Prognostic Outcomes in Acute Coronary Syndrome Patients Without Standard Modifiable Risk Factors: A Multi-Ethnic Study Of 8680 Asian Patients

IMPORTANCEThere are growing concerns that patients suffering from acute coronary syndrome (ACS) without standard modifiable cardiovascular risk factors (SMuRFs), including hypertension, hypercholesterolemia, diabetes and smoking, have increased mortality.OBJECTIVEThis study examined the outcomes of ACS in patients without SMuRFs (termed SMuRF-less) in a multi-ethnic Asian population which remains unknown.DESIGNThis retrospective study was conducted from 1st January 2011 to 31st March 2021.SETTINGThis study was conducted in a tertiary healthcare institution in Singapore.PARTICIPANTSConsecutive patients presenting with ACS disease were recruited in the study.EXPOSUREThe outcomes of SMuRF-less patients were compared with SMuRF patients.MAIN OUTCOMES AND MEASURESThe primary outcome was cardiovascular mortality. Secondary outcomes were all-cause mortality, readmission, cardiogenic shock, stroke and heart failure. Multivariable regression analysis adjusted for covariates including age, sex, ethnicity, chronic kidney disease, ACS type, cardiac arrest, and left main and/or left anterior descending coronaryRESULTSOf the 8680 patients studied, 8.6% were SMuRF-less patients. SMuRF-less patients were significantly younger and had fewer comorbidities including stroke and chronic kidney disease, but higher rates of ventricular arrhythmias and inotropic or invasive ventilation requirement compared to the SMuRF group. 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) in SMuRF-less patients compared to SMuRF patients. Both groups had similar readmission (RR: 1.10, 95% CI 0.87–1.39, p=0.413) and heart failure (RR: 0.82, 95% CI 0.56–1.21, p=0.326) rates. Kaplan-Meier curve showed higher 30-day cardiovascular mortality in the SMuRF-less group compared to SMuRF group (HR: 1.84, 95% CI 1.45-2.33, pCONCLUSION AND RELEVANCEAlthough the proportion of ACS patients without standard risk factors in our Asian population is lower than those reported in the West, they also have worse short-term mortality compared to those with SMuRF. This calls for a global focus on the management of this unexpectedly high-risk subgroup of patients.