Real-world evaluation of the impact of statin intensity on adherence and persistence to therapy: A Scottish population-based study

Renata Cristina Rezende Macedo do Nascimento; Tanja Mueller; Brian Godman; Sean MacBride Stewart; Simon Hurding; Francisco de Assis Acurcio; Augusto Afonso Guerra Junior; Juliana Alvares Teodoro; Alec Morton; Marion Bennie; Amanj Kurdi

doi:10.1111/bcp.14333

Real-world evaluation of the impact of statin intensity on adherence and persistence to therapy: A Scottish population-based study

Br J Clin Pharmacol. 2020 Dec;86(12):2349-2361. doi: 10.1111/bcp.14333. Epub 2020 May 30.

Authors

Affiliations

¹ Department of Pharmacy, School of Pharmacy, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
² Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
³ Division of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.
⁴ Division of Public Health Pharmacy and Management, School of Pharmacy, Sefako Makgatho Health Sciences University, Pretoria, South Africa.
⁵ Prescribing and Pharmacy Support Unit, NHS Greater Glasgow & Clyde, Glasgow, UK.
⁶ Directorate for Health Finance, The Scottish Government, Edinburgh, UK.
⁷ SUS Collaborating Centre for Technology Assessment and Excellence in Health, School of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
⁸ Strathclyde Business School, University of Strathclyde, Glasgow, UK.
⁹ Public Health and Intelligence Strategic Business Unit, NHS National Services Scotland, Edinburgh, UK.
¹⁰ Department of Pharmacology and Toxicology, College of Pharmacy, Hawler Medical University, Erbil, Iraq.

Abstract

Aim: To assess associations between statin intensity and adherence, persistence and discontinuation of statin therapy in Scotland.

Method: Retrospective cohort study, using linked electronic health records covering a period from January 2009 to December 2016. The study cohort included adult patients (≥18 years) newly initiating statins within Greater Glasgow and Clyde, Scotland. Study outcomes comprised adherence, discontinuation and persistence to treatment, stratified by three exposure groups (high, moderate and low intensity). Discontinuation and persistence were calculated using the refill-gap and anniversary methods, respectively. Proportion of days covered (PDC) was used as a proxy for adherence. Kaplan-Meier survival curves and Cox proportional hazard models were used to evaluate discontinuation, and associations between adherence/persistence and statin intensity were assessed using logistic regression.

Results: A total of 73 716 patients with a mean age of 61.4 ± 12.6 years were included; the majority (88.3%) received moderate intensity statins. Discontinuation rates differed between intensity levels, with high-intensity patients less likely to discontinue treatment compared to those on moderate intensity (prior cardiovascular disease [CVD]: HR 0.43 [95% CI 0.34-0.55]; no prior CVD: 0.80 [0.74-0.86]). Persistence declined over time, and high-intensity patients had the highest persistence rates. Overall, 52.6% of patients were adherent to treatment (PDC ≥ 80%), but adherence was considerably higher among high-intensity patients (63.7%).

Conclusion: High-intensity statins were associated with better persistence and adherence to treatment, but overall long-term persistence and adherence remain a challenge, particularly among patients without prior CVD. This needs addressing.

Keywords: Scotland; cardiovascular disease; drug utilisation; high-intensity therapy; medication adherence; statins.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Cardiovascular Diseases* / drug therapy
Cardiovascular Diseases* / epidemiology
Female
Humans
Hydroxymethylglutaryl-CoA Reductase Inhibitors* / therapeutic use
Male
Medication Adherence
Middle Aged
Retrospective Studies
Scotland / epidemiology

Substances

Hydroxymethylglutaryl-CoA Reductase Inhibitors