An assessment of reported adverse drug reactions in a Tertiary Care Hospital in South India: A retrospective cross-sectional study.

Objective: The primary objective of this study was to assess the causality of ADRs using World Health Organization-Uppsala Monitoring Centre (WHO-UMC), Naranjo and Liverpool ADR Causality Assessment Tool (LCAT). Other primary objective was to assess the agreement between the WHO-UMC criterion, Naranjo algorithm and LCAT. The secondary objective was to assess the reported adverse drug reactions in a tertiary care hospital in South India.

Materials and Methods: This was a cross-sectional retrospective study. All the ADRs which were reported by the Pharmacovigilance Unit between July 2016 and March 2017 were assessed. Causality assessment was performed by two well-trained independent pharmacologists by applying the three methods-WHO, Naranjo and LCAT. Concurrence between the two algorithms was compared using the Cohen's weighted kappa statistic.

Results: Causality assessment of adverse reactions according to Naranjo criteria shows that 81% cases were of probable type, 9.5% cases were possible and 9.5% cases were unlikely. Causality assessment of adverse reactions according to WHO-UMC criteria shows that 85.7% cases were of probable type, 4.8% cases were possible, 4.8% cases were unlikely and 4.8% cases were definite. Causality assessment of adverse reactions according to Liverpool criteria shows that 61.9% cases were of probable type, 4.8% cases were possible and 33.3% cases were definite. Cohen's kappa test shows that negative and poor concurrence was seen between WHO and Naranjo causality comparison (κ = -0.161). Positive but poor concurrence based on kappa values was seen between Liverpool and Naranjo's causality comparison (κ = 0.133). Negative and poor concurrence based on kappa values was seen between WHO and Liverpool causality comparison (κ = -0.161).

Conclusion: The most frequent causality category observed by the WHO-UMC criteria, Naranjo as well as the Liverpool algorithm was "Probable." Full concurrence was not found between any of two scales of causality assessment.