Objectives.According to some studies, women with heart disease receive fewer procedures and have higher in-hospital death rates than men. These studies vary by data source (hospital discharge abstract versus detailed clinical information) and severity measurement methods. The authors examined whether evaluations of gender differences for acute myocardial infarction patients vary by data source and severity measure.Methods.The authors considered 10 severity measures: four using clinical medical record data and six using discharge abstracts (diagnosis and procedure codes). The authors studied all 14,083 patients admitted in 1991 for acute myocardial infarction to 100 hospitals nationwide, examining in-hospital death and use of coronary angiography, coronary artery bypass graft surgery (CABG), and percutaneous transluminal coronary angioplasty (PTCA). Logistic regression was used to calculate odds ratios for death and procedure use for women compared with men, controlling for age and each of the severity scores.Results.After adjusting only for age, women were significantly more likely than men to die and less likely to receive CABG and coronary angiography. Severity measures provided different assessments of whether women were sicker than men; for all cases, clinical data-based MedisGroups rated women's severity compared with men's, whereas four code-based severity measures viewed women as sicker. After adjusting for severity and age, women were significantly more likely than men to die in-hospital and less likely to receive coronary angiography and CABG; women and men had relatively equal adjusted odds ratios of receiving PTCA. Odds ratios reflecting gender differences in procedure use and death rates were similar across severity measures.Conclusions.Comparisons of severity-adjusted in-hospital death rates and invasive procedure use between men and women yielded similar findings regardless of data source and severity measure.