Enhanced persistence with tiotropium compared with other respiratory drugs in COPD

BACKGROUND: Tiotropium is a once-daily inhaled anticholinergic maintenance treatment with demonstrated effectiveness in chronic obstructive pulmonary disease (COPD). OBJECTIVE: To compare persistence of tiotropium-use with other inhaled respiratory drugs in COPD in current clinical practice. METHODS: The PHARMO database includes, among others, drug-dispensing and hospital discharge records for 2> or = million subjects in the Netherlands. All probable COPD-patients were identified by new respiratory drug use (age >54 years) or COPD-hospitalisations. New users of tiotropium, ipratropium, long-acting beta-agonists (LABAs), or fixed combination of LABA and inhaled corticosteroids (LABA+ICS), in 1998-2003, were included in the study. Persistence was assessed quarterly during the first year of follow-up. Patients with a proportion of days covered (PDC) > or =80% were considered persistent. Persistence was analysed using generalised estimating equations model. RESULTS: About 37% of new users of tiotropium continued treatment for 1 year, compared with 14% for ipratropium, 13% for LABA, and 17% for LABA+ICS. Multivariate analyses showed that tiotropium-users were 2-3 times more persistent with their therapy than patients using ipratropium (relative risk [RR]: 2.0; 95% confidence interval [CI]: 1.8-2.3), LABA (RR: 2.9; 95% CI: 2.4-3.6), or LABA+ICS (RR: 2.4; 95% CI: 2.1-2.8), respectively. Sub-analyses in patients with a prior hospitalisation for COPD showed that 1-year persistence rates were increased for all treatments (varying from 33% for patients using LABA+ICS to 61% for patients using tiotropium), while persistence with tiotropium was again 2-3 times higher compared with other treatments. CONCLUSION: Persistence with tiotropium was higher compared to other inhaled respiratory drugs in COPD in clinical practice.