Utilization of colonoscopy in the community: A preliminary report

Background: Colonoscopy is a commonly performed procedure, but population-based data on the utilization of colonoscopy are lacking. In early 1994, Mayo Medical Center (MMC) implemented an open-access policy for colonoscopy, whereby a consultation with a gastroenterologist was no longer necessary prior to ordering a colonoscopy. Aim: To describe the utilization rate for colonoscopy in the community before and after this change in access. Methods: All colonoscopies in Olmsted County, MN are performed at MMC or the Olmsted Medical Center with the majority being at MMC. Under the auspices of the Rochester Epidemiology Project, information can be obtained about the procedures (including colonoscopy) performed on local residents by either institution. Using this database, all Olmsted County residents who underwent colonoscopy from 1990 through 1995 were identified. Per capita utilization rates were determined and changes in the age- and gender-specific colonoscopy utilization rates were assessed using Poisson regression. Results: The figure illustrates the gender-specific annual colonoscopy utilization rates (number of patients undergoing colonoscopy per 100,000 population) adjusted by age to the 1990 US white population. The arrow indicates the timing of the change in access to colonoscopy at MMC. Colonoscopy utilization rates were greater in men than women and increased with age in both genders. The rise in utilization of colonoscopy by calendar year was statistically significant (p<0.0001) even after adjusting for age and gender. Conclusions: 1) A significant increase in the utilization of colonoscopy was observed at the time of a change in access to colonoscopy for primary care physicians. 2) Further investigation is under way to determine whether the change in utilization is explained entirely by the change in access or by confounding factors such as heightened awareness of colorectal cancer screening.