Real-time active surveillance for drug-induced Thrombocytopenia: A prospective interventional study.

Background: Drug-induced thrombocytopenia (DITP) is a severe adverse drug event that is frequently missed due to overlapping causes, such as sepsis or other conditions. In Vietnam, the spontaneous reporting system for DITP events has shown limited benefits, highlighting the need for active surveillance methods such as real-time signal monitoring. Objective: To develop and implement a real-time signal monitoring tool for DITP in hospitalized patients with pharmacist-led interventions. Methods: We included inpatients aged ≥18 years admitted between March 1 and November 1, 2024. Suspected DITP cases were identified using an integrated set of signals from a real-time active surveillance tool. Pharmacists assessed drug-event causality using the World Health Organization causality scale and provided management recommendations. Positive predictive values (PPV) were calculated for the alert. Results: 1337 positive signals were generated, involving 258 patients. Patients were predominantly male (66.7%) with a mean age of 65.1 (16.7) years, and most were admitted to the intensive care unit or emergency department. The overall PPV was 3.3%. Antibiotics were the most frequently suspected drug class associated with DITP, with confirmation rates varying by agent. Linezolid, heparin and meropenem had the highest confirmed associations, at 28.6%, 26.6% and 12.5%, respectively. In 17 cases with pharmacist intervention, drug discontinuation was documented in all cases, platelet transfusion in 3 patients, and recovery in 94.1% (16/17) of patients. Conclusion: Implementation of a real-time signal-based active surveillance system was associated with improved identification and structured assessment of suspected DITP cases, supporting the feasibility of routine active monitoring in clinical practice.