Patterns of Antiplatelet Therapy in Patients Who Have Experienced an Acute Coronary Event: A Descriptive Study in UK Primary Care

Quality of care for secondary cardiovascular disease prevention in 2009-2017: population-wide cohort study of antiplatelet therapy use in Scotland

BACKGROUND

Antiplatelet therapy (APT) can substantially reduce the risk of further vascular events in individuals with established atherosclerotic cardiovascular disease (ASCVD). However, knowledge regarding the extent and determinants of APT use is limited.

OBJECTIVES

Estimate the extent and identify patient groups at risk of suboptimal APT use at different stages of the treatment pathway.

METHODS

Retrospective cohort study using linked NHS Scotland administrative data of all adults hospitalised for an acute ASCVD event (n=150 728) from 2009 to 2017. Proportions of patients initiating, adhering to, discontinuing and re-initiating APT were calculated overall and separately for myocardial infarction (MI), ischaemic stroke and peripheral arterial disease (PAD). Multivariable logistic regression and Cox proportional hazards models were used to assess the contribution of patient characteristics in initiating and discontinuing APT.

RESULTS

Of patients hospitalised with ASCVD, 84% initiated APT: 94% following an MI, 83% following an ischaemic stroke and 68% following a PAD event. Characteristics associated with lower odds of initiation included female sex (22% less likely than men), age below 50 years or above 70 years (aged <50 years 26% less likely, and aged 70-79, 80-89 and ≥90 years 21%, 39% and 51% less likely, respectively, than those aged 60-69 years) and history of mental health-related hospitalisation (45% less likely). Of all APT-treated individuals, 22% discontinued treatment. Characteristics associated with discontinuation were similar to those related to non-initiation.

CONCLUSIONS

APT use remains suboptimal for the secondary prevention of ASCVD, particularly among women and older patients, and following ischaemic stroke and PAD hospitalisations.

Long-Term Adherence and Persistence to Low-Dose Aspirin for the Prevention of Cardiovascular Disease: A Population-Based Cohort Study

METHODS

Using information from electronic health records in Germany and the United Kingdom (UK) in a common data model, we followed adults with ≥2 low-dose aspirin prescriptions (75-100 mg) during 2007-2018 for up to 10 years. Included individuals had no low-dose aspirin prescriptions in the year before the follow-up started (date of first low-dose aspirin prescription) and ≥12 months' observation. Adherence was determined using the medication possession ratio (MPR), and persistence was defined as continuous treatment disregarding gaps between prescriptions of <60 days; analyses were undertaken according to indication (primary/secondary CVD prevention).

RESULTS

We identified 144,717 low-dose aspirin users from Germany and 190,907 from the UK. Among patients with 5-10 years' follow-up, median adherence among secondary CVD prevention users was 60% in Germany and 75% in the UK. Among primary prevention users, median adherence was 50% for both countries. Persistence among secondary CVD prevention users was 58.3% at 2 years, 47.0% at 5 years, 35.2% at 10 years (Germany), and 67.5% at 2 years, 58.0% at 5 years, and 46.8% at 10 years (UK). Among primary CVD prevention users, persistence was 52.8% at 2 years, 41.6% at 5 years, 32.1% at 10 years (Germany), 56.3% at 2 years, 45.4% at 5 years, and 33.8% at 10 years (UK).

CONCLUSIONS

Long-term adherence and persistence to low-dose aspirin are suboptimal; efforts for improvement could translate into a lower CVD burden in the general population.

Patterns of antiplatelet drug use after a first myocardial infarction during a 10-year period

AIMS

The aims of the present study were to assess antiplatelet drug use patterns after a first myocardial infarction (MI) and to evaluate the determinants of antiplatelet nonpersistence.

METHODS

The present study was conducted in 4690 patients from the Utrecht Cardiovascular Pharmacogenetics cohort with a first MI between 1986 and 2010, who were followed for a maximum of 10 years. Medication use and event diagnosis were obtained from the Dutch PHARMO Record Linkage System. Antiplatelet drug users were classified as persistent users (gap between prescriptions ≤90 days), nonpersistent users (>90-day gap and no refills), and restarters (a new prescription after a >90-day gap). The association between potential determinants and antiplatelet nonpersistence was analysed using Cox regression.

RESULTS

The proportions of persistent users decreased from 84.0% at the 1-year follow-up to 32.8% at 10 years for any antiplatelet drug, and 77.3% to 27.5% for aspirin; and 39.0% to 6.4% for clopidogrel at 6 years. Most nonpersistent users restarted antiplatelet drugs later, leading to 89.3% overall antiplatelet drug users at 10 years after MI. Diabetes (hazard ratio [HR] 0.44; 0.32-0.60), hypertension (HR 0.77; 0.60-0.99), hypercholesterolaemia (HR 0.49; 0.39-0.62) and more recent MI diagnosis period (2003-2007: HR 0.69, 0.61-0.79; 2008-2010: HR 0.38, 0.19-0.77, compared to ≤ 2002 period) lowered the risk of antiplatelet nonpersistence, while vitamin K antagonist (VKA) comedication (HR 18.97; 16.91-21.28) increased this risk.

CONCLUSIONS

A large proportion of patients with a first MI still used antiplatelet drugs after 10 years. The frequent discontinuations during this time frame are expected to reduce the effectiveness of antiplatelet drugs as secondary prevention of cardiovascular diseases. Diabetes, hypertension, hypercholesterolaemia, VKA comedication and MI diagnosis period were determinants of antiplatelet nonpersistence.