Agreement Between WHO-UMC Causality scale and the Naranjo Algorithm for Causality Assessment of Adverse Drug Reactions at Health Care Services in Yogyakarta

Hafifah Ernawati (Magister of Clinical Pharmacy Student, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta The Indonesian Food and Drug Authority Regional Office in Yogyakarta, Jl. Tompeyan I No.55244, Tegalrejo, Yogyakarta)
Zullies Ikawati (Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta)
Ika Puspita Sari (Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta Academic Hospital, Universitas Gadjah Mada, Yogyakarta)
Siti Asfijah Abdoellah (Directorate of Safety, Quality, and Export-Import Control of Drugs, Narcotics, Psychotropics, Precursors, and Addictive Substances, The Indonesian Food and Drug Authority, Jalan Percetakan Negara Nomor 23 Jakarta 10560)
Fivy Kurniawati (Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta, Indonesia)

JURNAL MANAJEMEN DAN PELAYANAN FARMASI (Journal of Management and Pharmacy Practice)
Vol 16, No 3

Background: The WHO-UMC system and Naranjo algorithm are the most widely used tools for evaluating the causality of adverse drug reactions (ADRs) reports. Despite their wide application, a direct comparison of these methods in the context of Indonesia's ADR reporting has not yet been explored.Objectives: This study aimed to compare the agreement of causality assessment and correlation between the two methods of the WHO-UMC system and the Naranjo algorithm.Methods: In this study, 255 suspected adverse drug reactions (ADR) from 169 safety reports were analyzed in 2023, reported at healthcare services in Yogyakarta. Two independent raters performed causality assessments using the WHO-UMC criteria and Naranjo algorithm. The raters were blinded to each other's assessment results, and the assessments were conducted at different locations and times. The agreement between the two ADR causality scales was assessed using Cohen's kappa. Spearman’s correlation was also used to find the correlation between the two scales.Results: ADRs were most frequently reported by pharmacists, with the most commonly suspected drug class being antibiotics. The agreement between the two methods for all ADR cases was a Cohen's Kappa coefficient value of 0.384, indicating minimal agreement. The correlation between the two methods was 0.501, indicating a moderately positive relationship.Conclusion: A minimal moderate level of agreement was observed between the WHO-UMC and Naranjo scales. The level of agreement for serious ADR cases was classified as weak, whereas for non-serious ADR cases, it was classified as minimal. The correlation between the two methods was moderately positive.