FROM:
J Manipulative Physiol Ther 2003 (Sep); 26 (7): 460–467 ~ FULL TEXT
Anthony Rosner, PhD
Foundation for Chiropractic Research and Education, 1330 Beacon Street, Suite 315, Brookline, MA 02446, USA
For 50 years, the accepted standard by which the usefulness of a therapeutic treatment is judged has been the randomized controlled trial (RCT), building from Hippocrates' premise 2000 years ago that experience combined with reason was the therapy of choice for patients; that is, any treatment plan should both seem reasonable in theory and then be tested experimentally. Assuming that threats to both internal and external validity could be ruled out, the RCT became what is commonly regarded as the highest quality of clinical outcome study that could be mounted to allow inferences about cause and effect relationships to be drawn. The thinking was that the more rigorous and fastidious the design, the more credibility could be attached to the conclusions drawn from the outcomes of the study and the more likely the intervention was thought to have brought about those outcomes. [ 1 ] One of the strongest proponents of the RCT through the 1950s and 1960s was the British epidemiologist Archie Cochrane, who held that this type of experimental approach was essential for upgrading the quality of medical evidence. [ 2 ] In common hierarchical schemes of clinical experimental design, the RCT has been ranked the highest in rigor, as shown in Table 1.3 Even greater rigor has been presumed to occur with the statistical combination and weighting of the results of multiple RCTs in a meta-analysis to generate a more conclusive estimate of effect size. [ 4-5 ]
From the point of view of clinical practice, however, especially in areas in which physical treatments are applied, the principles of fastidious treatments and blinding begin to wear thin and in a few recent examples regarding spinal manipulation, appear to have fallen apart completely. This difficulty is by no means confined to physical treatments, as the literature pertaining to the use of medications has also suggested that the inexperienced use and/or uncritical acceptance of the results of RCTs can lead to confusion. In this presentation, a few representative samples will be introduced as 7 case studies, which ironically would be ranked among the lowest in experimental rigor by the aforementioned hierarchy of clinical evidence. [ 3 ]
At times, authors of studies have been known to present their data in more than 1 forum in the scientific literature, resulting in what has become referred to as mass-produced or “salami” publications. Because the exclusivity of such data is unknown, it will be oversampled by the unsuspecting author of a meta-analysis or systematic literature review and thus will be given more weight than it merits. One such instance has been reported in the evaluation of nonsteroidal anti-inflammatory drugs (NSAIDs) in treating rheumatoid arthritis, in which 44 publications of 31 clinical trials were found to result in an oversampling of at least 18%. Twenty of these studies were published in 2 different sources, 10 studies were published in 3 different sources, and 1 study was published in 5 different sources. The fact that these data were published elsewhere was not noted in 32 of the 44 articles. Even more unsettling is the finding that in about half of the articles, the first author and total number of authors were different, and there appeared to be important discrepancies between versions of the same trial. [ 7 ]
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