Fig. 1

Schematic representation of the four different diagnostic methods used to evaluate HMGB1 levels for AE-IPF diagnosis. The symbols show the HMGB1 level during the AE phase (●) and the HMGB1 level during the stable phase (○). Patients with and without AE separately were connected. The arrow with the solid line shows the diagnostic value of the AE phase and the arrow with the dotted line shows the diagnostic value of the stable phase. (A) Test-1. Diagnosis comparing the HMGB1 levels of AE and stable phases ignoring the intra- and inter-patient variations. (B) Test-2. Diagnosis by the difference from the baseline HMGB1 level shown by the two dot chain lines. The lengths of red and blue lines were compared. (C) Test-3. Diagnosis by the difference between the levels of the consecutive HMGB1 measurements. Lengths of red and blue lines were compared. (D) Test-4. Diagnosis by comparing the differences from the mean HMGB1 levels of three or more measurements during stable phase, shown by horizontal dashed lines. Lengths of red and blue lines were compared. HMGB1: high-mobility group box 1; AE: acute exacerbation.