2012 HSR&D/QUERI National Conference Abstract
3027 — Is an Opt-In Recruitment Strategy Associated with a Higher Rate of Study Enrollment
Ling BS, and Dobrosky S, VA Pittsburgh; Larkin A, and Hawley S, Ann Arbor VA;
To determine the impact of an IRB-required opt-in strategy on participant recruitment in a multisite randomized controlled trial aimed at increasing colorectal cancer screening.
Recruitment occurred within the primary care clinic at two VA medical centers from February 2009 to June 2011. At Site 1, an opt-in strategy (potential participant had to actively signal approval for future contact after being mailed the introductory letter) was initally adopted. After nine months, recruitment was modified to an opt-out approach (non-response to the initial approach followed by further contact unless the potential participant requests none). At Site 2, an opt-out strategy was utilized throughout. We compared the rate of enrollment (## enrolled/## eligible) between the opt-in versus the opt-out strategy and assessed for demographic differences as well as associations with completion of colorectal cancer screening. Contingency tables with Chi-square tests were used to test for significant differences.
At Site 1, during the opt-in period, 756 mailings were sent of which 32 subsequently enrolled into the study (4.2%), compared to 106 of 934 potentially eligible subjects during the opt-out period (11.1%, P <0.001). The enrollment rate at Site 2 (opt-out throughout) was 15% (339/2210). The rates of recruitment at Site 1 and Site 2 when both utilzed the opt-out were not statistically different. When participants who enrolled via opt-in were compared to those enrolled via opt-out at Site 1 only, those enrolled via opt-in were more often white (64% vs. 46%, P <0.05) than those enrolled during opt-out. No differences by education, age, or income were found. Those enrolled by opt-in had higher rates of screening adherence than those enrolled via opt-out (49% vs. 35%, P <0.05).
A higher rate of enrollment was seen during opt-out period. The recruitment approaches differed by the race enrolled. We also found the opt-in approach associated with higher rates of screening adherence.
An opt-out strategy appears to translate to higher rates of enrollment and may be worth consideration for future similar minimal risk studies. Further work should be done to evaluate the impact of opt-out vs. opt-in strategies on Veterans within certain demographic groups, as well as on specific study outcomes.