Endoscopic procedures and diagnoses are not influenced by seasonal variations

Background: The occurrences of various GI diseases are thought to be influenced by seasonal variations. The present study was done to test the hypothesis that seasonal variations in endoscopic diagnoses reflect underlying patterns in the performance of endoscopic procedures. Methods: The Clinical Outcomes Research Initiative (CORI) uses a computerized endoscopic report generator to collect endoscopic data from 73 diverse practice sites throughout the United States. We used the CORI database to analyze the date-specific occurrence of EGD and colonoscopy, as well as the endoscopic diagnoses of gastric ulcer, duodenal ulcer, and colorectal cancer. Time trends are analyzed by autocorrelation and by linear and nonlinear regression. Results: Between January 2000 and December 2003, the number of EGDs and colonoscopies increased 2.5- and 4.1-fold, respectively. The rate of duodenal ulcer fell from 21.2 (15.6-27.5) to 19.0 (15.8-22.8) per 1000 EGDs. The rate of gastric ulcer fell from 42.6 (33.3-50.1) to 33.4 (29.5-38.7) per 1000 EGDs. The rate of colorectal cancer fell from 109.9 (98.3-122.8) to 72.2 (67.4-77.2) per 1000 colonoscopies. The time trends of neither endoscopic procedures nor endoscopic diagnoses revealed any seasonal variation or other cyclic pattern. Conclusions: The performance of endoscopic procedures is unaffected by any seasonal variation.