Table 2.

ROC curve of serum IgG, IgA, IgM, C3, C4 and IgA/C3 ratio in predicting IgAN

	Full cohort							PSM cohort
	Area	P	Cut-off point	Sensitivity (%)	Specificity (%)	Youden index	Area	P	Cut-off point	Sensitivity (%)	Specificity (%)	Youden index
IgG	0.810	< 0.001	8.32	77.85	76.63	0.5448	0.629	< 0.001	8.32	58.13	68.63	0.2676
IgA	0.715	< 0.001	2.245	70.45	63.61	0.3415	0.696	< 0.001	2.12	74.51	56.37	0.3088
IgM	0.587	< 0.001	1.31	49.01	66.86	0.1587	0.580	0.005	1.20	54.90	61.76	0.1667
C3	0.657	< 0.001	1.081	66.84	60.06	0.2690	0.621	< 0.001	1.08	64.71	61.27	0.2598
C4	0.628	< 0.001	0.25	57.12	65.09	0.2221	0.558	0.044	0.25	49.50	63.24	0.1274
IgA/C3 ratio	0.767	< 0.001	2.102	75.03	67.46	0.4249	0.734	< 0.001	2.410	58.82	77.45	0.3627

C3 complement 3, C4 complement 4, IgA immunoglobulin A, IgAN immunoglobulin A nephrology, IgG immunoglobulin G, IgM immunoglobulin M, PSM propensity score matched, ROC receiver operating characteristic