Unplanned 30-day readmission, comorbidity, and impact on mortality after incident atrial fibrillation hospitalization in Western Australia, 2001-2015.

BACKGROUND

The healthcare burden of atrial fibrillation (AF) is dominated by hospitalizations, but data on 30-day unplanned readmissions after AF hospitalization and impact on mortality are limited.

OBJECTIVE

To assess causes and trends of 30-day unplanned readmission in incident (first-ever) hospitalized AF patients, and the risk of readmission for subsequent all-cause mortality.

METHODS

Patients aged 25-94 years, with an incident AF hospitalization (principal diagnosis) between 2001 and 2015, and surviving 30 days post discharge, were identified from linked Western Australian hospitalization and mortality data. Unplanned 30-day readmissions were categorized by principal diagnosis. Multivariable logistic and Cox regression analyses determined the independent predictors of readmission and the hazard ratio (HR) with 95% confidence intervals (CI) of readmission for subsequent 1-year mortality.

RESULTS

Of 22,814 patients, 57.7% male, mean age 67.8 ± 13.8 (standard deviation) years, 9.5% experienced 1 or more 30-day unplanned readmissions, with standardized rates increasing 2.0% annually (95% CI, 1.0%-3.1%). Among all readmissions, 64.8% were cardiovascular-related, with AF (31.7%), coronary events (12.2%), and heart failure (8.5%) being the most frequent. In 30-day survivors, 4.3% died within 1 year. Patients with any cardiovascular or noncardiovascular readmission (vs none) had a multivariable-adjusted mortality HR of 2.12 (95% CI, 1.82-2.45). Coexistent comorbidities were independently associated with 30-day unplanned readmission and 1-year mortality.

CONCLUSION

Following incident AF hospitalization, 30-day unplanned readmissions were common, mostly cardiovascular-related, but any readmission, regardless of cause, was associated with a 2-fold higher adjusted mortality risk. Our findings also support the importance of comorbidity optimization within an integrated care pathway to reduce adverse outcomes in AF patients.