Retrospective analysis of the risk factors for linezolid-induced thrombocytopenia in adult Japanese patients

Abstract

Background: Thrombocytopenia is a major side effect of linezolid therapy. However, there are few reports about the risk factors for linezolid-induced thrombocytopenia.

Objective: The aim of this study is to evaluate the risk factors for thrombocytopenia in patients who undergo linezolid therapy.

Setting: Aomori Prefectural Central Hospital in Japan, a tertiary 695 beds hospital.

Method: A retrospective review was performed using the hospital's medical records. From January 2010 to August 2012, 75 adult patients who received linezolid therapy were enrolled in this study.

Main outcome measure: Linezolid-induced thrombocytopenia was defined as a decrease in the patient's platelet count to <10 × 10⁴/μL or a reduction of ≥30 % from their baseline value. Odds ratios (OR) for thrombocytopenia were analyzed using multivariate stepwise logistic regression analysis.

Results: Thrombocytopenia occurred in 29 patients (38.6 %), seven of whom required platelet transfusions. The patients who developed thrombocytopenia were significantly older, displayed a significantly higher frequency of renal insufficiency, and received linezolid therapy for significantly longer than the patients without thrombocytopenia. Stepwise logistic regression analysis suggested that receiving linezolid therapy for ≥14 days was a significant risk factor for thrombocytopenia [OR 13.3, 95 % confidence interval (CI) 3.2-55.6, p < 0.01], whereas the creatinine clearance rate exhibited a significant negative correlation with the incidence of the condition [OR 0.98, 95 % CI 0.96-0.99, p = 0.037]. The incidence of thrombocytopenia among the patients who demonstrated creatinine clearance rates of <30 mL/min was 60 % (12/20), which was significantly higher than that observed among the patients who displayed creatinine clearance rates of more than 60 mL/min (26.4 %, 9/34, p = 0.014).

Conclusion: Receiving linezolid therapy for ≥14 days and a low creatinine clearance rate were suggested to be risk factors for linezolid-induced thrombocytopenia. The platelet counts of patients with these risk factors should be closely monitored.