PITFALLS IN PRESENTING AND INTERPRETING CLINICAL-TRIAL DATA

Information generated by a clinical trial, when conveyed to health pro fessionals and prospective patients, is affected by the original desig n of the trial and by the manner in which the results are presented. O ne problem in study design is the management of comparison groups in r andomized assignments. When a comparison group is treated with an acce pted standard compound, the chosen standard drug may be one that is as sociated with more side effects and complications than later modificat ions of the standard. Inadequate dosing of the comparison group can in flate the relative effect size of the experimental compound. Choosing a standard with a verifiable dose reference range can avoid this pitfa ll. In reporting results, relative score changes on a rating scale are meaningless without reference to an absolute value reflecting a clini cally relevant degree of remission. The validity of rating instruments chosen must be judged in the context of the specific population to wh ich it is applied. In the reporting of effects, the emphasis on signif icance of differences may obscure the critical distinction between sta tistical significance and clinical relevance, and graphs can appear to overstate a change over time by truncating the ordinate axis.