Figure 2

Adjusted monthly COPD-related mean costs per patient by drug cohort^a,b. KEY: AC – anticholinergic; CI – confidence interval; COPD – chronic obstructive pulmonary disease; FSC – fluticasone propionate-salmeterol 250/50 mcg. ^aEach cost component was estimated from separate regression models and represents a predicted, rather than an observed value. Pharmacy and medical costs may not sum to total. Costs are in 2009 USD. ^bCosts obtained from generalized linear models with log-link and gamma distribution controlling for age, region, Charlson comorbidity index score, number of short-acting beta-agonist canisters, number of oral corticosteroid prescriptions, comorbid asthma or upper respiratory tract infection or lower respiratory tract infection, home oxygen therapy, physician specialty on the index date, and pre-period COPD-related pharmacy costs (logged). ^cSignificant difference between FSC and AC (referent group) cohorts at alpha level 0.05.