Impact of Type 2 Diabetes Mellitus on Short- and Long-term Mortality after Isolated Aortic Valve Replacement

Background: Diabetes mellitus (DM) adversely affects morbidity and mortality for major atherosclerosis-related cardiovascular diseases and is an independent risk factor for the development of aortic stenosis. Clinical data about the impact of DM on outcomes of patients undergoing aortic valve replacement (AVR) revealed inconsistent results. The aim of the current study was to investigate the impact of type 2 DM on short- and long-term mortality on patients undergoing isolated AVR.

Methods: We performed an observational cohort study in a large tertiary medical center over a period of fourteen years. All data from patients who had undergone isolated
AVR surgery between 2004 and 2018 were obtained from our departmental database. The study population included 1053 patients, of them 346 (33%) with DM and 707 (67%) without DM. In-hospital, 1-, 3- and 5-year mortality outcome variables were evaluated. Mean follow-up was 69±43 months.

Results: In-hospital mortality was similar between patients with and without DM (3.5% vs. 2.5%, p=0.517). However, DM-patients had significantly more acute kidney injury (15% vs. 7.2%, p<0.001). Long-term mortality (1, 3, 5 and 10 years) was higher in DM type 2 compared with non-diabetic patients (8.1% vs. 5.7%, p=0.169; 12.1% vs. 8.3%, p=0.064; 19.4% vs. 12.9%, p=0.007 and 30.3% vs. 23.5% p=0.020). Kaplan-Meier analysis demonstrated that all-cause mortality was higher in diabetics compared to non-diabetics (p<0.001) (Figure) and in insulin dependent compared to non-insulin dependent DM (p=0.039). Also after adjustment for confounders by multivariable analysis DM (HR 1.33 CI 1.03-1.72, p=0.027) and insulin treatment (HR 1.76 CI 1.05-2.94, p=0.033) were predictors for late mortality.

Conclusions: Type 2 DM is an independent predictor for long-term mortality after isolated AVR surgery. Mortality is even higher when the diabetes treatment strategy included insulin.