medwireNews: Using nonsteroidal anti-inflammatory drugs (NSAIDs) and not meeting physical activity guidelines are both modifiable clinical risk factors for radiographic progression among people with knee osteoarthritis (OA), say researchers.
However, “[t]he strongest risk factors for radiographic OA progression were baseline structural disease severity measures, indicating that once OA is clearly established on x-ray, OA progression is likely,” write Milena Simic (The University of Sydney, New South Wales, Australia) and co-authors in Arthritis Research & Therapy.
Simic and team analyzed data for 498 participants of the Long-term Evaluation of Glucosamine Sulfate study, in which individuals with chronic knee pain (≥4 on a scale of 0–10) and medial tibiofemoral narrowing (but retaining ≥2 mm of joint width) were randomly assigned to use glucosamine sulfate and/or chondroitin sulfate versus placebo for 2 years.
At the end of the follow-up period (1–2 years), 12% of the total cohort had radiographic OA progression, defined as joint space narrowing of at least 0.5 mm from baseline.
After adjusting for age, sex, obesity, high blood pressure, no glucosamine/chondroitin supplements, and baseline structural disease severity, the researchers found that people who used NSAIDs at baseline were a significant 2.05 times more likely to experience radiographic progression than those who did not.
Simic et al suggest that “NSAID users may represent people with greater symptoms, and thus more severe disease,” but note that “this theory is unlikely to fully explain the findings because high baseline pain was not associated with radiographic OA progression in the multivariable analysis.”
In addition, people who did not meet physical activity guidelines (five sessions, >150 min/week) were a significant 2.07 times more likely to have radiographic OA progression than those who were physically active.
“Despite anecdotal suggestions that high physical activity may be detrimental to OA progression via increased cumulative loading, our results suggest that maintaining adequate physical activity is not associated with increased risk and may potentially slow OA progression,” the researchers remark.
There were no significant associations between disease progression and age, sex, or obesity, but a minimal baseline medial joint space width below 3.13 mm and varus alignment at or below 178º were both individually associated with significantly increased likelihoods of progression, at odds ratios of 2.53 and 2.23, respectively, on multivariable analysis.
Simic and co-authors therefore conclude: “Interventions targeting the prevention of radiographic OA progression are likely to be most effective during the early stage of knee OA, when only mild features are evident on radiographs.”
They add: “Clinicians should routinely assess known risk factors to identify people at the greatest risk of progression and the potential need for joint replacement surgery.”
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