One in four patients who suffered a major heart attack: ST-elevation myocardial infarction (STEMI), had no known risk factors such as dyslipidemia (imbalance of lipids like cholesterol), hypertension, diabetes mellitus or smoking. In fact, more women, with no known cardiovascular risk factors suffered heart attacks, compared to men, a study by doctors of the Institute of Cardiology, Madras Medical College (MMC) has found.
The study, ‘Outcomes of ST Segment Elevation Myocardial Infarction without Standard Modifiable Cardiovascular Risk Factors - Newer Insights from a Prospective Registry in India’, found that the absence of standard modifiable cardiovascular risk factors (SMuRF) in STEMI does not confer lower risks during hospitalisation. Despite the absence of risk factors, these patients have adverse outcomes similar to those with risk factors. This study was recently published in Global Heart, an international journal.
Aiming to study patients with their first diagnosis of STEMI and to assess the influence of SMuRFs on clinical outcomes, doctors turned to the MMC STEMI Registry, to compare patients with and without SMuRFs. The registry is a prospective registry, enrolling acute STEMI patients above 18 years of age. All consecutive patients without prior coronary artery disease enrolled in the registry from September 2018 to October 2019 were included for the study.
Among the 2,379 patients studied, 605 (25.4%) had no SMuRF. While 44% of total patients had one SMuRF, 26% had two SMuRFs.
The study, the authors said, has four main findings. First, the incidence of STEMI without SMuRFs is high in patients from low and middle income countries. Second, the in-hospital mortality, complications and 12-month mortality in SMuRF-less STEMI patients was similar to those with SMuRFs. Third, more women with STEMI were SMuRF-less than men, and last, suboptimal sleep duration (sleep duration less than six hours per day or more than nine hours per day), a recently-identified modifiable risk factor, did not account for the risk associated with SMuRF-less STEMI.
“The key learning is that one-fourth of patients who develop a major heart attack do not have any known risk factors. Women are more likely to develop heart attacks in the absence of risk factors. For this, we need public health education on the importance of preventive health check-ups in apparently healthy persons,” lead author G. Justin Paul, professor of cardiology, MMC and State Heart Disease Nodal Officer, National Health Mission, Tamil Nadu, said.
Doctors, in their analysis, found that more women (27.1%) were SMuRF-less than men (22.1%). “This could be due to socio-cultural reasons where women may get less preventive health evaluations. Hence, their risk factors might not have been identified earlier. The gender difference being unfavourable to women in healthcare, both in investigations, management and outcomes is well known and is called the Yentl phenomenon. This could also be responsible for this finding,” he explained. He underscored the importance of encouraging women to undergo cardiac health check-ups regularly.
The study highlighted that not having a risk factors does not necessarily confer a lower risk once a patient develops a heart attack. This underscores the need for evidence, based on timely revascularisation therapy and pharmaco-therapy for both patients with and without SMuRFs, and the need for studies to evaluate the role of yet-to-be-identified risk factors in STEMI.
