Increased risk of stroke and mortality following new-onset atrial fibrillation during hospitalization

The outcome of patients who develop new-onset atrial fibrillation (AF) during hospitalization is unknown, and the management of this patient population is not specifically addressed by current guidelines. We investigated the incidence of death and inhospital stroke among a large cohort of hospitalized inpatients who developed new-onset AF.

All patients ≥50 years of age admitted to a tertiary academic medical centre (20 April 2005 to 31 December 2011; n = 84 919) were studied. Demographic variables were compared among patients categorized as having new-onset, pre-existing, or no AF. A propensity-matched analysis was employed to compare outcomes by generalized estimating equations. Primary endpoints were all-cause 30-day and 1-year mortality and inhospital stroke. New-onset AF occurred in 1749 (2.1%) hospitalized patients. Among patients with new-onset AF, mortality at 30 days and 1 year was higher compared with patients without AF (at 30 days: OR 2.28, 95% CI 1.72–3.02, P < 0.0001; at 1 year: RR 1.53, 95% CI 1.36–1.73, P < 0.0001), and compared with patients with pre-existing AF at 30 days (OR 1.52, 95% CI 1.06–2.17, P = 0.02) —an effect that persisted as non-significant trend at 1 year (RR 1.14, 95% CI 0.98–1.34, P = 0.09). Risk of inhospital stroke was higher in patients with new-onset AF compared with patients without AF (OR 4.53, 95% CI 1.36–15.11, P = 0.02). Among patients with new-onset AF, the CHA₂DS₂-Vasc score correlated with incidence of inhospital stroke.

New-onset AF among hospitalized inpatients is independently associated with an increased incidence of stroke and mortality.