Guidelines for management of osteoarthritis published by the American College of Rheumatology and the European League Against Rheumatism: why are they so different?

Because of different methodology the ACR and EULAR guidelines differ significantly in their recommendations despite an identical evidence base. Guidelines that use a strictly evidence-based approach are less likely to incur bias than those that rely more on expert consensus. Although expert consensus is useful in areas in which there are little trial data, clear delineation should be made between evidence-based statements and expert opinion. Following the dissemination of guidelines for the management of OA, emphasis should now be placed on discussion and implementation of the recommendations and subsequent revision of guidelines as new evidence comes to light.