A team from Nottingham, England, assessed the prevalence of previously undetected inflammatory bowel disease (IBD).
They investigated subjects found to be fecal occult blood (FOB)-positive in a randomized trial of FOB screening for colorectal cancer.
All FOB-positive subjects were investigated by colonoscopy or flexible sigmoidoscopy and barium enema.
Subjects with IBD were referred back to their general practitioner for any further investigation and treatment.
A total of 75,253 subjects (aged 45-74) were sent FOB tests, and 44,838 (60%) completed a series of tests on one or more occasions.
Of 133,000 test series, 1.5% were found to be positive.
During investigation, 53 cases of previously undetected IBD (52 of ulcerative colitis) were found; 52% had proctosigmoiditis only, whereas 25% had pancolitis.
Only 17% were completely asymptomatic, with a half or more reporting some rectal bleeding (54%) or diarrhea (50%).
The overall prevalence of undetected ulcerative colitis was 69/105 in people offered screening and 116/105 in people accepting screening.
The researchers found that the prevalence was higher in men.
| Only 17% of patients with previously undetected UC were completely asymptomatic.
| American Journal of Gastroenterology |
Of 32 subjects followed up 2-12 years after diagnosis, 91% continued to have few or no symptoms. Only 38% were receiving any treatment for their colitis at the time the study was published.
Author G. F. Howarth, of the University Hospital in Nottingham, said on behalf of the group, "In comparison with detected disease, undetected ulcerative colitis is relatively common but does usually cause some symptoms."
"It generally appears to follow a benign course. However, a significant proportion has extensive colitis and may therefore be at an increased risk of colorectal cancer," it was concluded.