Hypertension is a progressive long term condition that is characterised by raised blood pressure which can lead to an increased risk of hospitalisation and mortality. As hypertension can initially present as an asymptomatic condition, there may be large numbers of people living with undiagnosed hypertension. Some patients will still have raised blood pressure despite being on multiple antihypertensive medications. This is referred to as resistant hypertension. We will look at responses to medications used for hypertension over time and study how the response to these medications are affected by a variety of factors including demographic related factors and such as age, ethnicity and sex and other factors including BMI, liver and kidney function tests. This study aims to help us understand the reasons behind why certain groups of people are more likely to be resistant to anti-hypertensive medications than others.
Study Aims and Objectives: This study aims to investigate the factors influencing the response to antihypertensive medications among patients newly diagnosed with hypertension. Specifically, the objectives are to:
-Assessing how age, sex, ethnicity, and socioeconomic status (indexed by IMD - Index of Multiple Deprivation) influence medication efficacy.
-Evaluate the role of BMI, liver, and kidney function in blood pressure control and medication response.
-Identify patterns of antihypertensive medication response over time to inform tailored treatment strategies.
Study Population of Interest: The study will involve adults aged 18 years and above, newly diagnosed with hypertension, identified within the Clinical Practice Research Datalink (CPRD) GOLD and CPRD Aurum databases. Patients will be selected based on diagnostic codes for hypertension, with a follow-up period extending from the date of diagnosis until the end of the study period, death, or loss to follow-up.
Primary Exposures and Outcomes: The primary exposure is the initiation of antihypertensive medication following a new diagnosis of hypertension. The primary outcomes include changes in blood pressure control over time and the incidence of resistant hypertension, defined as uncontrolled blood pressure despite the use of three or more antihypertensive medications, including a diuretic.
Study Design: This is an observational, retrospective cohort study utilising data from CPRD GOLD and CPRD Aurum, linked with Hospital Episode Statistics (HES) Admitted Patient Care and Office for National Statistics (ONS) Death Registration Data to enhance demographic and outcome data.
Methods: Patient demographics, medications, BP readings, BMI, liver and kidney function tests will be extracted from the CPRD databases. Ethnicity data will be refined using CPRD Ethnicity Records. The main statistical modelling approach include:
-Cox Proportional Hazards Model: To analyse time to control blood pressure and the onset of resistant hypertension.
-Multivariable Logistic Regression: To assess impacts of demographics, physiological measures, and socioeconomic status on treatment efficacy.
Primary outcomes: Association between age, sex, ethnicity and BMI with blood pressure response in patients newly diagnosed with hypertensive to the 1st antihypertensive medication.
Secondary outcomes: Association between liver function and kidney function tests with blood pressure response in patients newly diagnosed with hypertensive to the 1st antihypertensive medication.
Samuel Seidu - Chief Investigator - University of Leicester
Hanad Osman - Corresponding Applicant - University of Leicester
Billy Church - Collaborator - University of Leicester
Francesco Zaccardi - Collaborator - University of Leicester
Kamlesh Khunti - Collaborator - University of Leicester
Navjot Kaur - Collaborator - University of Leicester
pankaj gupta - Collaborator - University of Leicester
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;CPRD Aurum Ethnicity Record;CPRD GOLD Ethnicity Record