The SMuRFs paradox in STEMI: insights from a metropolitan STEMI network

Background Management of standard modifiable cardiovascular risk factors (SMuRFs) is central to secondary prevention after ST-segment elevation myocardial infarction (STEMI). Paradoxically, “SMuRF-less” patients have been linked to higher long-term mortality in some studies, though findings are inconsistent. Data on in-hospital outcomes remain limited, particularly in German STEMI populations. Purpose To characterize SMuRF-less patients within a German metropolitan STEMI network and compare their outcomes with SMuRF-positive patients. Methods This multicentre STEMI registry included patients enrolled between January 2024 and October 2025. SMuRF status was defined by hypertension, diabetes, dyslipidemia, or smoking; ≥1 factor classified patients as SMuRF-positive. Outcomes were in-hospital mortality, cardiogenic shock (CS), culprit lesion, and stent implantation. Unadjusted and adjusted logistic regressions were performed, adjusting for age (<65/≥65), sex, infarction type, and pre-existing coronary artery disease. A two-sided p<0.05 was considered significant. Results Of 1,128 recorded STEMI patients, 867 had complete SMuRF data and were included in analysis. Baseline characteristics were generally balanced between the groups, with notable differences observed in infarction type, pre-interventional resuscitation, and pre-existing coronary artery disease (Table). In unadjusted analyses, SMuRF-less patients exhibited higher odds of in-hospital mortality (OR 3.57, 95% CI 2.07–6.15, p<0.001) and cardiogenic shock (OR 2.45, 95% CI 1.28–4.71, p<0.01), but lower likelihood of culprit lesions (OR 0.21, 95% CI 0.12–0.37, p<0.001) and stent implantation (OR 0.33, 95% CI 0.19–0.56, p<0.001) (Figure). These associations remained consistent after adjustment using binary logistic regression (Figure). Pre-interventional resuscitation emerged as the strongest independent predictor of mortality (OR 13.59, 95% CI 8.98–20.56) and was significantly more frequent among SMuRF-less patients. Sensitivity analyses excluding resuscitated cases showed that differences in mortality and cardiogenic shock were no longer significant, whereas the lower rates of culprit lesions and stent implantation in SMuRF-less patients persisted (Figure). Incorporating resuscitation status as a post-hoc adjustment in the regression model confirmed the robustness of these findings (data not shown). In final analysis, SMuRF-less STEMI patients less frequently presented with a culprit lesion and less often required urgent revascularization (71.3% vs. 92.1%, p<0.001). Conclusion In-hospital outcome differences between SMuRF-less and SMuRF-positive STEMI patients were largely driven by higher pre-interventional resuscitation rates, suggesting potential survivorship or information bias. After adjustment, mortality and CS did not differ significantly. The consistently lower incidence of culprit lesions in SMuRF-less patients warrants external validation.TableFigure