S-Adenosylmethionine for osteoarthritis of the knee or hip

BACKGROUND: Osteoarthritis is the most common form of joint disease and theleading cause of pain and disability in the elderly. S-Adenosylmethionine may be a viable treatment option but the evidence about its effectiveness and safety is equivocal.OBJECTIVES: We set out to compare S-Adenosylmethionine (SAMe) with placebo or no specific intervention in terms of effects on pain and function and safetyoutcomes in patients with knee or hip osteoarthritis.SEARCH STRATEGY: We searched CENTRAL, MEDLINE, EMBASE, CINAHL and PEDro up to 5August 2008, checked conference proceedings and reference lists, and contactedauthors.SELECTION CRITERIA: Randomised or quasi-randomised controlled trials thatcompared SAMe at any dosage and in any formulation with placebo or nointervention in patients with osteoarthritis of the knee or hip.DATA COLLECTION AND ANALYSIS: Two independent authors extracted data usingstandardised forms. We contacted investigators to obtain missing outcomeinformation. We calculated standardised mean differences (SMDs) for pain andfunction, and relative risks for safety outcomes. We combined trials usinginverse-variance random-effects meta-analysis.MAIN RESULTS: Four trials including 656 patients were included in the systematic review, all compared SAMe with placebo. The methodological quality and thequality of reporting were poor. For pain, the analysis indicated a small SMD of-0.17 (95% CI -0.34 to 0.01), corresponding to a difference in pain scoresbetween SAMe and placebo of 0.4 cm on a 10 cm VAS, with no between trialheterogeneity (I(2) = 0). For function, the analysis suggested a SMD of 0.02 (95%CI -0.68 to 0.71) with a moderate degree of between-trial heterogeneity (I2 =54%). The meta-analyses of the number of patients experiencing any adverse event,and withdrawals or drop-outs due to adverse events, resulted in relative risks of1.27 (95% CI 0.94 to 1.71) and 0.94 (95% CI 0.48 to 1.86), respectively, butconfidence intervals were wide and tests for overall effect were not significant.No trial provided information concerning the occurrence of serious adverseevents.AUTHORS' CONCLUSIONS: The current systematic review is inconclusive, hampered by the inclusion of mainly small trials of questionable quality. The effects of SAMeon both pain and function may be potentially clinically relevant and, althougheffects are expected to be small, deserve further clinical evaluation inadequately sized randomised, parallel-group trials in patients with knee or hiposteoarthritis. Meanwhile, routine use of SAMe should not be advised.