A retrospective study of the risk factors for linezolid-induced thrombocytopenia and anemia.

Myelosuppression is major treatment-related adverse events of linezolid therapy and result in treatment termination in some cases. We aimed to identify the risk factors for linezolid-induced thrombocytopenia and anemia. We retrospectively retrieved demographic and laboratory data from the medical records of 221 Japanese patients who were undergoing linezolid therapy. Thrombocytopenia and anemia were defined as an unexplained reduction of >30% in the patient's platelet count and hemoglobin level, respectively, from the baseline. Thrombocytopenia developed in 48.4% of patients, and anemia developed in 10.4% of patients during linezolid therapy. In multivariate analysis, creatinine clearance (adjusted odds ratio = 0.94 [0.92-0.95], P < 0.001), hemodialysis (3.32 [1.14-9.67], P = 0.011), and the duration of linezolid therapy (1.14 [1.07-1.21], P < 0.001) were found to be significant risk factors for linezolid-induced thrombocytopenia. Patients with creatinine clearance rates of <60 mL/min and those on hemodialysis were found to be at high risk of linezolid-induced thrombocytopenia. In addition, a high incidence of linezolid-induced thrombocytopenia was even detected among the patients that had received linezolid therapy for <7 days. As for anemia, the duration of linezolid therapy (1.04 [1.01-1.07], P = 0.011) was shown to be a risk factor for anemia, and a high incidence of anemia was seen among the patients who received linezolid for >15 days. In conclusion, we recommend that among patients receiving linezolid therapy the platelet counts of those with risk factors for linezolid-induced thrombocytopenia should be monitored closely throughout treatment, and the hemoglobin levels of patients that receive linezolid for >15 days should be carefully monitored on a weekly basis to detect anemia.