Mibu A1, Nishigami T2, Tanaka K3, Manfuku M4, Yono S3
1Konan Women’'s University, Physical Therapy, Kobe, Japan, 2Konan Women's University, Kobe, Japan, 3Tanabe Orhopaedics, Osaka, Japan, 4Breast Care Sensyu Clinic, Kishiwada, Japan
Background: Chronic musculoskeletal pain is a complex phenomenon that involves various contributing factors, including structural and functional abnormality, psychosocial factors, and peripheral/central sensitization. Among these, central sensitization (CS), defined as increased responsiveness of nociceptive neurons in the central nervous system to normal or subthreshold afferent input, may be responsible for hypersensitivity. Hypersensitivity includes mechanical hyperalgesia, allodynia, and/or referred pain, which is often present in chronic musculoskeletal disorders, such as osteoarthritis, low back pain, and rheumatoid arthritis. Although CS is a shared pain mechanism in musculoskeletal pain, the disease-specific characteristics of CS have not been clarified.
Purpose: The purpose of this study was to investigate differences in the effects of CS on pain-related symptoms between patients with chronic low back pain (CLBP) and those with knee osteoarthritis (KOA).
Methods: Seventy-nine subjects with CLBP (57 women; age: 57.4 ± 14.8 years) and 46 subjects with KOA (41 women; age: 66.7 ± 7.7 years) were recruited for this study. Pain intensity and pain interference (Brief Pain Inventory [BPI]), health-related quality of life (QoL) (EuroQoL 5-dimension [EQ5D]), and CS (Central Sensitization Inventory [CSI]) were evaluated for all participants. BPI, EQ5D, and CSI scores were compared between the groups using Mann-Whitney U tests. Correlations between the CSI score, BPI, and EQ5D were investigated using Spearman's correlation coefficients for each group. Furthermore, we used the receiver operating characteristic curve for the CSI score to calculate the area under the curve (AUC) and cut-off points in order to discriminate pain interference in each group. The reference standard cases were set by the median partitioning of the BPI-pain interference score. The significance level was set at p 0.05 for all statistical analyses. Bonferroni's correction was applied to correlation analyses, resulting in a significance level of p 0.017.
Results: CSI scores were significantly higher for the CLBP group than for the KOA group (CLBP: 25.9 ± 12.4; KOA: 17.1 ± 9.3; p 0.01). The CSI score was significantly correlated with BPI-pain interference score (CLBP: ρ = 0.34, p 0.01; KOA: ρ = 0.53, p 0.001) and EQ5D score (CLBP: ρ = −0.37, p 0.001; KOA: ρ = −0.54, p 0.0001) for both groups. Significant correlation between the CSI score and BPI-pain intensity score was found only in the CLBP group. The AUCs were 0.71 for CLBP and 0.77 for KOA. The CSI score cut-off points were 38 for the CLBP group (sensitivity = 0.37, specificity = 0.97) and 17 for the KOA group (sensitivity = 0.81, specificity = 0.70).
Conclusion(s): Our results showed that CS was associated with pain-related symptoms in both the CLBP group and KOA group. However, there was a difference in the CSI score cut-off point between groups. These results suggest that the impact of CS on pain-related symptoms differ between CLBP and KOA.
Implications: When the CSI is used to estimate the influence of CS on pain-related symptoms, we should consider the difference in cut-off points between patient groups.
Keywords: Central sensitization, Chronic low back pain, Knee osteoarthritis
Funding acknowledgements: This study was financially supported by Eli Lilly Japan.
Purpose: The purpose of this study was to investigate differences in the effects of CS on pain-related symptoms between patients with chronic low back pain (CLBP) and those with knee osteoarthritis (KOA).
Methods: Seventy-nine subjects with CLBP (57 women; age: 57.4 ± 14.8 years) and 46 subjects with KOA (41 women; age: 66.7 ± 7.7 years) were recruited for this study. Pain intensity and pain interference (Brief Pain Inventory [BPI]), health-related quality of life (QoL) (EuroQoL 5-dimension [EQ5D]), and CS (Central Sensitization Inventory [CSI]) were evaluated for all participants. BPI, EQ5D, and CSI scores were compared between the groups using Mann-Whitney U tests. Correlations between the CSI score, BPI, and EQ5D were investigated using Spearman's correlation coefficients for each group. Furthermore, we used the receiver operating characteristic curve for the CSI score to calculate the area under the curve (AUC) and cut-off points in order to discriminate pain interference in each group. The reference standard cases were set by the median partitioning of the BPI-pain interference score. The significance level was set at p 0.05 for all statistical analyses. Bonferroni's correction was applied to correlation analyses, resulting in a significance level of p 0.017.
Results: CSI scores were significantly higher for the CLBP group than for the KOA group (CLBP: 25.9 ± 12.4; KOA: 17.1 ± 9.3; p 0.01). The CSI score was significantly correlated with BPI-pain interference score (CLBP: ρ = 0.34, p 0.01; KOA: ρ = 0.53, p 0.001) and EQ5D score (CLBP: ρ = −0.37, p 0.001; KOA: ρ = −0.54, p 0.0001) for both groups. Significant correlation between the CSI score and BPI-pain intensity score was found only in the CLBP group. The AUCs were 0.71 for CLBP and 0.77 for KOA. The CSI score cut-off points were 38 for the CLBP group (sensitivity = 0.37, specificity = 0.97) and 17 for the KOA group (sensitivity = 0.81, specificity = 0.70).
Conclusion(s): Our results showed that CS was associated with pain-related symptoms in both the CLBP group and KOA group. However, there was a difference in the CSI score cut-off point between groups. These results suggest that the impact of CS on pain-related symptoms differ between CLBP and KOA.
Implications: When the CSI is used to estimate the influence of CS on pain-related symptoms, we should consider the difference in cut-off points between patient groups.
Keywords: Central sensitization, Chronic low back pain, Knee osteoarthritis
Funding acknowledgements: This study was financially supported by Eli Lilly Japan.
Topic: Pain & pain management; Musculoskeletal
Ethics approval required: Yes
Institution: Konan women's University
Ethics committee: Institutional ethics committee of Konan Women's University
Ethics number: 218011
All authors, affiliations and abstracts have been published as submitted.
