Enhanced risk of traumatic brain injury in patients with chronic obstructive pulmonary disease.

This study tests our hypothesis that patients with chronic obstructive pulmonary disease (COPD) have an increased risk of traumatic brain injury (TBI).In this nationwide retrospective cohort study, we used a subset of Taiwan's National Health Insurance Research Database, involving 1 million randomly selected beneficiaries. Patients with newly diagnosed COPD between 2000 and 2008 were identified. They were subgrouped as 'COPDAE+' (if they had severe acute exacerbation of COPD during the follow-ups) or 'COPDAE-' (if they had no acute exacerbation), and were frequency matched with randomly selected subjects without COPD (the 'non-COPD' group). Baseline differences were balanced by the inverse probability of treatment weighting based on the propensity score. For each patient, the risk of TBI during the subsequent 5 years was determined. The competing risk of death was controlled.We identified 3734 patients in 'COPDAE+', and frequency matched them with 11,202 patients in 'COPDAE-' and 11,202 subjects in 'non-COPD'. Compared with those in 'non-COPD', patients in 'COPDAE+' and 'COPDAE-' had an increased risk of TBI: the adjusted HR for 'COPDAE+' was 1.50, 95% CI 1.31 to 1.73, and that for 'COPDAE-' was 1.21, 95% CI 1.09 to 1.34. The highest risk was observed in the 'COPDAE+' group that aged <65 (the adjusted HR was 1.92; 95% CI 1.39 to 2.64).COPD has been linked to complications beyond the respiratory system. In this study we showed that COPD is associated with an increased risk of TBI.