82 consecutive outpatients with Crohn's disease (n = 52) and ulcerative colitis 
(n = 30) were examined ambulatory. Rheumatic complaints, objective results and 
diagnosis were correlated to the activity of the underlying illness and the 
extent of the bowel affected. 61% of the examined patients complaint about 
rheumatic pains. In two thirds this could be attributed to noninflammatory 
causes (30% insertion tendinitis. 16% degenerative arthritis, 16% wrong 
carriage), which appeared to be independent of the activity and severity of the 
underlying disease. One fourth of the rheumatic complaints was caused by 
inflammation (21% arthritis, 5% sacroileitis). In these cases a dependency on 
the disease activity and the extent of the colon involvement could be found. No 
cause was found for 12% of the rheumatic complaints. In patients with ulcerative 
colitis suffering from arthritis a significant increase of disease activity 
(Rachmilewitz index) could be shown as compared to ulcerative colitis patients 
without arthritis (p < 0.02). For patients with Crohn's disease no significant 
correlation between arthritis and disease activity could be established. In 
these cases the occurrence of arthritis was associated with the colon 
involvement (Chi2 = 8.48). The data indicate the high frequency of rheumatic 
complaints in inflammatory bowel diseases due to noninflammatory causes.