Background: Although the dietary supplement glucosamine is commonly used to treat osteoarthritis pain, its effectiveness is unclear. Recent studies have had inconclusive results. Most of these studies evaluated knee osteoarthritis or included multiple joints, and none exclusively evaluated hip osteoarthritis. Rozendaal and colleagues studied the effects of glucosamine on the progression and pain of hip osteoarthritis in primary care patients.

The Study: This blinded, randomized, placebo-controlled trial included patients from primary care practices in the Netherlands. Eligible patients met American College of Rheumatology clinical criteria for hip osteoarthritis. Patients were excluded if they were already taking glucosamine; had severe osteoarthritis; had received or were awaiting hip replacement surgery; or had renal disease, liver disease, diabetes, or another comorbid condition that would prevent them from traveling to the research center. Patients who dropped out of the study because of hip replacement surgery or for violating the study protocol were encouraged to complete the data collection to minimize loss to follow-up.

Participants were randomly assigned to receive glucosamine, 1,500 mg daily, or placebo for two years. The primary outcomes were pain and function over 24 months and joint space narrowing after 24 months. Secondary outcomes included pain, function, stiffness, and pain medication use at intervals throughout the study. The authors determined the minimal clinically important differences on the pain and function scales used and for joint space narrowing.

Results: Of 222 eligible patients, 207 completed the evaluation at 24 months. The glucosamine and placebo groups were similar at baseline and had comparable adherence rates. Thirteen patients in the glucosamine group and seven in the placebo group underwent total hip arthroplasty during the study. Incomplete data were accounted for in the mixed-model analyses. None of the primary or secondary outcomes achieved the minimal clinically important differences. Adverse effects were balanced between treatment and placebo groups and were generally mild.

Conclusion: The authors conclude that glucosamine is no more effective than placebo in improving symptoms and delaying joint space narrowing in patients with hip osteoarthritis.