Bariatric surgery for patients with type 2 diabetes mellitus requiring insulin: Clinical outcome and cost-effectiveness analyses

• Published in: PLoS medicine 2020-12, Vol.17 (12), p.e1003228-e1003228
• Main Authors: McGlone, Emma Rose, Carey, Iain, Veličković, Vladica, Chana, Prem, Mahawar, Kamal, Batterham, Rachel L, Hopkins, James, Walton, Peter, Kinsman, Robin, Byrne, James, Somers, Shaw, Kerrigan, David, Menon, Vinod, Borg, Cynthia, Ahmed, Ahmed, Sgromo, Bruno, Cheruvu, Chandra, Bano, Gul, Leonard, Catherine, Thom, Howard, le Roux, Carel W, Reddy, Marcus, Welbourn, Richard, Small, Peter, Khan, Omar A
• Format: Article
• Language: English
• Subjects: Adult; Bariatric Surgery - economics; Biology and Life Sciences; Body mass index; Body weight loss; Care and treatment; Clinical outcomes; Cloning; Cost analysis; Cost Savings; Cost-Benefit Analysis; Databases, Factual; Datasets; Diabetes; Diabetes mellitus (non-insulin dependent); Diabetes Mellitus, Type 2 - diagnosis; Diabetes Mellitus, Type 2 - drug therapy; Diabetes Mellitus, Type 2 - economics; Diabetics; Dosage and administration; Drug Costs; Female; Gastrectomy - economics; Gastric Bypass - economics; Gastrointestinal surgery; Glucagon; Glucagon-like peptide 1; Glucose transport; Health Care Costs; Humans; Hyperglycemia; Hypoglycemic Agents - administration & dosage; Hypoglycemic Agents - economics; Insulin; Insulin - administration & dosage; Insulin - economics; Male; Medicine and Health Sciences; Middle Aged; Models, Economic; Na+/glucose cotransporter; Obesity; Obesity - diagnosis; Obesity - economics; Obesity - surgery; Patients; Protein transport; Quality of Life; Quality-Adjusted Life Years; Registries; Social Sciences; Surgery; Time Factors; Treatment Outcome; Type 2 diabetes; Weight control
• ISSN: 1549-1676; 1549-1277; 1549-1676
• DOI: 10.1371/journal.pmed.1003228

Although bariatric surgery is well established as an effective treatment for patients with obesity and type 2 diabetes mellitus (T2DM), there exists reluctance to increase its availability for patients with severe T2DM. The aims of this study were to examine the impact of bariatric surgery on T2DM resolution in patients with obesity and T2DM requiring insulin (T2DM-Ins) using data from a national database and to develop a health economic model to evaluate the cost-effectiveness of surgery in this cohort when compared to best medical treatment (BMT). Clinical data from the National Bariatric Surgical Registry (NBSR), a comprehensive database of bariatric surgery in the United Kingdom, were extracted to analyse outcomes of patients with obesity and T2DM-Ins who underwent primary bariatric surgery between 2009 and 2017. Outcomes for this group were combined with data sourced from a comprehensive literature review in order to develop a state-transition microsimulation model to evaluate cost-effectiveness of bariatric surgery versus BMT for patients over a 5-year time horizon. The main outcome measure for the clinical study was insulin cessation at 1-year post-surgery: relative risks (RR) summarising predictive factors were determined, unadjusted, and after adjusting for variables including age, initial body mass index (BMI), duration of T2DM, and weight loss. Main outcome measures for the economic evaluation were total costs, total quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) at willingness-to-pay threshold of GBP£20,000. A total of 2,484 patients were eligible for inclusion, of which 1,847 had 1-year follow-up data (mean age of 51 years, mean initial BMI 47.2 kg/m2, and 64% female). 67% of patients no longer required insulin at 1-year postoperatively: these rates persisted for 4 years. Roux-en-Y gastric bypass (RYGB) was associated with a higher rate of insulin cessation (71.7%) than sleeve gastrectomy (SG; 64.5%; RR 0.92, confidence interval (CI) 0.86-0.99) and adjustable gastric band (AGB; 33.6%; RR 0.45, CI 0.34-0.60; p < 0.001). When adjusted for percentage total weight loss and demographic variables, insulin cessation following surgery was comparable for RYGB and SG (RR 0.97, CI 0.90-1.04), with AGB having the lowest cessation rates (RR 0.55, CI 0.40-0.74; p < 0.001). Over 5 years, bariatric surgery was cost saving compared to BMT (total cost GBP£22,057 versus GBP£26,286 respectively, incremental difference GBP£4,2