Meta-analysis: Higher In-Hospital Mortality for Women with STEMI vs Men

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In-hospital mortality is higher after primary percutaneous coronary intervention (PCI) for ST-segment myocardial infarction (STEMI) in women compared with their male counterparts, according to a meta-analysis published online September 29, 2014, ahead of print in JAMA Internal Medicine.

Modifiable risk factors, such as women being less likely to receive newer evidence-based therapies and at lower priority for ambulance transport, may be at work, the researchers suggest.

Methods
Samir B. Pancholy, MD, of The Commonwealth Medical College (Scranton, PA) and colleagues analyzed in-hospital and 1-year mortality data from 35 randomized controlled trials and observational studies involving 68,536 patients (n = 18,555 women) with STEMI who underwent primary PCI within 12 hours of symptom onset. The studies were conducted in several different countries, including 6 in the United States.
In most studies, women were older and more likely to have diabetes, hypertension, and dyslipidemia than men, while more men than women were smokers.

 

Disparity Mainly Seen in the Short-Term

Data on in-hospital mortality were derived from 22 studies (n = 41,766). While 3.9% of men died in-hospital, the mortality rate for women was nearly doubled at 7.5%. Based on adjusted RRs from 12 of those studies, women remained significantly more likely to die in-hospital, though to a lesser extent.

At 1-year postprocedure, data from 12 studies (n = 28,936) showed all-cause mortality rates of 8.8% in women and 5.5% in men. However, after adjustment, the difference in mortality was no longer significant (table 1).

Table 1. Mortality Risk: Women vs Men

 

RR

95% CI

P Value

In-Hospital

    Unadjusted

    Adjusted

 

1.93

1.48

 

1.75-2.14

1.07-2.05

 

< .001

.02

At 1 Year

    Unadjusted

    Adjusted

 

1.58

0.90

 

1.36-1.84

0.69-1.17

 

< .001

.42

Meta-influence analysis found that no particular study exerted overwhelming influence on either in-hospital or 1-year mortality results.

After meta-regression analysis, the only significant source of heterogeneity for in-hospital mortality between men and women was prevalence of diabetes. There were none observed for mortality at 1 year.

Several Explanations for Discrepancy

Although the investigators stress the results should only be considered hypothesis generating due to study limitations, they suggest several reasons why women appear to face higher mortality, including “differences in traditional cardiovascular risk factors, sex-specific differences in clinical presentation, and response by the medical infrastructure in women compared with men with STEMI.”

The current meta-analysis supports this notion because the mortality difference was attenuated after “adjusting for cardiovascular risk factors and… clinical and hemodynamic status at presentation.”

Dr. Pancholy and colleagues highlight previous studies showing that women are less likely to receive newer evidence-based therapies and are a lower priority for emergency ambulance service when having possible STEMI. Women are also more likely to receive a missed diagnosis of STEMI before reaching the hospital and to require transfer after presenting at a non-PCI-capable facility.

“Because most of these risk factors are modifiable, appropriate measures to optimize health care utilization in women may reduce this gender gap,” they write.

Among the study limitations are the observational nature of the included studies and that patients were not randomized based on sex. Furthermore, cardioprotective medication use, a factor known to differ between sexes, could not be assessed.


Source:
Pancholy SB, Shantha GPS, Patel T, et al. Sex differences in short-term and long-term all-cause mortality among patients with ST-segment elevation myocardial infarction treated by primary percutaneous intervention: a meta-analysis. JAMA Intern Med. 2014;Epub ahead of print.

Disclosure:

  • Dr. Pancholy reports receiving speaker’s fees from Pfizer and Terumo and a research grant from Accumed Radial Systems.

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