Type 2 diabetes mellitus increases long-term mortality risk after isolated surgical aortic valve replacement

BACKGROUND: Diabetes mellitus (DM) adversely affects morbidity and mortality for major atherosclerosis-related cardiovascular diseases and is associated with increased risk for the development of aortic stenosis. Clinical data regarding the impact of DM on outcomes of patients undergoing aortic valve replacement (AVR) have revealed inconsistent results. The aim of the current study was to investigate and compare the impact of type 2 DM on short-, intermediate- and long-term mortality between DM and non-DM patients who undergo isolated AVR. METHODS: We performed an observational study in a large tertiary medical center over a 14-year period (2004–2018), which included all patients who had undergone isolated AVR surgery for the first time. Of the 1053 study patients, 346 patients (33%) had type 2 DM (DM group) and were compared with non-DM (non-DM group) patients (67%). Short-term (in-hospital), intermediate (1- and 3-years), and late (5- and 10-years) mortality were evaluated. Mean follow-up of was 69 ± 43 months. RESULTS: Short-term (in-hospital) mortality was similar between the DM compared with the non-DM group: 3.5% and 2.5% (p = 0.517). Intermediate-term mortality (1- and 3-year) was higher in the DM group compared with the non-DM group, but did not reach statistical significance: 8.1% vs. 5.7% (p = 0.169) and 12.1% vs. 8.3% (p = 0.064) respectively. Long-term (5- and 10-year) mortality was significantly higher in the DM group, compared to the non-DM group: 19.4% vs. 12.9% (p = 0.007) and 30.3% vs. 23.5% (p = 0.020) respectively. Among the 346 DM patients, 55 (16%) were treated with insulin and 291 (84%) with oral antiglycemic medication only. Overall in-hospital mortality among insulin-treated DM patients was 7.3% compared with 2.7% among non insulin-treated DM patients (p = 0.201). Long-term mortality was higher in the subgroup of insulin-treated DM patients compared with the subgroup of non-insulin treated DM patients with an overall mortality rate of 36.4% vs. 29.2% (p = 0.039). Furthermore, predictors for late mortality included DM (HR 1.39 CI 1.03–1.86, p = 0.031) and insulin treatment (HR 1.76 CI 1.05–2.94, p = 0.033), as demonstrated after adjustment for confounders by multivariable analysis. CONCLUSIONS: Type 2 DM is an independent predictor for long-term mortality after isolated AVR surgery.