Clinical characteristics and outcomes of patients with acute coronary syndrome without standard metabolic cardiovascular risk factors

Abstract Background/Introduction Patients with acute coronary syndrome (ACS) commonly present with hypertension, diabetes mellitus (DM), and dyslipidaemia as standard modifiable metabolic risk factors. However, little is known about patients with ACS who do not have these risk factors. Purpose This study investigated the clinical characteristics and outcomes of patients with ACS without these risk factors who underwent primary percutaneous coronary intervention (PCI). Methods This retrospective, single-centre observational study included 1131 consecutive patients with ACS who were admitted to a hospital between January 2013 and May 2021. After excluding patients who did not undergo revascularization or who underwent emergency coronary artery bypass surgery, 947 patients who underwent primary PCI were included in the analysis. Patients were classified into two groups: those with one or more of the following: hypertension, DM, or dyslipidaemia (risk group) and those without any of these factors (non-risk group). Major adverse cardiovascular events (MACE), including all-cause mortality, myocardial infarction (MI), stroke, and heart failure requiring rehospitalisation, were assessed at the 1-year follow-up. Results This study classified 78 patients (8.2%) in the non-risk group, who exhibited a significantly lower body mass index (BMI) [23.0 (interquartile range: 21.8–24.7) vs. 23.8 (interquartile range: 21.8–26.2) kg/m2, p = 0.016], compared to the risk group. There were no significant differences in smoking history between the two groups (51.2% vs. 48.9%, p = 0.39). Within 1 year after PCI, MACE occurred in 146 (15.4%) patients (88 [9.2%] with all-cause death, 13 [1.3%] with MI, 23 [2.4%] with stroke, and 27 [2.8%] with heart failure requiring rehospitalisation), with a significantly higher incidence in the non-risk group compared to the risk group (24.4% vs. 14.6%, p = 0.027). Multivariate analysis revealed that both being in the non-risk group and having a low BMI (< 21.5) were independent determinants for the incidence of MACE (hazard ratio [HR]: 1.52; 95% confidence interval [CI]: 1.01–2.29; p = 0.042 and HR: 3.08; 95% CI: 1.30–7.27; p = 0.010, respectively). Kaplan–Meier survival analysis showed a higher MACE rate in the non-risk group than in the risk group (p = 0.009). Conclusions Patients with ACS without hypertension, DM, or dyslipidaemia have a poorer prognosis than those with these risk factors, independent of the presence of a lower BMI, and the underlying pathophysiology in this subset of patients needs to be clarified.figure