Predictors of pain severity trajectory in older adults: a 10.7-year follow-up study.
OBJECTIVES
To identify distinct pain trajectories over 10.7 years and to examine predictors of identified pain trajectories in an older population and those with radiographic knee osteoarthritis (ROA).


METHODS
963 participants (aged 50-80 years) from a population-based cohort had baseline demographic, psychological, lifestyle and comorbidities data collected. T1-and T2-weighted magnetic resonance imaging (MRI) of the right knee was performed to measure knee structural pathology-cartilage defects, bone marrow lesions (BMLs) and effusion-synovitis. Group-based trajectory modelling (GBTM) was applied to identify trajectories of knee pain over 10.7 years measured by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).


RESULTS
Three distinct pain trajectories were defined: 'Minimal pain' (n = 501, 52%), 'Mild pain' (n = 329, 34%) and 'Moderate pain' (n = 165, 14%). In multivariable analysis, having cartilage defects, BMLs and effusion-synovitis were associated with an increased risk of being in the 'Mild pain' (relative risk [RR]: 1.40 to 1.92) and 'Moderate pain' trajectory (RR: 1.72 to 2.26), compared with the 'Minimal pain' trajectory. Being obese and having more painful sites were associated with 'Mild pain' and 'Moderate pain' trajectories, while unemployment, lower education level and presence of emotional problems were associated with 'Moderate pain' trajectory group. Similar results were found for those with ROA.


CONCLUSION
Distinct pain trajectories identified suggest that homogeneous subgroups exist, which might be useful for phenotypic assessment for pain management, particularly in knee osteoarthritis. Structural pathology was associated with worse pain trajectories, suggesting that peripheral stimuli are critical for the development and maintenance of pain severity. Environmental and psychological factors may exacerbate pain perception.
['Pan|F|F|', 'Tian|J|J|', 'Aitken|D|D|', 'Cicuttini|F|F|', 'Jones|G|G|']
D000368:Aged D000369:Aged, 80 and over D002358:Cartilage, Articular D015897:Comorbidity D018450:Disease Progression D015444:Exercise D005260:Female D005500:Follow-Up Studies D006801:Humans D007719:Knee Joint D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D009765:Obesity D020370:Osteoarthritis, Knee D010146:Pain D010147:Pain Measurement D012307:Risk Factors D012720:Severity of Illness Index D012959:Socioeconomic Factors D013585:Synovitis D013648:Tasmania
Pain Trajectory Knee osteoarthritis MRI Risk factor