Long-term efficacy and safety of sodium-glucose cotransporter-2 inhibitors as add-on to metformin treatment in the management of type 2 diabetes mellitus

BACKGROUND Drug intensification is often required for patients with type 2 diabetes mellitus on stable metformin therapy. Among the potential candidates for a combination therapy, sodium-glucose transporter-2 (SGLT2) inhibitors have shown promising outcomes. This meta-analysis was performed to compare the efficacy and safety of SGLT2 inhibitors with non-SGLT2 combinations as add-on treatment to metformin. METHODS Literature search was carried out in multiple electronic databases for the acquisition of relevant randomized controlled trials (RCTs) by following a priori eligibility criteria. After the assessment of quality of the included RCTs, meta-analyses of mean differences or odds ratios (OR) were performed to achieve overall effect sizes of the changes from baseline in selected efficacy and safety endpoints reported in the individual studies. Between-studies heterogeneity was estimated with between-studies statistical heterogeneity (I) index. RESULTS Six RCTs fulfilled the eligibility criteria. SGLT2 inhibitors as add-on to metformin treatment reduced % HbA1c significantly more than non-SGLT2 combinations after 52 weeks (P = .002) as well as after 104 weeks (P < .00001). Among other endpoints, SGLT2 inhibitors also reduced fasting plasma glucose levels, body weight, systolic, and diastolic blood pressures after 52 weeks and 104 weeks significantly (P < .00001) more than non-SGLT2 combinations. Incidence of hypoglycemia was significantly lower (P = .02) but incidence of suspected or confirmed genital tract infections was significantly higher (P < .00001) in SGLT2 inhibitors treated in comparison with non-SGLT2 combinations. CONCLUSION As add-on to metformin treatment, SGLT2 inhibitors are found significantly more efficacious than non-SGLT2 inhibitor combinations in the management of type 2 diabetes mellitus, although, SGLT2 inhibitor therapy is associated with significantly higher incidence of suspected or confirmed genital tract infections.