Effects of Intensive Lifestyle Intervention on All-Cause Mortality in Older Adults With Type 2 Diabetes and Overweight/Obesity: Results From the Look AHEAD Study

Abstract

OBJECTIVE Look AHEAD, a randomized trial comparing intensive lifestyle intervention (ILI) and diabetes support and education (DSE) (control) in 5,145 individuals with overweight/obesity and type 2 diabetes, found no significant differences in all-cause or cardiovascular mortality or morbidity during 9.6 (median) years of intervention. Participants in ILI who lost ≥10% at 1 year had lower risk of composite cardiovascular outcomes relative to DSE. Since effects of ILI may take many years to emerge, we conducted intent-to-treat analyses comparing mortality in ILI over 16.7 years (9.6 years of intervention and then observation) to DSE. In a secondary exploratory analysis, we compared mortality by magnitude of weight loss in ILI relative to DSE. RESEARCH DESIGN AND METHODS Primary outcome was all-cause mortality from randomization to 16.7 years. Other outcomes included cause-specific mortality, interactions by subgroups (age, sex, race/ethnicity, and cardiovascular disease history), and an exploratory analysis by magnitude of weight loss in ILI versus DSE as reference. Analyses used proportional hazards regression and likelihood ratio. RESULTS The incidence of all-cause mortality did not differ significantly in ILI and DSE (549 and 589 participants, respectively) (hazard ratio [HR] 0.91 [95% CI 0.81, 1.02]; P = 0.11). There were no significant differences between treatments in cause-specific mortality or within prespecified subgroups. ILI participants who lost ≥10% at 1 year had a 21% reduced risk of mortality (HR 0.79 [95% CI 0.67, 0.94]; P = 0.007) relative to DSE. CONCLUSIONS ILI focused on weight loss did not significantly affect mortality risk. However, ILI participants who lost ≥10% had reduced mortality relative to DSE.