Table 2.

Possible parameters related to CCR decrease > 50%.

Parameters	Standard	Number ratio	Relative risk	95% CI	P value
Age ≥10 years	<10 years	41 versus 132	0.81	0.09–7.30	0.852
Body surface area ≥1.0 m2	<1.0 m2	51 versus 122	1.77	0.24–12.96	0.573
MTX dosage (≥5 g/m2)	<5 g/m2	60 versus 113	0.98	0.24–4.10	0.979
S-creatinine 0 h ≥35 μmol/L	<35 μmol/L	58 versus 115	0.31	0.07–1.44	0.134
C MTX_24 h ≥65 μmol/L	<65 μmol/L	74 versus 99	0.83	0.26–2.65	0.758
Delayed MTX elimination	Normal elimination	53 versus 120	8.07	2.57–25.32	<0.001

S-creatinine 0 h: serum creatinine level before MTX infusion; C _MTX_24 h: serum MTX concentration in 24 hours after MTX infusion.