Introduction & Objective: Type 2 diabetes (T2D) and prediabetes are associated with poor walking endurance, a marker of physical function. Our main aim was to examine the long-term effects of metformin or intensive lifestyle intervention (ILS) in adults at high risk of T2D on their 6-minute walk test (6MWT) performance.
Methods: Participants at high risk of T2D were randomized in the 3y DPP to ILS (physical activity [PA] and weight loss goals), metformin 850 mg bid, or placebo, and subsequently followed in the DPP Outcomes Study with brief lifestyle classes offered to all and metformin continued open label. A 6MWT was conducted 15y after DPP ended (mean 20y after randomization, 64% had developed T2D). The associations between DPP interventions and 6MWT completion (defined as achieving a distance ≥200 meters with or without a walking aid) were assessed using logistic regression. Among test completers, differences in distance walked in 6 min (6MWD) by DPP interventions were evaluated using multivariable linear regression. Additional variables of interest included concomitant measures of BMI and grip strength along with mean measures of HbA1c and self-reported PA over ~20y.
Results: Data on 1830 participants (mean baseline age 50y) were analyzed. The DPP interventions were neither associated with test completion, nor 6MWD among test completers (362, 364 and 360 m in the lifestyle, metformin, and placebo groups respectively, p=0.8). Age, education, grip strength, and PA were each significantly associated with the 6MWT completion and 6MWD after adjustment. Grip strength, PA, and education were positively associated with 6MWD, while age, BMI and HbA1c were negatively associated with 6MWD.
Conclusion: Although we did not observe a sustained effect of the original randomized interventions, we confirmed that the 6MWT is related to other measures of physical ability such as PA and grip strength in persons at-risk for and with T2D, suggesting potential long-term benefits of maintaining a healthy lifestyle.
M. Munshi: Consultant; Sanofi. E.M. Venditti: None. A.H. Tjaden: None. W.C. Knowler: None. E.J. Boyko: None. R.J.W. Middelbeek: Research Support; Novo Nordisk. J.A. Luchsinger: Consultant; Merck KGaA. Other Relationship; EMD Serono, Wolters Kluwer Health. C. Lee: Employee; Pfizer Inc. H.P. Hazuda: None. M.E. Salive: None. S. Edelstein: None. T.W. Storer: None. D. Research Group: None.
National Institute of Diabetes and Digestive and Kidney Diseases (UDK048489, UDK048339, UDK048377, UDK048349, UDK048381, UDK048468, UDK048434, UDK048485, UDK048375, UDK048514, UDK048437, UDK048413, UDK048411, UDK048406, UDK048380, UDK048397, UDK048412, UDK048404, UDK048387, UDK048407, UDK048443, UDK048400)
