[Validity of the Chronic Pain Grade Scale in nonspecific chronic low back pain].

Background: Higher pain grades are associated with high psychological burden and increase the risk for the persistence of chronic low back pain (CLBP).

Objectives: Previous results on the criterion validity of the Chronic Pain Grade Scale (CPGS) have been extended to the context of inpatient multidisciplinary orthopedic rehabilitation (MOR) and have been supplemented with additional psychosocial and work-related measures.

Methods: In this multicenter study, psychological, work- and pain-related outcomes were examined among 1010 individuals with nonspecific CLBP (ICD-10: M51/53/54) prior to the beginning of an inpatient MOR stratified by pain grade (I-IV). Additionally, frequency distributions of scores regarding pain-specific self-efficacy, depression, and subjective prognosis of gainful employment by pain grade in patients were investigated.

Results: The CPGS differed between all pain grades in the psychological, work- and pain-related outcomes in the expected direction. In post hoc pairwise comparisons, grade IV was significantly different from the lower grades. Patients with higher pain grades showed unfavorable levels in psychosocial parameters and more frequently scores in the clinical range than expected.

Conclusions: These results confirm the criterion validity of the CPGS. The psychosocial risk pattern observed in higher pain grades supports the importance of conducting early pain-related and psychological diagnostic assessments and implementing systematic allocation to needs-based interdisciplinary multimodal treatments.