Longitudinal adherence to fecal occult blood testing impacts colorectal cancer screening quality

Existing cross-sectional quality measures for colorectal cancer (CRC) screening do not assess longitudinal adherence and thus may overestimate the quality of care. Our goal was to evaluate the adherence to repeated yearly fecal occult blood tests (FOBTs) in order to better understand the extent to which longitudinal adherence may impact screening quality.

This was a retrospective cohort analysis of 1,122,645 patients aged 50-75 years seen at any of the 136 Department of Veterans Affairs medical centers across the United States in 2000 and followed through 2005. The primary outcome was receipt of adequate CRC screening as defined by receipt of FOBTs in at least 4 out of 5 years or receipt of any number of FOBTs in addition to at least one colonoscopy, flexible sigmoidoscopy, or double-contrast barium enema. In a predefined subset of patients receiving exclusively FOBT, adherence with repeated testing was determined over the 5-year study period.

Only 41.1% of men and 43.6% of women received adequate screening. Of the 384,527 men who received exclusively FOBT, 42.1% received a single FOBT, 26.0% received 2 tests, 17.8% received 3 tests, and only 14.1% were documented to have received at least 4 tests during the study period. Among the 10,469 female veterans receiving FOBT alone, rates were similar with only 13.7% completing at least 4 FOBTs in the 5-year study period.

Adherence to repeated FOBT is low, suggesting that cross-sectional measurements of quality may overestimate the programmatic success of CRC screening.