A number of key studies are relevant:
The GAIT Study
GAIT was designed to test the short-term (6 months) effectiveness of glucosamine and chondroitin sulphate, either alone or in combination, in reducing pain in knee osteoarthritis. The two drugs were evaluated under an Investigational New Drug application that was filed with the US Food and Drug Administration (FDA).
The study, like most good medical studies, was done 'double blind', that is neither the patients nor the people administering to them knew which treatment the patient was on.
Patients were randomly assigned to different treatment subgroups -
- chondroitin sulphate alone (400 mg 3x a day)
- glucosamine hydrochloride alone (500 mg 3x a day)
- combined glucosamine hydrochloride/chondroitin sulphate (same doses but combined)
- celecoxib (Celebrex®) (200 mg per day)
- placebo (inactive dummy tablet)
The dosages for glucosamine and chondroitin were selected at 1500mg a day and 1200mg a day respectively as although the optimal daily dosage hasn't been determined as yet these levels are the commonly suggested daily amounts.
The celecoxib group was included as a positive control for the GAIT study. Celecoxib was used as it has been FDA approved for the management of osteoarthritis pain and investigators therefore expected participants in this group to experience pain relief and that this predictable response would help to validate the GAIT results.
The GAIT Findings
The patients were divided into two groups based on pain levels assessed by a validated index score (WOMAC) -
- mild pain (1,229 patients)
- moderate to severe pain (354 patients)
The effectiveness of the drugs was initially evaluated on all the patients grouped together. Then the two groups were evaluated separately.
The results of the overall group of 1583 patients in the GAIT study showed that neither glucosamine nor chondroitin sulphate either on their own or in combination were effective in reducing pain.
But when results of the group of patients with moderate to severe pain was analysed the investigators found that the combination of glucosamine and chondroitin sulphate WAS significantly effective for pain relief!
- Also, although the glucosamine and chondroitin sulphate subgroup showed significant improvements in WOMAC score in the moderate to severe pain patients, the celecoxib group showed no significant improvements in pain in the same moderate to severe pain patients. Why is this important? Well, the whole reason a celecoxib group was included was because there was an expectation, based on prior studies, that it would have a significant effect on pain i.e. act as a positive control group. It has therefore been suggested that perhaps the results from all the groups in GAIT are 'understated'.
- At first glance there appears to be a substantial number of patients participating in this study - 1583 in total. However, once the moderate to severe group was split into the treatment subgroups there were only 72 patients taking glucosamine and chondroitin and 70 taking a placebo. In terms of clinical trials these are relatively small patient numbers and this has implications for the recommendations from the GAIT study.
- With 744 patients taking either glucosamine or chondroitin or both there were sufficient numbers for some reassurance that side effects from taking these supplements are minor. However, it must be borne in mind that the GAIT study used pharmaceutical grade products that underwent strict quality control.
A 2005 article in the Journal of the American Pharmacists Association noted that "NO commercially available chondroitin product was deemed appropriate for use in GAIT." Why was that?
Because the potency of the product varied too much PLUS contaminants were found in several tests. This is why for the GAIT study the supplements were subjected to pharmaceutical regulation to ensure quality. In many European countries you can only get glucosamine and chondroitin on prescription from a doctor but in the USA and UK you can purchase glucosamine and chondroitin 'over the counter' without a prescription. This is because glucosamine and chondroitin are classed as 'dietary supplements' and not medications. On the plus side the classification as a dietary supplement means these products are easily accessible to everyone but on the negative side it means the contents are not as strictly regulated and the quality and purity of the products are therefore not assured.
The GAIT team are continuing their work by looking at whether glucosamine and chondroitin can actually alter the progression of osteoarthritis i.e. disease-modification. The results of this study can be expected in a couple of years time.
The GUIDE study
At the same that the GAIT study released their results a European group also presented results from a similar study at the 2005 Annual Meeting of the American College of Rheumatology. The Glucosamine Unnum-A-Die (Once a Day) Efficacy trial - commonly known as the GUIDE study - compared levels of pain and mobility in 318 osteoarthritis sufferers between the ages of 45 and 75 at 13 European hospitals. The patients were randomly allocated to one of the following groups.
- glucosamine sulphate in soluble powder form 1500mg daily
- acetaminophen (e.g. Tylenol® and paracetamol) 3000mg daily
All groups were allowed to take ibuprofen (Brufen®) as needed as a 'rescue' for pain relief.
The GUIDE findings
- Both glucosamine sulphate and acetaminophen were more effective in reducing pain than placebo.
- Patients taking glucosamine sulphate exhibited more relief than patients on acetaminophen.
It was concluded that once-daily 1500 mg oral doses of glucosamine sulphate may be the preferred treatment for knee osteoarthritis.
- It must be noted that unlike the GAIT study that was publicly funded the GUIDE study was sponsored by the manufacturers of the glucosamine compound that was used in the trial.
So both these studies suggest that, at least in the case of moderate pain, the combination of glucosamine and chondroitin sulphate in adequate dosage are helpful for your joint cartilage. But there is another big issue to talk about and that is - Are you getting what you think you're paying for?