OBJECTIVE: Updating a logistic causality assessment method to improve its agreement with consensual expert judgment (CEJ). STUDY DESIGN AND SETTING: A random sample of 53 drug-event pairs from a pharmacovigilance database were evaluated independently by CEJ and by a group of experts in pharmacovigilance using the logistic method. Causes of disagreement between both approaches were analyzed, and changes in the assessment of some criteria of the logistic method were proposed and tested in models. The model giving results closest to the CEJ was retained and compared with the initial version on another set of drug-event pairs. RESULTS: Finally, only the criterion "Search for nondrug cause" was changed into "Search for other causes." The assessment not investigated, possible other cause decreased the probability of drug causation instead of being neutral, whereas the assessment not applicable, not required remained neutral. This new version presents much improved specificity (0.56 vs. 0.33), relatively good sensitivity (0.96), and positive and negative predictive values (0.92 and 0.71). CONCLUSION: The updated logistic method presented here improves the initial version that had poor specificity and tended to overestimate drug causation. This new version presents satisfactory characteristics to be used in routine pharmacovigilance.
OBJECTIVE: Updating a logistic causality assessment method to improve its agreement with consensual expert judgment (CEJ). STUDY DESIGN AND SETTING: A random sample of 53 drug-event pairs from a pharmacovigilance database were evaluated independently by CEJ and by a group of experts in pharmacovigilance using the logistic method. Causes of disagreement between both approaches were analyzed, and changes in the assessment of some criteria of the logistic method were proposed and tested in models. The model giving results closest to the CEJ was retained and compared with the initial version on another set of drug-event pairs. RESULTS: Finally, only the criterion "Search for nondrug cause" was changed into "Search for other causes." The assessment not investigated, possible other cause decreased the probability of drug causation instead of being neutral, whereas the assessment not applicable, not required remained neutral. This new version presents much improved specificity (0.56 vs. 0.33), relatively good sensitivity (0.96), and positive and negative predictive values (0.92 and 0.71). CONCLUSION: The updated logistic method presented here improves the initial version that had poor specificity and tended to overestimate drug causation. This new version presents satisfactory characteristics to be used in routine pharmacovigilance.