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Mortality in STEMI Patients Without Modifiable Risk Factors: SWEDEHEART Registry Analysis
Quick Takes
- In a retrospective analysis of STEMI patients, those without traditional cardiovascular risk factors had a higher risk for all-cause mortality compared to those with these risk factors.
- The increased risk for all-cause mortality was highest among women without risk factors who were also least likely to receive appropriate secondary prevention therapies.
- Adjustment for medical therapy attenuated increased mortality risk.
Study Questions:
What are the clinical characteristics and outcomes in ST-segment elevation myocardial infarction (STEMI) patients without standard modifiable cardiovascular risk factors (SMuRFs) compared to patients with SMuRFs?
Methods:
This was a retrospective study of the SWEDEHEART registry that captures data on all patients admitted to a cardiac care unit in Sweden with MI. Adults with a diagnosis of STEMI were included. SMuRFs included current smoker status, hyperlipidemia, diabetes, or hypertension. The primary outcome of interest was all-cause mortality at 30 days after STEMI.
Results:
Between January 2005 and May 2018, 62,048 eligible STEMI patients were included in this analysis. This included 20,384 (32.9%) women with a median follow-up of 4.9 years (1.8-8.5 years). Overall, 9,228 patients (14.9%) had no documented SMuRFs before or during hospitalization. A higher proportion of patients without SMuRFs were men, but there was no significant difference in age compared to patients with SMuRFs.
Among patients with SMuRFs, the most common risk factor was hypertension (70.4%) followed by hyperlipidemia (48.4%), current smoking (32.6%), and diabetes (21.3%). Obesity was not an explanation for STEMI in patients without SMuRFs. At presentation, patients without SMuRFs had lower systolic blood pressure and heart rate and were more likely to present with cardiac arrest than patients with SMuRFs. Time difference from symptom onset to percutaneous coronary intervention was shorter by 12 minutes in patients without SMuRFs, but they had lower left ventricular ejection fraction and higher troponin levels but had a lower likelihood of multivessel coronary artery disease. These patients also had a culprit lesion in the left anterior descending artery compared to patients with SMuRFs. Patients without SMuRFs were less likely to receive statins, angiotensin-converting enzyme inhibitors (ACEI)/angiotensin-receptor blockers (ARB) or beta-blockers; this disparity was more pronounced for women.
In-hospital mortality was higher in patients without SMuRFs (9.6% vs. 6.5%) with higher incidence of cardiogenic shock (6.3% vs. 4.1%) and combined major adverse cardiovascular event (30.2% vs. 28.9%). This increased risk for all-cause mortality for patients without SMuRFs persisted at 30 days post-STEMI (11.3% vs. 7.9%) and after multivariable adjustment (hazard ratio, 1.24; 95% confidence interval, 1.10-1.39). The risk for heart failure and recurrent MI was not higher. Mortality in women was double that of men with and without SMuRFs. When adjusted for secondary preventive medical therapy, mortality in patients without SMuRFs was lower. Compared to patients with SMuRFs, increased risk for all-cause mortality persisted in men without SMuRFs for 9 years and in women for 12 years.
Conclusions:
In a retrospective analysis of STEMI patients, those without standard modifiable risk factors (SMuRFs) had a higher risk for all-cause and in-hospital and 30-day cardiovascular cause mortality. Patients without SMuRFs were less likely to receive statins, beta-blockers, and ACEI/ARB compared to those with SMuRFs. Increased risk for all-cause mortality was highest in women without SMuRFs compared to men. Following adjustment for receipt of medical therapies, mortality risk was attenuated. Increased risk for all-cause mortality persisted over several years in patients without SMuRFs.
Perspective:
Contemporary treatment of patients with coronary artery disease and acute coronary syndrome (ACS) largely relies on treatment of modifiable risk factors (abbreviated as SMuRFs per the authors of this study)—namely hypertension, dyslipidemia, smoking, and diabetes. While targeting these SMuRFs has led to a substantial improvement in survival after an ACS, there is a substantial proportion of ACS patients without them. In the present study, nearly 15% of STEMI patients did not have any SMuRFs. This highlights importance of occult, nontraditional risk factors that are not routinely assessed and unmet need for new biomarkers.
Patients without SMuRFs had an elevated risk for all-cause mortality after a STEMI that persisted over several years. Most notably though, this increased risk was higher for women. Evidence-based medical therapy was prescribed less frequently for patients without traditional risk factors and this disparity was again more pronounced for women. Most importantly, adjustment for guideline-concordant therapies with statins, ACEI/ARB, and beta-blockers attenuated this increased risk for mortality.
Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Dyslipidemia, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Prevention, Stable Ischemic Heart Disease, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Implantable Devices, SCD/Ventricular Arrhythmias, Nonstatins, Novel Agents, Statins, Acute Heart Failure, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Vascular Medicine, Hypertension, Smoking, Chronic Angina
Keywords: Acute Coronary Syndrome, Angiotensin Receptor Antagonists, Angiotensin-Converting Enzyme Inhibitors, Blood Pressure, Coronary Artery Disease, Diabetes Mellitus, Heart Arrest, Heart Failure, Hospital Mortality, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Hyperlipidemias, Hypertension, Percutaneous Coronary Intervention, Risk Factors, Secondary Prevention, Shock, Cardiogenic, Smoking, ST Elevation Myocardial Infarction, Stroke Volume, Troponin, Ventricular Function, Left
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