Prescription drug usage as measure of comorbidity resolution after bariatric surgery: a population-based cohort study

Obesity is a chronic and progressive disease associated with significant morbidity, mortality, and health-care costs. Bariatric surgery is the most effective intervention for sustainable weight loss and resolution of obesity-related comorbidities. Studies examining comorbidity resolution largely rely on individual self-reported outcomes and electronic record reviews. We present a population-based study looking at prescription medication utilization before and after bariatric surgery as a measure of comorbidity resolution.

All patients enrolled in the Center for Metabolic and Bariatric Surgery who underwent either gastric bypass or sleeve gastrectomy between 2013 and 2019 in Manitoba were included. Demographic information, follow up, and outpatient prescription dispensation data were obtained from the Manitoba Population Research Data Repository housed at the Manitoba Centre for Health Policy for 5 years pre- and post-surgery.

A total of 1184 patients were included. Antidepressants and selective serotonin reuptake inhibitors were the most commonly prescribed classes, and along with thyroid medication, utilization remained stable after bariatric surgery. Proton pump inhibitors and opioid class drugs increased at 1 year after surgery then returned to baseline. Glucose and lipid-lowering medications, including statins, biguanides, sulfonylureas, and insulin, were decreased. Antihypertensives, including ACE inhibitors, calcium channel blockers, angiotensin receptors blockers, thiazides, and beta blockers, similarly decreased.

This is the first Canadian study employing a provincial-wide prescription database to measure long-term comorbidity resolution after bariatric surgery. The use of administrative data eliminates potential biases and inaccuracies in follow up and self-reported outcomes. Consistent with the literature, prescriptions for the treatment of metabolic syndrome all decreased and were sustained at long-term follow up. Further studies are needed to delineate the effects of altered pharmaceutical utilization on patient quality of life and health-care expenditures.