Don’t expect glucosamine/chondroitin to treat knee osteoarthritis

People with knee osteoarthritis who took a placebo for 24 weeks also had about six in ten say the pain eased. Those on glucosamine or chondroitin were only four or five percentage points above that — small enough that it may be chance. Spending 700 to 1800 a year buys an effect that is basically the same as placebo.

Cost

About 2 to 5 yuan a day, or 700 to 1800 yuan a year.

Benefit

The GAIT trial enrolled 1583 people with knee osteoarthritis for 24 weeks. Among those on placebo (fake medicine), 60.1% also said pain eased. Glucosamine was only 3.9 percentage points higher (P=0.30). Chondroitin was 5.3 percentage points higher (P=0.17). Both together were 6.5 percentage points higher (P=0.09). These gaps are too small to rule out chance. In the same trial the real control drug celecoxib was 10.0 percentage points higher (P=0.008). It looks worthwhile because “cartilage building blocks” sound on-target, and placebo alone already helped six in ten people say it worked.

Notes

Controversy: In the same trial, among those who already hurt badly at the start, both together had a response rate of 79.2% versus 54.3% in the control group (P=0.002). The authors say this was dug out of the data afterward and is only a lead, not a conclusion. What actually has evidence for knee osteoarthritis is losing weight and building muscle; see Item 33 in this section (arthroscopic clean-out).

Sources · 1

1. Clegg DO et al. (2006). Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. NEJM. doi.org/10.1056/NEJMoa052771