Table 1.

Demographics and clinical phenotype

Characteristic0 mg Prednisone at 6 mo
(n=69)5 mg Prednisone at 6 mo
(n=17)>5 mg Prednisone at 6 mo
(n=61)P Valuea
Age at diagnosis (yr)56 (46, 67)71 (58, 74)63 (46, 70)0.03
Sex, female32 (46)8 (47)23 (38)0.58
Race, Caucasian50 (73)16 (94)53 (87)0.04
PR3-ANCA or cANCAb25 (36)5 (29)32 (52)0.10
Disease category
 GPA (WG)21 (30)2 (12)20 (33)0.23
 MPA30 (43)11 (65)32 (52)
 ANCA GN18 (26)4 (24)9 (15)
Organ involvement
 lung35 (51)7 (41)39 (64)0.15
 ear, nose, and throat31 (45)7 (41)28 (46)0.97
 organ systems involved (mean)3.0 (1.0, 3.0)3.0 (2.0, 3.0)3.0 (2.0, 4.0)0.22
Peak creatinine at disease onset (mg/dl)2.8 (1.6, 4.6)2.8 (1.9, 3.7)2.8 (1.4, 4.3)0.85
Follow-up (mo)30 (19, 64)31 (15, 41)26 (17, 40)0.30
Treatment
 prednisone dose at 6 mo (mg)05 (5, 5)17.5 (10.0, 30.0)<0.0001
 duration of prednisone treatment (mo)5 (4,6)15 (9, 31)13 (7, 19)<0.0001
 mean duration of prednisone treatment (mo)52020<0.0001
 methylprednisolone inductionc54 (78)11 (65)40 (66)0.22
 duration of cyclophosphamide induction (mo)6 (6, 8)6 (3, 7)7 (6, 12)0.05
  total duration of cyclophosphamide (mo)d6 (6, 10)6 (3, 12)8 (6, 12)0.13
 other immunosuppressione (mo)68 (99)
18 (0, 24)17 (100)
6 (0, 20)60 (98)
5 (0, 16)0.80
 patients taking azathioprine14 (20)5 (29)20 (33)0.27
 duration of azathioprine treatment (mo)12 (7, 26)9 (6, 32)16 (7, 28)0.70
  patients taking mycophenolate mofetil23 (33)5 (29)18 (30)0.91
  duration of mycophenolate mofetil treatment (mo)22 (6, 46)4 (3, 12)7 (1, 17)0.03
Outcomes
 relapse31 (45)13 (76)35 (57)0.27
 ESKDf7 (10)05 (8)0.53
 death6 (9)3 (18)8 (13)0.46
  • Data are expressed as n (%) or median (interquartile range). PR3, proteinase 3; cANCA, cytoplasmic anti-neutrophil cytoplasmic antibody; GPA, granulomatosis with polyangiitis; WG, Wegener’s granulomatosis; MPA, microscopic polyangiitis; ESKD, end stage kidney disease.

  • a P values were calculated by Fisher exact test for categorical variables and Kruskal–Wallis test for continuous variables. A significant P value (P<0.05) indicates at least two of the groups are statistically different, but further pair-wise comparisons were not done because the 5-mg prednisone group is so small.

  • b All patients who were not PR3-ANCA or cANCA positive were MPO-ANCA or pANCA positive with a negative antineutrophil antibody. ANCA-negative patients and patients positive for both MPO-ANCA and PR3-ANCA were excluded from this study.

  • c Methylprednisolone intravenous injection given as a part of induction therapy at least once at a dose of at least 250 mg.

  • d Total months a patient took cyclophosphamide over the reviewed course, including induction, maintenance, and relapse treatment.

  • e Total months a patient received immunosuppression therapy, not including prednisone or cyclophosphamide, including induction, maintenance, and relapse treatment.

  • f Patients with ESRD on presentation were excluded from this study.