Weight Loss for Patients With Obesity: An Analysis of Long-Term Electronic Health Record Data.

Background: Numerous studies have reported that losing as little as 5% of one's total body weight (TBW) can improve health, but no studies have used electronic health record data to examine long-term changes in weight, particularly for adults with severe obesity [body mass index (BMI) >= 35 kg/m(2)]. Objective: To measure long-term weight changes and examine their predictors for adults in a large academic health care system. Research Design: Observational study. Subjects: We included 59,816 patients aged 18-70 years who had at least 2 BMI measurements 5 years apart. Patients who were underweight, pregnant, diagnosed with cancer, or had undergone bariatric surgery were excluded. Measures: Over a 5-year period: (1) >= 5% TBW loss; (2) weight loss into a nonobese BMI category (BMI <30 kg/m(2)); and (3) predictors of %TBW change via quantile regression. Results: Of those with class 2 or 3 obesity, 24.2% and 27.8%, respectively, lost at least 5% TBW. Only 3.2% and 0.2% of patients with class 2 and 3 obesity, respectively, lost enough weight to attain a BMI <30 kg/m(2). In quantile regression, the median weight change for the population was a net gain of 2.5% TBW. Conclusions: Although adults with severe obesity were more likely to lose at least 5% TBW compared with overweight patients and patients with class 1 obesity, sufficient weight loss to attain a nonobese weight class was very uncommon. The pattern of ongoing weight gain found in our study population requires solutions at societal and health systems levels.