Background: Osteoarthritis (OA) is the most common form of arthritis and is often associated with disability and impaired quality of life.
Objective: The aim of the study was to assess the efficacy and tolerability of glucosamine sulfate (GS) in the treatment of knee OA.
Methods: Consecutive outpatients affected by primary monolateral or bilateral knee OA were enrolled in this double-blind, double-dummy, prospective, randomized, placebo-controlled trial. One group received GS 1500 mg QD for 12 weeks, and the other group received placebo QD for 12 weeks. The treatment period was followed by a 12-week treatment-free observation phase. Each patient was examined at baseline and at weeks 4, 8, 12, 16, 20, and 24. The primary efficacy criteria were pain at rest and during movement, assessed on a visual analog scale (VAS) of 0 to 100 mm. The secondary criteria included the Western Ontario and McMaster Universities (WOMAC) index for total pain score (W-TPS), total stiffness score (W-TSS), and total physical function score (W-TPFS). VAS, W-TPS, W-TSS, and W-TPFS were evaluated at baseline and at weeks 4, 8, 12, 16, 20, and 24. Analgesic drug consumption (ie, acetaminophen or NSAIDs) was also assessed.
Results: Patient demographics were similar in the GS and placebo groups. Of 60 randomized patients (30 per group), 56 completed the study (28 treated with GS and 28 who received placebo). Statistically significant improvements in symptomatic knee OA were observed, as measured by differences in resting pain at weeks 8, 12, and 16 (all, P < 0.05 vs placebo) and in pain during movement at weeks 12 and 16 (both, P < 0.05). W-TPS was lower with GS than placebo at weeks 8, 12, and 16 (all, P < 0.01), and at week 20 (P < 0.05). W-TSS was also lower with GS than placebo at weeks 8, 12, 16, and 20 (all, P < 0.05). W-TPFS was lower with GS than placebo at weeks 8 (P < 0.05), 12 (P < 0.01), 16 (P < 0.05), and 20 (P < 0.05). Drug consumption was lower in the GS group than the placebo group at weeks 8, 12, 16, and 20 (all, P < 0.05). The incidence of adverse events was 36.7% with GS and 40.0% with placebo.
Conclusions: GS 1500 mg QD PO for 12 weeks was associated with statistically significant reductions in pain and improvements in functioning, with decreased analgesic consumption, compared with baseline and placebo in these patients with knee OA. A carryover effect was detected after treatment ended.
Keywords: carryover effect; efficacy; glucosamine sulfate; knee osteoarthritis; tolerability.