Glucosamine therapy for treating osteoarthritis

Towheed TE, Maxwell L, Anastassiades TP, Shea B, Houpt J, Robinson V, Hochberg MC, Wells G

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Summary

Glucosamine for osteoarthritis

Does glucosamine work for treating osteoarthritis?
This Cochrane review looked at the best studies done to date on glucosamine. Twenty studies tested over 2500 people with osteoarthritis of the knee or hip. Most of the studies were 2 to 3 months long. To test how well glucosamine works, researchers compared people who had either glucosamine (as a pill or an injection), fake pills or injections, or a non-steroidal anti-inflammatory drug (NSAID).

What is osteoarthritis and glucosamine?
Osteoarthritis (OA) is the most common form of arthritis that can affect the hands, hips, shoulders and knees. In OA, the cartilage that protects the ends of the bones breaks down and causes pain and swelling. Drug and non-drug treatments are used to relieve pain and/or swelling. Glucosamine can be found naturally in the body and is one of the building blocks of cartilage. It is thought that taking glucosamine supplements may help stop cartilage breakdown, build cartilage and decrease swelling. But there is debate about its effects.

How well does glucosamine work?
Pain: The high quality studies showed that pain improved about the same whether people took glucosamine or fake pills. If all of the studies are examined (including low quality and old studies), then glucosamine improved pain more than fake pills.

Pain may improve by 13 more points on a scale of 0 to 100 with glucosamine than with fake pills.

Studies testing only the Rotta brand of glucosamine (including low quality and old studies) showed that glucosamine improved pain more than fake pills.

Function: The high quality studies show that glucosamine improved pain more than fake pills when measured by one type of scale, but improved the same amount as fake pills when measured by another scale. This result is the same whether all of the studies (including low quality and old studies) or whether studies using the Rotta brand of glucosamine are analysed.

How safe is it?
The number of people taking glucosamine who had side effects was about the same as the number who took fake pills. Side effects mainly included stomach upset and other joint pain.

What is the bottom line?
It was shown in a previous Cochrane review that glucosamine taken for 6 weeks decreases pain and improves function (physical ability) in people with osteoarthritis.

When compared to the previous review, this review which analyzes newer studies and more high quality studies, shows there is "platinum" level evidence that pain does not improve as much when taking glucosamine for 2 to 3 months. Depending on the scale used to measure function (physical ability), function may not improve at all or as much.
Glucosamine seems to be safe.

This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2008 Issue 3, Copyright © 2008 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This record should be cited as: Towheed TE, Maxwell L, Anastassiades TP, Shea B, Houpt J, Robinson V, Hochberg MC, Wells G. Glucosamine therapy for treating osteoarthritis. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD002946. DOI: 10.1002/14651858.CD002946.pub2

This version first published online: January 22. 2001
Date of last substantive update: February 23. 2005

Abstract

Background

Osteoarthritis (OA) is the most common form of arthritis, and it is often associated with significant disability and an impaired quality of life.

Objectives

To review all randomized controlled trials (RCTs) evaluating the effectiveness and toxicity of glucosamine in OA.

Search strategy

We searched MEDLINE, PREMEDLINE, EMBASE, AMED, ACP Journal Club, DARE, CDSR, and CENTRAL. We also wrote letters to content experts, and hand searched reference lists of identified RCTs and pertinent review articles. All searches were updated in January 2005.

Selection criteria

Relevant studies met the following criteria: 1) RCTs evaluating the effectiveness and safety of glucosamine in OA, 2) Both placebo controlled and comparative studies were eligible, 3) Both single blinded and double blinded studies were eligible.

Data collection and analysis

Data abstraction was performed independently by two investigators and the results were compared for degree of agreement. Gotzsche's method and a validated tool (Jadad 1996) were used to score the quality of the RCTs. Continuous outcome measures were pooled using standardized mean differences (SMD) as the measure of effect size. Dichotomous outcome measures were pooled using relative risk ratios (RR).

Main results

Analysis restricted to eight studies with adequate allocation concealment failed to show benefit of glucosamine for pain and WOMAC function. Collectively, the 20 analyzed RCTs favoured glucosamine with a 28% (change from baseline) improvement in pain (SMD -0.61, 95% CI -0.95, -0.28) and a 21% (change from baseline) improvement in function using the Lequesne index (SMD -0.51 95% CI -0.96, -0.05). However, the results are not uniformly positive, and the reasons for this remain unexplained. WOMAC pain, function and stiffness outcomes did not reach statistical significance.

In the 10 RCTs in which the Rotta preparation of glucosamine was compared to placebo, glucosamine was found to be superior for pain (SMD -1.31, 95% CI -1.99, -0.64) and function using the Lequesne index (SMD -0.51, 95% CI -0.96, -0.05). Pooled results for pain (SMD -0.15, 95% CI -0.35, 0.05) and function using the WOMAC index (SMD 0.03, 95% CI -0.18, 0.25) in those RCTs in which a non-Rotta preparation of glucosamine was compared to placebo did not reach statistical significance. In the four RCTs in which the Rotta preparation of glucosamine was compared to an NSAID, glucosamine was superior in two, and equivalent in two. Two RCTs using the Rotta preparation showed that glucosamine was able to slow radiological progression of OA of the knee over a three year period (SMD 0.24, 95% CI 0.04, 0.43).

Glucosamine was as safe as placebo in terms of the number of subjects reporting adverse reactions (RR=0.97, 95% CI, 0.88, 1.08).

Authors' conclusions

This update includes 20 studies with 2570 patients. Pooled results from studies using a non-Rotta preparation or adequate allocation concealment failed to show benefit in pain and WOMAC function while those studies evaluating the Rotta preparation show that glucosamine was superior to placebo in the treatment of pain and functional impairment resulting from symptomatic OA. WOMAC outcomes of pain, stiffness and function did not show a superiority of glucosamine over placebo for both Rotta and non-Rotta preparations of glucosamine. Glucosamine was as safe as placebo.

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