Population-wide cohort study of statin use for the secondary cardiovascular disease prevention in Scotland in 2009–2017

OBJECTIVE: To estimate the extent of suboptimal statin use for the secondary prevention of atherosclerotic cardiovascular disease (ASCVD) at different stages of the treatment pathway and identify patient groups at risk of suboptimal treatment. METHODS: National retrospective cohort study using linked National Health Service Scotland administrative data of adults hospitalised for an ASCVD event (n=167 978) from 2009 to 2017. Proportions of patients initiating, adhering to, discontinuing and reinitiating statins were calculated. We separately examined treatment following myocardial infarction (MI), ischaemic stroke and peripheral arterial disease (PAD) hospitalisations. Multivariable logistic regression and Cox proportional hazards models were used to assess the roles of patient characteristics in the likelihood of initiating and discontinuing statins. RESULTS: Of patients hospitalised with ASCVD, only 81% initiated statin therapy, 40% of whom used high-intensity statin. Characteristics associated with lower odds of initiation included female sex (28% less likely than men), age below 50 years or above 70 years (<50 year-olds 26% less likely, and 70-79, 80-89 and ≥90 year-olds 22%, 49% and 77% less likely, respectively, than 60-69 year-olds), living in the most deprived areas and history of mental health-related hospital admission. Following MI, 88% of patients initiated therapy compared with 81% following ischaemic stroke and 75% following PAD events. Of statin-treated individuals, 24% discontinued treatment. Characteristics associated with discontinuation were similar to those related to non-initiation. CONCLUSIONS: Statin use remains suboptimal for the secondary ASCVD prevention, particularly in women and older patients, and following ischaemic stroke and PAD hospitalisations. Improving this would offer substantial benefits to population health at low cost.