Relation of CTD-ILD preliminary core set instruments to aspects of OMERACT filter in CTD-ILD
| CTD-ILD | Dyspnoea | Cough | HRQoL | Lung physiology | Lung imaging | Survival | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Instruments | D-12 | MRC | LCQ | SGRQ | SF-36 | PtGA | FVC | DLCO | HRCT—overall extent of disease | All-cause mortality | Time to decline in FVC |
| Truth | |||||||||||
| Face validity | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Content validity | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Construct validity | Y | Y | NT | Y | Y | NT | Y | ± | Y | Y | NT |
| Criterion validity | NT | NT | NT | NT | NT | NT | No | No | Y | Y | NT |
| Discrimination | |||||||||||
| Discriminatory | Y | Y | NT | Y | Y | NT | ± | ± | Yes, except± for GGO | No | Y |
| Reliable | Y | Y | NT | NT | Y | NT | Y | N | Yes, except± for GGO | Y | NT |
| Reproducible | NT | NT | NT | NT | NT | NT | Y | ± | Y | N/A | NT |
| Sensitive to change | Y | Y | NT | NT | Y | NT | Y | ± | Yes but relatively slow | N/A | Y |
| Feasibility | |||||||||||
| Cost effective | Y | Y | Y | Y | Y | Y | Y | Y | Y | No* | Y |
| Interpretability | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Readily available | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Safe for patients | Y | Y | Y | Y | Y | Y | Y | Y | ± | Y | Y |
| Patient-derived content† | Y | No | No | No | No | N/A | N/A | N/A | N/A | N/A | N/A |
PtGA is adopted under HRQoL, though it is an independent instrument.
*Not cost effective as a primary efficacy endpoint but highly cost effective as a secondary endpoint to detect treatment toxicity—see text for discussion on ‘survival’
†US Food and Drug Administration advocates patient-reported instruments be developed by qualitative data supplied by patients.18 ,19
±, ambiguous; CTD-ILD, connective tissue disease associated interstitial lung disease; D-12, Dyspnea-12; DLCO, diffusion capacity of lung for carbon monoxide; FVC, forced vital capacity; GGO, ground glass opacity; HRCT, high-resolution CT; LCQ, Leicester Cough Questionnaire; MRC, Medical Research Council Dyspnea Scale; N/A, not applicable; NT, not yet tested; OMERACT, Outcome Measures in Rheumatology; PtGA, Patient Global Disease Activity; SGRQ, St George's Respiratory Questionnaire; SF-36, Short Form 36; Y, yes.