Risk of lower extremity amputations in patients with type 2 diabetes using sodium-glucose co-transporter 2 inhibitors

Aims To compare the influence of sodium-glucose co-transporter 2 inhibitors (SGLT2i) and dipeptidyl peptidase-4 inhibitors (DPP-4i) on the risk of lower extremity amputations in patients with type 2 diabetes in Slovenia. Methods This retrospective cohort study included patients aged 40 years or more who were administered a newly introduced SGLT2i or DPP-4i between June 2014 and June 2018. Patients treated with insulin at baseline and patients with a history of amputation were excluded. Patients were matched in a 1:1 ratio using propensity score matching. Survival analysis was performed; hazard ratio (HR) and ratios of cumulative hazards at 1, 2, 3, and 4 years were estimated. On-treatment and intention-to-treat approaches were used. Results The study cohort (mean age: 64 years) consisted of 2,939 new users of SGLT2i (empagliflozin, 59%; dapagliflozin, 41%) matched to 2,939 new users of DPP-4i. In the on-treatment analysis (median follow-up of 2 years), the incidence of amputations was higher in SGLT2i than in DPP-4i users (4.2 vs. 2.7 per 1,000 patient years), resulting in a HR of 1.58 (95% CI 0.85-2.92; p = 0.145). An intention-to-treat analysis yielded to similar HR of 1.86 (95% CI: 1.10-3.14; p = 0.020). There was no difference in amputation rates in the first two years, but SGLT2i users had a 2.81-fold higher (95% CI: 1.63-4.84; p = 0.007) cumulative hazard of amputation at 4 years than did DPP-4i users. Conclusions Compared with DPP-4i use, SGLT2i use did not result in a statistically significant higher overall risk of lower extremity amputations. However, the results suggest that SGLT2i may increase the risk of amputation with long-term use.