Table 4.
Known group validity.
| Measure | FVC > 75% (n = 89) mean (SD) | FVC ≤ 75% (n = 76) mean (SD) | Mean difference (95% CI) | p-value |
|---|---|---|---|---|
| SGRQ | 37.82 (18.13) | 46.68 (18.16) | 8.86 (3.20,14.53) | 0.002 |
| EQ-5D | 0.74 (0.18) | 0.64 (0.22) | −0.10 (−0.16,-0.03) | 0.003 |
| MRC | 2.38 (1.03) | 2.93 (0.87) | 0.55 (0.24,0.86) | <0.001 |
| HADS | 9.83 (7.90) | 11.41 (6.50) | 1.58 (−0.75,3.91) | 0.18 |
| K-BILD | 58.87 (14.31) | 52.19 (12.21) | −6.68 (−10.94,-2.41) | 0.002 |
| UCSD | 31.41 (25.07) | 41.02 (26.28) | 9.61 (0.81,18.42) | 0.033 |
| SGRQ-I | 39.16 (21.84) | 47.37 (21.35) | 8.21 (1.46,14.96) | 0.017 |
A comparison between those with a forced vital capacity (FVC) greater than or equal or less than 75% predicted for EQ-5D-5 L: EQ-5D: EuroQol five Dimension, HADS: hospital anxiety and depression scale, K-BILD: King’s Brief Interstitial Lung Disease Questionnaire, mMRC: Medical Research Council dyspnea score, SGRQ: St George’s Respiratory Questionnaire, SGRQ-I, St George’s Respiratory Questionnaire–interstitial lung disease, UCSD-SOBQ: University of California, San Diego shortness of breath questionnaire. All questionnaires other than UCSD-SOBQ were able to distinguish between subgroups. N: number of participants.