A couple of days after Thanksgiving, I described my adventure with a knee that was no longer cooperating with the rest of the body. That post drew over 20 comments, with many suggestions on what to do next.
I was not a good patient, and did not introduce the knee to the medical establishment. I did find a description of simple exercises designed to aid arthritic knees, a category which might plausibly include my own. Those exercises, designed to strengthen muscles around the knee, certainly helped.
I also began taking daily doses of glucosamine in one of those combos available at Costco.
Over the next few weeks, I jumped back into our early morning walks, slowly increasing the distance every day or two until I managed to make it through the whole walk of about 3 miles. It was slower going than usual, but I made it. And, gradually, the occasional sharp pains became less frequent, and the knee is almost back to normal. It still offers reminders that special care and attention is necessary, but it is no longer disrupting my typical day.
I was ready to declare victory for glucosamine. Then I looked again at the available scientific literature.
Consumer Reports refers to a “natural medicine” database and reports an optimistic finding that glucosamine is
likely effective for osteoarthritis.
Some research suggests that glucosamine reduces pain of osteoarthritis in the knee about as well as the over-the-counter pain reliever acetaminophen (Tylenol). It also seems to reduce pain about as much as the nonsteroidal anti-inflammatory drugs (NSAIDs) ibuprofen (Motrin, Advil) and piroxicam (Feldene). But there is a difference between glucosamine sulfate and these drugs in the time it takes to reduce pain. The NSAIDs, such as Motrin, Advil, and Feldene, relieve symptoms and reduce pain usually within about 2 weeks, but the glucosamine sulfate takes about 4-8 weeks.
But the “Science-Based Medicine” blog is highly critical of mildly optimistic research results.
Although no one study can be definitive, this one is pretty convincing when viewed in the context of all the other published data. The authors rightly conclude that glucosamine doesn’t work any better than placebo, but they go on to say some rather strange things. They say it should not be recommended for “all” patients with osteoarthritic low back pain, implying that it might still be recommended for “some” patients. But if so, which patients and according to what criteria? They seem strangely defensive. They stress that glucosamine caused no side effects and could be used safely. They suggest that glucosamine might work for a subset of patients or for joints other than the spine. For instance, the knee. But another new study has confirmed that it is ineffective for the knee.
I don’t understand this. If they had found that a new antibiotic worked no better than a placebo for pneumococcal pneumonia, would they say it should not be recommended for “all” patients with pneumococcal pneumonia or would they simply say it should not be used for pneumococcal pneumonia? Would they speculate that it might work for a small subset of pneumonia patients or for infections in other parts of the body? Probably not. They thought glucosamine worked; they tested it; it didn’t. Why not just say so? Are they letting a prior belief in glucosamine influence their thinking? Unbiased science-based researchers are not usually so hesitant to give up on a treatment that repeatedly fails to pass tests.
A follow-up reported on a more recent study.
A new study was published 19 February 2008 in the prestigious Annals of Internal Medicine. It is arguably the best study to date, and may shed some light on the controversy. Carried out in the Netherlands in a primary care setting, it studied 222 patients with hip osteoarthritis over a 2 year period. Half the patients took glucosamine sulfate 1500 mg a day; half took a placebo. They concluded that glucosamine sulfate was no better than placebo in reducing symptoms and progression of hip osteoarthritis.
The Arthritis Foundation has a statement on glucosamine based on a widely-cited 2006 study.
While the study overall concluded that glucosamine and chondroitin were not better than placebo in reducing knee pain in the majority of people with OA, it did find that the combination of the two supplements provided significant pain relief for people with moderate-to-severe knee OA. Based on the findings from this study, the Arthritis Foundation recommends that individuals with knee OA speak to their doctors about whether combined glucosamine-chondroitin therapy might be a beneficial addition to their overall treatment plans….The more severe the pain, the better the response. People with moderate-to-severe knee OA pain experienced 25 percent greater pain relief than those taking other treatments.
Meanwhile, Quackwatch says any medical benefit is “unlikely.”
Actually, it’s a bit more blunt.
Chondroitin appears to be useless. Whether glucosamine is useful is conflicting, but the best-designed studies are negative. This usually means that negative evidence will eventually prevail. Decisions to use glucosamine must be based on information that is less complete than is desirable. In addition, product quality control may be a significant problem.
Despite the evidence, I’ll likely keep taking this stuff as long as my knee keeps improrive and the bottle isn’t empty.
Just call me Mr. Placebo!