© 2008 American Thoracic Society
Inhaled Corticosteroids and Pneumonia in COPD: An Association Looking for EvidenceFrom the Authors:We appreciate Dr. Turner's interest in our article on the risk of pneumonia in relation to use of inhaled corticosteroids among patients with chronic obstructive pulmonary disease (COPD) (1). We agree that observational studies of risk or benefit of medications are potentially biased by confounding by indication. Thus a greater risk of pneumonia in relation to inhaled corticosteroids might actually be the result of more severely ill patients being at both greater risk of pneumonia and also more likely to be treated with higher doses of inhaled corticosteroids. We therefore carefully adjusted for differences in severity between subjects who did and did not develop pneumonia according to the number of prescriptions dispensed for respiratory medications other than inhaled corticosteroids, the use of oral corticosteroids, and past use of antibiotics, as well as controlling for comorbidities that might affect the risk of pneumonia. It is noteworthy that the results of our study have been confirmed in two clinical trials (2, 3) where the possibility of confounding by indication is removed by the process of randomization. The large number of subjects in our study allowed us to demonstrate a significant impact on mortality and to show a dose response. While we did not have the results of imaging, it is difficult to imagine that subjects would be admitted to the hospital principally for pneumonia, without having any imaging of the chest. Therefore, we feel that the cases of pneumonia we studied were most likely confirmed radiologically. We did examine patterns of exposure to inhaled corticosteroids over time in relation to the risk of pneumonia and were able to show that the risk occurred principally with recent or current exposure and dissipated quickly if exposure did not occur within the previous 60 days. As for possible differences in risk according to type of inhaled corticosteroid, we were unable to examine this successfully in the Canadian context because first beclomethasone and then fluticasone have been the predominant inhaled corticosteroids prescribed for patients with COPD in Canada during the period of study. We feel the data available are sufficiently strong that physicians must balance the risk of pneumonia and other adverse effects of inhaled corticosteroids, especially at higher doses, against the limited benefit of these medications for many patients with COPD.
McGill University Health Centre FOOTNOTES Conflict of Interest Statement: P.E. has received speaker fees and has served on advisory boards for Altana, AstraZeneca, GlaxoSmithKline, Merck Frosst, and Novartis; in 2003–2007, he received an unrestricted research grant from GlaxoSmithKline. S.S. has been reimbursed for attending advisory board meetings, conferences, and participating as a speaker in scientific meetings financed by various pharmaceutical companies (AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Pfizer, and Sepracor); he received funding for research grants from AstraZeneca and GlaxoSmithKline. REFERENCES
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