Objective To explore the risk factors for linezolid-induced anemia and establish the risk prediction model in elderly patients.

Methods The data of elderly patients treated with linezolid from January 2014 to August 2020 were retrospectively collected including demographic characteristic, baseline laboratory results, combind diseases, and concomitant medications. According to the occurrence of anemia, the patients were divided into anemia group and non-anemia group. The differences of related indexes between the two groups were compared. The logistic regression analysis was used to screened the independent risk factors for linezolid-related anemia in elderly patients. Then a risk prediction model was established, and the ROC curve was used to evaluate the predictive value of the model.

Results A total of 115 elderly patients were included, among whom, 75 were males (65.2%) and 21 (18.3%) developed anemia during the linezolid treatment. The univariate and multivariate logistic regression analyses showed that the duration of linezolid therapy, estimated glomerular filtration rate (eGFR), concomitantwith amiodarone, and concomitant with tacrolimus/sirolimus were independent influence factors for linezolid-related anemia. Logistic regression formula was further constructed according to the above influence factors: Logit(P)＝0.160XT+2.580XAm+2.807XTac－0.024XeGFR－1.994. The area under the ROC curve of the joint predictor was 0.843, with a certain predictive power, and the sensitivity and specificity of it were respectively 90.5% and 70.5%. When the Youden index is the largest (0.607), the corresponding cut-off value on the ROC curve was 0.5.

Conclusion The independent influence factors for linezolid-related anemia in elderly patients were duration of linezolid therapy, eGFR, concomitant with amiodarone, and concomitant with tacrolimus/sirolimus. It would indicate that the elderly patients have a higher risk of linezolid-associated anemia when the actual value of the formula is greater than the cut-off value, and the hemoglobin should be monitored.