Clinical diagnostic scale: a useful tool in the evaluation of suspected hepatotoxic adverse drug reactions

Background/Aim: Due to an absence of specific markers, the diagnosis of drug-induced hepatotoxicity is necessarily based on circumstantial evidence and is often inaccurate. We have evaluated the use of the clinical diagnostic scale (CDS) in the causality assessment of hepatotoxic adverse drug reaction (ADR) reports. Methods: 135 hepatic adverse ADRs reported to the Committee on Safety of Medicines in North East England 1992-6 were evaluated. Initially, "International Consensus Criteria" were used to classify reactions as "drug-related", "drug-unrelated" and "indeterminate", Using the CDS, each ADR was then categorised as either definite drug hepatotoxicity (score >17), probable (14-17), possible (10-13), unlikely (6-9), or drug hepatotoxicity excluded (<6). Results: 49 ADRs were considered drug-related, 65 unrelated and 21 indeterminate, Reports classified as drug-related by consensus criteria scored higher on the CDS, with a median score of 12, range: 8-15, than either the indeterminate (8; [3-12]) or drug-unrelated reports (5; [2-11]) (p<0.0001), A CDS score of >9, identified 88% of the cases classified as drug-related hepatotoxicity by consensus criteria and excluded 98% of those unrelated to the drugs. Conclusions: CDS scoring correlates web with the international consensus classification and may be a useful tool in the routine evaluation of suspected hepatotoxic drug reactions.