Prognostic Outcomes in Acute Myocardial Infarction Patients Without Standard Modifiable Risk Factors: A Multiethnic Study of 8,680 Asian Patients

Abstract

BackgroundAn increasing proportion of patients with acute myocardial infarction (AMI) are presenting without standard modifiable risk factors (SMuRFs) of hypertension, hypercholesterolemia, diabetes, and smoking, but with an unexpectedly increased mortality. This study examined the SMuRF-less patients presenting with AMI in a multiethnic Asian population.MethodsWe recruited patients presenting with AMI from 2011 to 2021 and compared the prevalence, clinical characteristics, and outcomes of SMuRF-less and SMuRF patients. Multivariable analysis was used to compare the outcomes of 30-day cardiovascular mortality, all-cause mortality, readmission, cardiogenic shock, stroke, and heart failure. Kaplan–Meier curves were constructed for 30-day cardiovascular mortality, with stratification by ethnicity, gender and AMI type, and 10-year all-cause mortality.ResultsStandard modifiable risk factor-less patients, who made up 8.6% of 8,680 patients, were significantly younger with fewer comorbidities that include stroke and chronic kidney disease, but higher rates of ventricular arrhythmias and inotropic or invasive ventilation requirement. Multivariable analysis showed higher rates of cardiovascular mortality (HR 1.48, 95% CI: 1.09–1.86, p = 0.048), cardiogenic shock (RR: 1.31, 95% CI: 1.09–1.52, p = 0.015), and stroke (RR: 2.51, 95% CI: 1.67–3.34, p = 0.030) among SMuRF-less patients. A 30-day cardiovascular mortality was raised in the SMuRF-less group, with similar trends in men, patients with ST-segment elevation myocardial infarction (STEMI), and the three Asian ethnicities. All-cause mortality remains increased in the SMuRF-less group for up to 5 years.ConclusionThere is a significant proportion of patients with AMI without standard risk factors in Asia, who have worse short-term mortality. This calls for greater focus on the management of this unexpectedly high-risk subgroup of patients.

Angiographic severity in acute coronary syndrome patients with and without standard modifiable risk factors

“…The prevalence of SMuRF-less status in cardiovascular disease seems to range from 3 to 27% depending on the studied population (2, 5-7, 9, 14, 17-19). Our findings concur with existing literature, demonstrating that roughly 1 out of 10 patients who presented with ACS without any prior history of cardiovascular disease had no SMuRFs (2,7,17,20,21).…”

“…Moreover, our study adds to the growing body of literature that SMuRF-less patients with ACS suffer from excess early all-cause mortality risk (either in-hospital or at 30 days of follow-up) (5)(6)(7)21); yet the long-term post-ACS clinical course did not differ significantly among patients with and without SMuRFs of our study, which also concurs with some of the published reports (7,17). Interestingly, Figtree et al showed that the events contributing to higher all-cause mortality in SMuRF-less patients occurred in the first 30 days; yet allcause mortality remained increased in the SMuRF-less group at a 8-year patient follow-up (7).…”

Management and outcomes of patients admitted with type 2 myocardial infarction with and without standard modifiable risk factors

“…Consistent to this study, an analysis of Asian T1AMI cohort showed SMuRF-less patients were younger compared to their counterparts [18]. The study proposed genetic risk could be a factor resulting in earlier presentation of AMI in SMuRF-less patients [18].…”

“…The majority of studies on T1AMI cohort have shown SMuRF-less patients are either a similar age or older than SMuRF patients [2,3,5,16,20]. Consistent to this study, an analysis of Asian T1AMI cohort showed SMuRF-less patients were younger compared to their counterparts [18]. The study proposed genetic risk could be a factor resulting in earlier presentation of AMI in SMuRF-less patients [18].…”

“…Figtree et al identified 14.9% SMuRF-less patients in the SWEDEHEART STEMI sub-cohort, while another study by the same group using the Australian Global Registry of Acute Coronary Events (GRACE) and the Cooperative National Registry of Acute Coronary Syndrome Care (CONCORDANCE) registries identified a SMuRF-less prevalence in STEMI patients of 19% [3,5]. A study of SMuRF in a NSTEMI cohort derived using the United Kingdom Myocardial Infarction National Audit Project (MINAP) found as much as 23% of patients were SMuRF-less, whereas a study centred around an Asian population found only 8.6% of patients were SMuRFless [2,18]. However, none of these studies focussed on a T2AMI cohort.…”