One-year outcomes in atrial fibrillation presenting during infections: a nationwide registry-based study

Aims: Thromboprophylaxis guidelines for patients with concurrent atrial fibrillation (AF) during infections are unclear and not supported by data. We compared 1-year outcomes in patients with infection-related AF and infection without AF.

Methods and results: By crosslinking Danish nationwide registry data, AF naïve patients admitted with infection (1996-2016) were identified. Those with AF during the infection (infection-related AF) were matched 1:3 according to age, sex, type of infection, and year with patients with infection without AF. Outcomes (AF, thromboembolic events) were assessed by multivariable Cox regression. The study population comprised 30 307 patients with infection-related AF and 90 912 patients with infection without AF [median age 79 years (interquartile range 71-86), 47.6% males in both groups]. The 1-year absolute risk of AF and thromboembolic events were 36.4% and 7.6%, respectively (infection-related AF) and 1.9% and 4.4%, respectively (infection without AF). In the multivariable analyses, infection-related AF was associated with an increased long-term risk of AF and thromboembolic events compared with infection without AF: hazard ratio (HR) 25.98, 95% confidence interval (CI) 24.64-27.39 for AF and HR 2.10, 95% CI 1.98-2.22 for thromboembolic events. Further, differences in risks existed across different subtypes of infections.

Conclusion: During the first year after discharge, 36% of patients with infection-related AF had a new hospital contact with AF. Infection-related AF was associated with increased risk of thromboembolic events compared with infection without AF and our results suggest that AF related to infection may merit treatment and follow-up similar to that of AF not related to infection.