Time to Colonoscopy after Positive Fecal Blood Test in Four U.S. Health Care Systems

Abstract

To reduce colorectal cancer mortality, positive fecal blood tests must be followed by colonoscopy. We identified 62,384 individuals ages 50 to 89 years with a positive fecal blood test between January 1, 2011 and December 31, 2012 in four health care systems within the Population-Based Research Optimizing Screening through Personalized Regimens (PROSPR) consortium. We estimated the probability of follow-up colonoscopy and 95% confidence intervals (CI) using the Kaplan-Meier method. Overall differences in cumulative incidence of follow-up across health care systems were assessed with the log-rank test. HRs and 95% CIs were estimated from multivariate Cox proportional hazards models. Most patients who received a colonoscopy did so within 6 months of their positive fecal blood test, although follow-up rates varied across health care systems (P <0.001). Median days to colonoscopy ranged from 41 (95% CI, 40-41) to 174 (95% CI, 123-343); percent followed-up by 12 months ranged from 58.1% (95% CI, 51.6%-63.7%) to 83.8% (95% CI, 83.4%-84.3%) and differences across health care systems were also observed at 1, 2, 3, and 6 months. Increasing age and comorbidity score were associated with lower follow-up rates. Individual characteristics and health care system were associated with colonoscopy after positive fecal blood tests. Patterns were consistent across health care systems, but proportions of patients receiving follow-up varied. These findings suggest that there is room to improve follow-up of positive colorectal cancer screening tests. Understanding the timing of colonoscopy after positive fecal blood tests and characteristics associated with lack of follow-up may inform future efforts to improve follow-up.