Cardiovascular risk estimation and statin adherence: an historical cohort study protocol.

Background: Adherence to statins for the primary prevention of cardiovascular disease (CVD) is low. There is evidence that some facets of the initiation consultation, or the initiating clinician, are associated with adherence. CVD risk estimation is fundamental to statin initiation and shared decision making (SDM), because the benefits of statins are proportional to CVD risk. Absence of a recorded CVD score before statin initiation therefore indicates SDM is unlikely.

Aim: To investigate whether SDM, using CVD risk score as a proxy measure, is associated with adherence to statins and CVD outcomes.

Design & setting: A retrospective cohort study using a database of English primary care records.

Method: The cohort will include statin naïve patients aged 40-84 years initiated on statins for primary prevention between 2017 and 2020, categorised by the presence or absence of a CVD risk score at statin initiation. Statin adherence and persistence will be determined from subsequent statin prescriptions. Multivariable modelling, accounting for potential confounders, will determine the association between a recorded CVD risk score and subsequent statin adherence and with statin persistence. A secondary analysis will investigate the relationship to subsequent CVD outcomes and death.

Conclusion: This research uses a record of CVD risk score as a proxy for SDM, to investigate the link between SDM and medication adherence. It will shed light on relationship between how the initiation consultation is performed and subsequent adherence and persistence with treatment.