Report Finds No Evidence for Three Popular Osteoarthritis Treatments
But does that mean they don’t work?
If you rely on any of three popular treatments for osteoarthritis (OA) of the knee, you may have been surprised by a recent scientific review released by the federal Agency for Healthcare Research and Quality (AHRQ). The review analyzed a total of 76 clinical studies and found no benefit from the nutritional supplements glucosamine and chondroitin, injected hyaluronic acid preparations and arthroscopic surgery to clean the knee joint.
According to the review, glucosamine and chondroitin appear to be no more effective than placebo. In the case of hyaluronic acid injections, studies find they improve pain and function according to patient reports, but the study quality varies and it is hard to tell if there is any real clinical improvement in symptoms. The review also failed to find convincing benefit from an arthroscopic surgery procedure used to clean the knee joint (debridement), which in some cases involves flushing the joint space with saline solution (lavage) to remove debris and bits of cartilage that have broken off into the space.
Based on those findings, you might assume that all three treatments are ineffective. But that was not the report’s conclusion, says lead author David J. Samson, associate director of the AHRQ-supported Blue Cross and Blue Shield Association Evidence-based Practice Center in Chicago, which performs evidence-based reviews for industry and government.
“I want to make a very clear distinction between a lack of evidence to prove effectiveness and clear evidence that something is ineffective,” he says. “We are saying we are not sure whether these treatments are effective. We are not saying we know for sure that they are not effective.” (A Q&A with Samson follows.)
So what do you do if you rely on any of these to control symptoms of knee OA? Nothing different, if you are getting good results, says Patience White, MD, the Arthritis Foundation’s chief public health officer. Dr. White also notes that the AHRQ review was not designed to determine if certain subgroups of people could benefit from these treatments. She cites the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT) study as an example. Last year, the study raised concerns about the effectiveness of these popular OA treatments when the overall results of the study showed no significant pain relief in those who took the supplements. However, a closer analysis revealed that a small subgroup of people with moderate-to-severe pain did get significant relief. (Read more about the GAIT study.)
Regardless of the AHRQ review’s findings, Dr. White advises anyone who is concerned about the best treatment for OA to work closely with their doctor and try other treatments along with exercise and weight loss, which together help relieve knee pain from OA.
Q & A with David J. Samson, M.S., associate director of the AHRQ-supported Blue Cross and Blue Shield Association Evidence-based Practice Center in Chicago.
AT: How did you choose the studies you reviewed?
Samson: For the supplements and the hyaluronic acid injections, we looked at randomized clinical trials that compared those treatments with placebo treatments. There should be evidence first that makes it very clear they are more effective than placebo. If that evidence was not clear, then it was not worthwhile to look at studies comparing these treatments with others known to be effective.
For arthroscopy, we were mainly concerned with placebo. We looked at randomized comparisons, but also at observational studies where there wasn’t necessarily a comparison between arthroscopy and something else. We examined studies that looked at the outcomes of just doing arthroscopy, comparing it to baseline. Those are not the most rigorous studies -- they do not give clear indications of just how effective arthroscopy can be – but we did look at some of that evidence.
We looked at individual studies and also some meta analyses, that analyze the results from multiple individual studies. Meta analyses pool data together to try to get a sense of what the outcome is in general. There were six meta analyses on glucosamine and chondroitin, six on hyaluronic acid injections and six on arthroscopy.
AT: For the individual studies, was effectiveness judged by the criteria of the individual study or did you have the same criteria for all of them?
Samson: Studies varied on how they measured outcomes. We were interested in outcomes related to pain and function. The types of pain outcomes we looked at were mostly visual analog scale for pain, which is the zero-to-ten pain scale, with zero being the least pain and ten being the most. A lot of studies use that sort of outcome scale.
With the meta analyses, we rated both the quality of the methods of the meta analyses and the quality of methods of the individual clinical trials they examined. So we have a real sense of the quality of the conclusions of both the meta analyses and the individual studies.
One thing that came through in our studies is that meta analyses did not always do an adequate job of taking into account how the poor quality of randomized trials should influence the strength of your conclusion.
AT: Could the quality of those trials have affected the reliability of the results you found?
Samson: Yes, there can be problems with the way a study is conducted that can influence the results. So for example, results might show an advantage for one of these treatments, but the results can’t be clearly believed because of the way the study was done.
AT: Even though you found no evidence of efficacy, isn’t it possible these are helpful or maybe are helpful in certain populations of people?
Samson: That is quite possible. I want to make a very clear distinction between a lack of evidence to prove effectiveness and clear evidence that something is ineffective. What are trying to say in our report is that we don’t have clear evidence of effectiveness. We’re not saying that we know for sure that these treatments are ineffective. It is a very important difference in how you describe the conclusions of your report.
It’s possible that there could be good results in certain subgroups, but we don’t know for sure. We would like to see additional studies to make stronger conclusions.
AT: So is this something you would do again when there are more studies?
Samson: It is possible. We don’t have a contract with the Agency for Healthcare Research and Quality to do periodic updates, but if additional research comes up and it looks like it’s worth looking over again, I am sure that they take that account.
AT: Do you find these kinds of results in other areas -- that there is a treatment many people swear by and then you find that really there is no evidence that it works? Or is this unusual?
Samson: I hate to make generalizations, but we often find problems with the quality of the research. That is something a lot of people have been trying to improve over the last several years, to set standards for how to do scientific studies so the results can be looked on with confidence. There have been a lot of initiatives to try to improve the quality of research.
