30-day unplanned readmission rates and causes in patients hospitalised for acute coronary syndrome based on DANish CoMorbidity index for Acute Myocardial Infarction score

OBJECTIVE: This study aimed to investigate the association of the DANish CoMorbidity Index for Acute Myocardial Infarction (DANCAMI) score with 30-day unplanned readmission rates and causes in patients with acute coronary syndrome (ACS). METHODS: Using the US National Readmission Database, all index hospitalisations with a principal diagnosis of ACS between October 2015 and December 2019 were stratified by their DANCAMI score using International Classification of Diseases-10th edition codes. Thirty-day unplanned readmission rates and causes were analysed, including the assessment of factors associated with readmission. Multivariable regression analyses were reported as adjusted odds ratios (aOR) with 95% confidence intervals (95% CI). RESULTS: Of 2,066,328 ACS admissions, 173,304 (8.4%) had a DANCAMI score of 0, 602,640 (29.2%) had a DANCAMI score of 1-3, 327,046 (15.8%) had a DANCAMI score of 4-5, and 963,338 (46.6%) had a DANCAMI score ≥6. 189,240 (9.2%) had an unplanned readmission within 30 days. Patients with a higher DANCAMI score were more likely to be older and have an index presentation of non-ST-elevation ACS. A DANCAMI score ≥6 (aOR 1.30 95% CI 1.27-1.34), age (aOR 1.01 95% CI 1.01-1.01), female sex (aOR 1.09 95% CI 1.08-1.10), index ST-elevation ACS (aOR 1.03 95% CI 1.01-1.04), and atrial fibrillation (aOR 1.35 95% CI 1.33-1.37) were independently associated with readmission (all p < 0.001). Higher scores were associated with an increasing likelihood of readmission for non-cardiovascular causes. CONCLUSION: Increased DANCAMI score was associated with higher readmissions in patients with ACS. The DANCAMI score could be a valuable tool to assess risk.