Qiaofeng Ye1, Guangfei Wang1, Yidie Huang1, Jinmiao Lu1, Junqi Zhang1, Lin Zhu1, Yiqing Zhu1, Xiaoxia Li1, Jianger Lan1, Ziwei Li1, Yubing Liu1, Hong Xu2, Zhiping Li3. 1. Department of Clinical Pharmacy, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China. 2. Department of Nephrology, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China. hxu@shmu.edu.cn. 3. Department of Clinical Pharmacy, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China. zpli@fudan.edu.cn.
Abstract
INTRODUCTION: Systemic lupus erythematosus (SLE) can affect bone metabolism and homeostasis of serum electrolytes that are associated with abnormal levels of vitamin D. Mycophenolate mofetil (MMF) is a commonly used immunosuppressant with the active metabolite mycophenolic acid (MPA). The area under the plasma concentration-time curve (AUC) of MPA is often monitored during the treatment to assess the exposure levels. This study aims to explore the association between exposure levels of MPA and 25-hydroxyvitamin D [25(OH)D] levels in children with SLE. METHODS: Repeated measured data of children with SLE who were treated with MMF and under therapeutic drug monitoring (TDM) were retrospectively collected from the electronic medical records. MPA exposure levels were reflected by the area under the concentration-time curve over 24 h (AUC0-24h). Univariate and multivariate linear regression models were employed to analyze factors associated with 25(OH)D levels. Hierarchical linear models were developed to analyze the intra- and inter-individual effects of AUC0-24h on the variance of 25(OH)D levels. RESULTS: Data from 184 children with SLE (142 female and 42 male) with 518 follow-ups were collected. The median age was 14 years (range 3-18 years) at TDM. Children with normal 25(OH)D levels had significantly higher AUC0-24h than children with low 25(OH)D levels (98.71 vs. 84.05 mg·h/L, P = 0.004). Intra- and inter-individual effects of AUC0-24h on 25(OH)D levels were similar ([Formula: see text] = 0.034 vs. [Formula: see text] = 0.037) but only the intra-individual effect was significant (P = 0.001) in hierarchical models. Other associated factors include age, sex, season at measurement, glucocorticoid daily dose, and external vitamin D3 supplements. CONCLUSION: 25(OH)D levels are associated with MPA exposure levels, and may serve as a potential indicator to optimize the exposure level of MPA during treatment. AUC0-24h of 98.71 mg·h/L or AUC0-12h of 49.36 mg·h/L could be the targeted exposure level for children with SLE.
INTRODUCTION:Systemic lupus erythematosus (SLE) can affect bone metabolism and homeostasis of serum electrolytes that are associated with abnormal levels of vitamin D. Mycophenolate mofetil (MMF) is a commonly used immunosuppressant with the active metabolite mycophenolic acid (MPA). The area under the plasma concentration-time curve (AUC) of MPA is often monitored during the treatment to assess the exposure levels. This study aims to explore the association between exposure levels of MPA and 25-hydroxyvitamin D [25(OH)D] levels in children with SLE. METHODS: Repeated measured data of children with SLE who were treated with MMF and under therapeutic drug monitoring (TDM) were retrospectively collected from the electronic medical records. MPA exposure levels were reflected by the area under the concentration-time curve over 24 h (AUC0-24h). Univariate and multivariate linear regression models were employed to analyze factors associated with 25(OH)D levels. Hierarchical linear models were developed to analyze the intra- and inter-individual effects of AUC0-24h on the variance of 25(OH)D levels. RESULTS: Data from 184 children with SLE (142 female and 42 male) with 518 follow-ups were collected. The median age was 14 years (range 3-18 years) at TDM. Children with normal 25(OH)D levels had significantly higher AUC0-24h than children with low 25(OH)D levels (98.71 vs. 84.05 mg·h/L, P = 0.004). Intra- and inter-individual effects of AUC0-24h on 25(OH)D levels were similar ([Formula: see text] = 0.034 vs. [Formula: see text] = 0.037) but only the intra-individual effect was significant (P = 0.001) in hierarchical models. Other associated factors include age, sex, season at measurement, glucocorticoid daily dose, and external vitamin D3 supplements. CONCLUSION:25(OH)D levels are associated with MPA exposure levels, and may serve as a potential indicator to optimize the exposure level of MPA during treatment. AUC0-24h of 98.71 mg·h/L or AUC0-12h of 49.36 mg·h/L could be the targeted exposure level for children with SLE.