Background: Readmissions after hospitalizations for acute myocardial infarctions (AMI) managed with percutaneous coronary intervention (PCI) are quite common, form a major healthcare burden to a vulnerable population and contribute to rising healthcare costs. Thus understanding the national epidemiology is of paramount importance.
Methods: We queried the National Readmission Database for 2013 using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes for AMI and then procedure codes to identify all index admissions undergoing PCI. We then identified all unplanned readmissions within 30 days. We used hierarchical modeling to identify significant predictors of readmissions. We then elucidated the reasons for unplanned readmissions and how many were of cardiac versus non-cardiac etiology.
Results: Among 221,159 patients undergoing PCI for AMI, 20,076 (9.1%) were readmitted within 30 days. A quarter of all readmissions occurred in the first 72 hours, while half of all readmissions occurred by day 8. The top 3 readmission etiologies were coronary artery disease (CAD), repeat AMI and heart failure (HF). Cardiac issues accounted for 58.3% of readmissions, while non-cardiac issues accounted for 41.7%. Significant predictors of readmission included female gender, chronic kidney disease, diabetes mellitus, acute renal failure, dysrhythmias, valvular heart disease, fluid and electrolyte imbalances, Medicare and Medicaid insurance, nursing facility discharge and length of stay greater than 2 days. (Fig. 1).
Conclusions: Readmissions post AMI with PCI occur in one of ten patients, occur disproportionately within the initial time period post discharge and happen because of both cardiac/non-cardiac reasons. Both patient sociodemographic factors and comorbidities are associated with unplanned readmissions. Future efforts should focus on reducing unplanned readmissions after identifying high-risk patients.