[Effect of the presentation of results from clinical trials on the intention to prescribing: relativity of the relative risk]. / Influencia de la presentación de los resultados de los ensayos clínicos en la intención de prescribir: relativizando el riesgo relativo.

OBJECTIVE: To determine if the methods of reporting results of clinical trials affects the physician views on prescribing. DESIGN: Analysis of responses, from a convenience sample of primary care physicians, of one teaching exercise on prescribing intention which showed 5 different methods of reporting results: relative risk reduction (RRR), absolute risk reduction, the percent of event free patients, the number needed to treat (NNT) and RRR and mortality. SETTING: Curses of clinical management in Valencia and Barcelona. RESULTS: The willingness to prescribe was significantly influenced by the way in which data were presented, being major when they were showed as RRR and minor when mortality was added. CONCLUSIONS: The method of reporting trial results has an important influence on the prescribing intention. The reporting of clinical trial results, and their abstracts or citations, should be include the NNT and negative results, for avoiding a subjective bias of treatment effect magnification.