Table 1

Comparison of characteristics between ANCA-associated vasculitis patients with and without osteonecrosis of the femoral head

Total (n=186)†ONFH – (n=153)ONFH + (n=33)P value*
Age of onset, median (IQR), y70.5 (63.9–76.0)71.1 (64.6–76.3)68.7 (61.4–72.6)0.133
Female, n (%)122 (65.6)98 (64.1)24 (72.7)0.341
Body weight, mean±SD, kg55.0±11.155.0±11.054.8±11.70.896
BMI, median (IQR), kg/m221.6 (19.6–23.8)21.6 (19.6–23.8)21.8 (19.5–24.4)0.829
Alcohol (ethanol intake ≥320 g/week), n (%)‡19 (10.2)17 (11.1)2 (6.1)0.385
History of smoking, n (%)59 (31.7)48 (31.4)11 (33.3)0.826
Diagnosis, n (%)
 MPA123 (66.1)103 (67.3)20 (60.6)0.435
 GPA32 (17.2)27 (17.6)5 (15.2)
 EGPA31 (16.7)23 (15.0)8 (24.2)
BVAS domain, n (%)
 General135 (72.6)114 (74.5)21 (63.6)0.204
 Cutaneous35 (18.8)31 (20.3)4 (12.1)0.278
 Mucous membranes/eyes18 (9.7)17 (11.1)1 (3.0)0.154
 Ear/nose/throat53 (28.5)46 (30.1)7 (21.2)0.307
 Respiratory129 (69.4)108 (70.6)21 (63.6)0.432
 Cardiovascular10 (5.4)8 (5.3)2 (6.1)0.848
 Abdominal4 (2.2)4 (2.6)0 (0)0.348
 Renal107 (57.5)92 (60.1)15 (45.5)0.122
 Nervous system75 (40.3)63 (41.2)12 (36.4)0.609
BVAS, median (IQR)16 (10–20)16 (12–20)14 (6–19)0.070
ANCA positivity, n (%)
 MPO-ANCA147 (79.0)124 (81.0)23 (69.7)0.146
 PR3-ANCA24 (12.9)20 (13.1)4 (12.1)0.883
eGFR, median (IQR), mL/min67.1 (42.8–88.7)67 (43–87)69 (48–95)0.409
CRP, median (IQR), mg/dL8.0 (2.4–13.0)8.1 (3.1–12.9)6.1 (0.9–13.4)0.389
aPL positivity, n (%)31 (18.6)
/n=167
25 (18.1)
/n=138
6 (20.7)
/n=29
0.746
Induction treatments
 Methylprednisolone pulse, n (%)35 (18.8)26 (17.0)9 (27.3)0.171
 Initial prednisolone dose, median (IQR), mg/day40 (30–50)40 (30–50)40 (33–50)0.694
 Prednisolone dose on day 90, median (IQR), mg/day15 (13–20)
/n=183
15 (12.5–20)
/n=150
20 (15–25)
/n=33
0.009
 Cumulative prednisolone dose§ on day 90, median (IQR), mg2700
(1933–3725)
/n=183
2628
(1833–3532)
/n=150
2767
(2204–4879)
/n=33
0.192
 Rituximab, n (%)85 (45.7)76 (49.7)9 (27.3)0.019
 Cyclophosphamide, n (%)61 (32.8)47 (30.7)14 (42.4)0.194
Osteoporosis treatment, n (%)173 (93.0)141 (92.2)32 (97.0)0.325
 Bisphosphonates, n (%)133 (71.5)106 (69.3)27 (81.8)0.202
 Denosumab, n (%)12 (6.5)11 (7.2)1 (3.0)0.696
 Vitamin D/Ca, n (%)65 (34.9)55 (35.9)10 (30.3)0.688
Comorbidities
 Hypertension, n (%)49 (26.3)41 (26.8)8 (24.2)0.763
 Dyslipidaemia, n (%)114 (61.3)93 (60.8)21 (63.6)0.760
 Diabetes mellitus, n (%)34 (18.5)30 (19.6)4 (12.1)0.313
 Atrial fibrillation, n (%)10 (5.4)8 (5.2)2 (6.1)0.848
 Malignancy, n (%)11 (5.9)10 (6.5)1 (3.0)0.439
  • *P values were calculated with χ2 test, Fisher’s exact test or Mann-Whitney U test. P values <0.05 were considered significant.

  • †This study was conducted on 186 patients, unless otherwise noted.

  • ‡Ethanol intake of more than 320 g/week was defined as a risk factor for ONFH.19

  • §Methylprednisolone and other glucocorticoids were converted to an equivalent dose of prednisolone and included in the cumulative prednisolone dose.

  • ANCA, antineutrophil cytoplasmic antibody; aPL, antiphospholipid antibodies; BMI, body mass index; BVAS, Birmingham Vasculitis Activity Score; CRP, C reactive protein level; eGFR, estimated glomerular filtration rate; EGPA, eosinophilic GPA; GPA, granulomatosis with polyangiitis; MPA, microscopic polyangiitis; MPO, myeloperoxidase; ONFH, osteonecrosis of the femoral head; PR3, proteinase 3.