Table 3– Additional bivariate predictors of mortality and disease progression in unclassifiable interstitial lung disease (ILD): impact of multidisciplinary evaluation and reasons for an unclassifiable diagnosis.
VariablePatients nMortalityDisease progression#
HR (95% CI)p-valueOR (95% CI)p-value
Differential diagnoses includes
 Hypersensitivity pneumonitis911.13 (0.54–2.33)0.750.84 (0.28 to 2.53)0.75
 Idiopathic pulmonary fibrosis865.49 (1.91–15.74)0.0024.04 (1.28 to 12.75)0.02
 Nonspecific interstitial pneumonia551.08 (0.55–2.15)0.820.97 (0.35 to 2.69)0.95
 Connective tissue ILD430.71 (0.34–1.50)0.381.01 (0.34 to 2.99)0.99
Reasons for unclassifiable ILD
 Too old or frail for lung biopsy683.22 (1.48–6.97)0.0032.39 (0.85–6.70)0.10
 Conflicting clinical, radiological and pathological data240.53 (0.19–1.51)0.230.38 (0.12–1.21)0.10
 Mild or stable disease120.25 (0.03–1.85)0.180.28 (0.03–2.85)0.28
 Insufficient tissue on lung biopsy110.46 (0.06–3.39)0.452.90 (0.28–29.53)0.37
 Declined biopsy100.34 (0.05–2.52)0.291.87 (0.16–21.74)0.62
  • Hazard ratio (HR) and odds ratios (OR) are shown for the bivariate (unadjusted) relationship of each variable with the stated outcome. #: Disease progression was defined as any of the following within 12 months of the visit to the University of California San Francisco ILD Clinic: ≥10% decline in forced vital capacity, ≥15% decline in the diffusing capacity of the lung for carbon monoxide, lung transplantation, or death due to any cause (this was only assessable in a subgroup of patients with complete follow-up data: n = 66). : All patients with unclassifiable ILD had up to three suspected diagnoses recorded prospectively during multidisciplinary discussion as a “differential diagnosis”.