The Association between Therapeutic Drug Classes and Weight Change in Patients Attending a Medically Supervised Weight Loss Clinic

Introduction: Obesity is a leading public health problem in the developed and developing world. As the prevalence of obesity and its associated comorbidities increases, the number of the medications used by individuals living with obesity is also on the rise. Beyond the utility of these drugs for the treatment of obesity-related chronic diseases, many have unwanted side effects, including weight gain. Objectives: To characterize the number of medications used by patients of the Wharton Medical Clinic (WMC) both overall and by obesity class, and; to determine whether the amount of weight change differs according to therapeutic drug classes or chronic condition. Methods: Data was derived from a subset of bariatric patients (n=1426) who attended WMC for 3+ months. Study exposures included the number and type of medications taken, and type of the chronic diseases experienced. The primary study outcome was relative weight change. Results: Of the 153 medications listed by WMC patients, 32 have side effects that include weight gain. Over 3 months of follow-up, average weight loss was 4.7 kg; percentage weight change was greatest amongst patients with a history of stroke (6.1%), heart attack (5.3%) and hypertension (4.8%). Implications: Barriers to weight loss may include pharmacological treatment for pre-existing conditions. These findings have implications for setting realistic weight loss goals for long-term obesity management.