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Table 6 Sub-analysis of patients who all received a pulmonary HRCT. Baseline characteristics and sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR−), and area under the curve (AUC) for different diagnostic procedures in the detection of lung involvement in IRD patients with ILD

From: Assessing the diagnostic value of a potential screening tool for detecting early interstitial lung disease at the onset of inflammatory rheumatic diseases

Variable ILD group, number (%) Non-ILD group, number (%) Difference AUC
Number 38 (50.0%) 38 (50.0%)   
Age 59.7 ± 15.0 years 53.2 ± 14.7 years t(74) = 1.91,P = 0.060  
PFT 37 (97.4%) 37 (97.4%) χ2(1) = 0.000,P = 1.000  
Median ± SD
 DLCO 57.8 ± 19.3% 76.0 ± 19.7% t(71) = 3.99,P < 0.001 0.745 (0.633–0.857; P < 0.001)
DLCO < 80%: sensitivity = 86.5%, specificity = 36.1%, LR+ = 1.35, LR− = 0.37
 TLC 82.7 ± 20.8% 97.4 ± 12.9% t(51.1) = 3.49,P = 0.001 0.724 (0.598–0.849; P = 0.002)
TLC < 80%: sensitivity = 39.4%, specificity = 94.1%, LR+ = 6.70, LR− = 0.64
 FVC 78.9 ± 22.2% 91.3 ± 16.4% t(64.5) = 2.70,P = 0.009 0.667 (0.539–0.794; P = 0.014)
FVC < 80%: sensitivity = 55.6%, specificity = 78.5%, LR+ = 2.57, LR− = 0.57
 FEV1 80.5 ± 23.5% 91.1 ± 14.3% t(55.5) = 2.30,P = 0.025 0.649 (0.517–0.782; P = 0.029)
FEV1 < 80%: sensitivity = 54.3%, specificity = 78.4%, LR+ = 2.51, LR− = 0.58
 TLCO 74.6 ± 18.5% 82.8 ± 17.4% t(97) = 1.93,P = 0.058 0.615 (0.485–0.746; P = 0.095)
TLCO < 80%: sensitivity = 60.0%, specificity = 55.6%, LR+ = 1.35, LR− = 0.72
Chest X-ray 29 (76.3%) 29 (76.3%) χ2(1) = 0.000,P = 1.000  
Sensitivity = 72.4%, specificity = 58.6%, LR+ = 1.75, LR− = 0.47
HRCT 38 (100.0%) 38 (100.0%) χ2(1) = 0.000,P = 1.000  
Sensitivity = 100.0%, specificity = 52.6%, LR+ = 2.11, LR− = < 0.01
Combination of chest X-ray and/or
 DLCO < 80% Sensitivity = 89.5%, specificity = 26.3%, LR+ = 1.21, LR− = 0.40
 DLCO < 70% Sensitivity = 84.2%, specificity = 50.0%, LR+ = 1.68, LR− = 0.32
 FVC < 80% Sensitivity = 78.9%, specificity = 57.9%, LR+ = 1.88, LR− = 0.36
 FVC < 70% Sensitivity = 71.1%, specificity = 65.8%, LR+ = 2.08, LR− = 0.44
Combination of the following:
1. DLCO < 80% and/or chest X-ray and
2. HRCT
Sensitivity = 89.5%, specificity = 65.8%, LR+ = 2.62, LR− = 0.16
  1. DLCO Diffusing capacity for carbon monoxide, FEV1 Forced expiratory volume in 1 s, FVC Forced vital capacity, HRCT High-resolution computed tomography, LR Likelihood ratio, PFT Pulmonary function tests, TLC Total lung capacity, TLCO Transfer factor of the lung for carbon monoxide