Does a combination of self-reported signs related to central sensitization and pressure pain threshold allow for a more detailed classification of pain-related characteristics in patients with chronic musculoskeletal pain?: A cross-sectional study.

OBJECTIVES

The clinical utility of combining the central sensitization (CS) inventory (CSI) with the pressure pain threshold (PPT) in assessing the effect of central sensitization on pain is unknown. This study aimed to investigate the effects of CSI, PPT, and their interaction on pain and the characteristics of clinical symptoms in patients with chronic musculoskeletal pain grouped according to the CSI score and PPT value.

METHOD

A total of 187 participants with chronic musculoskeletal pain were recruited. PPT, brief pain inventory, widespread pain index, pain catastrophizing scale, EuroQol-5 dimension, and CSI were assessed. Multiple regression analyses were performed using pain intensity and interference scores as dependent variables and the CSI score and PPT value as independent variables. Hierarchical cluster analysis was also performed to classify the participants into subgroups according to the CSI score and PPT value. Following the classification, pain-related characteristics and health-related QOL were compared among the subgroups.

RESULTS

Multiple regression analyses demonstrated that only the CSI score significantly affected pain intensity and interference. As a result of the cluster analysis, three groups were identified: cluster 1 (n = 61, CSI low/PPT low group), cluster 2 (n = 78, CSI low/PPT high group), and cluster 3 (n = 48, CSI high/PPT low group). The CSI high/PPT low group had a higher incidence of pain-related symptoms than the CSI low group regardless of the PPT value.

CONCLUSIONS

Combined CSI and PPT may not fully allow a detailed classification of pain-related characteristics. The CSI may be clinically more useful for assessing the effect of CS on pain-related symptoms.