Table 1.
Baseline characteristics in the entire cohort and in the matched cohort
| Entire cohort | Matched cohort | |||||
|---|---|---|---|---|---|---|
| PDN group | Non-PDN group | P-value | PDN group | Non-PDN group | P-value | |
| n = 107 | n = 37 | n = 30 | n = 30 | |||
| Age, years | 64 [58–69] | 69 [61–73] | 0.016 | 65 [59–72] | 69 [61–72] | 0.452 |
| Sex, male | 63 (59%) | 23 (62%) | 0.876 | 15 (50%) | 18 (60%) | 0.505 |
| Body weight, kg | 57 [49–68] | 58 [49–69] | 0.703 | 56 [47–69] | 59 [47–70] | 0.365 |
| Smoking, pack years | 7 [0–38] | 20 [0–47] | 0.575 | 10 [0–30] | 16 [0–34] | 0.696 |
| Ever smoked | 55 (51%) | 21 (57%) | 0.145 | 17 (57%) | 17 (57%) | 0.999 |
| FVC, ml | 1890 (640) | 2280 (740) | 0.003 | 2260 (700) | 2180 (740) | 0.484 |
| %FVC, %predicted | 58.2 (14.2) | 71.0 (15.0) | < 0.001 | 71.5 (13.2) | 67.6 (14.0) | 0.217 |
| < 50% | 31 (29%) | 3 (8%) | 0.012 | 1 (3%) | 3 (10%) | 0.617 |
| %FVC decline, %predicted | ||||||
| 12 months before registration | 13.3 (9.5) | 5.2 (5.7) | < 0.001 | 12.0 (6.2) | 5.0 (5.3) | < 0.001 |
| FEV1, ml | 1630 (530) | 1910 (580) | 0.007 | 1880 (580) | 1820 (560) | 0.565 |
| %FEV1, %predicted | 64.0 (14.2) | 77.4 (14.2) | < 0.001 | 76.3 (11.7) | 73.7 (12.2) | 0.270 |
| DLco, % | 44.5 (18.2) | 56.2 (23.7) | 0.005 | 56.7 (14.7) | 54.3 (25.6) | 0.658 |
| Serum KL-6, U/mL | 1540 [1100–2590] | 1070 [740–1590] | 0.004 | 1420 [980–1960] | 1070 [750–1860] | 0.589 |
| Serum SP-D, ng/mL | 276 [176–437] | 243 [180–317] | 0.171 | 225 [130340] | 260 [200–340] | 0.424 |
| BAL lymphocyte, % | 17 [8–39] | 16 [5–39] | 0.546 | 22.9 [10.9–41.5] | 20.5 [5.5–29.8] | 0.520 |
| Antigen† | ||||||
| Bird-related | 78 (73%) | 31 (84%) | 0.495 | 24 (80%) | 24 (80%) | 0.999 |
| Home-related | 14 (13%) | 3 (8%) | 3 (10%) | 3 (10%) | ||
| Unknown | 15 (14%) | 3 (8%) | 3 (10%) | 3 (10%) | ||
| Treatment | ||||||
| Anti-fibrotic agent | 14 (13%) | 8 (22%) | 0.288 | 3 (10%) | 7 (23%) | 0.149 |
| PFD 11, NTD 3 | PFD 4, NTD 4 | PFD 1, NTD 2 | PFD 3, NTD 4 | |||
| Immunosuppressant | 49 (46%) | 0 | – | 10 (33%) | 0 | – |
| CYA 33, CYC 5, TAC 11 | CYC 5, CyA 4, TAC 1 | |||||
Values are given as the number (percentage), mean (SD), or median [25th and 75th percentiles]. P-values were obtained from a two-sided Mann–Whitney U test, a chi-square test, or Fisher’s exact test for the comparison between the PDN group and the non-PDN group in the entire cohort. P-values were obtained from McNemar’s test, the Wilcoxon signed-rank test, a paired t-test, or Fisher’s exact test for the comparison between the PDN group and the non-PDN group in the matched cohort. BAL bronchoalveolar lavage; BW body weight; CyA cyclosporine A; CYC cyclophosphamide; DLco diffusion capacity of the lungs for carbon monoxide; FEV1 forced expiratory volume in one second; FVC forced vital capacity; HP hypersensitivity pneumonitis; KL-6 Krebs von den Lungen-6; NTD nintedanib; PDN prednisolone; PFD pirfenidone; SD standard deviation; SP-D surfactant protein-D; TAC tacrolimus
†The causative antigens were deemed bird-related when an inhalation test using an avian antigen and/or test for a serum antibody to an avian antigen was positive or home-related when an environmental challenge test or test for a serum anti-Trichosporon asahii antibody was positive