Preliminary validation of a novel genetic knowledge scale for familial hypercholesterolemia: evaluation of face validity and core concepts

Abstract

The Multidimensional Model of Informed Choice (MMIC) was developed to evaluate informed decision making in the context of genetic testing. A need has been identified for validated MMIC measures specific to inherited cardiac conditions, including familial hypercholesterolemia (FH). FH is a common genetic condition that can cause premature atherosclerotic cardiovascular disease (ASCVD) if left untreated. The primary aim of this study was to initiate the validation of an 8-item knowledge scale specific to FH. The secondary aim of this study was to explore the key factors that influenced how participants decisions about genetic testing for FH. Once validated, this knowledge scale can be used as part of an MMIC measure to evaluate patient informed choice in the context of genetic testing for this condition. This study used semi-structured cognitive interviews (N = 10) paired with a traffic light coding system was used to assess the face validity of the items in the knowledge scale, along with the importance of their associated concepts. Conventional content analysis of the interviews was used to identify the key factors that influenced participants’ decision regarding genetic testing for FH. The items in the knowledge scale were interpreted correctly by all participants. Minor revisions were made based on participant feedback to improve the clarity of six items. Most participants (n = 9) considered the concepts covered by the knowledge scale to be either helpful or necessary to decide about genetic testing for FH. Conventional content analysis revealed three common motivations to pursue genetic testing which include family, insight into medical management, and the opportunity for patient empowerment. Importantly, participant responses highlighted a lack of awareness of genetic services among this patient population, along with the positive impact genetic counselling can have for those who are offered genetic testing for FH. The development and validation of a FH-specific MMIC measure aims to be used in research targeted at maximizing informed choice among this patient population. Additionally, we foresee that these findings will serve to highlight the importance of genetic testing among this patient population and inform appropriate pre-test counselling for this condition.