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Glucosamine and chondroitin for knee OA

 

Clinical bottom line

As many as 1 in 5 patients with knee arthritis will benefit from using oral glucosamine at 1,500 mg daily. The number needed to treat for response was 4.9. Glucosamine reduced joint space narrowing by 0.27 mm over three years compared with placebo.


Reference


F Richy et al. Structural and symptomatic efficacy of glucosamine and chondroitin in knee osteoarthritis. Archives of Internal Medicine 2003 163: 1514 to 1522.


Background

Bandolier originally looked at trials of glucosamine for arthritis in 1997 (Bandolier 46), and examined some systematic reviews and a randomised trial in Bandolier 85. All suggested that glucosamine was beneficial, with gathering evidence as more trials were published. Despite this there has been continued debate over its value. A new systematic review helps confirm the value of both glucosamine and chondroitin in knee osteoarthritis.

Systematic review

The review had an exhaustive search strategy up to March 2002, using eight electronic databases, together with had searches, and contact with manufacturers and researchers. For inclusion trials had to be randomised, double blind and placebo controlled, had to assess structural or symptomatic efficacy of oral glucosamine or chondroitin, have a treatment period of at least four weeks, use sensible outcomes, and be valid biological assays.

Results

Fifteen studies were included, with data on 1,775 patients (1,020 glucosamine and 755 chondroitin). Quality scores were high, and were higher for glucosamine trials (all scored 4 or 5 out of 5) than chondroitin trials (all scored 3, 4 or 5 out of 5, except one with insufficient details for scoring). Most studies used intention to treat analyses.

Glucosamine doses were mostly 1,500 mg daily. Trial duration was 6-8 weeks to three years. Chondroitin doses 800 to 2,000 mg daily, in trials of three months to one year.

The main results are shown in Table 1. Glucosamine significantly reduced joint space narrowing by about 0.27 mm compared with placebo over three years with 1,500 mg daily. Glucosamine and chondroitin improved continuous outcomes measured using the Lequesne index, the WOMAC index, and pain and mobility. The minimal differences between treatment and placebo were 2.1 points (1.5 to 2.7) for the Lequesne index, and 13 mm (10 to 16 mm) for pain after 90 days of treatment.

Table 1: Main results of systematic review of glucosamine and chondroitin

Outcome
Number of trials
Effect size (95% CI)
Glucosamine decreasing joint space narrowing
2
0.41 (0.21 to 0.60)
Continuous data, both treatments
Lequesne index reduced
10
0.43 (0.32 to 0.54
WOMAC arthritis index reduced
2
0.30 (0.11 to 0.49)
VAS pain reduced
12
0.45 (0.33 to 0.57)
Mobility increased
3
0.59 (0.25 to 0.92)
Dichotomous data, both treatments
Relative risk (95% CI)
More responders than placebo
9
1.6 (1.4 to 1.8)
Fewer adverse events than placebo
11
0.8 (0.6 to 1.1)

 

Responders (defined by authors on the basis of global assessment) were more frequent with glucosamine and chondroitin (Table 1), and the authors calculated a number needed to treat was 5, with an absolute risk increase of 20% (95% CI 15% to 25%). There was no difference between treatment and placebo for adverse effects. Four studies reported on serious adverse events, which were low and not different between treatment and placebo.

Comment

An excellent systematic review, this, both in its searching and the way it discusses its results. A minor quibble is the use of effect sizes, but ameliorated by giving readers more information in terms of absolute differences and NNTs. It calculated an NNT for a responder as 4.9 on the basis of global outcomes, rather similar to the value of 5.0 calculated in the original Bandolier review (Bandolier 46).

As many as 1 in 5 patients with knee arthritis will benefit from using oral glucosamine at 1,500 mg daily.