Dr. Maheu says it’s possible the ASU group would have had even less cartilage loss if the trial had been longer, but it is “very difficult to maintain placebo treatment in patients over such a long period of time.”

Furthermore, disease progression wasn’t what researchers set out to study. They added it to the trial when international research groups recommended against using joint-space width as a primary endpoint in OA studies because it’s difficult to measure properly.

Dr. Maheu says his team used the highest recommended methodological standards in evaluating both joint-space width and disease progression, and the results warrant further study. A follow-up trial to assess whether ASU might prevent or delay the need for total joint replacement surgery is underway.

Unlike earlier studies, the current trial did not find reduced pain, disease severity or NSAID use in patients taking ASU. Dr. Maheu says that is probably because the study wasn’t designed – and patients weren’t selected – to assess those factors. “Patients included [in the study] had a very low level of symptoms at baseline. More than 50 percent said that overall they felt OK,” he explains. “Demonstrating a symptomatic effect in patients with no or few symptoms is quite impossible.”

The study did, however, confirm ASU’s safety.

“There are very few safety concerns with ASU. Most adverse events are gastrointestinal upset,” Dr. Maheu notes.

Larry Bergstrom, MD, a geriatrician and specialist in integrative medicine at Mayo Clinic in Scottsdale, Ariz., says the study was well designed, well analyzed and much about it was positive. For instance, “the number needed to treat is 11, meaning one person gets benefit for every 11 patients treated, which is a good result,” he explains.

But he has a few concerns. “The main problem is that halfway through the study, they figured out that joint-space width wasn’t going to work, and in the end, there wasn’t a significant difference in joint-space width between the two groups,” he says. “They noticed, however, that for people having progressive loss of cartilage, the rate of loss was less for those taking the supplement than for those taking the placebo, so that became the main finding of the study. That conclusion seems valid, but they didn’t set out to look at the thing they found significant, which is always a bit of a red flag.”

Dr. Bergstrom also questions the validity of repeat X-rays taken over a period of years. “It is very hard to get a patient to stand in exactly the same pose over a three-year study. One slight turn can throw off the measurement a lot,” he says.

Finally, he wonders whether production of ASU is rigorously controlled to prevent variability among batches.

“I think the summary is that taking the supplement may slow progression of osteoarthritis of the hip and even delay hip replacement, but at least in this study, it didn’t make anyone feel better,” he says.