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University of Medicine and Dentistry of New Jersey-School of Osteopathic Medicine Stratford

To the Editor: In his March 2005 review article ("Cholinesterase inhibitors in the treatment of dementia." J Am Osteopath Assoc. 2005;105:145–158), Jay M. Ellis, DO, writes about treatment of patients with Alzheimer disease using rivastigmine tartrate, stating, "The 4.9 point difference in overall ADAS-Cog [the Alzheimer's Disease Assessment Scale – Cognitive Subscale] score increases in favor of rivastigmine over placebo in this 26-week trial is the largest observed for any of the cholinesterase inhibitors."

The implied message in Dr Ellis' statement is that rivastigmine may be the best acetylcholinesterase inhibitor currently available.

It is important for readers of JAOA—The Journal of the American Osteopathic Association to be reminded occasionally that such an implication is inappropriate because head-to-head trials are generally considered the best way to compare medications—and because rivastigmine has not been subjected to this form of trial with the two other cholinesterase inhibitors noted in the aforementioned literature review (ie, donepezil hydrochloride and galantamine hydrobromide).

It is generally inappropriate to compare different medications indirectly based on how each has performed against placebo in separate clinical trials because subjects in the respective study groups may have different baseline characteristics, or their conditions may progress at different rates in the absence of medical treatment. For an indirect comparison of medical interventions to show validity, there must be statistical analysis and adjustment (ie, metanalysis) based on the characteristics of the different study populations.¹

Under the authority of well-known federal regulations,^2–4 the US Food and Drug Administration regularly sends warning letters to pharmaceutical companies funding advertisements that make unsubstantiated superiority claims similar to those found in this March 2005 JAOA article. It is the responsibility of THE JOURNAL's readers to rectify similar situations in the literature, however inadvertent, when articles with unfounded superiority claims slip past the scientific peer review process and into print.

References
1. Song F, Altman DG, Glenny AM, Deeks JJ. Validity of indirect comparison for estimating efficacy of competing interventions: empirical evidence from published meta-analyses. BMJ. 2003;326:472. Available at: http://bmj.bmjjournals.com/cgi/content/full/326/7387/472. Accessed September 6, 2005.

2. Federal Trade Commission Act, 15 USC 45 (2005). Available at: http://www.fda.gov/opacom/laws/ftca.htm. Accessed September 6, 2005.

3. Federal Trade Commission Act, 15 USC 52 (2005). Available at: http://www.fda.gov/opacom/laws/ftca.htm. Accessed September 6, 2005.

4. Federal Food, Drug, and Cosmetic Act, 21 USC 9 (2005). Available at: http://www.access.gpo.gov/uscode/title21/chapter9_.html. Accessed September 6, 2005.

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Shah, S. K. Articles by Krueger, P. M. Search for Related Content PubMed PubMed Citation Articles by Shah, S. K. Articles by Krueger, P. M.