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Glucosamine 'no better than placebo'

People who take glucosamine and chondroitin for osteoarthritis are wasting their money, according to a new study published today.

Researchers from the University of Bern in Switzerland, conducted a meta-analysis of past studies on these popular complementary medicines, which is published in today's edition of British Medical Journal.

Osteoarthritis of the hip or knee is a chronic condition that can't be cured. Conventional medical treatment is centred on painkillers and anti-inflammatory drugs. But these treatments don't cure the condition, and people with the condition often have to live with chronic pain.

They may also cause serious side effects such as stomach ulcers and an increased risk of heart disease, especially if used long-term.

Recently people have turned to complementary medicines, with glucosamine and chondroitin among the most popular. Glucosamine in available in two forms, glucosamine hydrochloride and glucosamine sulphate (most commonly used in Australia).

Glucosamine and chondroitin are made from cartilage, which occurs naturally in the body covering bone ends in joints. The theory is that when swallowed, these compounds are absorbed from the gut and reach the joint where they help replace cartilage damaged by osteoarthritis.

Many general practitioners and rheumatologists recommend them to patients. In 2008, global sales of glucosamine supplements reached almost US$2 billion (A$2.13 billion), up 60% since 2003.

Same as placebo

The Swiss researchers analysed the results of 10 large scale randomised controlled trials, mostly funded by the manufacturers of the medicines.

All up, the studies covered 3803 patients with osteoarthritis of the knee or hip, who underwent treatment with one or both of these compounds over periods ranging from one week to three years.

The researchers analysed the effects of these compounds on pain, and on radiological damage to the hip and knee caused by osteoarthritis.

They found people taking these compounds experienced no significant difference in pain or in the degree of damage to the joint, compared to a placebo.

The researchers add there was no evidence the supplements are dangerous.

"We see no harm in having patients continue these preparations as long as they perceive a benefit and cover the cost of treatment themselves."

But, they add, "Health authorities and health insurers should not cover the costs for these preparations, and new prescriptions to patients who have not received treatment should be discouraged."

More results needed

Professor Graeme Jones of Hobart's Menzies Research Institute, and Medical Director of Arthritis Australia, disagrees with some of the findings of the study.

Jones says while is there no evidence that chondroitin is effective in the treatment of osteoarthritis, there's still some debate about the effectiveness of glucosamine.

"The study concludes that glucosamine doesn't work, however, if you look closely at the study's results, it shows that glucosamine hydrochloride doesn't work, but that glucosamine sulphate does seem to have some benefit," he says.

"We need further large scale studies of glucosamine sulphate to really know."

Jones says the Long Term Evaluation of Glucosamine Sulphate Study (LEGS), currently being conducted by the University of Sydney and funded by the National Health and Medical Council, may provide a clearer answer regarding the effectiveness of glucosamine.

He says many patients with osteoarthritis (of the knee in particular) do report improved symptoms on glucosamine sulphate, although its real mechanism of action remains unknown.

"It's safe, has very few side effects and patients shouldn't be discouraged from trying it," he says.