People without x-ray evidence of osteoarthritis in their knees but with MRI-identified lesions that worsen over time are significantly likelier to develop knee OA, compared with people whose lesions remain stable, according to results from a prospective cohort study.
For their research, published Oct. 14 in Annals of the Rheumatic Diseases, Dr. Leena Sharma of Northwestern University in Chicago and her colleagues recruited more than 1,000 patients at elevated risk of knee OA but with no radiographic evidence yet of disease (Kellgren/Lawrence measures of 0 [KL0] in both knees) to test their hypothesis that lesions seen worsening over time on MRI were predictive of knee OA within 4 years and of persistent symptoms between 4 and 7 years. Patients in the cohort (56% women, mean age 59.6 years) were assessed for cartilage damage, meniscal tears, meniscal extrusions, and bone marrow lesions at 12 and 48 months. Study inclusion required that patients remain at KL0 in both knees at 12 months to continue, and 849 patients had complete data at 12 and 48 months.
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Patients with lesions that had worsened on MRI between 12 and 48 months had significantly higher risk of incident radiographic KL1 and KL2 by 48 months, compared with patients whose lesions had not worsened. For example, 6.3% of patients with tibiofemoral cartilage damage that was stable at 48 months developed mild (KL1) disease at 48 months, compared with 9.5% of patients whose damage had worsened in that interval (odds ratio, 2.69; 95% confidence interval, 1.50-4.84). Half of patients with worsening meniscal extrusion developed mild knee OA by the endpoint, compared with 13.6% of patients with a stable lesion (OR, 5.73; 95% CI, 2.94-11.16). Higher risk of KL1 or KL2 at 48 months was significant for all the lesion types studied except bone marrow lesions. Worsening of these lesions between 12 and 48 months was also significantly associated with having persistent symptoms between 4 and 7 years. Having more lesion types that worsened was significantly associated with worse outcomes.
The findings, Dr. Sharma and her colleagues wrote, support the idea of stable and progressive disease phases with early indicators of each and that worsening lesions represent early osteoarthritis. “Given the absence of disease-modifying therapy for OA, widespread clinical application of MRI is difficult to justify,” the investigators wrote in their analysis (Ann Rheum Dis. 2015 Oct 14. doi: 10.1136/annrheumdis-2015-208129).
Nevertheless, they concluded, “prevention or delay of worsening of early-stage lesions should be considered as a target for emerging pharmacological and nonpharmacological treatments in an effort to prevent or delay full-blown disease. Candidate interventions should be studied at this stage, when they are more likely to be effective.” Investigators acknowledged that one limitation of the study was that its findings may not apply in populations not already at higher risk for knee OA.
The study was funded by the Osteoarthritis Initiative, a public-private partnership of the National Institutes of Health and Merck, Novartis, GlaxoSmithKline, and Pfizer, with industry funding administered by NIH.