Effects of weight gain on medical care costs

OBJECTIVE: To examine in middle-aged adults the effect of medical care costs of large, rapid weight gain compared to weight maintenance. DESIGN: Retrospective cohort study for a 3-y time period. SETTING AND PARTICIPANTS: Population-based sample (N = 15174) of men and women members of a large managed care organization, aged 35 - 65 y, with a body mass index (BMI) >425 kg/m(2) at baseline. Health-care utilization and costs were measured at baseline and over the 3-y follow-up period. RESULTS: Mean age at baseline was 49.7 y and mean BMI was 31.5 kg/m(2). During the 3-y follow-up period, 40.8% were classified as weight maintainers (+/-4 pounds), 45.3% gained 5 - 19 pounds, and 13.9% gained greater than or equal to20 pounds. A weight gain of greater than or equal to20 pounds was significantly associated with increased total medical care costs in all subgroups evaluated. Among all subjects, for those who gained greater than or equal to20 pounds compared to those who maintained weight, the adjusted 3-y increase in costs was $561. Among the subgroup with baseline comorbidities, the adjusted 3-y change in total medical care costs was $711. Multivariate analyses showed no significant differences between those who gained 5 - 19 pounds and those who maintained weight. Baseline BMI and comorbidities were also significant predictors of change in medical care costs, independent of weight gain. CONCLUSION: A large 3-y weight gain (greater than or equal to20 lb) in middle-aged overweight and obese adults is associated with a correspondingly larger increase in total medical care costs compared to weight maintainers. The prevention of large weight gains holds promise for significantly reducing future medical care costs. Future studies should examine the causes of rapid weight gain and evaluate approaches to prevent and reverse such weight gain.