Cost Utility of Sodium-Glucose Cotransporter 2 Inhibitors in the Treatment of Metformin Monotherapy Failed Type 2 Diabetes Patients: A Systematic Review and Meta-Analysis

Objectives: Type 2 diabetes mellitus (T2DM) and associated ailments are leading economic burdens to society. Sodium glucose cotransporter-2 (SGLT2) inhibitors are recent antidiabetic medications with beneficial clinical efficacy. This meta-analysis was conducted to quantitatively pool the incremental net benefit of SGLT2 inhibitors in T2DM patients who failed metformin monotherapy. Methods: Relevant economic evaluation studies of T2DM patients were identified from PubMed, Scopus, ProQuest, the Cochrane Library, and the Tufts Cost-Effective Analysis Registry until June 2018. Studies were eligible if they studied T2DM patients who failed metformin monotherapy and assessed the cost-effectiveness/utility between SGLT2 inhibitors and other treatments. Details of the study characteristics, economic model inputs, costs, and outcomes were extracted. Risk of bias was assessed using the biases in economic studies (ECOBIAS) checklist. The incremental net benefit was calculated with monetary units adjusting for purchasing power parity for 2017 US dollars. This was then pooled across studies stratified by the country's level of income using a random-effect model if heterogeneity was present and with a fixed-effect model otherwise. Heterogeneity was assessed using the Q test and I² statistic. Results: A total of 13 studies with 22 comparisons, mainly from high-income countries, were eligible. Six and 4 studies compared SGLT2 with dipeptidyl peptidase-4 inhibitors (DPP4i) and sulfonylureas, respectively. The pooled incremental net benefits (95% confidence interval) for these corresponding comparisons were $164.95 (–$534.71 to $864.61; I² = 0%) and $3675.09 ($1656.46-$5693.71; I² = 85.4%), respectively. These results indicate that SGLT2s were cost-effective in comparison with sulfonylureas but not DPP4i. Conclusion: SGLT2s were cost-effective as compared with sulfonylureas but not DPP4i. Most of the evidence was from high-income countries with few comparative drug groups, and the results might not be representative of the actual global scenario. Further studies from middle and lower economies and other comparators are still required.