Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 2006; 11: 20
The aim of this review was to summarise existing causality assessment methods for adverse drug reactions (ADR) and to discuss their strengths and weaknesses.
We conducted electronic searches in Medline (via Pubmed), Embase and the Cochrane databases to find all assessment methods.
Thirty-two different methods were found, falling into three broad categories: expert judgments, algorithms and probabilistic or Bayesian approaches. Expert judgments are individual assessments based on previous knowledge and experience in the field using no standardised tool to arrive at conclusions. Algorithms consist of a set of specific questions with scores for calculating the likelihood of a cause/effect relationship. Bayesian approaches use specific findings in a case to transform the prior estimate of probability into a posterior estimate of probability of drug causation. The prior probability is calculated from epidemiologic information and the posterior probability combines this background information with the evidence in the individual case to generate an estimate of causation. Different causality categories are adopted in each method and the categories are assessed using different criteria. Because assessment methods are also not entirely devoid of individual judgment, inter-rater reliability can be low.
Due to problems of reproducibility and validity, no single method is currently universally accepted. There is an urgent need for an ADR assessment method which is simple, valid and reproducible.
TJ is supported by a research fellowship provided by Dr Wilmar Schwabe Pharmaceuticals.
