Baseline* characteristics of the PS-matched population
| (n=number of treatment episodes) | Control group (n=235) | Prophylaxis group (n=235) | P value |
| Male gender, n (%) | 173 (73.6) | 161 (68.5) | 0.222 |
| Age, year, mean (SD) | 45.8 (16.3) | 45.5 (15.7) | 0.843 |
| Disease duration, year, mean (SD) | 3.1 (4.0) | 2.6 (3.9) | 0.200 |
| Underlying disease | |||
| Systemic lupus erythematosus, n (%) | 109 (46.4) | 112 (47.7) | 0.782 |
| Systemic sclerosis, n (%)† | 6 (2.6) | 5 (2.1) | 0.760 |
| Dermatomyositis, n (%) | 34 (14.5) | 34 (14.5) | 1.000 |
| Polymyositis, n (%) | 17 (7.2) | 10 (4.3) | 0.165 |
| GPA, n (%) | 16 (6.8) | 13 (5.5) | 0.565 |
| MPA, n (%) | 8 (3.4) | 8 (3.4) | 1.000 |
| EGPA, n (%) | 6 (2.6) | 7 (3.0) | 0.779 |
| Polyarteritis nodosa, n (%) | 7 (3.0) | 6 (2.6) | 0.779 |
| Rheumatoid arthritis, n (%)† | 9 (3.8) | 9 (3.8) | 1.000 |
| Adult-onset Still’s disease, n (%) | 2 (0.9) | 8 (3.4) | 0.106 |
| Behcet’s disease, n (%) | 11 (4.7) | 12 (5.1) | 0.831 |
| Cryoglobulinaemic vasculitis, n (%) | 1 (0.4) | 2 (0.9) | 0.562 |
| Ankylosing spondylitis, n (%) | 3 (1.3) | 0 (0.0) | 0.248 |
| Primary Sjogren’s syndrome, n (%) | 1 (0.4) | 0 (0.0) | 0.317 |
| Others, n (%)‡ | 5 (2.1) | 9 (3.8) | 0.278 |
| Initial steroid dose of 30–45 mg PD, n (%) | 70 (29.5) | 72 (30.9) | 0.747 |
| Initial steroid dose of 45–60 mg PD, n (%) | 29 (12.2) | 39 (16.7) | 0.165 |
| Initial steroid dose of ≥60 mg PD, n (%) | 138 (58.2) | 122 (52.4) | 0.201 |
| Concomitant immunosuppressive treatment | |||
| Steroid pulse treatment, n (%) | 84 (35.7) | 80 (34.0) | 0.699 |
| Oral cyclophosphamide, n (%) | 20 (8.5) | 25 (10.6) | 0.433 |
| Cyclophosphamide pulse treatment, n (%) | 54 (23.0) | 54 (23.0) | 1.000 |
| Cumulative steroid dose, mean (SD)§ | 2696.6 (2123.1) | 2898.6 (1558.8) | 0.240 |
| Lymphopenia, n (%)¶ | 73 (31.1) | 76 (32.3) | 0.766 |
*The baseline date was defined as the day on which PCP prophylaxis (prophylaxis group) or high-dose steroid (control group) was started.
†The main reason for the use of high-dose steroids in these diseases was associated interstitial lung disease.
‡Including Takayasu’s arteritis, temporal arteritis and relapsing polychondritis.
§Cumulative steroid (prednisone) dose during the previous 6 months.
¶Defined as <800 lymphocytes/mL.
EGPA, eosinophilic granulomatosis with polyangiitis; GPA, granulomatosis with polyangiitis; MPA, microscopic polyangiitis; PCP, pneumocystis pneumonia; PD, prednisone; PS, propensity score.