Antimicrobial-associated adverse drug reaction profiling and assessing the agreement between the WHO-UMC scale and the Naranjo algorithm for causality assessment at a tertiary care teaching hospital in India

Abstract

Background: Adverse drug reactions (ADRs) are not uncommon due to medications, especially antimicrobials (AMs), given to the patients during their stay in the hospital. Aim and Objective: The present study aims to assess the ADRs related to AMs, causality assessment using the World Health Organization-Uppsala Monitoring Centre (WHO-UMC) causality assessment scale and the Naranjo scale and to evaluate their agreement. Materials and Methods: A prospective, observational study conducted over a period of one year in general medicine and pulmonary medicine wards, including 206 patients. WHO-UMC scale and the Naranjo algorithm were used to assess the causality followed by evaluating the agreement between these two scales. Results: The most common antibiotic accounted for ADRs was Piperacillin+Tazobactam (36.10%). The most common organ system involved was gastrointestinal (83.30%), followed by skin and soft tissue (11.10%) and immunological (5.60%). While 58.30% of the ADRs were latent in onset, 30.60% and 11.10% were sub-acute and acute, respectively. The majority of the ADRs were mild (66.70%), followed by moderate (22.20%) and severe (11.10%) in nature. As per the WHO-UMC scale, 19.4% ADRs were certain, 47.2% were probable, 27.8% were possible, and 5.6% were found to be unlikely. As per Naranjo algorithm, 75% of the ADRs were probable and 25% were of possible. Overall agreement analysis showed “Poor” agreement between the WHO-UMC scale and the Naranjo algorithm (kappa statistics with 95% confidence interval = 0.2195 [0.0065, 0.4325]). Conclusion: Using both the WHO-UMC scale and the Naranjo algorithm is advisable for better evaluation of ADRs related to AMs.