After two years of treatment, glucosamine sulfate has no clinically meaningful effect on pain, function, or radiographic progression in patients with hip osteoarthritis, according to a paper in the Annals of Internal Medicine. After two years of treatment, glucosamine sulfate has no clinically meaningful effect on pain, function, or radiographic progression in patients with hip osteoarthritis, according to a paper in the Annals of Internal Medicine for February 19.

However, these findings should not be the final word on treatment of osteoarthritis with glucosamine, given shortcomings of the trial design, Drs. Johannes W. J. Bijlsma and Floris P. J. G. Lafeber write in an accompanying editorial.

Despite numerous clinical trials, definitive evidence of glucosamine's efficacy is lacking, the editorialists point out. They attribute much of the uncertainty to nonstandardized glucosamine preparations, inadequate allocation concealment, and differences in outcome measures.

The current randomized, placebo-controlled trial by Rianne M. Rozendaal and colleagues at the Erasmus Medical Center in Rotterdam, the Netherlands, is the first to examine the effect of glucosamine on osteoarthritis of the hip.

The research team took care to ensure the integrity of their results. The supplier of the glucosamine sulfate was required to double-check that the tablets were the correct dose, and all physicians, patients, and researchers were blinded to group assignment. The rate of completion was high (93 per cent), and the study was conducted without pharmaceutical company funding.

The 24-month study included 222 patients randomized to glucosamine sulfate 1500 mg daily or to placebo. Based on the theory that glucosamine is more effective in early osteoarthritis, patients with a Kellgren and Lawrence score of 4 were excluded. About half the patients had mild arthritis, with a score of 1 and symptom duration of three years or less.

Treatment allocation had no significant effect on pain scores, physical function, stiffness, use of pain medication, or joint space narrowing determined by radiography, Rozendaal's team reports.

"This well-designed, well-performed study" still fails to provide definitive answers as to the efficacy of glucosamine in osteoarthritis, Dr. Bijlsma and Dr. Lafeber point out, since the results apply only to patients with osteoarthritis of the hip in relatively early stages of the disease.