Uptake and positive predictive value of fecal occult blood tests: A randomized controlled trial

Abstract

Objective: The aim of this study is to compare the uptake of three mailed high-sensitivity fecal occult blood tests (FOBTs).

Methods: We conducted a parallel 3-arm randomized controlled trial in an integrated healthcare delivery system in Washington State. From January 2010 through February 2011, automated data were used to identify potentially eligible patients aged 50-74 due for colorectal cancer screening. Participants were mailed one of three FOBT kits (1-sample OC-Auto® fecal immunochemical test [FIT], 2-sample InSure® FIT, or 3-sample guaiac Hemoccult SENSA®), instructions, and a postage-paid return envelope. We performed a modified intent-to-treat analysis with return of any FOBT within 6 months of randomization as the primary outcome.

Results: Of the 9922 people invited, 2873 returned surveys, 2263 were randomized, and 2234 were analyzed. FOBTs were returned by 1431 participants. At 6 months post-randomization, the proportions screened by any FOBT were 0.69 (95% confidence interval [CI] 0.66-0.72) for the OC-Auto arm, 0.64 (95% CI: 0.61-0.68) for the InSure arm, and 0.61 (95% CI: 0.58-0.65) for the Hemoccult SENSA arm (P<0.001 for any difference). Pairwise comparisons showed significant differences between the OC-Auto group and each of the other groups after correction for multiple comparisons.

Conclusion: Uptake of mailed FOBT kits varies by kit type.

Trial registration: ClinicalTrials.gov NCT01052922.

Keywords: Colorectal neoplasms; Early detection of cancer; Intervention studies.

© 2013.

Figures

Figure 1

Participant recruitment and randomization for trial of fecal occult blood test uptake, Group Health, Washington State 2010-2012.

Figure 2

Test return within 6 months by randomization group. Blue, OC-Auto; red, InSure; green, Hemoccult SENSA, Group Health, Washington State 2010-2012.