Colonoscopy : Introduction and development, completion rates, complications and cancer detection
Abstract: In a population-based study in the county of Södermanland, 6066 colonoscopies performed in 4304 patients from 1979 to 1995 inclusive were evaluated. As indications, bleeding increased and polyps and unclear x-ray findings decreased. Surveillance (cancer, polyps, colitis) was fairly stable. Both the rate of complete colonoscopies (overall 75%), and the proportion of colonoscopies performed by experienced endoscopists increased over time. The annual number of barium enemas was relatively constant up to 1992, but then decreased. Completion rates decreased by female sex and by age, and increased by previous colonic surgery or long-standing colitis, but remained unchanged by time period or presence of diverticulosis. Completion rates were influenced by endoscopist's experience and to some extent by intensity of colonoscopy. There was a large inter-endoscopist variation, at each level of experience, in the ability to perform complete colonoscopy, implying substantial differences in individual learning curves. The overall morbidity was 0.4%, diagnostic morbidity 0.2% and therapeutic morbidity 1.2%. Most frequent complications were bleeding (0.2%) and perforation (0. 1 %), with no colonoscopy-related mortality. Bleeding was confined to therapeutic colonoscopy and occurred immediately, mostly after removal of large thick-stalk polyps. Perforations at diagnostic colonoscopy occurred in the left colon; they were diagnosed sooner than at therapeutic colonoscopy, at which the caecum was the most frequent perforation site. Bleeding complication rate was correlated to experience of the endoscopists. Colorectal cancers were diagnosed in 174 patients and in 6 patients were not detected at colonoscopy. Comparing these, there were no significant differences in gender, age, indications, presence of polyps or diverticulosis, time period, or experience of endoscopist. The mean completion rate for the endoscopists was lower in patients with undetected cancers. Coexisting inflammatory bowel disease was more common in patients with late diagnosis. The sensitivity was 96.7%, higher when the indication was bleeding, canoer or unclear x-ray, and lower when the colonoscopy was performed on other indications.
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