Surgery, cancer and mortality among patients with ulcerative colitis diagnosed 1962‐1987 and followed until 2017 in a Danish population‐based inception cohort

Summary Background Long‐term data on the natural disease course of unselected patients with ulcerative colitis (UC) are limited. Aims To determine the long‐term course and prognosis of UC, including patients’ risks of surgery, cancer and mortality, in a population‐based cohort followed for over 50 years Methods All incident patients with UC diagnosed between 1962 and 1987 in Copenhagen County, Denmark were included in a population‐based cohort. We extracted information about IBD‐related surgeries, cancers and mortality from patient files from 1962 to 1987, and from the Danish National Patient Registry, Cancer Registry, and Register of Causes of Death during 1988‐2017. Patients were matched with up to 50 individuals from the general population. Results We followed 1161 patients for a median of 34 years (range: 0.1‐56.0). Median age at diagnosis was 33 years (range: 2‐88). The cumulative probability of colectomy 10, 20, 30, 40 and 50 years after diagnosis was 22% (95% CI: 20%‐25%), 27% (95% CI: 25%‐30%), 31% (95% CI: 28%‐34%), 34% (95% CI: 31%‐37%), and 40% (95% CI: 36%‐44%), respectively. The risk of small intestinal, colon, rectal and anal cancer was higher than among controls, as was cancer of the skin, pancreas and thyroid. All‐cause mortality was lower than controls (adjusted RR: 0.90, 95% CI: 0.82‐0.99). Conclusion In this population‐based cohort of UC patients diagnosed between 1962 and 1987, 40% underwent colectomy within 50 years of diagnosis. Physicians need to be aware that UC patients are at increased risk of intestinal and extra‐intestinal cancers. However, UC patients’ risk of mortality is comparable to that of the background population.