Consistency between causality assessments obtained with two scales and their agreement with clinical judgments in hepatotoxicity.

Purpose: Reliability and usefulness of scales for causality assessment in hepatotoxicity have not been fully explored. The goal of this study was to examine consistency between causality assessments obtained with two commonly used scales and their agreement with initial clinical assessments in hepatotoxicity reported in Serbia, and to review usefulness of these scales.

Methods: We compared the two scales (CIOMS/RUCAM and NARANJO) in 80 cases reported during 1995-2009. The initial clinical assessments performed at the time of reporting served as a control for comparison with the subsequent causality assessments. The agreement between obtained causality assessments and the initial clinical assessments were analysed by Kappa weighted (K(w)) statistical test.

Results: In the 80 cases, the NARANJO scale showed better agreement with the initial clinical assessments (K(w): 0.62) than the CIOMS/RUCAM scale (K(w): 0.50) with moderate mutual agreement (K(w): 0.58). Results for 69 cases reported before the start of the study showed the same. In 11 cases reported in 2009 (after the start of the study) the CIOMS/RUCAM scale showed better agreement with the initial clinical assessments (K(w): 0.80) than the NARANJO scale (K(w): 0.70) with perfect mutual agreement (K(w): 1.0).

Conclusion: The two scales showed good similarity and the same was true when their outcomes were compared with the clinical judgments provided by the reporting physicians. Both scales may be useful in pharmacovigilance and clinical practice, but the CIOMS/RUCAM scale provides more specific data. Our results also confirmed that the quality of data and documentation influence the reliability of the method.