Turmeric extract may help relieve pain in knee OA
Turmeric extract supplements can help reduce knee pain associated with knee osteoarthritis, although there are no changes in knee effusion-synovitis or cartilage composition, a study suggests.
“[So far, there is] no approved disease-modifying drugs currently are available to treat osteoarthritis,” said the researchers.
The current treatment strategies such as NSAID and acetaminophen not only produce low to moderate effect on easing pain and do not slow structural progression, they are also associated with multiple side effects, they pointed out.
In the double-blind, single-centre study, 70 participants (mean age 62 years) with symptomatic knee osteoarthritis and effusion-synovitis on ultrasonography were randomized 1:1 to receive two capsules containing turmeric extract 1,000 mg daily or a matching placebo for 12 weeks. [Ann Intern Med 2020;doi:10.7326/M20-0990]
After 12 weeks, turmeric extract led to significant improvement in the primary outcome of knee pain assessed on a visual analogue scale (VAS) compared with placebo (mean, -23.8 vs -14.6 mm; difference, -9.1 mm; p=0.039).
Knee pain assessed by WOMAC* was also significantly improved in the turmeric group vs the placebo group (mean -84.2 mm vs -37.0 mm; difference, -47.2 mm; p=0.006).
However, there were no significant changes in the coprimary outcome of effusion-synovitis volume between the two groups (difference, 3.2 mL; p=0.075).
T2 relaxation time of the lateral femoral cartilage on MRI was also comparable among patients who received turmeric extract vs placebo (difference, -0.4 ms; p=0.30).
“The effect on pain was only moderate; however, it was achieved without any effect on knee structural measures assessed by MRI,” observed the researchers.
Post hoc analyses revealed that pain reductions were reported in patients who had a lower effusion-synovitis volume at baseline but not in those with a higher volume.
“[This] is an important hypothesis-generating finding. A possible explanation is that participants with a higher effusion-synovitis volume may have more severe disease,” said the researchers.
“[In addition,] we did not find any difference in the number of reported adverse events between groups, indicating that [turmeric extract] was safe and modestly effective in treating osteoarthritis in this short-term study,” they added.
Adverse events (AEs) occurred at comparable rates in the two groups, with 39 percent of patients receiving turmeric extract and 53 percent of those on placebo experiencing at least one AE of any grade (p=0.16). Two of the AEs in the turmeric group and five in the placebo group were considered to be possibly related to treatment.
One limitation of the study was the relatively short duration spanning just 12 weeks, which might not be sufficient to detect structural changes. As the treatment effect on pain had yet to plateau at the end of the study, the researchers believed that treatment effect may be greater with longer duration.
“Multicentre trials with larger sample sizes are needed to assess the clinical significance of these findings,” they suggested.
*WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index