Fitness Boosts Kidney Function in Type 2 Diabetes

Physical fitness has a significant impact on renal function and chronic kidney disease (CKD) among adults with type 2 diabetes mellitus (DM), according to a new study.

“Fitness status and increased physical activity are essential for diabetic health,” said lead author Shruti Gandhi, MD, an endocrinologist at the VA Medical Center and George Washington University School of Medicine and Health Sciences, Washington, DC, who noted that improved physical fitness can ameliorate kidney deterioration and reduce mortality.

The study assessed exercise capacity and progression to CKD and the association with mortality, as well as the effect of a 12-week exercise program on estimated glomerular filtration rate (GFR). The researchers looked at data for more than 2000 patients (primarily men) with type 2 DM, average age 61 years, who had normal kidney function when they completed an exercise stress test. Patients were stratified based on peak exercise capacity. Those who achieved less than 5.5 metabolic equivalents (METs) were classified as least fit; 5.5 to 7.5 METs, as low fit; 7.6 to 9.5 METs, as moderately fit; and more than 9.5 METs, as highly fit.

After an average of 7 years of follow-up, 572 patients developed CKD or died of any cause. Because there were not enough data for separate analysis, the researchers combined cases of CKD and deaths, Dr Gandhi explained. The combined death rate and progression to CKD was much lower among those who had an increased level of fitness. Compared with the least fit patients, the highly fit patients had a 68% lower combined CKD-death rate, and the moderately fit had a 51% lower rate of progression to CKD and death. Even the low-fit group had a 41% lower rate than that of the least fit, he said.

The researchers also assessed the effect of a 12-week supervised exercise program on kidney function in 67 patients with type 2 DM. The program combined aerobic exercise and resistance for at least 30 minutes twice a week. Patients also could exercise at home on their own, and about 50% exercised on 1 more day, he noted. The estimated GFR was measured before and after the exercise program.

After completing the exercise program, 15 patients whose initial estimated GFR indicated stage 3 CKD, or moderate kidney damage, improved their exercise capacity from an average of 7.2 METs to nearly 8.6 METs, Dr Gandhi reported. Their estimated GFR level decreased after the program; slightly more than half of the patients improved their CKD to stage 2, indicating mildly reduced kidney function.

In conclusion, Dr Gandi said, “Exercise capacity amongst diabetics was inversely associated with the rate of progression to CKD and mortality.” He noted that the study is small but “provides hope to patients with progressive kidney disease that there is something they can do to improve their kidney function and perhaps prevent or delay the need for dialysis.”

Dr Gandi presented the results on June 23, 2014 at the 16th International Congress of Endocrinology and the Endocrine Society’s 96th Annual Meeting and Expo in Chicago.