Published online October 1, 2007
PEDIATRICS Vol. 120 No. 4 October 2007, pp. 930-931 (doi:10.1542/peds.2007-1995)

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LETTER TO THE EDITOR

Cardiovascular Effects of Sibutramine

Paul Pisarik, MD, MPH
Department of Family Medicine,
University of Oklahoma,
Tulsa, OK 74120

To the Editor.—

In the study by Daniels et al¹ regarding the cardiovascular effects of sibutramine in the treatment of obese adolescents, the authors concluded that "there were no statistically significant differences in blood pressure between obese adolescents treated with sibutramine and those given placebo"; however, in their previous article from this same study, they observed that "[b]lood pressure and pulse rate statistically significantly differed between treatment groups at most visits to month 12."² How can 2 opposite conclusions be reached from the same study?

By the authors' own admission, the sibutramine study "was not specifically powered to assess changes in blood pressure and vital signs,"¹ yet they broke down the whole study into 3 groups (and not independent groups at that): those who lost <5% of their BMI; those who lost 5% of their BMI; and those who lost 10% of their BMI. They dismissed the second largest group (those who lost <5% of their BMI), in which there were adequate numbers of subjects who took sibutramine and placebo and in which sibutramine did, indeed, increase the systolic and diastolic blood pressure and pulse rate compared with those in the placebo group, but then focused on the groups of those who lost 5% and 10% of their BMI, in which there was no statistically significant difference between sibutramine and placebo but there were 10- and 20-fold more subjects in the sibutramine groups than the placebo groups—vastly underpowered. In fact, at least for diastolic blood pressure and pulse rate, if there were more subjects in the placebo group, there could have been a statistically significantly greater increase of those parameters by sibutramine compared with placebo.

Finally, in their methods section, it was mentioned that those subjects who received sibutramine who did not achieve a >10% BMI change were then randomly assigned to receive 15 mg of sibutramine or placebo. Therefore, there should have been 3 active groups (hence the 3:1 distribution of subjects to sibutramine and placebo): those sibutramine subjects who lost >10% of their BMI and stayed on the 10-mg dose of sibutramine; those who lost <10% of their BMI and were placed on placebo; and those who lost <10% of their BMI and were placed on 15 mg of sibutramine. How does that play into the systolic and diastolic blood pressure and pulse rate changes? What happen to those sibutramine subjects who lost <10% of their BMI and were placed on placebo?

REFERENCES

1. Daniels SR, Long B, Crow S, et al. Cardiovascular effects of sibutramine in the treatment of obese adolescents: results of a randomized, double-blind, placebo-controlled study. Pediatrics. 2007;120(1) . Available at: www.pediatrics.org/cgi/content/full/120/1/e147
2. Berkowitz RI, Fujioka K, Daniels SR, et al. Effects of sibutramine treatment in obese adolescents: a randomized trial. Ann Intern Med. 2006;145 :81 –90[Abstract/Free Full Text]

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PEDIATRICS (ISSN 1098-4275). ©2007 by the American Academy of Pediatrics

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This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Pisarik, P. Search for Related Content PubMed PubMed Citation Articles by Pisarik, P. Related Collections Heart & Blood Vessels Social Bookmarking                         What's this?