Association between age and readmission after percutaneous coronary intervention for acute myocardial infarction.

Objective: This study aimed to investigate the association between age and the risk of 30-day unplanned readmission among adult patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI).

Methods: This retrospective analysis included patients from the Nationwide Readmissions Database with AMI who underwent PCI during 2013-2014. We used multivariable logistic regression model to calculate adjusted odds ratios (AORs) for risk of readmission. To examine potential non-linear association, we performed logistic regression with restricted cubic splines (RCS).

Results: Of the 492 550 patients with AMI aged above 18 years undergoing PCI during the index hospitalisation, 48 630 (9.87%) were readmitted within 30 days. Although the crude readmission rate of younger patients (aged 18-54 years) was the lowest (7.27%), younger patients had higher risk of readmission compared with patients aged 55-64 years for all-causes (AOR 1.06 (1.01 to 1.11), p=0.0129) and specific causes, such as AMI and chest pain (both cardiac and non-specific) after adjusted for covariates. Patients aged 65-74 years were at lower risk of all-cause readmission. Older patients (age ≥75 years) had higher risk of readmission for heart failure (AOR 1.50 (1.29 to 1.74)) and infection (AOR 1.44 (1.16 to 1.79)), but lower risk for chest pain. RCS analyses showed a U-shaped relationship between age and readmission risk.

Conclusions: Our results suggest higher risk of readmission in younger patients for all-cause unplanned readmission after adjusted for covariates. The trends of readmission risk along with age were different for specific causes. Age-targeted initiatives are warranted to reduce preventable readmissions in patients with AMI undergoing PCI.