1 From the Center for Treatment of Rheumatic and Musculoskeletal Diseases, Diakonhjemmet Hospital (L.B.N., E.A.H., S.L.), the Institute of Clinical Medicine, University of Oslo (E.A.H.), and the Clinical Effectiveness Research Group, University of Oslo and Oslo University Hospital (M.B.) - all in Oslo; and the Department of Gastroenterology, VA Medical Center, White River Junction, VT (H.P.).