Predictors of nonadherence to screening colonoscopy

BACKGROUND: Colonoscopy has become a preferred colorectal cancer (CRC) screening modality. Little is known about why patients who are referred for colonoscopy do not complete the recommended procedures. Prior adherence studies have evaluated colonoscopy only in combination with flexible sigmoidoscopy, failed to differentiate between screening and diagnostic procedures, and have examined cancellations/no-shows, but not nonscheduling, as mechanisms of nonadherence. METHODS: Sociodemographic predictors of screening completion were assessed in a retrospective cohort of 647 patients referred for colonoscopy at a major university hospital. Then, using a qualitative study design, a convenience sample of patients who never completed screening after referral (n=52) was interviewed by telephone, and comparisons in reported reasons for nonadherence were made by gender. RESULTS: Half of all patients referred for colonoscopy failed to complete the procedure, overwhelmingly because of nonscheduling. In multivariable analysis, female sex, younger age, and insurance type predicted poorer adherence. Patient-reported barriers to screening completion included cognitive-emotional factors (e.g., lack of perceived risk for CRC, fear of pain, and concerns about modesty and the bowel preparation), logistic obstacles (e.g., cost, other health problems, and competing demands), and health system barriers (e.g., scheduling challenges, long waiting times). Women reported more concerns about modesty and other aspects of the procedure than men. Only 40% of patients were aware of alternative screening options. CONCLUSIONS: Adherence to screening colonoscopy referrals is sub-optimal and may be improved by better communication with patients, counseling to help resolve logistic barriers, and improvements in colonoscopy referral and scheduling mechanisms.