medwireNews: Findings from the Osteoarthritis Initiative suggest that knee pain is associated with accelerated cartilage volume loss and progression of osteoarthritis (OA).
The study included 2249 patients with radiographic knee OA (Kellgren–Lawrence grade ≥2) and 2120 individuals at risk for OA but without radiographic disease (Kellgren–Lawrence grade ≤1), with average baseline WOMAC pain scores of 3.7 and 1.9 points, respectively.
As reported in Arthritis Research & Therapy, greater WOMAC pain score at baseline was associated with a significantly increased rate of medial and lateral cartilage volume loss in both patient groups, with regression coefficients of 0.04–0.05 after adjustment for age, sex, BMI, and Kellgren–Lawrence grade.
Furthermore, baseline WOMAC pain score was significantly associated with disease progression (increase in Kellgren–Lawrence grade ≥1) over 4 years of follow-up among patients with radiographic knee OA (adjusted odds ratio [OR]=1.07), and was significantly associated with the development of radiographic OA among those without the disease at baseline (adjusted OR=1.07).
Yuanyuan Wang (Monash University, Melbourne, Victoria, Australia) and team also investigated the association between patterns of pain over time and OA progression. Among patients with radiographic OA at baseline, the average annual rate of cartilage volume loss in the medial compartment over 4 years was highest for those with persistent knee pain over 1 year, at 1.60%, compared with 1.47% for those with fluctuating knee pain, and 1.26% for patients with no knee pain.
Similarly, among individuals without radiographic OA, the average annual rate of medial cartilage volume loss over 4 years was 0.93%, 0.81%, and 0.63% in patients with persistent, fluctuating, and no knee pain, respectively, during the first year of follow-up.
Wang and team note that OA patients with persistent knee pain had a significantly higher risk for radiographic OA progression than those without knee pain (adjusted OR=1.82). Persistent pain was not significantly associated with the incidence of OA among patients who did not have the disease at baseline, but patients from this group who had fluctuating knee pain had a significantly increased risk for developing OA compared with those without knee pain (adjusted OR=1.62).
“These data suggest that knee pain is an important predictive factor for the deterioration of knee structural outcomes,” write the researchers.
And they conclude that “targeting people with fluctuating or persistent knee pain for early intervention will be important for preserving knee structure and delaying structural progression.”
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