Effects of presenting risk information in different formats to cardiologists. A Latin American survey.

OBJECTIVE Previous publications demonstrated that the presentation of treatment benefits in terms of relative risk reduction (RRR) rather than in terms of absolute risk reduction (ARR) or number of patients to treat (NNT) might favor the perception of outcome effectiveness. The objective was to perform a cognitive evaluation to assess how the manner in which risks and benefits of screening methods and treatments are presented can affect medical care decision-taking in a sample of cardiologists. METHODS Four-hundred and six Latin American cardiologists answered a questionnaire reporting the results of clinical trials presented as RRR, ARR or NNT, associated or not to biased graphs. RESULTS Cardiologists' decision-taking was different when comparing treatment benefits presented as RRR (62.2%) vs. ARR (40.4%) (p=0.000000), and as RRR vs. NNT (44.4%) (p=0.000000). However, their decision-taking was similar when information was presented as NNT or ARR (p=0.073). The inclusion of biased graphs was misinterpreted as an actual data difference (RRR: 61.6% vs. ARR: 14.0%, p=0.000000). CONCLUSIONS This study demonstrated that Latin American cardiologists could misinterpret statistical data when information of clinical trials is presented in terms of RRR. We emphasize the need to enhance cardiologists' training in quantitative techniques, to improve medical care decision-making.