Evaluating statin utilisation in clinical practice in Scotland : impact of statin intensity on adherence and persistence to therapy

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Mueller, Tanja and do Nascimento, Renata Cristina R. Macedo and Bennie, Marion and Godman, Brian and Hurding, Simon and MacBride Stewart, Sean and Guerra Júnior, Augusto Afonso and de Assis Acurcio, Francisco and Morton, Alec and Kurdi, Amanj (2018) Evaluating statin utilisation in clinical practice in Scotland : impact of statin intensity on adherence and persistence to therapy. In: 34th International Conference on Pharmacoepidemiology and Therapeutic Risk Management, 2018-08-22 - 2018-08-26, The Prague Congress Centre. (https://doi.org/10.1002/pds.4629)

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Abstract

Background: Based on recent clinical trial evidence, updated treatment guidelines in the UK recommend high-intensity statin therapy (atorvastatin 80mg) for secondary prevention of cardiovascular disease. However, with this high statin dose, there are concerns about a potential increase in the incidence of statin-related side effects, which might affect patients’ adherence and, in turn, clinical outcomes. Hence, this study aimed to evaluate the effect of statin intensity on adherence and persistence to therapy. Objectives: To evaluate adherence, discontinuation, and persistence to high-intensity statin in comparison to moderate and low-intensity in Scotland. Methods: Retrospective cohort study using linked health records. The study population included patients (≥ 18 years) initiated on statins between January 2010 and December 2015. Statin treatment was stratified into high, moderate, and low-intensity based on the current National Institute for Health and Care Excellence classifications. Treatment discontinuation and persistence were evaluated using the refill-gap and anniversary methods, respectively; adherence was assessed by calculating the proportion of days covered (PDC). Results: A total of 73,716 patients (mean age 62 years [SD 12.6]) initiated statins during the study period: high-intensity n=7,163 (9.7%), moderate-intensity n=65,125 (88.3%), and low-intensity n=1,428 (1.9%). High-intensity therapy was more common among males (10.7%) than females (8.6%), and most common (17.1%) in the youngest age group (18 – 24 years). The majority of patients initiating high-intensity treatment received either atorvastatin 20mg (43.1%) or 40mg (32.3%), while 22.8% received atorvastatin 80mg. Crude discontinuation rates (50.9% high-intensity versus 75.5% low-intensity) and 1-year persistence (74.7% high-intensity versus 53.1% low-intensity) differed significantly between intensity levels; crude adherence (PDC ≥ 80%) was highest among high-intensity patients with 63.7%, compared to 51.6% and 40.5% in moderate and low-intensity, respectively. Conclusion: Increasing the intensity of statin therapy does not seem to negatively impact adherence and persistence to treatment, although findings could be due to confounders (e.g. primary versus secondary prevention) and/or the low proportion of patients using the recommended high dose statin. Further analysis is ongoing to adjust for confounders, and to evaluate clinical outcomes associated with high-intensity statin therapy.

ORCID iDs

Mueller, Tanja ORCID logoORCID: https://orcid.org/0000-0002-0418-4789, do Nascimento, Renata Cristina R. Macedo, Bennie, Marion ORCID logoORCID: https://orcid.org/0000-0002-4046-629X, Godman, Brian, Hurding, Simon, MacBride Stewart, Sean, Guerra Júnior, Augusto Afonso, de Assis Acurcio, Francisco, Morton, Alec ORCID logoORCID: https://orcid.org/0000-0003-3803-8517 and Kurdi, Amanj ORCID logoORCID: https://orcid.org/0000-0001-5036-1988;
CORE (COnnecting REpositories)