Table 1.

Demographic and biochemical data of children with SLE

Variables	No. of observations	Values
No. of patients	–	184
Sex (F/M)	184	142/42
Age at SLE diagnosis (years)	184	10.82 (2.79), 11 [12–17]
MPA TDM times	518	2 [1–18]
SLE duration (years)	518	2.87 (2.64), 2 [0–12]
Age at MPA TDM (years)	518	13.45 (2.79), 14 [3–18]
Season at MPA TDM	518
Spring (March to May)		110 (21.24%)
Summer (June to August)		175 (33.78%)
Autumn (September to November)		107 (20.66%)
Winter (December to February)		126 (24.32%)
MPA concentrations (mg/L)
30 min pre-dose/trough	509	2.31 (1.75), 1.94 [0.12–15.45]
20 min post-dose	515	8.43 (9.46), 4.91 [0.13–71.40]
60 min post-dose	514	10.65 (9.14), 8.39 [0.34–79.80]
180 min post-dose	514	4.48 (3.12), 3.66 [0.30–25.10]
MPA AUC over 24 h (mg·h/L)	515	95.05 (45.40), 88.88 [6.00–294.98]
SLEDAI	380	5.96 (6.73), 4 [0–35]
β-CTx (ng/mL)	376	0.88 (0.82), 0.66 [0.03–5.85]
< 0.30 ng/mL (low)		61 (16.22%)
0.30–0.60 ng/mL (normal)		110 (29.26%)
> 0.60 ng/mL (high)		205 (54.52%)
Osteocalcin (ng/mL)	378	37.21 (42.55), 24.63 [0.50–256.00]
< 24.00 ng/mL (low)		184 (48.68%)
24.00–70.00 ng/mL (normal)		149 (39.42%)
> 70.00 ng/mL (high)		45 (11.90%)
25(OH) vitamin D (ng/mL)	378	19.81 (8.80), 18.43 [3.00–67.64]
< 15.00 ng/mL (low)		109 (28.84%)
15.00–35.00 ng/mL (normal)		248 (65.61%)
> 35.00 ng/mL (high)		21 (5.56%)
Serum calcium (mmol/L)	482	2.31 (0.17), 2.33 [1.68–2.89]
< 2.20 mmol/L (low)		96 (19.92%)
2.20–2.65 mmol/L (normal)		380 (78.84%)
> 2.65 mmol/L (high)		6 (1.24%)
Serum phosphorus (mmol/L)	480	1.33 (0.31), 1.33 [0.31–3.08]
Low		113 (23.54%)
Normal*		321 (66.88%)
High		46 (9.58%)

Data are presented as mean (standard deviation), median [range], or frequency (percentage)

SLE systemic lupus erythematosus, MPA mycophenolic acid, TDM therapeutic drug monitoring, AUC area under the MPA concentration–time curve, SLEDAI SLE disease activity index, β-CTx beta-CrossLaps, No. Number

*Normal serum phosphorus range 1.29–2.26 mmol/L for children ≤ 14 years old; 0.81–1.45 for children > 14 years old