Dose-Response Effects of Exercise on Glucose-Lowering Medications for Type 2 Diabetes: A Secondary Analysis of a Randomized Clinical Trial

Objective: To investigate whether a dose-response relationship exists between volume of exercise and discontinuation of glucose-lowering medication treatment in patients with type 2 diabetes. Patients and Methods: Secondary analyses of a randomized controlled exercise-based lifestyle intervention trial (April 29, 2015 to August 17, 2016). Patients with non–insulin-dependent type 2 diabetes were randomly assigned to an intensive lifestyle intervention (U-TURN) or standard-care group. Both groups received lifestyle advice and objective target-driven medical regulation. Additionally, the U-TURN group received supervised exercise and individualized dietary counseling. Of the 98 randomly assigned participants, 92 were included in the analysis (U-TURN, n=61, standard care, n=31). Participants in the U-TURN group were stratified into tertiles based on accumulated volumes of exercise completed during the 1-year intervention. Results: Median exercise levels of 178 (interquartile range [IQR], 121-213; lower tertile), 296 (IQR, 261-310; intermediate tertile), and 380 minutes per week (IQR, 355-446; upper tertile) were associated with higher odds of discontinuing treatment with glucose-lowering medication, with corresponding odds ratios of 12.1 (95% CI, 1.2-119; number needed to treat: 4), 30.2 (95% CI, 2.9-318.5; 3), and 34.4 (95% CI, 4.1-290.1; 2), respectively, when comparing with standard care. Cardiovascular risk factors such as glycated hemoglobin A_1c levels, fitness, 2-hour glucose levels, and triglyceride levels were improved significantly in the intermediate and upper tertiles, but not the lower tertile, compared with the standard-care group. Conclusion: Exercise volume is associated with discontinuation of glucose-lowering medication treatment in a dose-dependent manner, as are important cardiovascular risk factors in well-treated participants with type 2 diabetes and disease duration less than 10 years. Further studies are needed to support these findings. Study Registration: ClinicalTrials.gov registration (NCT02417012).