Inhaled corticosteroids and survival in chronic obstructive pulmonary disease: does the dose matter?

Recent data suggest that inhaled corticosteroids reduce the number of clinical exacerbations in chronic obstructive pulmonary disease (COPD). It remains unknown whether a dose/response relationship exists. The present study was conducted to evaluate the long-term impact of varying doses of inhaled corticosteroids on COPD mortality. Hospital discharge data were used to identify all patients aged > or = 65 yrs recently hospitalised due to COPD in Alberta, Canada (n = 6,740). The relative risk (RR) for all-cause mortality was compared across different dose categories of inhaled corticosteroids (none and low, medium and high doses) following hospital discharge. Inhaled corticosteroid therapy after discharge was associated with a 25% relative reduction in risk for all-cause mortality (RR 0.75, 95% confidence interval (CI) 0.68-0.82). Patients on medium- or high-dose therapy showed lower risks for mortality than those on low doses (RR 0.77, 95% CI 0.69-0.86 for low dose; RR 0.48, 95% CI 0.37-0.63 for medium dose; and RR 0.55, 95% CI 0.44-0.69 for high dose). Use of inhaled corticosteroids following hospital discharge for chronic obstructive pulmonary disease was associated with a significant reduction in the overall mortality rate. Low- was inferior to medium- or high-dose therapy in protecting against mortality in chronic obstructive pulmonary disease.