Table 4. Average values for various parameters in the group with high eGFR that is maintained during the follow-up (group 1: 35 patients with eGFR ≥60 mL/min/1.73 m²) compared to group 2 (42 patients with eGFR <60 mL/min/1.73 m²).

Variable	Group 1	Group 2	p value***
S creat	83	212	<0.0001
S creatf1	88	237	<0.0001
eGFR	96	33	<0.0001
eGFRf1	85	34	<0.0001
ΔeGFR	-13%	-3%
PU	2,09	2,29	0.486
PUf1	0,73	1,69	0.026
ΔPU	-65%	-26%
IgA (μg/mL)	4 756	5 226	0.190
Gd-IgA1 (U/1 μg IgA)*	100	115	0.101
Gd-IgA1 (U/mL)*	468 804	567 790	0.117
Gd-IgA1 (U/1 μg IgA) **	466	477	0.686
Gd-IgA1 (U/mL)**	2 210 341	2 371 748	0.545
IgG Ab	2 694	4 396	0.003
S creatf2	91
eGFRf2	77
PUf2	0.6

S creat_f1, eGFR_f1, PU_f1 –final values at the end of the follow-up (average 3.5 yrs); S creat_f2, eGFR_f2, PU_f2 –final values at the end of the follow-up (average 5.0 yrs); S-creat, serum creatinine (μmol/L); eGFR (MDRD, mL/min/1.73 m²); PU, proteinuria (g/24 h); IgG Ab, serum IgG autoantibody specific for Gd-IgA1 (U/mL). Both groups exhibited similar proteinuria at diagnosis (2.1 and 2.3 g/24 h, respectively), but patients in group 1 had lower proteinuria at the end of follow-up compared to patients in group 2 (0.7 vs. 1.7 g/24 h, respectively). Group 1 (n = 35), eGFR ≥60 mL/min/1.73 m²; group 2 (n = 42), eGFR <60 mL/min/1.73 m².

* serum Gd-IgA1 without neuraminidase pretreatment

** serum Gd-IgA1 with neuraminidase pretreatment

***p values means the risk to reject the null hypothesis (the medians are all equal). Confidence level is 90% (cut-off 0.1). Bold numbers indicate statistically significant P values.