journal.publications.chestnet.org 1177 Discontinuation of Inhaled Corticosteroids in COPD and the Risk Reduction of Pneumonia Samy Suissa, PhD; Janie Coulombe, MSc; and Pierre Ernst, MD BACKGROUND: e widespread use of inhaled corticosteroids (ICSs) for COPD treatment has been questioned. Recent studies of weaning some patients with COPD of ICSs found little or no adverse consequences compared with long-acting bronchodilators. It is unclear, however, whether discontinuation of ICSs reduces the elevated risk of pneumonia associated with these drugs. METHODS: Using the Quebec health insurance databases, we formed a new-user cohort of patients with COPD treated with ICSs during 1990 to 2005 and followed through 2007 or until a serious pneumonia event, deined as a irst hospitalization for or death from pneumonia. A nested case-control analysis of the cohort was used to estimate the rate ratio of serious pneumonia associated with discontinuation of ICS use compared with continued use, adjusted for age, sex, respiratory disease severity, and comorbidity. RESULTS: e cohort included 103,386 users of ICSs, of whom 14,020 had a serious pneu- monia event during 4.9 years of follow-up (incidence rate, 2.8/100/y). Discontinuation of ICSs was associated with a 37% decrease in the rate of serious pneumonia (rate ratio [RR], 0.63; 95% CI, 0.60-0.66). The risk reduction was rapidly evident, going from 20% in the first month to 50% by the fourth month ater discontinuation. e risk reduction was particularly marked with luticasone (RR, 0.58; 95% CI, 0.54-0.61) but less so with budesonide (RR, 0.87; 95% CI, 0.78-0.97). CONCLUSIONS: Discontinuation of ICS use in COPD is associated with a reduction in the elevated risk of serious pneumonia, particularly so with luticasone. CHEST 2015; 148(5):1177-1183 [ Original Research COPD ] Manuscript received March 13, 2015; revision accepted June 1, 2015; originally published Online First June 25, 2015. ABBREVIATIONS: ICS 5 inhaled corticosteroid; RAMQ 5 Régie de l’assurance maladie du Québec; RR 5 rate ratio AFFILIATIONS: From the Centre for Clinical Epidemiology (Drs Suissa and Ernst and Ms Coulombe), Lady Davis Institute, Jewish General Hospital; and the Department of Epidemiology and Biostatistics (Drs Suissa and Ernst), McGill University, Montreal, QC, Canada. FUNDING/SUPPORT: is research was funded in part by a grant from the Canadian Institutes of Health Research [CIHR MOP-49462] and the Canadian Foundation for Innovation [CFI 94480]. Dr Suissa is the recipient of the James McGill Professorship award. CORRESPONDENCE TO: Samy Suissa, PhD, Centre for Clinical Epidemiology, Jewish General Hospital, 3755 Cote Ste-Catherine, H-461, Montreal, QC, H3T 1E2, Canada; e-mail: samy.suissa@mcgill.ca © 2015 AMERICAN COLLEGE OF CHEST PHYSICIANS. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details. DOI: 10.1378/chest.15-0627