Glucosamine Hydrochloride Affects Subchondral Bone Growth
In a rabbit model of osteoarthritis (OA), treatment with glucosamine hydrochloride significantly reduced subchondral bone turnover, according to a study in Arthritis & Rheumatism (A&R) (2007;56:1537-1548).
Glucosamine hydrochloride—a dietary supplement not regulated by the FDA—has long been used to treat OA in humans, with mixed results. In 2001 and 2002, two large clinical trials showed that three years of glucosamine treatment slowed radiographic progression of OA in the knee. Yet in 2006, another randomized, placebo-controlled study in the New England Journal of Medicine found that glucosamine hydrochloride was no better than placebo at controlling knee pain from OA.
Previous studies of the biological workings of glucosamine in animals focused on how the drug affects joint cartilage; this new A&R study was the first to look at how the compound might change the subchondral bone. The authors decided to study subchondral bone changes “because it could explain beneficial outcomes observed in humans in some clinical trials,” says co-author Sheila Laverty, an equine surgeon at the University of Montreal’s veterinary school.
Laverty and colleagues first performed an anterior cruciate ligament transection (ACLT)—a surgical procedure that induces osteoarthritis symptoms—in the knee joints of 16 rabbits. Immediately following the procedure, half the rabbits were given daily doses of glucosamine. After eight weeks, the researchers performed necropsies on all the animals to measure subchondral bone turnover and bone density.
Compared with the control group, glucosamine-treated rabbits had significantly less bone turnover; in most of the bone parameters measured, the glucosamine-treated rabbits were identical to rabbits that had not undergone ACLT. Treatment with glucosamine, Laverty adds, “appeared to offer a protection against the reduction in bone mineral density, subchondral bone plate thickness, and bone connectivity associated with the development of osteoarthritis.”
Still, Laverty cautions against extrapolating these results in the rabbit model to humans. In the model, glucosamine was given from disease onset, while humans are usually studied much later in the disease trajectory. However, she says these findings “could provide some support for the use of glucosamine immediately following joint injury.”
Socioeconomic Factors Affect Access to Rheumatology Care
People with rheumatic diseases, studies have shown, have better treatment outcomes if they see a rheumatology specialist. But are certain segments of the patient population more likely than others to seek and receive specialty care?
To find out, two studies in the May issue of Arthritis Care & Research surveyed almost 1,000 systemic lupus erythematosus (SLE) patients (2007;57:593-600, 601- 607). The first found that elderly, male, and lower-income patients were the least likely to have seen a specialist in the previous year. The second found that Medicaid patients traveled much further than non-Medicaid patients to see the doctor (whether specialist or not) who treated their condition.
