Adverse drug reactions in persons initiated on treatment for drug-resistant tuberculosis in Kerala, India: A non-concurrent cohort study

Objectives: We conducted a study to estimate the incidence of adverse drug reactions (ADRs) in the drug-resistant tuberculosis (DR-TB) cohort in Kerala in 2020 and describe the characteristics of the reported ADRs. Methods: A non-concurrent cohort study was conducted among all patients with DR-TB across 14 districts in Kerala from January 1, 2020 to December 31, 2020. We collected data on ADRs from patients, "Nikshay" web-portal, treatment cards, case sheets, and registers. We described ADRs by organ system, causality, severity, preventability, predictability, and seriousness of the reaction using standard tools. Results: Of the 364 persons initiated on treatment, 304 (83.5%) had at least one of the 28 listed adverse reactions, with an incidence of 27.6 ADR per 100 person-months of treatment. Gastrointestinal disorders had the highest incidence 365 per 1046 (35%). A total of 1001 of 1046 (95.7%) ADRs were non-predictable, and 405 of 1046 (39%) were definitely preventable. A total of 83 of 304 (27.3%) patients had severe ADR, and 56 of 304 (18.4%) had serious ADR. A total of 87 of 304 (28.6%) patients with ADR required interruption of the probable offending drug, with 64 of 87 (73.6%) temporary and 23 of 87 (26.4%) permanent interruptions. Conclusions: Four-fifths of all patients on therapy had at least one of the 28 listed adverse reaction and one-fifth had serious ADR. ADRs can lead to treatment interruptions. Early detection and prompt management is essential for improving treatment outcomes in patients with DR-TB.