Table 2.
Change in Quantitative Computed Tomography Measures and Association between Continuous and Categorical Change in Quantitative Computed Tomography Measures and 2-Year Transplant-Free Survival in University of Michigan Test and University of Chicago Validation Cohorts
| University of Michigan |
University of Chicago |
|||||||
|---|---|---|---|---|---|---|---|---|
| Continuous qCT measure (%) | Mean ± SD | HR* | 95% CI | P Value | Mean ± SD | HR* | 95% CI | P Value |
| Lung volume | −0.2 ± 18.0 | 1.04 | 1.03–1.05 | <0.001 | −1.8 ± 19.7 | 1.03 | 1.01–1.05 | 0.003 |
| Vascular volume | 4.4 ± 23.4 | 1.01 | 1.00–1.02 | 0.134 | 16.2 ± 42.4 | 1.02 | 1.01–1.03 | <0.001 |
| Reticular opacity | 0.4 ± 5.8 | 1.09 | 1.06–1.12 | <0.001 | 0.0 ± 5.9 | 1.07† | 0.98–1.16 | 0.133 |
| Ground-glass opacity | −0.2 ± 15.6 | 1.02 | 1.01–1.04 | <0.001 | 3.9 ± 19.9 | 1.02 | 1.00–1.04 | 0.022 |
| Honeycombing | 0.2 ± 1.5 | 1.12 | 1.03–1.23 | 0.010 | −0.1 ± 0.7 | 1.01 | 0.43–2.35 | 0.989 |
| Categorical qCT measure (%) | “High” Strata, n (%) | HR* | 95% CI | P Value | “High” Strata, n (%) | HR* | 95% CI | P Value |
|---|---|---|---|---|---|---|---|---|
| Lung volume | 105 (30) | 3.20 | 2.07–4.94 | <0.001 | 35 (38) | 2.75 | 1.41–5.36 | 0.003 |
| Vascular volume | 286 (82) | 2.25 | 1.15–4.38 | 0.018 | 82 (89) | 0.88 | 0.31–2.47 | 0.802 |
| Reticular opacity | 45 (13) | 2.87 | 1.76–4.68 | <0.001 | 14 (15) | 1.40 | 0.58–3.36 | 0.457 |
| Ground-glass opacity | 40 (11) | 2.18 | 1.25–3.79 | 0.006 | 21 (23) | 3.40 | 1.55–7.48 | 0.002 |
| Honeycombing | 94 (27) | 1.90 | 1.24–2.92 | 0.003 | 12 (13) | 1.28 | 0.45–3.62 | 0.646 |
Definition of abbreviations: CI = confidence interval; HR = hazard ratio; qCT = quantitative computed tomography.
All models adjusted for presence of connective tissue disease, sex, race, smoking history, baseline body mass index, age, percent predicted FVC, percent predicted DlCO, and CALIPER-derived measures total lung volume, pulmonary vascular-related structure volume, percent ground-glass opacity, reticular opacity, and honeycombing. Lung volume and vascular volume (pulmonary vascular-related structure volume) are reported as relative change, whereas reticular opacity, ground-glass opacity, and honeycombing are reported as absolute change.
Per unit change in qCT measures when modeled continuously and for “high” versus “low” strata after dichotomization at the optimal threshold.
Proportional hazards assumption violated.