Baseline self-report ‘central mechanisms’ trait predicts persistent knee pain in the Knee Pain in the Community (KPIC) cohort

• Published in: Osteoarthritis and cartilage Vol. 28; no. 2; pp. 173 - 181
• Main Authors: Akin-Akinyosoye, K., Sarmanova, A., Fernandes, G.S., Frowd, N., Swaithes, L., Stocks, J., Valdes, A., McWilliams, D.F., Zhang, W., Doherty, M., Ferguson, E., Walsh, D.A.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-02-2020
• Subjects: Aged; Anxiety - psychology; Arthralgia - physiopathology; Arthralgia - psychology; Catastrophization - psychology; Central Nervous System Sensitization; Central pain mechanisms; Cognition; Depression - psychology; Fatigue - physiopathology; Female; Follow-Up Studies; Humans; Knee pain; Linear Models; Logistic Models; Male; Middle Aged; Osteoarthritis, Knee - physiopathology; Osteoarthritis, Knee - psychology; Outcome measures; Pain Threshold; Phenotypes; Pressure; Quantitative sensory testing; Self Report; Sleep Wake Disorders - physiopathology; Knee pain; Outcome measures; Phenotypes; Central pain mechanisms; Quantitative sensory testing
• ISSN: 1063-4584; 1522-9653
• DOI: 10.1016/j.joca.2019.11.004

We investigated whether baseline scores for a self-report trait linked to central mechanisms predict 1 year pain outcomes in the Knee Pain in the Community cohort.
1471 participants reported knee pain at baseline and responded to a 1-year follow-up questionnaire, of whom 204 underwent pressure pain detection thresholds (PPTs) and radiographic assessment at baseline. Logistic and linear regression models estimated the relative risks (RRs) and associations (β) between self-report traits, PPTs and pain outcomes. Discriminative performance for each predictor was compared using receiver-operator characteristics (ROC) curves.
Baseline Central Mechanisms trait scores predicted pain persistence (Relative Risk, RR = 2.10, P = 0.001) and persistent pain severity (β = 0.47, P < 0.001), even after adjustment for age, sex, BMI, radiographic scores and symptom duration. Baseline joint-line PPTs also associated with pain persistence (RR range = 0.65 to 0.68, P < 0.02), but only in univariate models. Lower baseline medial joint-line PPT was associated with persistent pain severity (β = −0.29, P = 0.013) in a fully adjusted model. The Central Mechanisms trait model showed good discrimination of pain persistence cases from resolved pain cases (Area Under the Curve, AUC = 0.70). The discrimination power of other predictors (PPTs (AUC range = 0.51 to 0.59), radiographic OA (AUC = 0.62), age, sex and BMI (AUC range = 0.51 to 0.64), improved significantly (P < 0.05) when the central mechanisms trait was included in each logistic regression model (AUC range = 0.69 to 0.74).
A simple summary self-report Central Mechanisms trait score may indicate a contribution of central mechanisms to poor knee pain prognosis.