About 27 million Americans, including one in 10 people over the age of 60, suffer from osteoarthritis. The condition results from bony changes and a loss of cartilage -- the flexible tissue that serves as a cushion between the bones -- in joints.
Chondroitin sulfate, a naturally occurring component of cartilage, is widely used in the treatment of the joint condition.
Chondroitin Sulfate for Arthritis Pain Relief
While several studies have found chondroitin sulfate with or without glucosamine to be beneficial for the relief of osteoarthritis pain, others have failed to show a benefit.
"Osteoarthritis of the hand is very common and symptoms can range from mild to crippling," Gabay tells WebMD. "That is why we wanted to study chondroitin sulfate in this subset of patients."
The study included 162 patients with hand pain caused by osteoarthritis treated daily with either 800 milligrams of chondroitin sulfate (80 patients) or placebo treatments (82 patients) for six months.
Neither the patients nor the investigators knew which treatment was being given.
At the end of the treatment phase of the study, the chondroitin sulfate patients reported significantly less hand pain than the placebo-treated patients, and they had larger improvements in morning stiffness.
They showed somewhat more improvement in grip strength, although the difference could have been due to chance. They were no less likely than the placebo-treated patients to use acetaminophen to control hand pain.
Gabay characterizes the difference in the two groups as "modest." But he says the study shows a clear benefit for chondroitin sulfate over placebo for the treatment of hand pain caused by osteoarthritis.
Different Studies, Different Results
The study was funded by the Swiss drug-maker IBSA Switzerland, which markets the widely prescribed chondroitin sulfate drug Condrosulf in Europe.
Gabay said the company had no influence on the design of the trial or the analysis of the findings.
But osteoarthritis and lupus specialist Sharon L. Kolasinski, MD, of the University of Pennsylvania, says the fact that the trial study was funded makes it more difficult to interpret the results.
"Unfortunately, this fits a pattern," she tells WebMD. "What we have seen with both glucosamine and chondroitin over the years is that the European studies, which are often funded by manufacturers, tend to show positive results, while studies with funding from other sources are less positive."
One of the largest studies of chondroitin sulfate and glucosamine for the treatment of osteoarthritis pain was conducted by the National Center for Complementary and Alternative Medicine (NCCAM).
The Glucosamine/chondroitin Arthritis Intervention Trial (GAIT), published in 2006, found chondroitin combined with glucosamine to be somewhat effective for the treatment of moderate-to-severe osteoarthritis-related knee pain.
But the supplements, either given together or alone, failed to show significant benefits for other patients and were less effective for managing pain in these patients than the pain reliever Celebrex.
Variation in Supplements
Kolasinski, who is a spokeswoman for the American College of Rheumatology, says because chondroitin sulfate is not regulated as a drug in the U.S. patients can't be sure they are getting what they are paying for when they buy the supplements.
Several studies have found a wide variation in the dosage of the cartilage component in different over-the-counter brands of chondroitin sulfate.
But Kolasinski does not discourage her osteoarthritis patients from trying chondroitin sulfate or glucosamine because she says both have been shown to be safe, even if their efficacy remains unproven, over many years of use.
"We really don't have good drugs that are free of side effects, so it makes sense that patients would want to try these supplements," she says. "But the usual pattern I see is that patients who take them eventually stop because the effect is not very impressive over the long term."