OBJECTIVES: The prevalence of chronic obstructive pulmonary disease (COPD) in Hong Kong has been estimated to be 0.35 per 1000 population. The cost of management can therefore translate into an enormous burden on the health care budget. Current pharmacotherapy includes bronchodilators plus anticholinergics. Patient compliance can be a problem due to multiple daily dosing, hence the present study aims to evaluate the potential benefits of tiotropium with once-daily dosage. METHODS: The cost of management of COPD was estimated by retrospective review of the history of a cohort of COPD patients admitted to the Prince of Wales Hospital (PWH) in Hong Kong from January 1, 2001 to December 31, 2001. Cost items included hospitalization, procedures, laboratory tests, medications and outpatient clinic visits. The cost-effectiveness (CE) model for COPD developed by Boehringer-Ingelheim was used to assess the CE of COPD therapies. All analysis was based on local cost data, and probabilities of events and efficacy data of tiotropium were adopted from overseas published randomized controlled trials as there is yet no local published data. The study was performed from the perspective of a public hospital. RESULTS: Data of 30 patients admitted to the PWH due to COPD were analyzed with the model. Compared to ipratropium, the once-daily dosage of tiotropium showed a decrease in number of exacerbations (0.89 vs. 1.21), a decrease in the management cost due to exacerbations (US$2550 vs. 4183) and the cost per exacerbation avoided due to tiotropium was US$4278. CONCLUSION: Based on our preliminary results, tiotropium appears to be a more cost-effective agent in the treatment of COPD when compared to ipratropium.