Comparative Effectiveness of 2 Diabetes Prevention Lifestyle Programs in the Workplace: The City and County of San Francisco Diabetes Prevention Trial

INTRODUCTION: Data on the comparative effectiveness of Diabetes Prevention Programs (DPPs) in the workplace are limited. METHODS: Between September 2015 and July 2016, employees of the City and County of San Francisco who were at risk for type 2 diabetes (N = 158) were randomly assigned to one of 2 DPP-derived programs recognized by the Centers for Disease Control and Prevention: an in-person YMCA-DPP (n = 78) or an online virtual lifestyle management DPP (VLM-DPP) offered through Canary Health (n = 80). The primary outcome was change in body weight assessed at 6 and 12 months. Follow-up ended in August 2017. RESULTS: Both the YMCA-DPP and VLM-DPP yielded a significant reduction in percentage body weight at 6 months. For the YMCA-DPP, mean percentage change at 6 months was -2.70% (95% confidence interval [CI], -3.91% to -1.48%) and at 12 months was -2.46% (95% CI, -4.24% to -0.68%). For the VLM-DPP, mean percentage change at 6 months was -2.41% (95% CI, -4.07% to -0.77%) and at 12 months was -1.59% (95% CI, -3.51% to 0.33%). The mean between-condition difference at 6 months was -0.25% (95% CI, -2.04% to 1.55%) and at 12 months was -0.84% (95% CI, -3.03% to 1.34%). No significant differences were observed between conditions. The YMCA-DPP had a slightly higher reduction in waist circumference than VLM-DDP at 6 months (mean between-condition difference -2.00 cm [95% CI, -4.24 to 0.25 cm]). Participant engagement, expressed as mean number of completed core program sessions, was significantly higher for the YMCA-DPP than the VLM-DPP. Participants of the YMCA-DPP completed an average of 10.2 sessions (95% CI, 9.0 to 11.4), and participants of the VLM-DPP completed an average of 5.9 sessions (95% CI, 4.7 to 7.1). The adjusted mean between-condition difference was 4.2 sessions (95% CI, 2.54 to 5.99). CONCLUSION: Both the YMCA-DPP and VLM-DPP yielded weight loss at 6 months, which was maintained at 12 months in the YMCA-DPP. The workplace may be an effective setting to offer DPPs.