The French Imputability Method

This method was first devised in 1978 (Dangou-mau et al., 1978), revised in 1985 (when it was published simultaneously in French and in English) (Begaud et al., 1985). It is the only imput-ability (causality assessment) method to have legal status. It is probably one of the most widely used, if not the most widely used, imputability method, having been applied to more than 100 000 reports, and yet it remains widely misunderstood.

The method was derived when the regional network was developing, to ensure that all the Centres worked and assessed reports in reasonably the same way. It has a few basic principles, designed to ensure the highest possible sensitivity when used routinely on incoming reports. It is because of this that the term "causality assessment" may not really be applicable in that it is not causation per se that is assessed, but the possibility of involvement, a subtle distinction.

BASIC PRINCIPLES The basic principles are

• That the causality be judged only on the data present in the case, in abstraction of all published data concerning the drug-reaction association. Each case is judged on its own merits (intrinsic imputability) to ensure maximal identification of possible new reactions. This also ensures time-independent classification. Previous publications and labelling, which vary over time, are only indicated, and are not an integral part of the imputability.

• That the causality be assessed on each drug-reaction pair presented by the patient at the time of the event, or that could be involved (such as previously stopped medication that could result in unidentified withdrawal symptoms).

This method is thus very dependent on the Regional Centre/drug information centre system, where there is early interaction with the reporter, so that information can be accrued in real-time, rather than having to judge a case a posteriori on incomplete information as is usually the case in most paper-based spontaneous reporting systems where the reporter has already made up his mind on causality when reporting, and information is only present on the drug suspected by the reporter who often has no formal pharmacological or ADR-assessment training.

The method relies on a set of criteria that are, in fact, common to all causality assessment methods, so that it is easy to reapply other causality methods if the proper information has been obtained. It is perforce very general in its definition of criteria, and much attention has been devoted to refining definitions of these criteria for specific reactions, and even for specific drug-reaction associations (Habibi et al., 1988; Fournier et al., 1989; Roujeau et al., 1989; Vigeral et al., 1989; Benichou, 1990; Benichou and Solal Celigny, 1991).

There are six main criteria, three for chronology (time sequence), and three for semiology (signs and symptoms). These are:

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  • gabriel
    What is imputability score?
    11 months ago
  • Sabrina
    How to calculate french imputability?
    10 months ago

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