Abstract: Objective To explore the factors that affecting the blood concentration of tacrolimus in children with nephrotic syndrome and to establish a risk prediction model. Methods Information was collected retrospectively on 90 children diagnosed with NS and meeting inclusion/exclusion criteria from January 2017 to October 2019, including demographic information, laboratory test indicators, combined medication, and tacrolimus steady-state trough concentration and dose. Univariate analysis was used to screen for factors affecting low and high exposure to tacrolimus concentration, Then a risk prediction model was established by multivariate Logistic regression method. Results Univariate analysis result showed that dose, azithromycin and red blood cell volume were the significant factors affecting low and high exposures of tacrolimus steady-state trough concentration (P<0.05). The low exposure risk model established by multivariate Logistic regression was Logit(P)=2.521-1.419(dose)-2.401(with azithromycin)+0.964(serum cystatin C)-1.93 6 erythrocyte volume (<35%) and with a better accuracy, specificity and sensitivity. Conclusion In children with nephrotic syndrome, the effects of dose, combined azithromycin and erythrocyte volume on tacrolimus steady-state trough concentration should be considered. The low exposure risk model can be used to predict the probability of low blood concentration exposure in children to avoid the occurrence of tacrolimus adverse reactions and improve the therapeutic effect.

Key words: children, tacrolimus, nephrotic syndrome, blood concentration, influenceing factors, adverse drug reaction