The two dietary supplements chondroitin and glucosamine have been around for some time. They are being promoted mostly for osteoarthritis; some claim that they reduce pain, others even believe that they restore the damaged cartilage and thus reverse the disease process. But neither for a symptomatic nor causal therapy has the evidence so far been truly convincing. A new trial might change this situation.
This study compared the efficacy and safety of chondroitin sulfate plus glucosamine hydrochloride (CS+GH) versus celecoxib in patients with knee osteoarthritis and severe pain.
The ‘Double-blind Multicentre Osteoarthritis interVEntion trial with SYSADOA’ (MOVES) was conducted in France, Germany, Poland and Spain and evaluated treatment with CS+GH versus celecoxib in 606 patients with Kellgren and Lawrence grades 2–3 knee osteoarthritis and moderate-to-severe pain (Western Ontario and McMaster osteoarthritis index (WOMAC) score ≥301; 0–500 scale). Patients were randomised to receive 400 mg CS plus 500 mg GH three times a day or 200 mg celecoxib every day for 6 months. The primary outcome was the mean decrease in WOMAC pain from baseline to 6 months. Secondary outcomes included WOMAC function and stiffness, visual analogue scale for pain, presence of joint swelling/effusion, rescue medication consumption, Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) criteria and EuroQoL-5D.
The results show that the adjusted mean change (95% CI) in WOMAC pain was −185.7 (−200.3 to −171.1) (50.1% decrease) with CS+GH and −186.8 (−201.7 to −171.9) (50.2% decrease) with celecoxib, meeting the non-inferiority margin of −40: −1.11 (−22.0 to 19.8; p=0.92). All sensitivity analyses were consistent with that result. At 6 months, 79.7% of patients in the combination group and 79.2% in the celecoxib group fulfilled OMERACT-OARSI criteria. Both groups elicited a reduction >50% in the presence of joint swelling; a similar reduction was seen for effusion. No differences were observed for the other secondary outcomes. Adverse events were rare and similarly distributed between groups.
The authors concluded that CS+GH has comparable efficacy to celecoxib in reducing pain, stiffness, functional limitation and joint swelling/effusion after 6 months in patients with painful knee osteoarthritis, with a good safety profile.
This is a rigorous trial, and I do trust its findings. However, I am not entirely sure what they actually mean: is CS+GH as effective or as ineffective as the COX-2-inhibitor celecoxib? The most recent meta-analysis on the subject found that diclofenac (150 mg/day) was likely to be more effective in alleviating pain than celecoxib (200 mg/day). But that does, of course, not necessarily imply that celecoxib is ineffective.
The other big issue here is safety. COX-2-inhibitors had a bad press because of the risk of cardiovascular side-effects. In comparison, the CS+GH supplement is an almost risk-free alternative. Bearing in mind that we are dealing with long-term treatments here, I think the results of this study might persuade me, had I to choose between these two treatments, to opt for the dietary supplement.