Analysis of prognostic differences and risk factors in patients with atrial fibrillation known before ischemic stroke and atrial fibrillation diagnosed after ischemic stroke.

Aims: To compare the 1-year prognoses of patients with atrial fibrillation known before stroke (KAF) with those diagnosed after (AFDAS) and to explore the reasons for any observed differences.

Methods: 420 ischemic stroke patients were assigned to the KAF and AFDAS group. Follow-up information for both groups included the incidence of ischemic stroke recurrence, poor neurofunctional outcomes, and all-cause mortality within one year after the original ischemic stroke episode. The differences in the two groups' prognoses were assessed, and Cox/logistic regression models were employed to identify the underlying factors influencing this prognostic gap.

Results: AFDAS had significantly lower rates of ischemic stroke recurrence (11.06% vs. 19.34%, P = 0.018) and poor neurofunctional outcome (25.48% vs. 36.79%, P = 0.012) compared to KAF. One-year all-cause mortality was similar between the two groups (7.69% vs. 9.91%, P = 0.424). AFDAS had a significantly lower risk of ischemic stroke recurrence even after adjusting for mortality factors (HR, 0.542; 95% CI, 0.325-0.903; P = 0.019). The incidence rate of ischemic stroke recurrence was significantly lower in AFDAS compared to KAF after adjustment for non-cardiac factors (HR, 0.561; 95% CI, 0.316-0.995; P = 0.042). However, there was no discernible difference in the two groups after adjustment for cardiac factors (HR, 0.659/0.588; 95% CI, 0.390-1.115/0.327-1.058; P = 0.120/0.077). The probability of a poor neurofunctional outcome was 3.758-fold higher in patients with recurrent ischemic stroke compared to those without recurrence (HR, 3.758; 95% CI, 1.587-8.900; P = 0.003). Compared to KAF, AFDAS was 88% less likely to have a poor neurofunctional outcome (HR, 0.120; 95% CI, 0.052-0.277; P < 0.001).

Conclusion: Patients with AFDAS have a better prognosis than those with KAF.