Baseline mean (SD) physiologic and quality-of-life measurements in four subgroups based on disease severity at the time of diagnosis and the length of total diagnostic delay
| Moderate-to-severe disease at diagnosis (FVC≤80% predicted) | Mild disease at diagnosis (FVC>80% predicted) | |||||
| Diagnostic delay<1 year (N=29) | Diagnostic delay>1 year (N=58) | P value | Diagnostic delay<1 year (N=47) | Diagnostic delay>1 year (N=126) | P value | |
| FVC (% predicted) | 69.55 (7.17) | 68.34 (9.11) | 0.53 | 104.43 (16.46) | 98.19 (12.82) | <0.01 |
| DLCO (% predicted) | 47.19 (11.10) | 51.12 (14.59) | 0.22 | 54.40 (14.50) | 52.86 (12.67) | 0.50 |
| 6MWT distance (m) | 425.40 (116.53) | 434.68 (107.12) | 0.73 | 433.48 (119.36) | 447.59 (102.86) | 0.47 |
| SpO2 after 6MWT* | 83.88 (11.67) | 86.81 (6.80) | 0.17 | 90.60 (5.41) | 89.04 (6.38) | 0.16 |
| SGRQ, total score | 53.22 (16.72) | 51.72 (17.62) | 0.80 | 40.91 (14.63) | 49.33 (17.65) | 0.03 |
| SGRQ-Ider, total score | 50.29 (18.34) | 47.01 (21.99) | 0.63 | 34.37 (19.97) | 45.41 (22.26) | 0.02 |
| CAT, total score | 16.78 (6.46) | 17.02 (7.14) | 0.88 | 14.07 (7.46) | 16.08 (6.75) | 0.11 |
| CAT, dyspnoea score | 3.75 (1.46) | 3.68 (1.26) | 0.83 | 2.72 (1.69) | 3.35 (1.43) | 0.02 |
| CAT, cough score | 2.79 (1.29) | 2.42 (1.12) | 0.18 | 2.26 (1.31) | 2.42 (1.24) | 0.48 |
P values based on univariate analysis.
*On room air.
CAT, COPD assessment test; DLCO, diffusing capacity for carbon monoxide; FVC, forced vital capacity; 6MWT, six min walk test; SGRQ, St. George’s Respiratory Questionnaire; SGRQ-Ider, IPF-specific SGRQ, derived from the original SGRQ; SpO2, peripheral capillary oxygen saturation.