preferred_name: Patients greater than or equal to 86 years of age who underwent a screening colonoscopy and did not have a history of colorectal cancer or other valid medical reason for the colonoscopy, including: iron deficiency anemia, lower gastrointestinal bleeding, familial adenomatous polyposis, lynch syndrome (i.e., hereditary non-polyposis colorectal cancer), inflammatory bowel disease (i.e., crohn's disease or ulcerative colitis), abnormal finding of gastrointestinal tract, weight loss, or changes in bowel habits