Increased risk of peripheral arterial occlusive disease in patients with Bell's palsy using population data

OBJECTIVE This population-based cohort study investigated the risk of developing peripheral arterial occlusive disease (PAOD) in patients with Bell's palsy. METHODS We used longitudinal claims data of health insurance of Taiwan to identify 5,152 patients with Bell's palsy newly diagnosed in 2000-2010 and a control cohort of 20,608 patients without Bell's palsy matched by propensity score. Incidence and hazard ratio (HR) of PAOD were assessed by the end of 2013. RESULTS The incidence of PAOD was approximately 1.5 times greater in the Bell's palsy group than in the non-Bell's palsy controls (7.75 vs. 4.99 per 1000 person-years). The Cox proportional hazards regression analysis measured adjusted HR was 1.54 (95% confidence interval (CI) = 1.35-1.76) for the Bell's palsy group compared to the non-Bell's palsy group, after adjusting for sex, age, occupation, income and comorbidities. Men were at higher risk of PAOD than women in the Bell's palsy group, but not in the controls. The incidence of PAOD increased with age in both groups, but the Bell's palsy group to control group HR of PAOD decreased as age increased. The systemic steroid treatment reduced 13% of PAOD hazard for Bell's palsy patients, compared to those without the treatment, but not significant. CONCLUSIONS Bell's palsy appears to be associated with an increased risk of developing PAOD. Further pathophysiologic, histopathology and immunologic research is required to explore the underlying biologic mechanism.