Bariatric surgery is expensive but improves co-morbidity: 5-year assessment of patients with obesity and type 2 diabetes.

BACKGROUND Bariatric surgery can be effective in weight reduction and diabetes remission in some patients, but is expensive. The costs of bariatric surgery in patients with obesity and type 2 diabetes mellitus (T2DM) were explored here. METHODS Population-based retrospectively gathered data on patients with obesity and T2DM from the Hong Kong Hospital Authority (2006-2017) were evaluated. Direct medical costs from baseline up to 60 months were calculated based on the frequency of healthcare service utilization and dispensing of diabetes medication. Charlson Co-morbidity Index (CCI) scores and co-morbidity rates were measured to compare changes in co-morbidities between surgically treated and control groups over 5 years. One-to-five propensity score matching was applied. RESULTS Overall, 401 eligible surgical patients were matched with 1894 non-surgical patients. Direct medical costs were much higher for surgical than non-surgical patients in the index year (€36 752 and €5788 respectively; P < 0·001) mainly owing to the bariatric procedure. The 5-year cumulative costs incurred by surgical patients were also higher (€54 135 versus €28 603; P < 0·001). Although patients who had bariatric surgery had more visits to outpatient and allied health professionals than those who did not across the 5-year period, surgical patients had shorter length of stay in hospitals than non-surgical patients in year 2-5. Surgical patients had significantly better CCI scores than controls after the baseline measurement (mean 3·82 versus 4·38 at 5 years; P = 0·016). Costs of glucose-lowering medications were similar between two groups, except that surgical patients had significantly lower costs of glucose-lowering medications in year 2 (€973 versus €1395; P = 0.012). CONCLUSION Bariatric surgery in obese patients with T2DM is expensive, but leads to an improved co-morbidity profile, and reduced length of hospitalization.