Knowledge outcomes in a randomized trial of telephone vs. in-person disclosure of genetic testing: The COGENT study.

Abstract

1534 Background: Telephone disclosure (TD) of genetic testing is non-inferior to in-person disclosure (IPD) for most outcomes but did not meet non-inferiority for knowledge change. We sought to understand which concepts patients don’t understand and factors associated with lower knowledge. Methods: Patients were recruited to a multi-center, randomized trial (NCT01736345) comparing TD to IPD of genetic test results. 819 patients were randomized (IPD = 418; TD = 401); 165 declined randomization and requested IPD. Knowledge was assessed after pre-test counseling (V1) and test disclosure (V2). Results: There were no significant differences in genetic or multi-gene (MG) knowledge between disclosure groups after V1 and V2. On average, patients answered 73% (SD 1.19) of genetic knowledge and 57% (SD 1.78) of mg knowledge items correctly.After V1, most understood implications of a positive result (87%), that results are not deterministic (84%) and risks for their children (91%). Understanding of uninformative negative, true negative and variant of uncertain significance (VUS) results was lower (post-V1: 33%, 65%, 29%; post-V2 : 37%, 65%, 25%). In multivariable analyses, lower genetic knowledge after V1 was associated with study site, being older (p < 0.01), single (p < 0.01), non-white (p < 0.01), not Ashkenazi Jewish (p = 0.01), and not having a mutation in the family (p = 0.03), having more relatives with cancer (p < 0.01) and not graduating college (p < 0.01). Lower mg knowledge after V1 was associated with site and being non-white (p = 0.01). Lower genetic knowledge after V2 was not associated with disclosure method but associated with study site, being older (p < 0.01), not graduating college (p < 0.01) and being non-white (p < 0.01). Lower mg knowledge after V2 was only associated with not graduating college (p = 0.02). Conclusions: While there were no significant differences in genetic knowledge by disclosure method, understanding of several concepts (e.g. VUS and negative results) were lower regardless of arm. Several factors, including age, education and race/ethnicity were associated with lower knowledge. Interventions to improve genetic knowledge in real-world and diverse populations are needed. Clinical trial information: NCT07136345.