Table 2.
Performance of pulmonary function test thresholds for prevalent radiographic interstitial lung disease on chest high-resolution computed tomography images in patients with systemic sclerosis
| Sensitivity | Specificity | Positive Predictive Value | Negative Predictive Value | |
|---|---|---|---|---|
| Entire cohort | ||||
| FVC % predicted (n=265) | ||||
| <80 (conventional and optimal) | 0.69 | 0.73 | 0.86 | 0.49 |
| DLCO % predicted (n=214) | ||||
| <60 (conventional) | 0.58 | 0.70 | 0.82 | 0.41 |
| <62 (optimal) | 0.60 | 0.70 | 0.83 | 0.42 |
| <70 (alternative) | 0.80 | 0.51 | 0.80 | 0.52 |
| <80 (alternative) | 0.92 | 0.32 | 0.77 | 0.63 |
| Combination of PFT thresholds % predicted (n=214) | ||||
| FVC <80 and DLCO <60 | 0.46 | 0.81 | 0.85 | 0.38 |
| FVC <80 or DLCO <60 | 0.79 | 0.57 | 0.82 | 0.53 |
| FVC <80 and DLCO <62 | 0.49 | 0.81 | 0.86 | 0.40 |
| FVC <80 or DLCO <62 | 0.80 | 0.56 | 0.81 | 0.53 |
| FVC <80 and DLCO <65 | 0.53 | 0.78 | 0.85 | 0.41 |
| FVC <80 or DLCO <65 | 0.82 | 0.46 | 0.78 | 0.52 |
| FVC <80 and DLCO <70 | 0.61 | 0.76 | 0.86 | 0.45 |
| FVC <80 or DLCO <70 | 0.87 | 0.43 | 0.78 | 0.57 |
| FVC <80 and DLCO <80 | 0.66 | 0.73 | 0.85 | 0.47 |
| FVC <80 or DLCO <80 | 0.94 | 0.27 | 0.76 | 0.65 |
| Autoantibody Scl-70 positive patients | ||||
| FVC <80 (n=78) | 0.75 | 0.05 | 0.98 | 0.05 |
| DLCO <60 (n=62) | 0.70 | 1.00 | 1.00 | 0.10 |
| FVC <80 or DLCO <60 (n=62) | 0.85 | 0.50 | 0.98 | 0.10 |
| Autoantibody Scl-70 negative patients | ||||
| FVC <80 (n=183) | 0.63 | 0.73 | 0.78 | 0.57 |
| DLCO <60 (n=150) | 0.50 | 0.68 | 0.70 | 0.48 |
| FVC <80 or DLCO <60 (n=150) | 0.74 | 0.57 | 0.72 | 0.60 |
PFT = pulmonary function test; FVC = forced vital capacity; DLCO = diffusing capacity of the lung for carbon monoxide. FVC ≥80% and DLCO ≥60% predicted represent traditional normal cut points based on 95% confidence interval in healthy population.