Table 1.
Background characteristics of study participants
| Cohort 1 | Cohort 2 | ||
|---|---|---|---|
| Aug 2003–Sept 2009 | Oct 2009–Dec 2019 | P-value | |
| Number of patients | 807 | 2980 | |
| Age | 58 (14) | 62 (14) | <0.0001 |
| ≥65 (years) | 35.4 | 48.3 | <0.0001 |
| Sex, female (%) | 83.1 | 80.4 | 0.08 |
| RA disease backgrounds | |||
| Disease duration (month) | 71 (21, 168) | 59 (14, 145) | 0.01 |
| Stage | <0.0001 | ||
| I (%) | 14.0 | 23.8 | |
| II (%) | 41.4 | 43.9 | |
| III (%) | 20.3 | 17.7 | |
| IV (%) | 24.3 | 14.6 | |
| RF, positive (%) | 85.4 | 78.0 | <0.0001 |
| ACPA, positive (%) | 80.9 | 75.1 | 0.10 |
| Treatment of RA | |||
| b/ts-DMARDs | <0.0001 | ||
| TNF inhibitors | 700 | 1483 | |
| IL-6R inhibitors | 106 | 604 | |
| CTLA4-Ig | 0 | 630 | |
| JAK inhibitors | 0 | 263 | |
| Others | 1 | 0 | |
| Number of past b/ts-DMARDs use | 0.2 (0.5) | 0.7 (1.0) | <0.0001 |
| b/ts-DMARDs naïve (%) | 83.9 | 57.5 | <0.0001 |
| Concomitant MTX use (%) | 81.9 | 73.7 | <0.0001 |
| MTX dose (mg/week) | 8 (8, 10) | 12 (8, 16) | <0.0001 |
| Concomitant GC use (%) | 46.9 | 22.1 | <0.0001 |
| GC dose, prednisone equivalent (mg/day) | 5.0 (2.5, 5) | 5.0 (2.5, 7.5) | 0.0002 |
| RA disease activity | |||
| CRP (mg/dl) | 1.70 (0.50, 4.08) | 0.88 (0.17, 2.94) | <0.0001 |
| ESR (mm/h) | 52 (31, 77) | 44 (22, 75) | <0.0001 |
| MMP-3 (pg/ml) | 201 (101, 377) | 135 (63, 296) | <0.0001 |
| CDAI | 29.5 (14.2) | 25.4 (12.8) | <0.0001 |
| HAQ | 1.330 (0.819) | 1.314 (0.845) | 0.35 |
| Past history and comorbidity | |||
| Pneumonia (%) | 3.0 | 8.7 | <0.0001 |
| Malignancy (%) | 6.2 | 10.9 | <0.0001 |
| Fracture (%) | 6.7 | 14.4 | <0.0001 |
| Coexisting lung disease (%) | 18.2 | 27.0 | <0.0001 |
| Other clinical features | |||
| BMI (kg/m2) | 21.5 (3.5) | 22.3 (4.0) | <0.0001 |
| eGFR (ml/min/1.73m2) | 90.1 (29.1) | 81.9 (28.3) | <0.0001 |
| Alb (g/dl) | 3.7 (0.5) | 3.7 (0.6) | 0.055 |
| IgG (mg/dl) | 1575 (509) | 1510 (491) | 0.001 |
| Neutrophils (/μl) | 5300 (2200) | 4600 (2100) | <0.0001 |
| Lymphocytes (/μl) | 1300 (500) | 1400 (600) | 0.06 |
| FBS (mg/dl) | 100 (25) | 95 (20) | 0.01 |
| HbA1c (%) | 5.8 (0.9) | 5.8 (0.7) | 0.27 |
| KL-6 (U/ml) | 227 (182, 312) | 233 (174, 334) | 0.83 |
| PCP prophylaxis | |||
| Risk factors (%) | 0.004 | ||
| 0 | 237 (29.4) | 1028 (34.5) | |
| 1 | 366 (45.4) | 1146 (38.4) | |
| 2 | 165 (20.5) | 664 (22.3) | |
| 3 | 38 (4.7) | 142 (4.8) | |
| Fulfilling prophylaxis criteria (%) | 25.2 | 27.1 | 0.29 |
| PCP prophylaxis at baseline (%) | 113 (14.0) | 1512 (50.7) | <0.0001 |
| PCP onset | |||
| Number of PCP onset (%) | 13 (1.6) | 13 (0.4) | 0.004 |
| - in participants administrated prophylaxis at baseline (%) | 1 (0.9) | 7 (0.5) | 0.44 |
| - in participants receiving prophylaxis at onset (%) | 1 (0.9) | 4 (0.3) | 0.25 |
Data are mean (s.d.), median (1st IQR, 4th IQR) or %. P values by unpaired t test, Mann–Whitney U test or χ2 test. Cohort 1: subjects who did not receive strategic prophylaxis against PCP. Cohort 2: subjects who received strategic PCP prophylaxis. CDAI, clinical disease activity index. IL-6R; IL 6 receptor, CTLA4; cytotoxic lymphocyte antigen 4, JAK; janus kinase, GC; glucocorticoid, CDAI; clinical disease activity index, eGFR; estimated glomerular filtration rate. FBS; fasting blood sugar; PCP: pneumocystis pneumonia.