© 2005 American Thoracic Society
Testosterone Supplementation during Respiratory RehabilitationFrom the Authors:We are pleased to respond to Drs. Puhan and Schünemann regarding our study (1). It deserves to be stressed that our trial studied short-term effectiveness of testosterone, strength training, and their combination in improving muscle mass and strength. It was a single-center trial; this facilitated standardizing interventions and outcome measurements but limited sample size. We emphasized that our results, though quite encouraging, deserve further investigation in larger studies of longer duration.
In this initial investigation of testosterone administration to men with COPD, we focused on men whose testosterone level was somewhat low (though normal ranges are difficult to define). However, recent work has shown that the dose–response relationship to testosterone supplementation is linear (2), raising the possibility that physiologic responses may not depend strongly on baseline levels. As was clearly stated, patients were entered into the study based on testosterone level at initial screening ( We present 45 baseline descriptors of this study population. Drs. Puhan and Schünemann focus on three variables that they feel exhibit "important baseline imbalances" among the four groups. They suggest statistical adjustment for these imbalances. However, the paper they cite (3) as supporting such adjustments deals with clinical trials with, on average, 10 times our study population. Further, in this paper unadjusted analyses are recommended unless baseline factors for covariate adjustment are predeclared on the basis of their strong relation to outcome. We believe that the modest differences among groups in these three variables (that in no case reaches statistical significance) would not be expected to influence change in either body composition or muscle strength with these interventions. We reassert that our randomization procedures resulted in well-balanced study groups. We correctly stated that ours was the first demonstration that strength increases accompany androgenic steroid supplementation in COPD. The work of Creutzberg and coworkers (4) deserves citation, but it was published while our paper was under review. That study confirms our finding that androgenic steroids increase lean body mass, but it fails to detect enhanced muscle strength, perhaps because a group receiving anabolic steroids without exercise training was not included.
a Los Angeles Biomedical Institute at Harbor-UCLA Medical Center, Torrance, California FOOTNOTES Conflict of Interest Statement: R.C. has been an investigator in a multicentered trial of Oxandrolone (an oral steroid) in COPD sponsored by Biotechnology General Corporation (total payments to site of approximately $75,000); L.C. does not have a financial relationship with a commercial entity that has an interest in the subject of this letter; J.P. does not have a financial relationship with a commercial entity that has an interest in the subject of this letter; M.I.L. does not have a financial relationship with a commercial entity that has an interest in the subject of this letter; M.F. does not have a financial relationship with a commercial entity that has an interest in the subject of this letter; T.W.S. does not have a financial relationship with a commercial entity that has an interest in the subject of this letter. REFERENCES
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400 ng/dl). As good experimental design dictates, serum samples from all study phases were later batch analyzed, with the sample drawn immediately before randomization defined as the baseline level. As a result, 29% of subjects had baseline levels above 400 ng/dl, but only 13% had values above 450 ng/dl. (Drs. Puhan and Schünemann misread our results: 44% of the 85 screened patients had testosterone > 400 ng/dl.)