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Glucosamine and/or chondroitin sulfate may be no better than placebo for knee OA
Glucosamine, chondroitin sulfate patients showed the greatest mean loss in joint space width.
The 2-year results of a Level I study indicate that glucosamine and chondroitin sulfate, used alone or in combination, are no more beneficial than placebo in slowing the progression of knee osteoarthritis.
Using a subset of patients enrolled in the Glucosamine/Chondroitin Sulfate Arthritis Intervention Trial (GAIT), Allen D. Sawitzke, MD, and colleagues prospectively studied 572 patients with Kellgren/Lawrence Grade II and III osteoarthritis (OA) and a baseline joint space width of at least 2 mm who were randomized to receive one of the following treatments for 24 months:
- 500 mg of glucosamine three times daily;
- 400 mg of chondroitin sulfate three times daily;
- a combination of glucosamine and chondroitin sulfate;
- 200 mg of celecoxib daily; or,
- a placebo.
Investigators in the multicenter, double-blind study radiographically measured the mean joint space width at baseline, 12 months and 24 months and used the mean change from the baseline joint space width as the primary outcome measure. They expected a 0.4 mm mean change in the joint space width for the placebo group at 2 years and considered a reduction of at least 2 mm in joint space width loss to be clinically significant.
Joint space width
The 2-year results of 357 patients (581 knees) revealed no significant difference in the mean joint space width loss between the placebo and treatment groups. After controlling for design and clinical factors, the investigators discovered that the placebo group had a mean joint space width loss of 0.166 mm at 2 years. The glucosamine group showed the least mean loss of 0.013, while the combination glucosamine and chondroitin sulfate had the greatest mean loss of 0.194.
However, the investigators found that patients with Kellgren/Lawrence Grade II knees showed a trend toward improvement with the dietary supplements compared to those in the placebo group.
“We were unable to show benefit for any of the treatment arms,” Sawitzke, a rheumatologist and associate professor of internal medicine at the University of Utah School of Medicine, told Orthopedics Today. “However, no benefit shown is not the same as no benefit exists.”
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The study has been published in Arthritis & Rheumatism.
Limitations
The findings may have weakened the evidence for continued long-term use of these agents for disease modification, he said. “[We had] limited power secondary to the number of patients, the duration and the variability from radiograph to radiograph within a patient series,” Sawitzke said.
The next step in the research would include another randomized double-blind trial with fewer agents and adequate power, he said.
For more information:
- Allen D. Sawitzke, MD, can be reached at the University of Utah School of Medicine, 30E 1900 SSOM 4B200, Salt Lake City, UT 84132; 801-581-7724; e-mail: allen.sawitzke@hsc.utah.edu. He has no direct financial relationship with any product or company mentioned in this article. The study was supported by the National Institutes of Health.
Reference:
- Sawitzke AD, Shi H, Finco MF, et al. The effect of glucosamine and/or chondroitin sulfate on the progression of knee osteoarthritis: A report from the Glucosamine/Chondroitin Arthritis Intervention Trial. Arthritis Rheum. 2008;58(10): 3183-3191.