Effect of Bariatric Surgery on Cardiovascular Events and Metabolic Outcomes in Obese Patients with Insulin-Treated Type 2 Diabetes: a Retrospective Cohort Study

AimsTo compare non-fatal cardiovascular (CV) events and metabolic outcomes, among obese patients with insulin-treated type 2 diabetes who underwent bariatric surgery compared with a propensity-matched non-bariatric cohort.MethodsA retrospective cohort study was conducted among 11,125 active patients with type 2 diabetes from The Health Improvement Network (THIN) database. Propensity score matching (up to 1:6 ratio) was used to identify patients who underwent bariatric surgery (N=131) with a non-bariatric cohort (N=579). Follow-up was undertaken for 10 years (9686 person-years) to compare differences in metabolic outcomes and CV risk events that included the following: acute myocardial infarction (AMI), stroke, coronary heart disease (CHD), heart failure (HF) and peripheral artery disease (PAD). Cox proportional regression was used to compute the outcomes between groups.ResultsThe mean age was 52 (SD 13) years (60% female); the baseline weight and BMI were 116 (SD 25) kg and 41 (SD 9) kg/m(2), respectively. Significant reductions in weight and BMI were observed in bariatric group during 10 years of follow-up. Bariatric surgery had a significant cardioprotective effect by reducing the risk of non-fatal CHD (adjusted hazard ratio [aHR] 0.29, 95% CI 0.16-0.52, p<0.001) and PAD events (aHR 0.31, 95% CI 0.11-0.89, p=0.03). However, the surgery had no significant effect on AMI (aHR 0.98, p=0.95), stroke (HR 0.87, p=0.76) and HF (HR 0.89, p=0.73) risks. Bariatric surgery had favourable effects on insulin independence, HbA1c and BP.ConclusionAmong obese insulin-treated patients with type 2 diabetes, bariatric surgery is associated with significant reductions in non-fatal CHD and PAD events, lower body weight, HbA1c, BP and a greater likelihood of insulin independency during 10 years of follow-up.