Sex differences in in-hospital outcomes and readmission rates after percutaneous coronary intervention

Previous studies have reported worse outcomes in women following percutaneous coronary intervention (PCI), but contemporary studies examining sex differences in in-hospital outcomes and 90-day readmission risk are lacking. Therefore, we sought to compare 90-day readmission rates and in-hospital adverse outcomes after PCI.

We used the United States National Readmissions Database to stratify all inpatient PCIs from 2017 to 2018 by sex. We then performed propensity score matching of the two groups based on demographics, medical history, hospital characteristics, clinical presentation, socioeconomic status, and procedures. The primary outcome of interest was 90-day readmission to the hospital. Secondary outcomes included 30-day readmission, in-hospital mortality, and additional in-hospital outcomes. We performed Cox proportional-hazards modeling to compare the hazard of readmission between women and men and logistic regression to calculate odds ratios for the secondary outcomes of interest.

After propensity score matching, 206,556 women and 205,134 men were included. At index hospitalization, women experienced higher odds of in-hospital mortality, hypovolemic shock, and need of blood transfusion, while men experienced higher odds of cardiac arrest, intracranial hemorrhage, and acute kidney injury. Women had a higher hazard of 30-day readmission (hazard ratio 1.16, 95% confidence interval 1.14-1.18, P < 0.01) and 90-day readmission (hazard ratio 1.14, 95% confidence interval 1.12-1.15), with the greatest difference seen among younger women <45 years of age. Findings were similar after stratification into different age groups and clinical presentations.

Substantial sex differences in outcomes after PCI persist, with variable sex differences in in-hospital complications, and women at higher risk of 30- and 90-day readmission to the hospital. Given the clinical and reimbursement implications of readmissions to patients and health systems, urgent efforts are needed to close these gaps.