Randomised controlled trialcited by the Tayebat archiveabstract only checked A-SUP-13 standard review
Glucosamine for knee pain (GAIT)
Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis.
Overview
Clegg DO et al.. N Engl J Med 2006 · PMID 16495392 · DOI 10.1056/NEJMoa052771
Not better than placebo overall.
Does the study support the specific claim? Yes · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Knee OA pain.
- How was the study done?
RCT.
- How many people, animals or samples were studied?
1,583.
- What was actually found?
No overall benefit.
- How large was the observed effect?
+3.9 points n.s.
- What do the results mean in everyday life?
Little benefit.
- What are the study's limitations?
Subgroup.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Harm.
Scientific in-depth review
1. Full reference
- Authors
- Clegg DO, Reda DJ, Harris CL, Klein MA, O'Dell JR, Hooper MM, Bradley JD, Bingham CO, Weisman MH, Jackson CG, Lane NE, Cush JJ, Moreland LW, Schumacher HR, Oddis CV, Wolfe F, Molitor JA, Yocum DE, Schnitzer TJ, Furst DE, Sawitzke AD, Shi H, Brandt KD, Moskowitz RW, Williams HJ
- Journal
- N Engl J Med
- Year
- 2006
- Identifier
- PMID 16495392 DOI 10.1056/NEJMoa052771
- Verification
- verified – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract; grants: NIAMS NIH HHS
2. Research question
Efficacy of glucosamine, chondroitin, combination for knee OA pain
3. Study design and population
- Study design
- Randomised controlled trial – Multicentre double-blind placebo- and celecoxib-controlled RCT (GAIT)
- Population
Symptomatic knee osteoarthritis
- Country
USA
- Period
24 weeks
- Sample size
1,583
- Inclusion and exclusion criteria
see abstract
4. Methods and endpoints
- Exposure / intervention
Glucosamine 1500 mg, chondroitin 1200 mg, both
- Comparator
Placebo; celecoxib 200 mg
- Endpoints
20% reduction in knee pain
- Statistical methods
Response rates
5. Actual results
- Results
Placebo response 60.1%; glucosamine +3.9 points (P=0.30); chondroitin +5.3 (P=0.17); combination +6.5 (P=0.09); celecoxib +10.0 (P=0.008); moderate-severe pain subgroup combination 79.2% vs 54.3% (P=0.002).
- Absolute risks
not reported in abstract
- Authors' conclusion
Glucosamine and chondroitin did not reduce pain effectively overall; combination may help moderate-severe subgroup (exploratory).
6. Strengths
- Large RCT with active control
7. Weaknesses
- High placebo response
- Exploratory subgroup
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Simplified RoB 2.
9. Assessment of the statistical interpretation
See results.
10. Relevance to the specific claim
11. Independent contrary findings
Subgroup signal.
12. Transferability to Germany and Europe
High: biology and trial populations comparable to European adults.
13. Overall methodological judgement
Null overall.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | low |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | correctly reported |
14. Open questions
15. Linked fact checks
- When popular oral supplements (calcium, beta-carotene, vitamin E, omega-3, multivitamins, glucosamine, selenium, vitamin A) were tested in large long-term placebo-controlled trials, most failed to deliver the promised prevention of disease. – Studies supporting the claim
- Certain supplements caused specific harms: more hip fractures (vitamin A), kidney stones (vitamin C), falls and fractures (high-dose vitamin D), type 2 diabetes (selenium), and no benefit for knee pain (glucosamine). – Studies supporting the claim
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
Listed in the archive bibliography of the oral-supplements rule without its own interpretation; used implicitly to support the rule summary that supplements 'failed or caused harm' in large trials.
- A. What was actually studied?
Efficacy of glucosamine, chondroitin, combination for knee OA pain
- B. What did the authors find?
Placebo response 60.1%; glucosamine +3.9 points (P=0.30); chondroitin +5.3 (P=0.17); combination +6.5 (P=0.09); celecoxib +10.0 (P=0.008); moderate-severe pain subgroup combination 79.2% vs 54.3% (P=0.002).
- C. What conclusions do the authors themselves draw?
Glucosamine and chondroitin did not reduce pain effectively overall; combination may help moderate-severe subgroup (exploratory).
- D. What does the archive derive from it?
Supports 'glucosamine failed'.
- E. Is this derivation scientifically justified?
Yes overall.
- Adequacy of the interpretation (by the archive)
- correctly reported