How do the experiences and beliefs of adults and children with heterozygous familial hypercholesterolaemia influence their adherence to treatment? A systematic review of qualitative evidence protocol.

BACKGROUND: Heterozygous familial hypercholesterolaemia (FH) is a genetic disorder characterised by elevated levels of low density lipoprotein (LDL) cholesterol from birth, estimated to affect 1 in 250 of the UK population. Left untreated, FH substantially increases an individual's risk of premature coronary heart disease (CHD) and associated mortality. This risk can be minimised with timely diagnosis and successful treatment with medication and lifestyle changes, as advocated in national and international guidelines. Despite these recommendations, the limited research available suggests adherence to treatment may be sub-optimal. This review will identify and synthesise the available qualitative research regarding the experiences and beliefs of adults and children with FH in relation to their condition and its treatment, and the influence of these upon treatment adherence.

METHODS: The following electronic databases will be searched from their inception: Cochrane library, MEDLINE, Embase, PsycINFO (via OVID) and CINAHL. Studies available in English and reporting primary qualitative data will be included. Database searching will be supplemented with searches in relevant specialist websites. The references of identified papers will also be hand searched. Two reviewers will independently screen titles and abstracts of identified studies, with full texts of potentially relevant papers retrieved for review against pre-defined inclusion and exclusion criteria. The Critical Appraisal Skills Programme (CASP) Qualitative Research checklist will be used to assess quality of the included studies, and the results will be taken into consideration when reporting the findings. A data extraction tool will be created for use in this review to extract study findings relevant to the review questions. A thematic synthesis approach will be taken to analyse the results.

DISCUSSION: Adherence to treatment recommendations is crucial for the successful management of FH and subsequent decrease in risk of CHD later in life. Common identified themes could provide an understanding of the beliefs and experiences which influence adherence to treatment recommendations and provide an insight into perceived barriers and facilitators. The findings are intended to be used in the development of future interventions or guidelines regarding treatment of children and adults with FH.

SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number: CRD42018085946.