NICE Guidelines for hypertension medications To define hypertension using prescriptions we used the guidelines available by NICE: https://www.nice.org.uk/guidance/ng136/resources/visual-summary-pdf-6899919517

These codelists were derived from the CPRD data dictionary, reported codes are in the form of SNOMED CT.

Observations The observation file provides the SNOMED CT codes which relate to hypertension, these were further subdivided into:

- invitation for hypertension monitoring,

- self-controlled hypertension,

- review of hypertension,

- well controlled hypertension,

- moderate/poorly controlled hypertension

Blood pressure readings

These values were further subdivided into systolic and diastolic codes, when these codes have associated 'values' which are high (guidelines in brackets), they can indicate a patient has hypertension

- Systolic (>130)
- Diastolic (>80)

Prescriptions

Both codes for medications prescribed for hypertension as well as resistant hypertension are included.