Patterns of inpatient care for acute myocardial infarction and 30-day, 3-month and 1-year cardiac diseases readmission rates in Spain.

BACKGROUND: Acute myocardial infarction (AMI) is a common cause of hospital discharges and readmissions. Readmissions may indicate poor patient care and avoidable health expenditure, being key in quality improvement strategies. Our aim was to analyse cardiac diseases (CDs) readmissions in patients with AMI in Spain.

METHODS: A retrospective analysis of 33,538 hospital discharges with AMI being the "principal diagnosis" at hospitals of the Spanish National Health System in 2012 was performed using administrative data. We developed a logistic regression model and calculated 30-day, 3-month and 1-year CDs risk-standardized readmission rates (RSRRs) using a multivariate mixed model.

RESULTS: Variables of the model (AMI location, age, previous angina pectoris/myocardial infarction or acute coronary syndrome, chronic kidney disease, rheumatic valvular disease, diabetes mellitus, vascular disease, female sex, chronic pulmonary disease, and anemia) were able to predict 30-day, 3-month and 1-year readmission rates and RSRRs after AMI (5.4%, 9.3% and 20.2%, respectively). For RSRRs the area under the ROC curve was 0.74 (p=0.0037), 0.77 (p=0.0041), and 0.73 (p=0.0025) for 1, 3months and 1-year readmission rate, respectively. Angioplasty, cardiology as the medical unit responsible for the discharge and a higher volume of activity (>204 AMI) were all significantly (p<0.001) associated with lower mortality, risk of development of heart failure and RSRRs.

CONCLUSIONS: Angioplasty, cardiology as the medical unit responsible for the discharge and a higher volume of activity explain variability in CDs readmission rates after AMI, which can have implications for strategies to reduce readmissions rates.