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.