[Risk factors for development of hematotoxicity in elderly patients treated with Linezolid]

Objective: To analyze the clinical data, especially the occurrence of hematotoxicity, of hospitalized elderly patients who took Linezolid (LZD), and to further explore the related risk factors. Methods: Our study enrolled the elderly inpatients treated with linezolid at the Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School from January 2018 to September 2021. The hospital information system data were retrieved to retrospectively analyze the clinical characteristics of patients, particularly the clinical characteristics and related risk factors of patients who experienced hematotoxic reactions to LZD. Results: Of the 233 eligible cases included, 103 patients received empirical use of LZD (44.21%). The total effective rate was 76.39% (178/233). Among the 57 effective cases who received blood drug concentration monitoring, the trough concentration of LZD was high in 36.84 % (21/57) of elderly patients. Moreover, there were 15 patients with thrombocytopenia alone, 3 patients with decreased hemoglobin (HB) alone, and 3 patients with both thrombocytopenia and HB decrease. The patients who experienced hematotoxicity (developed a certain degree of hemoglobin decrease and/or thrombocytopenia) were more likely to be complicated with renal impairment (χ²=6.642, P=0.036), concomitantly using proton pump inhibitor (PPI) (χ²=4.566, P=0.033), and had a longer course of LZD treatment (P=0.041). There was no linear correlation between the trough concentration of LZD and glomerular filtration rate evaluated by Modification of Diet in Renal Disease Formula (eGFR_MDRD) (R=0.226, P=0.136). Conclusions: The elderly patients, especially those with renal impairment, concomitant treatment with PPI, and a longer course of LZD treatment, exhibited a higher risk of hematotoxicity during LZD treatment. Hence, we should strengthen the protection of renal function, reduce drug interaction, and dynamically monitor the blood drug concentration of LZD to adjust its dose, thus implementing safer and more effective treatments.