Women’s higher risk of death after MI explained by age, comorbidities

Women who present at a hospital with non-ST segment elevated MI (non-STEMI) are more likely to die than men, but they are also six years older on average and have a higher burden of comorbidities, researchers reported in Circulation: Cardiovascular Interventions.

When adjusting for age, comorbidities, other demographics and hospital characteristics, lead researcher Tanush Gupta, MD, and colleagues reported women had a 10 percent decreased risk of in-hospital mortality.

“A potential reason for risk-adjusted in-hospital mortality being lower in women in our study could be more robust multivariable adjustment accounting for the higher prevalence of important noncardiovascular comorbidities in women such as depression, hypothyroidism, collagen vascular diseases, chronic pulmonary diseases, etc., that were not typically included in prior studies,” the authors wrote.

Gupta et al. studied 4.7 million patients (42.5 percent women) with non-STEMI from the 2003 to 2014 National Inpatient Sample databases. Crude in-hospital mortality rates were 4.7 percent for women and 3.9 percent for men, although women had a higher mean number of Elixhauser comorbidities (3.2 vs. 2.7 in men).

Unadjusted mortality favored men overall, the researchers found, because young women were significantly more likely to die in the hospital than young men. As age increased, the survival scales tilted toward women, who were more likely to survive to discharge in the 70 and older cohort.

“These findings are consistent with those of prior studies and are likely related to different pathophysiology of CAD (coronary artery disease) in premenopausal and middle-aged women,” Gupta et al. wrote.

Previous research has shown that women are less likely to receive early invasive management in the setting of MI when compared to men. That held true in this study; 29.4 percent of women and 39.2 percent of men were treated with an early invasive strategy—defined as coronary angiography with or without revascularization within 48 hours of admission.

Gupta and colleagues suggested this difference was driven by women’s higher rates of known complications with invasive strategies, which could nudge physicians toward alternative treatments.

“Although women were less likely to be treated with an early invasive strategy compared with men, the lower use of an early invasive strategy was not responsible for the higher crude inhospital mortality in women, which could be entirely explained by older age and higher comorbidity burden,” the researchers wrote. “Therefore, it is likely that the lower use of an early invasive strategy in women versus men with NSTEMI represents reasoned clinical judgment rather than an inappropriate sex-based treatment bias.”

The researchers noted they didn’t have detailed clinical and laboratory data, so they were unable to assess the severity of symptoms or specific reasons for why patients received or didn’t receive invasive care.