Effects of SGLT2 inhibitors on clinical cancer survival in patients with type 2 diabetes

According to the preclinical data, sodium-glucose cotransporter 2 (SGLT2) inhibitors (SGLT2is) may exert anticancer effects. Here, we clarified the cancer-specific mortality (primary outcome) and all-cause mortality (secondary outcome) of SGLT2is and their dose-dependency in patients with cancer undergoing standard curative treatments. We analyzed data from patients with type 2 diabetes mellitus (T2DM) diagnosed with cancer between January 1, 2016, and December 31, 2018, enrolled from the Taiwan Cancer Registry database. Kaplan-Meier method was used to estimate all-cause mortality and cancer-specific mortality, comparing survival curves between SGLT2i users and nonusers using the stratified log-rank test. Cox proportional hazards regression was conducted to identify independent predictors for all-cause and cancer-specific mortality among the covariates. We performed 1:2 propensity score matching of our data, which yielded a final cohort of 50,133 patients with cancer; of them, 16,711 and 33,422 were in the SGLT2i user and nonuser groups, respectively. The adjusted hazard ratio (aHR) for cancer-specific and all-cause mortality in SGLT2i users compared with nonusers was 0.21 (95% confidence interval [CI]: 0.20–0.22) and 0.22 (95% CI: 0.21–0.23). We divided the patients into four subgroups stratified by quartiles (Q) of cumulative defined daily doses per year (cDDDs), and all-cause and cancer-specific mortality was noted to significantly decrease with increases in dosage (from Q1 to Q4 cDDDs) in SGLT2i users compared with in nonusers (P < 0.001). SGLT2is increase overall survival and cancer-specific survival in patients with cancer in a dose-dependent manner.