BACKGROUND: Diabetes mellitus is a major cardiovascular risk factor for the development of coronary artery disease, but knowledge about the impact of diabetes mellitus on the outcome of patients with myocardial infarction with non-obstructive coronary arteries is limited. The aim of this study was to investigate the prognostic impact of diabetes mellitus on in- and out-of-hospital adverse events in troponin-positive patients with non-obstructive coronary arteries.

METHODS AND RESULTS: A total of 373 troponin-positive patients with non-obstructive coronary arteries between 2010 and 2021 at Bergmannsheil University Hospital Bochum were enrolled, including 65 diabetics and 307 nondiabetics. The median follow-up was 6.2 years. The primary study end point was a composite of in-hospital major adverse cardiovascular events (MACE). Secondary endpoints covered MACE during follow-up.Mean age of the study cohort was 62.9 years and 49.3 % were male. Although the overall rate of in-hospital MACE was higher in diabetics (41.5 %) than in non-diabetics (33.9 %), this difference did not reach statistical significance (p = 0.240). The in-hospital mortality rate was low in both groups, 0 % of diabetes group versus 2.9 % of non-diabetic patients. During follow-up, diabetic patients had a significantly higher rate of MACE (51.9 % vs. 31.1 %, p = 0.004) and a significantly higher all-cause mortality rate than non-diabetic patients (42.3 % vs. 20.1 %, p < 0.001).

CONCLUSION: Our study reveals that the impact of diabetes mellitus on cardiovascular outcomes in troponin-positive patients with non-obstructive coronary arteries intensifies over the long term, leading to increased rates of both cardiovascular adverse events and overall mortality.