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Papers of the Week

Papers: 15 Jul 2023 - 21 Jul 2023

Clinical, Methodology

Human Studies, Neurobiology

Arthritis, Inflammation/Inflammatory

2023 Jul 11

J Pain


The Natural History of Knee Osteoarthritis Pain Experience and Risk Profiles.


Chang AH, Almagor O, Lee JJ, Song J, Muhammad LN, Chmiel JS, Moisio Pt KC, Sharma L


The study aimed to characterize the natural history of pain experience, concurrently considering intermittent and constant pain over 4 years and determine baseline factors associated with unfavorable trajectories in individuals with chronic knee pain. The OAI (Osteoarthritis Initiative) is a prospective, observational study of people with or at higher risk for knee osteoarthritis. The Intermittent and Constant Osteoarthritis Pain (ICOAP) was assessed annually at 48-to-96-month OAI visits. Twenty-eight baseline sociodemographic, knee-specific, and health-related characteristics were assessed. Group-based dual-trajectory modeling identified pain experience patterns indicated by ICOAP intermittent and constant pain scores over 4 years. Multivariable multinomial logistic regression models determined baseline factors associated with membership in each dual-trajectory group. Four longitudinal pain experience patterns were identified [n=3584, mean age=64.8 (SD 9.0) years, BMI=28.6 (5.0) kg/m; 57.9% women]. Group 1 (37.7%) had minimal intermittent and no constant pain; Group 2 (35.1%) mild intermittent and no constant pain; Group 3 (18.5%) mild intermittent and low-grade constant pain; and Group 4 (8.7%) moderate intermittent and constant pain. Baseline widespread pain, knee stiffness, back pain, hip pain, ankle pain, obesity, depressive symptoms, more advanced radiographic disease, and analgesic use were each associated with an increased risk of membership in less favorable Groups 2-4. These distinct courses of pain experience may be driven by different underlying pain mechanisms. The benchmarked ICOAP scores could be used to stratify patients and tailor management. Addressing and preventing the development of modifiable risks (e.g., widespread pain, knee joint stiffness), may reduce the chance of belonging to unfavorable dual-trajectory groups. PERSPECTIVE: Concurrently tracking intermittent versus constant pain experience, group-based dual-trajectory modeling identified 4 distinct pain experience patterns over 4 years. The benchmarked Intermittent and Constant OA Pain (ICOAP) scores in these dual trajectories could aid in stratifying patients for tailored management strategy and intensity of care.