Fig. 2
a to d Receiver operating characteristic curves. CPGS versus STarT-G total score and PHQ-4 versus STarT-G sub-score (baseline and 12 months). CPGS = Chronic Pain Grade Scale (dichotomized: Grade 0,I and II versus Grade III and IV), STarT-G = German version of the STarT-Back Tool, PHQ4 = Patient Health Questionnaire (4 items, dichotomized: none and mild versus moderate and severe psychological distress), 12 M = at 12 months. nA = 294, nB = 294, nC = 242, nD = 243