To the Editor: The recent study by Roy H. Perlis, M.D., and colleagues (1) addressed an important relationship between author-industry affiliation and study outcomes in clinical trials. The authors examined funding source and author financial conflict of interest in 397 clinical trials published in four psychiatric journals over a 3-year period. The authors defined conflict of interest as “any report of consulting or speaking fees…stock ownership, or employment by the study sponsor” (p. 1957). Their results suggested that author conflict of interest was prevalent and significantly associated with positive trial outcomes in all of the 162 randomized, double-blind, placebo-controlled studies. Further, the authors stated that in these studies, “industry support itself was not significantly associated with a positive outcome” (p. 1958).
Dr. Perlis and colleagues also noted that, to their knowledge, no previous studies have investigated the “extent and implications” of funding source and author-industry affiliation in psychiatric clinical trials (p. 1957). I would like to bring to the authors’ attention a published study in which my colleagues and I investigated relationships between funding source, study quality, author-industry affiliation, and study outcome in all published randomized, double-blind trials (N=86) of second-generation antipsychotics for the treatment of schizophrenia (2). We defined a study as having author-industry affiliation if the primary author was listed as an employee or agent of the sponsoring pharmaceutical company. Although our results showed a correlation between author-industry affiliation and study outcome in industry-funded studies, this was not significant. We did find a significant relationship between funding source and study outcome, with industry-funded studies favoring the innovative (sponsored) treatments over standard therapies to a greater degree than nonindustry-funded studies.
The relationship between funding source and study outcome was investigated in several other published studies (3–8). Similar to our findings, these studies all demonstrated that industry support was associated with positive study outcome. Findings reported by Dr. Perlis and colleagues are interesting in that industry support itself was not associated with positive study outcomes, yet author conflict of interest was. I invite the authors to comment further on this possible discrepancy.
I applaud the call of Dr. Perlis and colleagues for strategies to ensure transparency in the reporting of all clinical trials, regardless of outcome. Hopefully, the psychiatric community will continue to meaningfully address the subject of bias and conflict of interest in industry-supported research.
1.Perlis RH, Perlis CS, Wu Y, Hwang C, Joseph M, Nierenberg AA: Industry sponsorship and financial conflict of interest in the reporting of clinical trials in psychiatry. Am J Psychiatry 2005; 162:1957–1960
2.Montgomery JH, Byerly M, Carmody T, Li B, Miller DR, Varghese F, Holland R: An analysis of the effect of funding source in randomized clinical trials of second generation antipsychotics for the treatment of schizophrenia. Controlled Clinical Trials 2004; 25:598–612
3.Davidson RA: Source of funding and outcome of clinical trials. J Gen Intern Med 1986; 3:155–158
4.Djulbegovic B, Lacevic M, Cantor A, Fields KK, Bennett CL, Adams JR, Kuderer NM, Lyman GH: The uncertainty principle and industry-sponsored research. Lancet 2000; 356:635–638
5.Lexchin J, Bero LA, Djulbegovic B, Clark O: Pharmaceutical industry sponsorship and research outcome and quality: systematic review. BMJ 2003; 326:1167–1170
6.Yaphe J, Edman R, Knishkowy B, Herman J: The association between funding by commercial interests and study outcome in randomized controlled drug trials. Fam Pract 2001; 18:565–568
7.Kjaergard LL, Als-Nielsen B: Association between competing interests and authors’ conclusions: epidemiological study of randomized clinical trials published in the BMJ. BMJ 2002; 325:249
8.Rochon PA, Gurwitz JH, Simms RW, Fortin PR, Felson DT, Minaker KL: A study of manufacturer-supported trials of nonsteroidal anti-inflammatory drugs in the treatment of arthritis. Arch Intern Med 1994; 154:157–163