Comparative effectiveness of tiotropium and ipratropium in prevention of hospital readmission for COPD: a population-based cohort study

Abstract

Background: In the treatment of chronic obstructive pulmonary disease (COPD), tiotropium bromide has a longer duration of action than ipratropium bromide; however, tiotropium bromide is a more expensive alternative treatment. At issue is whether tiotropium reduces the risk for hospital readmissions for COPD compared with ipratropium.

Objectives: A population-based cohort study was conducted to assess whether tiotropium reduces the risk for hospital readmissions for COPD compared with ipratropium.

Methods: British Columbia (BC) linked provincial administrative health databases were used to identify new patients with COPD (aged ≥45 years) with a first hospital admission for COPD from 2003 to 2011. The study period was defined as the 30-day tiotropium or ipratropium treatment-initiation period after hospital discharge. Patients were followed up for ≤6 months from drug initiation to hospital readmission for COPD. In a subanalysis, the 2 treatment groups were matched on age, sex, and high-dimensional propensity scores derived from 200 empirically identified and predefined covariates. The risk for hospital readmission was estimated using multivariate Cox proportional hazards and logistic regression analyses.

Results: In total, 3723 patients with COPD were dispensed tiotropium (n = 992) or ipratropium (n = 2731) within 30 days from the index hospital admission for COPD. The mean age of these patients was 72.8 years, and 50.8% were women. Tiotropium-treated patients were more likely to be in a higher income category and were more likely to use a greater number of medications compared with ipratropium-treated patients. Among the subset of 1500 matched patients, 215 (14.3%) were readmitted to hospital within 6 months. There was no statistically significant group difference in hospital readmissions using either analytical approach (hazard ratio = 0.98 [95% CI, 0.72-1.34]; odds ratio = 0.97 [95% CI, 0.70-1.36]).

Conclusions: In this select group of patients, neither tiotropium nor ipratropium was effective in significantly decreasing the risk for rehospitalization for COPD within 6 months.