Risk of relapse in new cases of ulcerative colitis and indeterminate colitis

Changes in morbidity pattern of ulcerative colitis have created a need to update understanding of the course of the disease. A follow-up study was done of relapse rates and progression of inflammation in 571 non-selected patients with ulcerative and indeterminate colitis. Relapse rate ten years after diagnosis was 70 percent in definite ulcerative colitis, 22 percent in probable ulcerative colitis, and 77 percent in indeterminate colitis. During the study period, there was no change in the relapse rate. In relapsing proctitis, 52 percent developed more extensive inflammation. Fifty-four percent of patients with only one attack of colitis had persistent signs of inflammatory bowel disease. Shift in morbidity pattern to a greater proportion of patients with proctitis at diagnosis and a shorter time from onset of symptoms to diagnosis had no influence on the relapse rate. Indeterminate colitis has a worse prognosis than definite ulcerative colitis. Considering the documented efficacy of sulfasalazine, the high relapse rate calls for studies of the effectiveness of such treatment in everyday practice.