Prevalence and Association of Neuropathic Pain and Central Sensitization in Participants with Knee Osteoarthritis: Establishing a Cutoff Score for the Central Sensitization Inventory

Objective: This study examined the prevalence of Neuropathic pain (NP) and its association with central sensitization (CS) among individuals with symptomatic knee osteoarthritis (OA). Methods: A cross-sectional study was conducted in Saudi Arabia and included participants from community service centers and hospitals who aged ≥45 years and diagnosed with knee OA according to National Institute for Health and Care Excellence (NICE) criteria. Exclusion criteria included language barriers, inability to walk or stand independently, and pregnancy. NP was measured using the Arabic version of painDETECT questionnaire, and CS was measured using the central sensitization inventory (CSI). Multivariable logistic regression was performed to examine associations between CSI scores and NP, and Receiver Operator Characteristics analysis was used to determine an optimal cutoff score for CSI that was associated with NP. Results: This study included a total of 155 participants with knee OA, 11% (n=17) were classified as having NP. After excluding 30 participants with unclear NP classification, 125 participants were included in the final analysis. Increased CSI scores was independently associated with increased odds of NP (OR = 1.10; 95% CI: 1.05–1.15) after adjusting for age, sex, body mass index, and employment status. A cutoff score of ≥26 for CSI was identified participants with NP, with 94% sensitivity and 63% specificity. Conclusion: CS was associated with the presence of NP in individuals with knee OA. A cutoff score of ≥26 for CSI demonstrated a high sensitivity in predicting NP in people with knee OA, suggesting its utility as an effective screening tool for guiding an appropriate intervention and measuring response to treatment in this population.