This study aims to gather information to what extent patients follow the treatment regimen of low-dose aspirin for primary and secondary prevention of diseases of the heart and blood vessels. Researcher will collect information about the percentage of time a patient has access to the medication, how long patients continue with the medication and of the proportion of patients who switch from dual-antiplatelet therapy (including low-dose aspirin) to a single antiplatelet therapy. The study will make use of secondary healthcare data sources converted in to Observational Medical Outcomes Partnership (OMOP) common data model within the Observational Health Data Sciences and Informatics (OHDSI) network.

Inclusion Criteria:

• Aged ≥18 years

• Patients will be selected if they have at least two prescriptions for low-dose aspirin (75-100 mg) between 2008 and 2018 for either:

  • Primary prevention of CVD This is defined as patients who have no history of CVD any time prior to initiation of low-dose aspirin treatment are presumed to use for primary CVD prevention
  • Secondary prevention of CVD This is defined as patients who have a history of CVD any time prior to initiation of low-dose aspirin treatment

• Patients with at least two prescriptions of low-dose aspirin with a dosage of 75-100mg within the first year of the index date.

• Restricted to patients with observation for at least 12 months before and 12 after the index date.

Exclusion Criteria:

- Prescription of low-dose aspirin in 12 months before the index date.

The population included in the study cohort will consist of patients who receive low-dose aspirin (75-100mg) for either the primary or secondary prevention of CVD.

For those being treated with low-dose aspirin for primary CVD prevention, no previous CVD events must have occurred any time prior to initiation of low-dose aspirin treatment. CVD events consist of myocardial infarction, stroke (including ischaemic stroke and transient ischaemic attack), unstable angina, angina, and ischaemic heart disease.

Availability of this study's data will later be determined according to Bayer's commitment to the EFPIA/PhRMA "Principles for responsible clinical trial data sharing". This pertains to scope, timepoint and process of data access. As such, Bayer commits to sharing upon request from qualified researchers patient-level clinical trial data, study-level clinical trial data, and protocols from clinical trials in patients for medicines and indications approved in the US and EU as necessary for conducting legitimate research. This applies to data on new medicines and indications that have been approved by the EU and US regulatory agencies on or after January 01, 2014. Interested researchers can use www.clinicalstudydatarequest.com to request access to anonymized patient-level data and supporting documents from clinical studies to conduct research. Information on the Bayer criteria for listing studies and other relevant information is provided in the Study sponsors section of the portal.