A Study of Agreement Between Who-Uppsala Monitoring Centre Criteria, Naranjo Algorithm, and Liverpool Algorithm for Causality Assessment of Adverse Drug Reactions

Abstract

Objective: A standard causality assessment tool of an adverse drug reaction (ADR) is essential to compute the risk-benefit assessment of the medication taken by the patient and categorize its relationship likelihood. It should be reproducible and should not differ with the background and experience of the evaluator. Though there are a large number of causality assessment tools, none is unanimously accepted worldwide. So, this study was done to assess the agreement between three frequently used methods of causality assessment, the World Health Organisation-Uppsala Monitoring Centre (WHO-UMC) system, the Naranjo’s algorithm, and the Liverpool algorithm.
 Methods: 172 ADR forms from the pharmacovigilance unit were randomly selected for the study. Causality assessment was done using three different methods, the WHO-UMC system, Naranjo’s algorithm, and the Liver pool algorithm. Cohen’s Kappa statistics was applied to look for agreement between the causality assessment methods.
 Results: The agreement between the WHO-UMC criteria and Naranjo’s algorithm was the highest (136), with a Kappa value of 0.511, suggesting a moderate level of agreement. A maximum number of disagreements were noted between the WHO-UMC system and the Liverpool algorithm method (110).
 Conclusion: A moderate agreement exists between the WHO-UMC system and the Naranjo algorithm. There is poor agreement between the Liverpool algorithm and the other two scales. Therefore, it is recommended that both the WHO-UMC system and the Naranjo algorithm be used for causality assessment of ADRs.