Stroke risk among adult patients with third, fourth or sixth cranial nerve palsy: a Nationwide Cohort Study

Abstract

Purpose: This study sought to determine whether isolated third, fourth and sixth cranial nerve palsies (NPs) are associated with increased short- and long-term risk of a subsequent stroke. Methods: This was a nationwide retrospective propensity score-matched cohort study. A cohort of patients with NP (n = 466) and a randomly selected, propensity-matched control cohort (n = 2281) were extracted from the Korean national insurance claim database. Subjects were tracked for 5 years total, subdivided into periods of 0–1 years, 1–3 years and 3–5 years. We assessed the risk of stroke using hazard ratios (HRs) and confidence intervals (CIs) after adjustments using Cox regression at different time intervals. Results: The median follow-up was 3.1 years. Stroke developed in 18.9% of the NP cohort and 7.5% of the control cohort. Stroke risk after NP was highest in the first year [14.7 per 100 person-year at 0–1 years (HR = 6.6), 3.1 per 100 person-year at 1–3 years (HR = 1.6) and 4.3 per 100 person-year at 3–5 years (HR = 2.8)]. Each type of NP was also associated with stroke risk: within 0–1 years, stroke risk was increased in third (HR = 7.6), fourth (HR = 6.0) and sixth (HR = 5. 84) NPs. In the 3- to 5-year period, risk was increased in sixth (HR = 4.7) and fourth (HR = 3.3) NPs, but not third (HR = 0.6) NPs. Conclusion: Patients in the NP cohort were more likely to have a stroke than those in the matched control cohort; the increased risk was both time- and cranial nerve-dependent.