Table 3.

Clinical features, complement assessment, genetic screening, and histologic features in patients classified according to the clusters obtained through cluster analysis

VariableCluster 1Cluster 2Cluster 3Cluster 4Overall P Value
N62323346
Sex, % men614155610.24
Data at onset
 Age, yr15 (±11.6)17.2 (±13)14.5 (±10.4)28.8 (±19.8)a,b,c<0.001
 Microhematuria, %90939464a,b,c<0.001
 Gross hematuria, %37345020a,c0.04
 Proteinuria, %939485890.51
 Nephrotic syndrome, %2972a,c,d2424<0.001
 Renal impairment, %1019639a,c<0.001
 Trigger event, %383123220.29
 Familiarity for nephropathy, %23c163110.05
Serum C3, mg/dl34.7 (±30.2)34.5 (±37.9)31 (±25.6)86.7 (±35.6)a,b,c<0.001
Serum C4, mg/dl21.1 (±10.3)19.1 (±13)23.5 (±7.9)23.6 (±7.5)0.17
Plasma SC5b-9, ng/ml1494 (±1325)c,d1558 (±1285)c,d591 (±1062)416 (±395)<0.001
Low serum C3 and normal C4, %8172c9450a,b,c<0.001
LPV carriers, %3222154a,b0.004
C3NeF positive, %5353759a,b,c<0.001
LPV carriers and/or C3NeF, %75637914a,b,c<0.001
Data during follow-up, %
 Nephrotic syndrome5288a,c,d52500.003
 High BP26442763a,c<0.001
 CKD18b,c,d473654<0.001
 ESRD2d66220.003
 Thrombotic microangiopathy20013a,c<0.01
Histologic features
 Time onset to biopsy, yr, median (IQR)0.6 (0.2–3.6)0.2 (0.1–1.7)0.6 (0.2–1.8)0.4 (0.0–3.3)0.31
Light microscopy
 Sclerotic glomeruli, %4 (±8)8 (±15)c1 (±3)17 (±21)a,b,c<0.001
 Crescents, %1 (±4)3 (±9)18 (±31)a,b,d4 (±10)a<0.001
 Degree of mesangial proliferatione2 (±0.9)1.4 (±1.1)a,c2 (±0.8)1.7 (±0.9)0.01
 Degree of endocapillary proliferatione1.2 (±1.1)1.6 (±1)1.3 (±1.2)0.5 (±0.8)a,b,c<0.001
 Degree of interstitial inflammatione0.5 (±0.6)b,d0.8 (±0.6)0.6 (±0.8)1 (±1)c<0.001
 Degree of interstitial fibrosise0.3 (±0.6)0.5 (±0.6)0.3 (±0.6)0.8 (±0.9)a,c<0.001
 Degree of arteriolar sclerosise0.2 (±0.5)0.2 (±0.5)0 (±0.2)0.6 (±1)a,b,c<0.001
IFe
 C32.7 (±0.5)2.7 (±0.5)2.8 (±0.3)2.5 (±0.7)a,c0.03
 IgA0.1 (±0.4)0.7 (±0.8)a,c,d0.1 (±0.3)0.2 (±0.7)<0.001
 IgG0.4 (±0.7)d2 (±0.9)a,c,d0.5 (±0.8)1 (±1.2)<0.001
 IgM0.7 (±0.8)1.2 (±0.9)0.8 (±0.7)0.8 (±1)0.12
 C1q0.3 (±0.5)d1.6 (±0.9)a,c,d0.3 (±0.6)0.6 (±1)<0.001
 Fibrinogen0.4 (±0.8)0.6 (±0.9)0.3 (±0.8)0 (±0.1)a,b,c0.01
Electron microscopy, %
 Mesangial deposits83b,c,d524453<0.001
 Subepithelial deposits57c,d3819360.004
 Subepithelial hump-like deposits201419160.88
 Subendothelial deposits84939a,b,d66a,b<0.001
 Intramembranous granular deposits594116a,b,d41<0.001
 Intramembranous highly electron-dense ribbon-like deposits7073a,b,d0<0.001
  • Quantitative variables are expressed as mean (±SD) unless otherwise specified. Serum C3: reference 90–180 mg/dl; serum C4: reference 10–40 mg/dl; plasma SC5b-9: reference ≤400 ng/ml. IQR, interquartile range.

  • a Significantly different versus cluster 1.

  • b Significantly different versus cluster 2.

  • c Significantly different versus cluster 3.

  • d Significantly different versus cluster 4.

  • e Degrees of mesangial proliferation, endocapillary proliferation, interstitial inflammation, interstitial fibrosis, and arteriolar sclerosis as well as IF findings were graded using a scale of 0–3, including 0, trace (0.5+), 1+, 2+, and 3+.