Prevalence and factors associated with Haematological side effects in MDR/RR-TB Patients on Linezolid-Based Regimens in Uganda: A Multicentre Retrospective Study

Background: Linezolid holds a critical role in the management of multidrug-resistant and rifampicin-resistant tuberculosis (MDR/RR-TB), a severe global health threat. The World Health Organisation strongly recommends its inclusion in treatment regimens for these challenging forms of tuberculosis. Despite its efficacy, linezolid is frequently associated with haematological toxicity, a complication insufficiently documented in resource-limited settings like Uganda. Objective: This study aimed to ascertain the prevalence and identify associated factors of haematological side effects in MDR/RR-TB patients receiving linezolid-based regimens in Uganda. Methods: A multicentre retrospective study was conducted, reviewing patient records from four Ugandan hospitals (2020 – 2024). Data were collected on the prevalence of anaemia : Haemoglobin (Hb) level below 12 g/dL for women or below 13 g/dL for men. Thrombocytopenia: Platelet count below 150,000/µL. Leukopenia: White blood cell (WBC) count below 3,700/mm³.Modified Poisson regression with robust error variance identified independent risk factors for these haematological side effects. Results: Out of 412 eligible patients, 62.9% developed at least one haematological side effect. Thrombocytopenia (56.6%) and leukopenia (56.3%) were the most common, followed by anaemia (43.7%). Most of these side effects occurred within the first month of linezolid initiation. Risk factors for developing at least one of the side effects included rural residence (adjusted Prevalence Ratio (aPR) 1.6; 95% CI: 1.11–2.33), divorced/widowed status (aPR 4.1; 95% CI: 1.58–10.77), and smoking (aPR 1.7; 95% CI: 1.28–2.80). Despite the high prevalence of side effects, 86% achieved treatment success (cure and completion); however, loss to follow-up was higher among those with toxicities, at 15.1% (39/259) and 5.9% (9/153) in those without hematologic side effects. Conclusion : Linezolid-related haematological toxicities are common and occur early in treatment. Targeted monitoring of high-risk patients may improve treatment adherence and outcomes.