Association Between Plasma Beta-endorphin and WOMAC Score in Female Patients with Knee Osteoarthritis

Abstract

BACKGROUND: β-endorphin plays a role in the descending pain control in the central nervous system. Central sensitization may be involved in the generating and maintenance of osteoarthritis (OA) pain. However, the correlation between β-endorphin and pain severity in OA has shown conflicting results. The aim of this study was to investigate the association between plasma β-endorphin and the severity of the disease. METHODS: This study was an observational cross-sectional study carried out on 60 female subjects with knee OA who fulfilled the inclusion criteria. Plasma β-endorphin was measured by a commercial enzyme-linked immunosorbent assay (ELISA) kit. Osteoarthritis knees were classified by the Kellegren-Lawrence (KL) grading (1-4) criteria. The Western Ontario McMaster University Osteoarthritis (WOMAC) scoring method was used to assess self-reported physical function, pain and stiffness. RESULTS: The mean of the participants' ages was 58 years old, ranging from 42 to 83 years. Overall, more than 70% of the participants were overweight with a mean of body mass index (BMI) of 27.59. More than 54% of the participants were diagnosed of having KL grading 3 or 4. Plasma β-endorphin was correlated inversely with the WOMAC subscale of stiffness (r=-0.286, p=0.0311), but no correlation was noted with the WOMAC subscale of pain and physical activity. There was no significant difference of the mean of plasma β-endorphin among the KL gradings. CONCLUSIONS: Plasma β-endorphin is associated with better WOMAC total score and stiffness subscale, but not associated with KL grading of OA. KEYWORDS: knee osteoarthritis, female, β-endorphin, WOMAC, Kellgren-Lawrence

Efficacy and Safety of Undenatured Type II Collagen in The Treatment of Osteoarthritis of The Knee: A Randomized, Double-blind, Placebo-controlled Trial

“…Higher scores indicate a worse clinical condition. (18,19) LFI was used to assess the effectiveness of therapeutic interventions for patients with knee osteoarthritis. It consisted of three sections about pain or discomfort, maximum distance walked, and activities of daily living.…”