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Table 5 Receiver operator curve validation of multivariable models predicting the presence of specific PFT abnormalities

From: Respiratory symptoms and disease characteristics as predictors of pulmonary function abnormalities in patients with rheumatoid arthritis: an observational cohort study

Characteristics included in model Full cohort (n = 159) Cohort excluding reported lung disease (n = 129)
  AUC 95% CIa P value AUC 95% CIa P value
Model predicting restriction       
   Pulmonary symptoms only 0.66 (0.51 to 0.81) - 0.63 (0.51 to 0.80) -
   Symptoms + other factorsb 0.79 (0.59 to 0.92) 0.046* 0.79 (0.61 to 0.92) 0.040*
Model predicting obstruction       
   Pulmonary symptoms only 0.62 (0.50 to 0.74) - 0.62 (0.51 to 0.75) -
   Symptoms + other factorsc 0.91 (0.78 to 0.98) 0.0001* 0.86 (0.75 to 0.94) 0.0005*
   Symptoms + factors + lung disease 0.96 (0.91 to 0.99) 0.080** - - -
Model predicting impaired diffusion       
   Pulmonary symptoms only 0.66 (0.58 to 0.73) - 0.66 (0.57 to 0.75) -
   Symptoms + other factorsd 0.85 (0.75 to 0.93) 0.0003* 0.85 (0.73 to 0.93) 0.001
   Symptoms + factors + lung disease 0.86 (0.74 to 0.94) 0.41** - - -
  1. PFT, pulmonary function test. a95% confidence interval (CI) obtained with repeated sampling and calculation of area under the curve (AUC) for 1,000 bootstrap resamples with replacement. bOther factors included were those from the final predictive multivariable model (body mass index and current prednisone use). cOther factors included were those from the final predictive multivariable model (gender, exercise, current smoking, body mass index, presence of rheumatoid factor, and current prednisone use). dOther factors included were those from the final predictive multivariable model (age, current smoking, body mass index, and current prednisone use). *P values represent the comparison of AUC functions for the symptoms + other factors model vs. the symptom-only model. **P values represent the comparison of AUC functions for the symptoms + factors + lung disease model vs. the symptoms + factors model.