The number of heart attack survivors in the United States who experienced repeat attacks within a year decreased between 2008 and 2017, especially among women, yet women’s awareness of their risk of death from heart disease also decreased, according to data from a pair of studies published in Circulation.
Recurrent MI rates drop, but not enough
Although the overall morbidity and mortality from coronary heart disease (CHD) in the United States has been on the decline for decades, CHD remains the leading cause of death and disability in both sexes, wrote Sanne A.E. Peters, PhD, of Imperial College London, and colleagues.
To better assess the rates of recurrent CHD by sex, the researchers reviewed data from 770,408 women and 700,477 men younger than 65 years with commercial health insurance or aged 66 years and older with Medicare who were hospitalized for myocardial infarction between 2008 and 2017. The patients were followed for 1 year for recurrent MIs, recurrent CHD events, heart failure hospitalization, and all-cause mortality.
In the study of recurrent heart disease, the rate of recurrent heart attacks per 1,000 person-years declined from 89.2 to 72.3 in women and from 94.2 to 81.3 in men. In addition, the rate of recurrent heart disease events (defined as either an MI or an artery-opening procedure), dropped per 1,000 person-years from 166.3 to 133.3 in women and from 198.1 to 176.8 in men. The reduction was significantly greater among women compared with men (P < .001 for both recurrent MIs and recurrent CHD events) and the differences by sex were consistent throughout the study period.
However, no significant difference occurred in recurrent MI rates among younger women (aged 21-54 years), or men aged 55-79 years, the researchers noted.
Heart failure rates per 1,000 person-years decreased from 177.4 to 158.1 in women and from 162.9 to 156.1 in men during the study period, and all-cause mortality decreased per 1,000 person-years from 403.2 to 389.5 for women and from 436.1 to 417.9 in men.
Potential contributing factors to the reductions in rates of recurrent events after a heart attack may include improved acute cardiac procedures, in-hospital therapy, and secondary prevention, the researchers noted. In addition, “changes in the type and definition of MI may also have contributed to the decline in recurrent events,” they said. “Also, the introduction and increasing sensitivity of cardiac biomarkers assays, especially cardiac troponin, may have contributed to an increased detection of less severe MIs over time, which, in turn, could have resulted in artifactual reductions in the consequences of MI,” they said.
The study findings were limited by several factors including the use of claims data, lack of information on the severity of heart attacks, and inability to analyze population subgroups, but the results were strengthened by the use of a large, multicultural database.
Despite the decline seen in this study, overall rates of recurrent MI, recurrent CHD events, heart failure hospitalization, and mortality remain high, the researchers said, and the results “highlight the need for interventions to ensure men and women receive guideline recommended treatment to lower the risk for recurrent MI, recurrent CHD, heart failure, and mortality after hospital discharge for MI,” they concluded.