Sex Differences in Readmissions After Acute MI

Study Questions:

Do rates of readmission following acute myocardial infarction (AMI) differ by sex and age?

Methods:

Data from the Healthcare Cost and Utilization Project-State Inpatient Database for California were used for the present analysis. Patients were included if they were between the ages of 18-64 years and had been diagnosed with AMI. Readmission diagnoses were categorized using the Centers for Medicare and Medicaid Services’ Condition Categories. Data on time of readmission within the 30-day post-AMI discharge were also collected. Patients who were transferred from another hospital, died during the AMI hospitalization, left against medical advice, or resided outside California were excluded. Data collected between January 2007 and November 2009 were included in this analysis.

Results:

A total of 42,518 patients under the age of 65 with AMI were included, of which 26.4% were female and 11.2% (4,775) had one or more readmissions. Women were more likely to be African American or Hispanic, and have Medicare or Medicaid for a primary insurance. Women were also more likely to have cardiovascular risk factors and additional comorbidities compared to men. The 30-day readmission rate was higher for women compared to men (15.5% vs. 9.7%, p < 0.0001); however, no difference in timing of readmission between men and women was noted. The risk of readmission was highest on days 2-4 post-AMI discharge. Women were more likely to be readmitted for noncardiac diagnoses (44.4% vs. 40.6%, p = 0.01); however, absolute rates of cardiac diagnoses were higher in women than men as well. After controlling for potential confounders including sociodemographic factors, cardiovascular risk factors, comorbidities, and length of stay, female sex remained a significant predictor of 30-day readmission (hazard ratio, 1.22, 95% confidence interval, 1.15-1.30).

Conclusions:

The investigators concluded that although timing of readmission is similar between men and women, younger women have a higher risk for readmission after a cardiac event compared to men.

Perspective:

This study notes increased rates of 30-day readmission after AMI for younger women. Further research related to factors associated with readmission among young women may help promote interventions that translate into reduced readmission rates.

Clinical Topics: Prevention

Keywords: Cardiovascular Diseases, Comorbidity, Female, Inpatients, Length of Stay, Medicaid, Medicare, Myocardial Infarction, Patient Discharge, Patient Readmission, Risk Factors, Secondary Prevention, Sex Characteristics


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