Weighing Harm in Therapeutic Decisions of Smear-Negative Pulmonary Tuberculosis

Purpose. To relate the intuitive weight of harm by commission and harm by omission in therapeutic decisions for pulmonary tuberculosis, and to compare it with a weight based on probabilities. Methods. Clinicians were asked for an estimation of probabilities related with the outcome of treated and nontreated pulmonary tuberculosis and for the toll of wrong decisions. Three ratios of the weight of forgoing a treatment in false-negative patients against the weight of treating false-positives were calculated. The first was based on intuitive estimations, whereas the second and third were based on calculated, either through intuitive estimations of probabilities or through literature data. The association between experience and the difference between the intuitive and the calculated ratios was assessed. Results. Eighty-one participants from Ecuador, Laos, Nepal, and Rwanda responded. The ratio of intuitive weights was 2.0 (interquartile range [IQR], 1.0-4.0) and the ratio of calculated weights based on intuitive probabilities was 64 (IQR, 25.0-169.6; P < 0.001). The ratio of calculated weight based on literature probabilities was 30 (IQR, 17.9-59.2). No association (R(2) = 0.03) was found between experience and accuracy in estimating the weight of errors. Conclusion. The weight of a false negative is more important than the weight of a false positive for therapeutic decisions in pulmonary tuberculosis. The ratio of the intuitively estimated weights was much lower than the calculation based on intuitively estimated influencing factors. Clinicians were accurate in estimating probabilities but failed to incorporate them into therapeutic decisions.