Background Medicare's Hospital Readmissions Reduction Program assesses financial penalties to hospitals based on risk-standardized readmission rates after specific episodes of care, including acute myocardial infarction. Detailed information about the type of patients included in the penalty is unknown. Methods and Results Starting with administrative data from Medicare, we conducted physician-adjudicated chart reviews of all patients considered 30-day readmissions after acute myocardial infarction from July 2012 to June 2015. Of 197 readmissions, 68 (34.5%) received percutaneous coronary intervention and 18 (9.1%) underwent coronary artery bypass grafting on index hospitalization. The remaining 111 patients did not receive any intervention. Of the 197 patients, 56 patients (28.4%) were considered too high risk for invasive management, 23 (11.7%) had nonobstructive coronary artery disease on diagnostic catheterization and therefore no indication for revascularization, 19 patients had a type II myocardial infarction (9.6%) for which noninvasive, outpatient workup was recommended, and 13 (6.6%) declined further care. The most common readmission diagnoses were cardiac causes and noncardiac chest discomfort, infection, and gastrointestinal bleeding. Conclusions Our results demonstrate that more than a quarter of the patients included in the penalty do not receive revascularization either because of provider assessment of risk or patient preference, and nearly one tenth have type II myocardial infarction. As such, administrative codes for prohibitive procedural risk, patient-initiated "do not resuscitate" status, or type II myocardial infarction may improve the risk-adjustment of the metric. Furthermore, provider organizations seeking to reduce readmission rates should focus resources on the needs of these patients, such as care coordination, hospice services when requested by patients, and treatment of noncardiac conditions.
Keywords: acute myocardial infarction; cardiovascular disease; medication therapy; readmission; revascularization.