Sodium-glucose cotransporter 2 inhibitor versus metformin as first-line therapy in patients with type 2 diabetes mellitus: a multi-institution database study

Background Sodium-glucose co-transporter 2 inhibitors (SGLT2i) has shown evidence of cardiovascular benefit in patients with type 2 diabetes mellitus (T2DM). Currently metformin is the guideline-recommended first-line treatment. We aimed to investigate the benefit of SGLT2i vs metformin as first-line therapy. Methods Electronic medical records from Chang Gung Research Database during 2016-2019 were retrieved for patients with T2DM. Patients aged < 20, not receiving anti-diabetic medication, first-line treatment neither metformin nor SGLT2i were excluded. Primary outcomes were heart failure hospitalization, acute coronary syndrome, ischemic stroke, and all-cause mortality. Patients were followed up for events or December 31, 2019, whichever comes first. Results After exclusion criteria, a total of 41,020 patients with T2DM were eligible for analysis. There were 1100 patients with SGLT2i as first-line and 39,920 patients with metformin as first-line treatment. IPTW was used for propensity score matching. During one year follow-up, the hazard ratio (HR) of patients on SGLT2i as first-line treatment to patients on metformin as first-line treatment were HR 0.47 (95% CI 0.41-0.54, p < 0.0001) in heart failure hospitalization, HR 0.50 (95% CI 0.41-0.61, p < 0.0001) in acute coronary syndrome, HR 1.21 (95% CI 1.10-1.32, p < 0.0001) in ischemic stroke, and HR 0.49 (95% CI 0.44-0.55, p < 0.0001) in all-cause mortality. Conclusions In patients with T2DM, SGLT2i as first-line treatment may be associated with decreased events of heart failure hospitalization, acute coronary syndrome, and all-cause mortality, compared with metformin as first-line treatment. However, there may be an increased events of ischemic stroke using SGLT2i compared to metformin.