Clinical Trials of various sorts are intended to be the final word in evaluating both the safety and the efficacy of medications. In psychiatry, they’re more complicated because the outcome parameters are from the subjective reporting of either observers or subjects converted to objective data by rating forms and checklists. Unfortunately, they’ve moved to center stage as a major focus all sorts of research misconduct. The problems of conflict of interest are rampant and a major Achilles Heel is in the analysis of the raw information. There are so many clear examples of the manipulation of the analytic tools of science in the service of distortion that the entirety of the psychiatric clinical trial literature has come under suspicion.
There are nodes all along the chain of steps in clinical trials where bias might effect the outcome, but most of the attention focuses on what happens after the data has been collected. The stakes are high, and it’s in that netherworld between the time the raw results are reported and the time the paper is submitted the where distortions break out in epidemic proportions. Critics are limited to the written word, and can only use indirect means to find evidence that the raw results have been inappropriately manipulated.
One recent example embodies the controversy about data transparency. Dr. Robert Gibbons et al published two papers in the Archives of General Psychiatry last year addressing the efficacy and safety of the SSRIs in depression. They did a meta-analysis of Eli Lilly’s trials of Prozac in children and adults and Effexor in adults only [if you’re not familiar with these papers, put "Gibbons" in the search engine of this blog for more than you’d ever want to know]. A number of people cried foul, and submitted letters to the publishing journal. After a saga of back and forth negotiations with the editor, two of the letters were finally published recently, along with Gibbons et al’s responses. My letter was published only on this blog [an anatomy of a deceit 4…].
Several things: In the paper and in numerous media outings afterwards, Dr. Gibbons repeatedly made the point that his meta-analysis would not have been possible if Eli Lilly hadn’t graciously allowed him access to the raw data for all of their Prozac Clinical Trials – a unique opportunity. His meta-analysis involved complex statistical methods with innumerable references to parameters of data inclusion or exclusion which were impossible to follow, particularly with the paucity of data included in his papers.
Moreover, there is computational error. Only 4 of 12 stated odds ratios for treatment benefit can be confirmed from the response and remission data.2 Two of 12 number-needed-to-treat computations are seriously inaccurate (16.95 Gibbons et al vs 10.1 actual; 38.71 Gibbons et al vs 15.38 actual). The inarguable error of these straightforward computations puts in doubt the soundness of the authors’ very complex multivariate statistical computations.
Finally, with respect to the “computational error” in our second article on the benefits of antidepressant treatment, we clearly state that for the analysis of response and remission, the results of the analysis were based on “a mixed effects logistic regression model adjusting for study.” It is not possible for anyone [including Dr Carroll] to replicate these computations, which require the individual study–level data. Dr Carroll’s discrepancy for the 2 number-needed-to- treat estimates was because we based them on the logtime [sensitivity analysis] rather than the linear-time model. The estimates of number needed to treat of 10.10 [response] and 15.31 [remission] are the correct estimates for the linear-time model and also show the reduced efficacy in elderly individuals relative to youths and adults.
With Dr. Gibbons’ widely publicized articles reanalyzing already published trials, the only justification for doing the meta-analysis in the first place was that he had access to individual study–level data. The way he explained getting different results from others, or even those analyzing these same studies first time around, was his access to individual study–level data. And now he’s claiming that the only possible way to check his work is to have access to individual study–level data. I agree with him, and that’s the exact reason that the push for data transparency in Clinical Trials is essential and gaining steam. In fact, in this pair of articles, Robert Gibbons is a powerful ombudsman for the argument of Ben Goldacre, Fiona Godlee, Healthy Skepticism, Glenis Willmott, AllTrials, and almost anyone else who isn’t entangled with the Academic·Pharmaceutical Complex.