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.

VariablesSensitivitySpecificityPositive Predictive ValueNegative Predictive Value
Entire cohort
  FVC % predicted, n = 265
    < 80 (conventional and optimal)0.690.730.860.49
  DLCO % predicted, n = 214
    < 60 (conventional)0.580.700.820.41
    < 62 (optimal)0.600.700.830.42
    < 70 (alternative)0.800.510.800.52
    < 80 (alternative)0.920.320.770.63
  Combination of PFT thresholds % predicted, n = 214
    FVC < 80 and DLCO < 600.460.810.850.38
    FVC < 80 or DLCO < 600.790.570.820.53
    FVC < 80 and DLCO < 620.490.810.860.40
    FVC < 80 or DLCO < 620.800.560.810.53
    FVC < 80 and DLCO < 650.530.780.850.41
    FVC < 80 or DLCO < 650.820.460.780.52
    FVC < 80 and DLCO < 700.610.760.860.45
    FVC < 80 or DLCO < 700.870.430.780.57
    FVC < 80 and DLCO < 800.660.730.850.47
    FVC < 80 or DLCO < 800.940.270.760.65
Autoantibody Scl-70–positive patients
  FVC < 80, n = 780.750.050.980.05
  DLCO < 60, n = 620.701.001.000.10
  FVC < 80 or DLCO < 60, n = 620.850.500.980.10
Autoantibody Scl-70–negative patients
  FVC < 80, n = 1830.630.730.780.57
  DLCO < 60, n = 1500.500.680.700.48
  FVC < 80 or DLCO < 60, n = 1500.740.570.720.60
  • FVC ≥ 80% and DLCO ≥ 60% predicted represent traditional normal cutpoints based on 95% CI in healthy population. PFT: pulmonary function test; FVC: forced vital capacity.