In this observational study, residual, unmeasured confounders may explain the apparent association between glucosamine use and reduced mortality. Example: Patients taking regular glucosamine supplements may be more likely to engage in other beneficial health-related behaviors than those patients not regularly taking glucosamine supplements. Thus, glucosamine use may simply be a surrogate marker for healthy behaviors that affect mortality.
Dr. Chevalier noted patients often ask about other supplements and dietary interventions and the role these entities may play in management of OA. One of the most frequently discussed alternative therapies is turmeric, a spice that comes from the Curcuma longa plant.
In a randomized, double-blind, placebo-controlled trial of 70 patients with symptomatic knee OA and effusion synovitis as identified by ultrasound, two capsules of Curcuma longa extract were given daily to the intervention group for 12 weeks. The two primary outcomes of the study were changes in knee pain on a visual analog scale (VAS) and effusion synovitis volume assessed by magnetic resonance imaging (MRI).4
At 12 weeks, the intervention group improved the VAS pain score by –9.1 mm (95% CI, –17.8 to –0.4 mm; P=0.039) by comparison to the placebo group. However, the between-group change in effusion synovitis volume as assessed by MRI was 3.2 mL (95% CI, –0.3 to 6.8; P=0.075), which was not statistically significant. These results may indicate some symptomatic benefit may be accrued with the turmeric use, but longer follow-up may be necessary to detect any improvement in objective measures of knee effusion or synovitis.
Hand OA can be a particularly debilitating and difficult-to-treat condition. Thus, it’s helpful to understand if existing treatments for other forms of arthritis are worthwhile to try in patients with this condition.
On this note, Dr. Chevalier referenced a study by Davis et al., which investigated the effect of 1 mg of daily colchicine vs. placebo on hand pain and function for 12 weeks in older patients (aged 48–79 years) with hand OA. A total of 64 patients were enrolled and randomized to receive colchicine or placebo. The primary outcome was the VAS hand pain score, and secondary outcomes were tender and swollen joint count, grip strength, C-reactive protein level, Michigan Hand Outcomes Questionnaire total, function and pain scores. Unfortunately, no statistically significant differences were seen between the intervention and control groups for any of the primary or secondary outcomes.5 These disappointing results indicate the quest continues to find effective therapies for the management of hand OA.
The Future
What is on the horizon for OA treatment? Nerve growth factor (NGF) inhibitors are certainly an interesting area of future research. NGF plays a critical role in pain modulation and, thus, represents a potential therapeutic target in the treatment of OA. Additionally, sprifermin, a recombinant human fibroblast growth factor 18, is currently under investigation as a potential disease-modifying medication for OA.
