Increased risk of chronic obstructive pulmonary disease in patients with bipolar disorder: A population-based study

Background: We conducted this nationwide study to examine the prevalence and incidence of chronic obstructive pulmonary disease (COPD) among patients with bipolar disorder in Taiwan. Methods: We used a random sample of 766,427 subjects who were aged >= 18 years in 2005. Patients with at least one primary diagnosis of bipolar disorder were identified. Study participants with one primary or secondary diagnosis of COPD for either ambulatory or inpatient care were also identified. We compared the prevalence of COPD in patients with bipolar disorder and the general population in 2005. In addition, we further investigated this cohort from 2006 to 2010 to detect incident cases of COPD in patients with bipolar disorder compared with the general population. The factors associated with COPD among patients with bipolar disorder were also analyzed. Results: The prevalence of COPD in patients with bipolar disorder was higher than in the general population in 2005 (5.68% vs. 2.88%, odds ratio 2.03; 95% confidence interval, 1.53-2.67). The average annual incidence of COPD in patients with bipolar disorder was also higher than in the general population (2.03% vs. 1.03%, risk ratio 1.94; 95% confidence interval, 1.65-2.29) from 2006 to 2010. Limitations: Some risk factors for COPD such as substance use, obesity, or lifestyle pattern were not available in this study. Conclusions: Patients with bipolar disorder had a higher prevalence and incidence of COPD compared with the general population. Higher prevalence of COPD among bipolar patients was associated with increased age, males, hypertension, and second-generation antidepressant use.