Weight loss and retention in a commercial weight-loss program and the effect of corporate partnership

Background: No studies report whether improvements to commercial weight-loss programs affect retention and weight loss. Similarly, no studies report whether enrolling in a program through work (with a corporate partner) affects retention and weight loss. Objectives: To determine whether: (1) adding evidence-based improvements to a commercial weight-loss program increased retention and weight loss, (2) enrolling in a program through work increased retention and weight loss and (3) whether increased weight loss was because of longer retention. Design, Setting and Participants: Data were collected on 60 164 adults who enrolled in Jenny Craig's Platinum Program over 1 year in 2001-2002. The program was subsequently renamed the Rewards Program and improved by increasing treatment personalization and including motivational interviewing. Data were then collected on 81 505 participants of the Rewards Program who enrolled during 2005 (2418 of these participants enrolled through their employer, but paid out-of-pocket). Measurements: Retention (participants were considered active until >= 42 consecutive days were missed) and weight loss (percent of original body weight) from baseline to the last visit (data were evaluated through week 52) were determined. Results: Alpha was set at 0.001. Mean (95% confidence interval (CI)) retention (weeks) was significantly higher among Rewards (19.5 (19.4-19.6)) compared with Platinum (16.3 (16.2-16.4)) participants, and Rewards Corporate (25.9 (25.0-26.8)) compared with Noncorporate (21.9 (21.7-22.1)) participants. Modified intent-to-treat analyses indicated that mean (95% CI) percent weight loss was significantly larger among Rewards (6.36 (6.32-6.40)) compared with Platinum (5.45 (5.41-5.49)) participants, and Rewards Corporate (7.16 (6.92-7.40)) compared with Noncorporate (6.20 (6.16-6.24)) participants, with and without adjustment for baseline participant characteristics. In all cases, greater weight loss was secondary to longer retention. Limitations: The study was not a randomized controlled trial, rather, a translational effectiveness study. Conclusions: Improvements to a commercial program and enrolling through a corporate partner are associated with greater weight loss that is because of improved retention. International Journal of Obesity (2010) 34, 742-750; doi: 10.1038/ijo.2009.276; published online 12 January 2010