Eleven-year trends in gender differences of treatments and mortality in ST-elevation acute myocardial infarction in northern Italy, 2000 to 2010

Abstract

The aim of this study was to assess recent trends in hospital mortality and in the treatment techniques for patients with ST-segment elevation myocardial infarction according to gender. Data on hospitalizations for ST-segment elevation myocardial infarction from 2000 to 2010 were extracted from hospital discharge record databases (International Classification of Diseases, Ninth Revision, Clinical Modification, codes) in the Lombardy Region of Italy. The impact of female gender on in-hospital mortality was assessed by multivariable regression after adjusting for invasive approach use (i.e., coronary angiography, angioplasty or coronary artery bypass graft), age, and co-morbidities. A total of 89,562 patients, men (66.5%) and women (33.5%), were enrolled. The use of an invasive approach increased over time in both sexes although it was higher in men (from 54.9% in 2000 to 91.9% in 2010 in men; from 36.8% in 2000 to 72.0% in 2010 in women). This pattern was driven by the subgroup of patients aged ≥75 years, whereas differences between sexes were not observed in patients <65 years and were small in patients aged 65 to 74 years. In-hospital mortality presented a small decrease from 7.6% in 2000 to 6.2% in 2010 in men (p for trend = 0.004), whereas it remained higher and substantially constant over time in women (16.6% in 2000, 15.5% in 2010, p for trend = 0.09). At multivariable regression, female gender did not emerge as an independent predictor of mortality (p = 0.13). However, a significant gender-age interaction was found, with female gender being a significant predictor of increased mortality in patients aged ≥75 years (odds ratio [OR] 1.33) while predicting a reduced mortality in patients aged <75 years (OR 0.93, p for interaction <0.0001). The use of an invasive approach was an independent predictor of mortality (OR 0.23, p <0.0001), the magnitude of mortality reduction being higher in men than in women and in patients aged <75 years than in those aged ≥75 years. In conclusion, a weak temporal trend in mortality reduction is observed in men only, which is driven by patients aged ≥75 years. In-hospital mortality remains higher in women than in men, although female gender is not a significant predictor of mortality. Despite temporal increases in the use of an invasive approach, women are more often treated conservatively.