Background: The benefits of inhaled corticosteroids (ICS) in reducing the mortality related to chronic obstructive pulmonary disease (COPD) are controversial.
Objective: To estimate whether ICS in monotherapy or in combination with long-acting beta(2)-agonists (LABA) reduces the mortality rate among COPD patients compared to those treated with LABA monotherapy.
Methods: Using data from the Canadian province of Quebec's health administrative databases, a nested case-control study was conducted. A cohort of COPD patients aged 50 years and over between 1996 and 2000 was initially formed. Patients were included if they filled at least 6 prescriptions of an inhaled bronchodilator, received at least 1 medical service for COPD, and did not receive any diagnosis of asthma over a 12-month period. For each case of death identified in the cohort, up to 37 controls were time matched. For cases and controls, the exposure to ICS and LABA was assessed within the 3 months prior to the date of death for cases and date of selection for controls. Adjusted mortality rate ratios were estimated by conditional logistic regression comparing patients using ICS monotherapy or ICS/LABA combination therapy with patients using LABA monotherapy.
Results: This study included 5996 cases of death and 54,750 controls. The mortality rates were found to be lower among users of ICS monotherapy than users of LABA monotherapy (OR 0.69; 95% CI 0.53 to 0.88) and lower among users of an ICS/LABA combination than users of LABA monotherapy (OR 0.73; 95% CI 0.56 to 0.96). No significant differences were observed between users of ICS/LABA combination therapy and users of ICS monotherapy (OR 1.07; 95% CI 0.93 to 1.23).
Conclusions: ICS were found to be associated with a reduction in mortality rate when compared to LABA among patients with COPD. However, the ICS/LABA combination therapy did not provide any additional benefit on mortality when compared to ICS monotherapy.