medwireNews: Researchers have identified some reliable determinants for predicting which patients with knee osteoarthritis (OA) are most likely to benefit from intra-articular hyaluronic acid (IAHA) injections.
The key factors associated with a better response were higher levels of knee pain, younger age, and less severe structural damage.
The team, led by Jean-Pierre Pelletier (University of Montreal Hospital Research Centre, Quebec, Canada), comments: “In an era of OA therapeutic choice paucity, this will help in selecting patients for whom IAHA can be an effective way to locally treat knee OA symptoms.”
The study participants, selected from the Osteoarthritis Initiative database, included 310 individuals with radiographic OA who had received one IAHA treatment in one or both knees (404 treatments overall). Participants were divided into three groups according to their baseline level of pain: low pain (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] score 0–3), moderate pain (WOMAC score 4–7), or high pain (WOMAC score ≥8).
As reported in Arthritis Research & Therapy, patients with high pain at baseline were significantly more likely than those in the other groups to respond to IAHA treatment, with 46% of these patients experiencing WOMAC improvements of at least 20% within 6 months of receiving the injections. This compared with 27% of those in the moderate-pain group and 19% of those in the low-pain group.
Within the high-pain group, responders were significantly younger than non-responders at baseline, at a mean of 62 versus 67 years, and they had a significantly greater cartilage volume in the medial compartment on magnetic resonance imaging, at 4334 versus 3675 mm3.
Further analysis of responders in the high-pain group demonstrated that these individuals also experienced improvements in function and stiffness, compared with worsening scores in these areas among non-responders. In addition, 41% of responders experienced a greater than 40% improvement in their WOMAC pain score, which the researchers describe as “a clear landmark that [yields] even more clinical importance.”
Although longer-term and controlled studies are required to validate these initial findings, the authors believe that the determinants they have identified “could be implemented in clinical practice as a useful guide for physicians.”
By Catherine Booth
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