Comparison of heart failure risk and medical costs between patients with type 2 diabetes mellitus treated with dapagliflozin and dipeptidyl peptidase-4 inhibitors: a nationwide population-based cohort study

Background Dapagliflozin is one of the novel glucose-lowering agents, which has recently been reported to reduce the risk of hospitalization for heart failure (hHF). The present study aimed to compare the differences between the risk of hHF after using dapagliflozin and dipeptidyl peptidase-4 inhibitors (DPP-4i) as second-line drugs for the treatment of type 2 diabetes mellitus using the latest nationwide population data in Korea. Additionally, we aimed to examine the impact of clinical outcomes on direct medical costs in the two groups. Methods The present population-based, retrospective cohort study was conducted using the nationwide claims data between September 01, 2014 and June 30, 2018. New users of dapagliflozin and DPP-4i were identified from the database and the differences in patients' characteristics between the two groups were analyzed using propensity score-weighted analysis. Cox proportional hazards regression analysis was used to estimate the risk of hHF. A simple model was used for the estimation of direct medical costs for 3 years. Results In total, 23,147 patients in the dapagliflozin group and 237,187 patients in the DPP-4i group were selected for the analysis. The incidence rates of hHF were 3.86 and 6.79 per 1000 person-years in the dapagliflozin and DPP-4i groups, respectively. In the entire study population, the hazard ratio for hHF in the dapagliflozin group compared to the DPP-4i group was 0.58 (95% confidence interval 0.46-0.74), with 0.55 (95% confidence interval 0.41-0.74) among patients with underlying cardiovascular disease and 0.66 (95% confidence interval 0.46-0.95) among patients without underlying cardiovascular disease. The direct medical costs were $57,787 lower in the dapagliflozin group than in the DPP-4i group for 3 years. Conclusions This study showed that dapagliflozin lowers the risk for hHF and subsequently reduces direct medical costs compared to DPP-4i. The protective effect against hHF was more evident among patients with underlying cardiovascular disease.