The UK has well established guidelines for recommending statins and blood pressure lowering drugs to patients to reduce the risk of heart attacks and strokes. Statins are recommended to patients who are at high risk of heart attacks and strokes. Blood pressure lowering drugs are recommended based on both a patient’s blood pressure and their risk of heart attacks and strokes. GPs use the guideline recommendations, their own judgement, and discussions with the patient to decide on treatment. For example, when considering whether to prescribe blood pressure drugs, GPs will take into account not only the broad national guidelines but also (i) the risk of reducing blood pressure too much, which may lead to dizziness and falls, (ii) the risk of kidney disease, heart failure and stroke if a patient is not treated, and (iii) patient choice. Therefore, there are likely to be differences in the ways that the same patient would be treated across different GPs within the UK.
This study aims to determine whether the right patients are receiving treatment and whether there are groups of patients who are not receiving treatment when they should be. Results will be compared to a similar study from New Zealand, where guidelines are the same for statins but different for blood pressure.
Performing comparisons between countries with different guidelines will help us understand whether differences in guidance affect the way statins and blood pressure-lowering drugs are used in practice.
Background
The UK has well established guidelines for the management of cardiovascular disease risk factors. Lipid lowering treatment is recommended based on predicted absolute cardiovascular disease risk. Blood pressure lowering treatment is recommended largely on the basis of blood pressure cut-offs.
Each GP is advised to combine guideline recommendations, clinical judgement and shared decision making with the patient to decide upon treatment. Adherence to guidelines therefore depends on a multitude of GP and patient factors.
Aim
The overall aim of this study is to examine the prevalence of prescriptions for blood pressure lowering treatment and lipid lowering treatment, and to identify missed opportunities and inequalities in care.
Methods
Initially, using a cohort of patients registered in a CPRD Aurum practice between 1st January 2011 and 31st December 2019, this study will describe use of blood pressure lowering and lipid lowering medications in the 12 months after a cardiovascular disease risk assessment, stratified by individual cardiovascular disease risk factors and predicted ten year risk of cardiovascular disease. Univariate logistic regression models will be used to determine the crude association of each risk factor with prescriptions. We will investigate whether prescribing is guideline compliant and assess inequalities by age, sex, ethnicity and socioeconomic status, adjusting for age and sex to identify independent effects.
These analyses will determine whether the right patients are receiving treatment. This CPRD study will be compared to similar analyses using data from New Zealand. The UK and New Zealand provide a useful comparison in settings due to their disparate blood pressure but similar lipid lowering guidelines. These analyses will enable us to understand whether GPs tend to use risk to guide treatment decisions, and to what extent differences in guidance influence treatment decisions.
The outcomes will be prescription of:
• blood pressure lowering medications, and
• lipid lowering medications
in 12 months following a risk assessment. The primary outcome will be prescription in the 6-12 months following risk assessment.
Emily Herrett - Chief Investigator - London School of Hygiene & Tropical Medicine ( LSHTM )
Emily Herrett - Corresponding Applicant - London School of Hygiene & Tropical Medicine ( LSHTM )
Krishnan Bhaskaran - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Laurie Tomlinson - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Patient Level Index of Multiple Deprivation