes, often, or very active compared with 57% elsewhere. This association was true even after adjustment for age, sex, location, length of time receiving dialysis, and need for assistance with walking (odds ratio, 1.79; 95% confidence interval, 1.45 - 2.22; P < .001).

Aerobic exercise was also correlated with lower mortality. Compared with never and rarely active patients, those who were infrequently active had an 11% reduction in mortality (hazard ratio [HR], 0.89; 95% CI, 0.72 - 1.10), sometimes-active patients had a 16% reduction (HR, 0.84; 95% CI, 0.67 - 1.05), often-active patients had a 19% reduction (HR, 0.81; 95% CI, 0.68 - 0.96), and very active patients had a 40% reduction (HR, 0.60; 95% CI, 0.47 - 0.77; P for trend < .001). The researchers adjusted for numerous clinical and demographic factors.

Patients who reported higher levels of aerobic exercise also tended to have better scores on quality-of-life outcomes. The difference was 9.9 points (95% CI, 7.75 - 11.99 points) on a 100-point scale of kidney disease burden; 6.7 points (95% CI, 5.79 - 7.56 points) on physical quality of life, where the possible range was 4.8 to 66.7; and 3.7 points (95% CI, 2.76 - 4.65 points) for mental quality of life out of a range of 1.4 to 74.7 points.

Higher levels of aerobic activity were also associated with lower scores for symptoms of depression (adjusted odds ratio, 0.43; 95% CI, 0.35 - 0.52).

Strength and flexibility activities did not show a strong association with either quality of life or mortality.

In another study published in the issue of the journal, by Eduardo Lacson Jr, MD, MPH, from Clinical Sciences, Epidemiology, and Research, Fresenius Medical Care North America, Waltham, Massachusetts, patients who reported feeling "down in the dumps" or "downhearted and blue" when surveyed in their first 120 days of dialysis treatment were more likely to be hospitalized within a year.

Specifically, 8776 incident patients (of 41,585 total patients treated in 2006 at Fresenius Medical Care North America) who reported having depressive feelings at least "a little bit of the time" were 13% more likely to be hospitalized within a year and to spend 20% more days in the hospital, after adjustments for age, sex, race, diabetes, and other survey and laboratory measurements.

"These data are consistent with our earlier work describing depressive symptoms as a significant risk factor for mortality in the early dialysis treatment period," the authors write.

"Physical activity or exercise seem to be an effective treatment for depression and consequently may reduce mortality and hospitalization," write Denise Mafra, RD, PhD, from the Graduate Program in Medical Sciences, Fluminense Federal University, Niterói, Brazil, and Denis Fouque, MD, PhD, from the Renal Unit, Centre Hospitalier Lyon Sud, France, in an editorial discussing both studies. They note that more research is needed to determine the best type of exercise, as well as what intensity and frequency should be recommended.

The DOPPS program is supported by Amgen, Kyowa Hakko Kirin, AbbVie Inc, Sanofi Renal, Baxter Healthcare, Vifor Fresenius Medical Care Renal Pharma Ltd, and Fresenius Medical Care. Additional support for specific projects and countries is also provided in Canada by Amgen, BHC Medical, Janssen, Takeda, Kidney Foundation of Canada (for logistics support); in Germany by Hexal, DGfN, Shire, WiNe Institute; and in Japan by the Japanese Society for Peritoneal Dialysis. One author on the DOPPS study has research funding from Baxter Healthcare Inc and serves on an advisory board for Amgen Inc. Dr Lacson and coauthors are employees of Fresenius Medical Care. The other authors have disclosed no relevant financial relationships.

Clin J Am Soc Nephrol. 2014;9:1669-1670, 1702-1719. Lopes abstract, Lacson abstract


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