Bronchiectasis and increased risk of ischemic stroke: a nationwide population-based cohort study

Background: Bronchiectasis is characterized by permanent dilatation of the bronchial tree caused by recurrent airway infection and inflammation. The association of atherosclerosis and inflammation is well established. However, studies on the relationship between bronchiectasis and stroke are scant. Objective: We conducted a population-based cohort study to investigate the incidence and risk of ischemic stroke in patients with bronchiectasis. Methods: Data of 1,295 patients newly diagnosed as bronchiectasis between 2000 and 2008 were retrieved from the Taiwan National Health Insurance Research Database. A total of 6,475 controls without bronchiectasis at a ratio of 5: 1 were randomly selected from the general population based on frequency-matched age and sex to the patients. All participants were followed up to the date of ischemic stroke development, censoring, or the end of 2010. The Cox proportional hazard model was used to identify the risk of ischemic stroke in patients with bronchiectasis compared with those without bronchiectasis. Results: The patients with bronchiectasis exhibited a higher incidence rate of ischemic stroke (9.18 vs 4.66 per 1,000 person-years) than the patients without bronchiectasis, with an adjusted hazard ratio of 1.74 (95% confidence interval = 1.28-2.35). The patients with bronchiectasis and any comorbidities exhibited a 2.66-fold adjusted hazard ratio of ischemic stroke compared with those with neither bronchiectasis nor comorbidity (95% confidence interval = 1.85-3.84). The patients with bronchiectasis carried a dose response of ischemic stroke according to the number of emergency visits and hospitalizations per year. Conclusion: This study indicated that bronchiectasis is an independent risk factor of ischemic stroke.