Table 1

Demographic, histological and clinical features at second renal biopsy and at disease outcome in patients from different groups (expressed as mean (SD) unless differently specified)

VariableOverallGroup 1
Nephritic flare
Group 2
Proteinuric flare
Group 3
lack of response
P value
Number of patients92284618
Age at second biopsy35.1 (10.6)34.7 (11.1)36.6 (10.36)31.7 (10.1)0.32
Females, n (%)80 (86.9)26 (92.9)39 (84.8)15 (83.3)0.54
Arterial hypertension, n (%)47 (51)24 (85.7)17 (36.9)6 (33.3)0.008
Proteinuria, g/24 hours4.1 (3.5)6.0 (5.1)3.75 (2.41)2.1 (1.0)0.003
SCr mg/dL1.4 (1.3)2.4 (1.7)0.8 (0.17)0.9 (0.3)<0.001
GFR ml/min/1.73 m271.9 (35)33.3 (14.1)94.8 (27.1)82.8 (30.3)<0.001
C3 mg/dL67.3 (29.3)61.8 (28.5)67.6 (28.8)75.6 (30.5)0.28
C4 mg/dL17.6 (21.3)14.7 (20.8)20.4 (24.9)15.5 (.48)0.37
Antibodies
 Anti-dsDNA in 87 pts, n (%)79 (90.8)2639140.84
 aPL in 84 pts, n (%)56 (66.7)1429130.47
 Anti-ENA in 69 pts, n (%)35 (50.7)82160.93
Prednisone dosage, mg/day8.8 (6.8)9.73 (8.07)8.68 (6.8)7.5 (4.1)0.82
Antimalarial use*, n (%)16 (21.6)8440.69
Immunosuppression†, n (%)44 (50.5)52080.053
 MMF1821240.13
 AZA112540.30
 CNI30300.84
 CYC11000.81
Class ISN/RPS2003‡, n
 I10010.15
 II30210.12
 III90630.28
 IV4221156<0.001
 V1401040.09
 Mixed2061130.91
AI4.7 (3.8)5.9 (3.7)4.5 (3.8)3.8 (3.7)0.4
CI4.0 (2.4)6.1 (2.6)2.9 (1.5)3.9 (2.2)<0.001
Time between first and second biopsy (years)6.7 (4.9)8.2 (5.1)6.9 (4.6)3.5 (4.1)<0.001
Time from repeated biopsy to end of follow-up (years)10.3 (9.8)8.9 (9.4)10.4 (9.1)12.1 (12.4)0.61
ESKD, n (%)25 (27.2)18 (60.7)6 (13)2 (11)<0.001
  • Comparison between continuous variables: one way ANOVA with Bonferroni correction; comparison between proportions: χ² test.

  • *Data available for 74 patients.

  • †Data and referred percentages are calculated 87 patients.

  • ‡Data for 89 patients.

  • eGFR glomerular filtration rate; aPL antiphospholipid antibodies; AI, activity index; ANOVA, analysis of variance; anti-dsDNA, antibodies antidouble stranded DNA; anti-ENA, antiextractable nuclear antigens antibodies; AZA, azathioprine; CI, chronicity index; CNI, calcineurin inhibitors; CYC, cyclophosphamide; ESKD, end-stage kidney disease; ISN/RPS, International Society of Nephrology/Renal Pathology Society; MMF, mycophenolate mofetil; pts, patients; SCr, serum creatinine.