Table 2.

Differences between single- and double-positive patients

VariableSingle Positivea (n=53)Double Positivea (n=35)P Value
Age, yr47±1959±170.003
Males27 (51)19 (54)0.76
Lung involvementb15 (28)13 (39)0.29
Serum creatinine at presentation, mg/dl7.2 (3.5–10.0)7.2 (3.9–10.1)0.92
Dialysis dependent at presentation32 (60)20 (57)0.76
Year of diagnosis0.11
 1986–200012 (23)15 (43)
 2001–200620 (38)8 (23)
 2007–201521 (39)12 (34)
ESRD at end of follow-up36 (68)25 (71)0.73
Histopathologic class0.03
 Focal7 (13)4 (11)
 Crescentic37 (70)18 (51)
 Mixed9 (17)8 (23)
 Sclerotic0 (0)5 (14)
Normal glomeruli, percentagec0 (0–26)0 (0–13)0.40
Cellular crescents, percentagec61±3258±320.63
Sclerotic glomeruli, percentagec2 (0–16)13 (0–28)0.07
Interstitial fibrosis and tubular atrophyc0.07
 0–136 (72)18 (53)
 2–314 (28)16 (47)
Interstitial infiltratec0.10
 0–122 (44)9 (27)
 2–328 (56)25 (73)
Tubulitisc0.20
 018 (36)17 (50)
 132 (64)17 (50)
Intensive treatmentd34 (71)14 (45)0.02
Maintenance therapy with azathioprine or mycophenolate mofetile7 (14)13 (38)0.01
  • Data are presented as numbers (%), means±SD, or medians (interquartile range).

  • a Single-positive patients were positive for serum anti-glomerular basement membrane (anti-GBM) antibodies and negative for ANCA. Double-positive patients were positive for anti-GBM antibodies and positive for ANCA.

  • b Total, n=86 patients.

  • c Total, n=84 patients.

  • d Intensive treatment consisted of at least seven plasma exchanges, corticosteroids, and cyclophosphamide, mycophenolate mofetil, or rituximab. Excluding patients without intensive treatment and relatively preserved renal function at presentation. Total, n=79 patients.

  • e The minimal duration of maintenance therapy was 3 months. Total, n=84 patients.