Effectiveness of glucosamine for symptoms of knee osteoarthritis: results from an internet-based randomized double-blind controlled trial

Abstract

Purpose: To present the safety and effectiveness results of a prototypical 12-week, double-blind, randomized placebo-controlled trial of glucosamine among subjects with knee osteoarthritis who were recruited and followed entirely over the Internet.

Methods: The study comprised 205 subjects aged 45 years or older with symptomatic knee osteoarthritis who were recruited over the Internet; eligibility was authenticated through medical record review. Participants were assigned randomly to 1.5 g/d of glucosamine (n = 101) or placebo (n = 104), of whom 108 completed the intervention (93 in each arm). The primary outcome measure was the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (Likert version). Additional outcome measures included the physical function and stiffness subscales and overall score of the questionnaire, and analgesic use.

Results: There was no difference between treatment and control groups in terms of change in pain score (2.0 +/- 3.4 vs. 2.5 +/- 3.8, P = 0.41), stiffness (0.7 +/- 1.6 vs. 0.8 +/- 1.5, P = 0.52), physical function (5.2 +/- 9.5 vs. 4.6 +/- 9.6, P = 0.49), overall score (7.8 +/- 13.1 vs. 7.8 +/- 13.5, P = 0.81), and analgesic use (133 +/- 553 vs. -88 +/- 755, P = 0.12). Stratification by osteoarthritis severity, glucosamine product, and use of a nonsteroidal anti-inflammatory drug, as well as exclusion of opiate users, did not alter the results. The number and type of adverse events reported was similar between the groups.

Conclusion: Our results suggest that although glucosamine appears to be safe, it is no more effective than placebo in treating the symptoms of knee osteoarthritis.