Clinical Outcomes of ST Elevation Myocardial Infarction Patients Without Standard Modifiable Risk Factors

Background: Standard modifiable cardiovascular risk factors (SMuRFs; hypertension, diabetes mellitus, dyslipidemia, and smoking) are widely recognized as risk factors for coronary artery disease. However, the associations between absence of SMuRFs and long-term clinical outcomes in ST-segment elevation myocardial infarction (STEMI) patients are unclear.

Methods: Consecutive STEMI patients who underwent primary percutaneous coronary intervention (PCI) between 1999 and 2015 were retrospectively analyzed. The primary endpoint was up to 5-year all-cause mortality. Clinical characteristics and outcomes were compared between patients with at least one of the SMuRFs and those without any SMuRFs.

Results: Of 1963 STEMI patients, 126 (6.4 %) did not have any SMuRFs. Patients without SMuRFs were significantly older, had lower body mass index, and were more likely to be female. During a median follow-up period of 4.9 years, the cumulative incidence of death was significantly higher in patients without SMuRFs than in those with SMuRFs (log-rank p < 0.0001). Landmark analysis showed that patients without SMuRFs had higher mortality within 30 days of STEMI onset (log-rank p = 0.0045) and >30 days after STEMI onset (log-rank p = 0.0004). Multivariable Cox hazards analysis showed that absence of SMuRFs was associated with a higher risk of mortality (hazard ratio, 1.59; 95 % confidence interval, 1.14-2.21; p = 0.006).

Conclusions: Of STEMI patients undergoing primary PCI, patients without any SMuRFs had higher mortality than those with at least one of the SMuRFs. Patients without any SMuRFs have a poor prognosis and require more attention.