Newly diagnosed versus previously diagnosed or no diabetes mellitus in patients with acute coronary syndrome: a systematic review and meta-analysis

Abstract

Introduction: Νewly diagnosed diabetes mellitus (NDDM) among acute coronary syndrome (ACS) patients represents a distinct clinical entity, although available data remain inconclusive. This systematic review and meta-analysis compared ACS patients with NDDM to those without diabetes mellitus (DM) and those with previously diagnosed DM (PDDM).

Methods: We searched PubMed, Scopus, and CENTRAL until 10 December 2024. We assessed myocardial necrosis, prognosis, coronary artery disease (CAD) extent, left ventricular ejection fraction (LVEF) at discharge, and cardiometabolic profiles. ROBINS-E and GRADE assessed bias risk and evidence certainty, respectively.

Results: Out of 257,859 ACS patients from 34 studies, 5.2% had NDDM. NDDM patients had higher mean peak hs-cardiac troponin I levels compared to PDDM patients (MD 18,389.15 [95% CI 2975.96, 33802.34]) and intermediate post-discharge prognosis between PDDM and non-DM patients [5-MACE; RR 0.80 (95% CI 0.71, 0.91); RR 1.21 (95% CI 1.08, 1.37), respectively]. NDDM patients had similar discharge LVEF to PDDM patients but lower than non-DM patients (MD -2.06% [95% CI -2.93, -1.18]). Their cardiometabolic profile resembled PDDM.

Conclusions: Although the evidence was mostly low-certainty, the high prevalence of NDDM and its potentially unfavorable outcomes compared to non-DM patients could stimulate further research on the effects of intensified DM screening and preventive measures in the community and among ACS patients.

Registration: This systematic review and meta-analysis was registered with PROSPERO (CRD42024501412).

Keywords: Acute coronary syndrome; cardiovascular prevention; diabetes mellitus; myocardial infarction; newly diagnosed diabetes mellitus.