Implementing a primary-tertiary shared care model for enhancing cascade testing for familial hypercholesterolaemia:...

Area of Science:

• Genetics
• Cardiovascular Medicine
• Public Health

Background:

• Familial hypercholesterolaemia (FH) is an underdiagnosed genetic disorder leading to elevated LDL cholesterol and premature cardiovascular disease.
• Cascade genetic testing is underutilized for identifying affected relatives.
• Implementation strategies are crucial for integrating genetic medicine into non-specialty settings.

Purpose of the Study:

• To evaluate a multifaceted implementation strategy aimed at increasing cascade genetic testing for relatives of individuals with FH.
• To assess the effectiveness of a primary-tertiary shared care model in promoting FH cascade testing.

Main Methods:

• A multisite effectiveness-implementation hybrid type III pre-post study conducted between 2022 and 2024.
• Comparison of a control period (genetic counsellor-led testing) with an implementation period (index cases distributing EOI forms to relatives).
• Relatives were contacted by genetic counsellors and received pre- and post-testing packages, shared with their GPs.

Main Results:

• The number of cascade genetic tests per index case significantly increased from 0.24 to 0.52 (IRR=4.62, p=0.032) in the implementation period.
• No significant difference was observed in the proportion of relatives with a confirmed FH gene change per index case (IRR=2.15, p=0.207).
• No significant difference was found in the proportion of index cases with at least one cascade test (OR=1.49, p=0.442).

Conclusions:

• The implemented shared care model successfully increased FH cascade testing compared to standard care.
• Findings support a greater role for cascade testing within primary care settings.
• This model offers opportunities for integrating genetic screening into routine general practice for autosomal dominant conditions like FH.