Colorectal cancer
The risk of colorectal cancer is significantly increased in people with ulcerative colitis after ten years if involvement is beyond the splenic flexure. People with backwash ileitis might have an increased risk for colorectal carcinoma. Those people with only proctitis usually have no increased risk. It is recommended that people have screening colonoscopies with random biopsies to look for dysplasia after eight years of disease activity, at one to two year intervals. Mortality
People with ulcerative colitis are at similar or perhaps slightly increased overall risk of death compared with the background population. However, the distribution of causes-of-death differs from the general population. Specific risk factors may predict worse outcomes and a higher risk of mortality in people with ulcerative colitis, including: C. difficile infection and cytomegalovirus infection (due to reactivation). Epidemiology
Together with Crohns disease, about 11.2 million people were affected as of 2015. Each year, ulcerative colitis newly occurs in 1 to 20 per 100,000 people (incidence), and there are a total of 5-500 per 100,000 individuals with the disease (prevalence). In 2015, a worldwide total of 47,400 people died due to inflammatory bowel disease (UC and Crohns disease). The peak onset is between 30 and 40 years of age, with a second peak of onset occurring in the 6th decade of life. Ulcerative colitis is equally common among men and women. With appropriate treatment the risk of death appears similar to that of the general population.
While usually associated with Crohns disease, ileitis (inflammation of the ileum) also occurs in UC. About 17% of individuals with UC have ileitis. Ileitis more commonly occurs in the setting of pancolitis (occurring in 20% of cases of pancolitis), and tends to correlate with the activity of colitis. This so-called "backwash ileitis" can occur in 10–20% of people with pancolitis and is believed to be of little clinical significance. Severity of disease
In addition to the extent of involvement, UC is also characterized by severity of disease. Severity of disease is defined by symptoms, objective markers of inflammation (endoscopic findings, blood tests), disease course, and the impact of the disease on day-to-day life. Most patients are categorized through endoscopy and fecal calprotectin levels. Indicators of low risk for future complications in mild and moderate UC include the following parameters: exhibiting less than 6 stools daily and lack of fever/weight loss. Other indicators include lack of extraintestinal symptoms, none to little elevation in CRP, ESR, and calprotectin, and later age of diagnosis (over 40 years). Mild disease correlates with fewer than four stools daily; in addition, mild urgency and rectal bleeding may occur intermittently. Mild disease lacks systemic signs of toxicity (eg. fever, chills, weight changes) and exhibits normal levels of serum inflammatory markers (erythrocyte sedimentation rate and C-reactive protein).Moderate to severe disease correlates with more than six stools daily, frequent bloody stools and urgency. Moderate abdominal pain, low-grade fever, 38 to 39 °C (100 to 102 °F), and anemia may develop (75% of normal).