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Inhaled Corticosteroids in Chronic Obstructive Pulmonary Disease
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
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IN RESPONSE:
We appreciate Dr. Sutherland's careful review of our meta-analysis. Dr. Sutherland questions whether we considered pooled data from 3 studies reported in a previous meta-analysis (1), which we referred to in our paper. We included only 1 of the 3 studies (2) in our analysis. One of the studies (3) included in this previous meta-analysis was excluded by our predetermined criteria; this study included patients with asthma. The third study by Derenne (4) was not included in our analysis because the data were reported only in abstract form and could not be extracted from the original abstract. In addition, the author could not be contacted.
We included data from the study by Pauwels and coworkers (5) as mean rather than median values because the variant of the t-test used in meta-analyses is robust to large deviations from normality (6). In this study, the baseline distributions had very low coefficients of variation in both groups (0.17 and 0.16), suggesting that outliers contributed to the skewness in change from baseline. When a sample from a symmetrical population contains outliers, the sample median is a better estimate of the population mean than the sample mean. We were unable to obtain data from the authors to verify our assumption. We believed it was necessary to include this very large study (1277 patients) in our meta-analysis because it met our inclusion criteria and favored a treatment effect. If we reanalyze our data with this study excluded, however, the overall treatment effect remains nonsignificant (−4.98 mL/y; P = 0.11). Sensitivity analysis demonstrated that the difference between the actual means and the reported medians would need to be extraordinarily large (> 2-fold) to change the statistical conclusions of our model.
We made an error in analyzing the treatment effect reported by Vestbo and associates (7) (3.1 mL/y rather than −3.1 mL/y). This error, however, did not alter the conclusions of our analysis because the effect on our results is minor. Using the corrected value, the overall treatment effect is −5.31 ± 3.0 mL/y (P = 0.08) as opposed to the originally reported −5.0 ± 3.2 mL/y (P = 0.11).
Our meta-analysis confirms the Global Initiative for Chronic Obstructive Lung Disease Workshop's opinion that inhaled corticosteroids do not modify the long-term decline in lung function of COPD (8). We agree with Dr. Sutherland that patient-centered measures of outcome, such as respiratory-related quality of life, are more important than FEV1 in assessing the value of interventions to improve the well-being of patients with COPD. Pending future investigations, clinicians should not prescribe inhaled corticosteroids with the belief that this therapy will attenuate the decline in FEV1.
Kristin B. Highland, MD
Medical University of South Carolina; Charleston, SC 29425
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
- Copyright ©2004 by the American College of Physicians
