Successful colonoscopy; completion rates and reasons for incompletion.

Factors such as poor bowel preparation or obstructing colonic disease may confound the reporting of colonoscopy completion rates, as these factors are outside of the control of the endoscopist performing the procedure. By adjusting for these factors when calculating a colonoscopy completion rate, it may be possible to make a more accurate assessment of a unit's or individuals' competence. Details of two thousand two hundred and sixteen colonoscopies performed by four consultants and their trainees between 1993-2000 were analysed retrospectively from a prospective endoscopy database. Crude (all cases) and adjusted (excluding poor bowel preparation and disease as causes of incompletion) rates were recorded for each sex, and by age according to cause. Overall crude and adjusted completion rates were 77.9% and 85.0% respectively. There was a significant difference between male and female completion rates due to a difference in the incidence of excess looping and intolerance of the procedure (adjusted rate 88.9% in males vs. 81.6% in females, p<0.05). There was a non-significant trend to lower completion rates in patients over 75 years of age compared to younger patients. Completion rates were significantly higher following bowel resection (adjusted rates 93.5% vs. 82.8%, p<0.05). There was no significant difference between completion rates for inpatient and outpatient referrals (P=0.36). Reporting colonoscopy completion rates by adjusting for factors such as poor bowel preparation and obstructing colonic disease allows for direct comparisons of completion rates reported by different units. Reporting completion rates in this way also highlights the effect of inadequate bowel preparation on successful colonoscopy.