Validation and reliability of the German version of the Chronic Pain Grade questionnaire in primary care back pain patients.

In 1992 Von Korff and his co-workers developed a simple, brief questionnaire to assess the severity of chronic pain problems, the Chronic Pain Grade (CPG). The present study was conducted to analyse the psychometric properties of the translated German version of the CPG within a population of primary care back pain patients (n=130). Factor analysis yielded two factors which accounted for 72% of the variance of the questionnaire.