Persistent versus paroxysmal atrial fibrillation and risk of in-hospital ischaemic stroke

Background/Introduction Atrial fibrillation (AF) is a major risk factor for thromboembolic events, particularly ischaemic stroke. AF subtype may reflect differences in arrhythmia burden and atrial remodelling; however, whether persistent AF confers a greater in-hospital stroke risk compared with paroxysmal AF remains uncertain. Purpose To compare the risk of in-hospital ischaemic and embolic stroke between persistent and paroxysmal AF, and to evaluate in-hospital mortality and length of stay (LOS). Methods We conducted a retrospective cohort study using the United States National Inpatient Sample (NIS) from 2018 to 2021. Adult hospitalisations with paroxysmal (ICD-10 code I48.0) or persistent (ICD-10 code I48.1) AF were identified. Primary outcomes were ischaemic stroke (ICD-10 code I63) and embolic stroke (ICD-10 codes I63.1 and I63.4). Secondary outcomes were in-hospital mortality and LOS. Multivariable logistic regression was used to evaluate the independent association between AF subtype and stroke outcomes, adjusting for demographic and clinically relevant cardiovascular and systemic comorbidities. LOS was analysed using linear regression after log transformation (ln[LOS+1]). Results A total of 72,901 AF hospitalisations were identified, of which 20,763 (28.5%) were persistent. Ischaemic stroke occurred in 443 patients (0.6%) and embolic stroke in 166 (0.2%). Overall in-hospital mortality was 1.6%. Persistent AF was independently associated with higher odds of ischaemic stroke compared with paroxysmal AF (OR 1.29; 95% CI 1.05–1.58; p=0.014) and demonstrated a stronger association with embolic stroke (OR 1.67; 95% CI 1.21–2.29; p=0.002). Persistent AF was not independently associated with an increase in in-hospital mortality. In linear regression analysis, persistent AF was associated with longer LOS. After log transformation, persistent AF remained independently associated with prolonged hospitalisation (β 0.094; p<0.001), corresponding to an approximate 9–10% increase in LOS compared with paroxysmal AF. Conclusions Persistent AF is independently associated with increased risk of in-hospital ischaemic and embolic stroke compared with paroxysmal AF, with a stronger association observed for embolic stroke. Persistent AF is also associated with prolonged hospitalisation. These findings highlight the prognostic importance of AF subtype and may support more intensive risk stratification strategies in patients with persistent AF.