Objective: To assess the clinical efficacy of chondroitin sulfate (CS) in comparison with the nonsteroidal antiinflammatory drug (NSAID) diclofenac sodium (DS) in a medium/longterm clinical study in patients with knee osteoarthritis (OA).
Methods: This was a randomized, multicenter, double blind, double dummy study. 146 patients with knee OA were recruited into 2 groups. During the first month, patients in the NSAID group were treated with 3 x 50 mg DS tablets/day and 3 x 400 mg placebo (for CS) sachets; from Month 2 to Month 3, patients were given placebo sachets alone. In the CS group, patients were treated with 3 x 50 mg placebo (for diclofenac) tablets/day and 3 x 400 mg CS sachets/day during the first month; from Month 2 to Month 3, these patients received only CS sachets. Both groups were treated with 3 x 400 mg placebo sachets from Month 4 to Month 6. Clinical efficacy was evaluated by assessing the Lequesne Index, spontaneous pain (using the Huskisson visual analog scale), pain on load (using a 4 point ordinal scale), and paracetamol consumption.
Results: Patients treated with the NSAID showed prompt and plain reduction of clinical symptoms, which, however, reappeared after the end of treatment; in the CS group, the therapeutic response appeared later in time but lasted for up to 3 months after the end of treatment.
Conclusion: CS seems to have slow but gradually increasing clinical activity in OA; these benefits last for a long period after the end of treatment.