Chronic obstructive pulmonary disease and anxiety disorders: a nationwide population-based study in Taiwan.

Objective Few studies have investigated the relationship between chronic obstructive pulmonary disease (COPD) and anxiety disorder outcomes. We sought to investigate the association in a large national sample. Methods Cases were identified from Taiwan's National Health Insurance Research Database who were aged 15 years and above, with a new primary diagnosis of COPD (International Classification of Diseases, Ninth Revision codes: 491, 492, 494 and 496) between 2000 and 2007. The 29,951 cases identified were compared to 29,951 controls matched on sex, age, urban/rural residence and socioeconomic status based on insurance premium. Both groups were followed until the end of 2008 for instances of anxiety disorders. Competing risk-adjusted Cox regression analyses were applied, adjusting for matching variables, Charlson comorbidity index, hospital admission days and daily dose of prednisone. Results Of the 59,902 subjects, 3951 were found to have anxiety disorders during a mean (SD) follow-up period of 5.5 (2.5) years. COPD, female, urban residence, lower dose of prednisone use, depressive disorders and higher outpatient visits were independent predictors of incident anxiety disorder. Conclusions COPD was associated with increased risk of an anxiety disorder diagnosis, independent of a number of potential confounding factors. [ABSTRACT FROM AUTHOR]