The Diagnostic Odyssey and Cost-Effectiveness of Genomic Testing in Indigenous Children in British Columbia, Canada

Speaker(s)

Regier D1, Weymann D2
1University of British Columbia, Vancouver, BC, Canada, 2Cancer Control Research, BC Cancer Research Institute, Vancouver, BC, Canada

OBJECTIVES: Genomic testing is used to diagnose childhood rare diseases. Benefits of testing are not equitably distributed to Indigenous peoples because of underrepresentation in the variant libraries needed for results interpretation. Access to research-based whole-genome sequencing (WGS) may enable additional diagnoses. We estimate the diagnostic rate and cost-effectiveness of WGS for Indigenous children with developmental and/or seizure disorders.

METHODS: We obtained the diagnostic rate and cost of WGS in Indigenous children from a single-arm clinical trial in British Columbia (BC), Canada. We abstracted real-world standard of care (SOC) outcomes data from BC's Children’s and Women’s Hospital (C&W). Longitudinal and time-to-event analysis characterized key outcomes. Results were inputted into a state-transition Markov model examining two strategies. The first is SOC, involving chromosomal microarray followed by second-tier genetic and biochemical testing, with last-tier exome sequencing. The second is first-tier WGS. We calculated incremental cost per additional diagnosis over a 10-year time horizon, from the healthcare payer perspective.

RESULTS: Our cohort included 63 Indigenous children who underwent WGS. For SOC, we estimated that 25.8% (95% CI: 14.8,36.7) of children would receive a diagnosis at a cost of $11,822 per patient (95% CI: 9,312,14,322). First-tier WGS diagnosed 38.9% (95% CI: 31.3,46.6) of children at a cost of $11,876 (95% CI: 6,909,16,843). Incremental costs and diagnoses were $54 (95% CI: -5,525,5,633) and 13.2% (95% CI -0.29,26.7), respectively. Mean time to diagnosis among diagnosed patients was 24 weeks for WGS compared to 50 for SOC. The incremental cost per additional diagnoses was $409 with 50% cost-effective at a willingness-to-pay threshold of $9,992.

CONCLUSIONS: Using real-world data, we determine the impacts of research-based WGS for diagnosing genetic causes of developmental and seizure disorders in Indigenous children. We find that first-tier access to WGS provides additional diagnoses to Indigenous families, sooner. Expanding access may provide favorable trade-offs between costs and benefits.

Code

EE334

Topic

Clinical Outcomes, Economic Evaluation, Medical Technologies, Study Approaches

Topic Subcategory

Comparative Effectiveness or Efficacy, Cost-comparison, Effectiveness, Utility, Benefit Analysis, Diagnostics & Imaging, Prospective Observational Studies

Disease

Personalized & Precision Medicine, Rare & Orphan Diseases