NEW YORK – New research has highlighted progress made so far in implementing a population-wide genomic screening (PWGS) program in South Carolina, while providing a look at the gaps that remain in reaching and engaging the population more broadly.
"As more institutions seek to implement population-based screening programs, it will be critical to understand barriers and facilitators and share best practices," first and corresponding author Caitlin Allen, a public health sciences researcher at the Medical University of South Carolina (MUSC), said in an email, explaining that "[o]ur approach to incorporating implementation science methods allows us to systematically identify and address facilitators and barriers."
As they reported in the American Journal of Human Genetics on Thursday, the researchers turned to a so-called "reach, effectiveness, adoption, implementation, and maintenance" (RE-AIM) framework to take a closer look at early participant outcomes in their own population screening program, known as In Our DNA SC.
"We completed interim analysis of a large-scale PWGS program based on pre-identified aims using the RE-AIM implementation science framework," the authors explained, noting that "[a]ssessment of implementation outcomes from the first approximately 20,000 individuals recruited provides the opportunity to evaluate the impact of the program to date and plan for additional future modifications."
The program is focused on screening for pathogenic or likely pathogenic variants linked to conditions classified as Tier 1 by the US Centers for Disease Control and Prevention — from hereditary breast and ovarian cancer syndrome or Lynch syndrome to familial hypercholesterolemia — using Helix sequences on a panel of 11 genes, together with free genetic counseling for individuals positive for risky Tier 1 variants.
"To our knowledge, this is the first population-based genomic screening study focused on the Southeast USA," senior author Daniel Judge, director of cardiovascular genetics at MUSC and principal investigator of the In Our DNA SC genomic screening program, said in an email. "We hope that expanded demographic representation in genomic screening will help to better understand the range of normal and abnormal human genetic variation."
In the new study, Allen, Judge, and their coauthors noted that 20,478 participants enrolled in In Our DNA SC during the first 14 months of the program. Most of the 13,643 samples collected in the same time frame were obtained through at-home collection, but samples also came in through community events or clinical appointments at a dozen participating clinics.
Roughly half of the participants who enrolled went on to finish the program, the researchers reported, leading to the identification of pathogenic or likely pathogenic variants linked to Tier 1 conditions in 137 In Our DNA SC participants.
"These findings align with the expected frequencies of between [1 to 2 percent] of the population that has a pathogenic/likely pathogenic variant associated with a CDC Tier 1 condition," Allen explained, noting that the team has since found another 226 program participants with pathogenic or likely pathogenic variants in the 11 genes targeted.
More than 77 percent of individuals with pathogenic or likely pathogenic variants from the first stage of the program agreed to meet with a genetic counselor, and 80 percent of those participants have gone through the genetic counseling process.
While non-Hispanic white female participants between the ages of 40 and 49 were overrepresented in the program, younger and more diverse participants tended to join the program via events taking place in the community.
Members of the In Our DNA SC team plans to continue offering free genomic screening in South Carolina, with the goal of screening at least 100,000 individuals, Allen said. They are also building a related research database and supporting infrastructure so that other MUSC researchers can explore genetic contributors to health outcomes.
More generally, Allen explained, "the tools and resources we developed to track key metrics of reach, effectiveness, adoption, implementation, and maintenance outcomes in real time can be used by other programs working to [start] population-based screening."