Pneumonia and pneumonia related mortality in patients with COPD treated with fixed combinations of inhaled corticosteroid and long acting β2 agonist: observational matched cohort study (PATHOS)

Objective To investigate the occurrence of pneumonia and pneumonia related events in patients with chronic obstructive pulmonary disease (COPD) treated with two different fixed combinations of inhaled corticosteroid/long acting beta(2) agonist. Design Observational retrospective pairwise cohort study matched (1:1) for propensity score. Setting Primary care medical records data linked to Swedish hospital, drug, and cause of death registry data for years 1999-2009. Participants Patients with COPD diagnosed by a physician and prescriptions of either budesonide/formoterol or fluticasone/salmeterol. Main outcome measures Yearly pneumonia event rates, admission to hospital related to pneumonia, and mortality. Results 9893 patients were eligible for matching (2738 in the fluticasone/salmeterol group; 7155 in the budesonide/formoterol group), yielding two matched cohorts of 2734 patients each. In these patients, 2115 (39%) had at least one recorded episode of pneumonia during the study period, with 2746 episodes recorded during 19 170 patient years of follow up. Compared with budesonide/formoterol, rate of pneumonia and admission to hospital were higher in patients treated with fluticasone/salmeterol:rate ratio 1.73 (95% confidence interval 1.57 to 1.90; P<0.001) and 1.74 (1.56 to 1.94; P<0.001), respectively. The pneumonia event rate per 100 patient years for fluticasone/salmeterol versus budesonide/formoterol was 11.0 (10.4 to 11.8) versus 6.4 (6.0 to 6.9) and the rate of admission to hospital was 7.4 (6.9 to 8.0) versus 4.3 (3.9 to 4.6). The mean duration of admissions related to pneumonia was similar for both groups, but mortality related to pneumonia was higher in the fluticasone/salmeterol group (97 deaths) than in the budesonide/formoterol group (52 deaths) (hazard ratio 1.76, 1.22 to 2.53; P=0.003). All cause mortality did not differ between the treatments (1.08, 0.93 to 1.14; P=0.59). Conclusions There is an intra-class difference between fixed combinations of inhaled corticosteroid/long acting beta(2) agonist with regard to the risk of pneumonia and pneumonia related events in the treatment of patients with COPD. Trial registration Clinical Trials.gov NCT01146392.