Different types of fat molecules called lipids are produced and processed by the body for its usual functions. These include cholesterol, triglycerides and other lipids. The overproduction of cholesterol without an external cause is termed primary hypercholesterolaemia (PH), while the overproduction or defective processing of other lipids is called mixed dyslipidaemia (MD). In PH or MD, these lipids may accumulate, especially in blood vessels. Through the years, the accumulations will eventually produce a blood clot, which can block blood flow. This produces heart attacks, strokes, kidney problems, and even gangrene in the feet, depending on which blood vessel was blocked.
PH and MD are treated with medications that control the level of lipids through different mechanisms. These include statins, ezetimibe, PCSK9 inhibitors (which inhibit a protein called proprotein convertase subtilisin/kexin type 9), and other medications. Additionally, there are health policies influencing diet and exercise that have been deployed in England.
We wish to determine how the number of patients with PH and MD has changed for the past decade (2009-2018), their patient profile, how those patients are shifted from one treatment to another, how many patients have either achieved control on each treatment, or experienced outcomes related to blood vessel obstruction that PH and MD may cause, and how much health care resource use was expended in caring for PH and MD patients. This study using a linked dataset from primary care and secondary care would be helpful in achieving that objective.
Primary hypercholesterolaemia (PH) and mixed dyslipidaemia (MD) portend a higher risk of cardiovascular events due to the thrombogenic milieu afforded by increased production and dysfunctional metabolism of cholesterol and other lipids.
The treatment of PH and MD involves administration of various medications, including statins, ezetimibe, PCSK9 inhibitors, weight control, and lifestyle modification, based on clinical practice guidelines. However, it is important to understand how these medications and treatments have been implemented in England. Additionally, it would be important to understand the changes in the epidemiology of PH and MD in England, the health outcomes PH and MD patients experience, and how much healthcare resources were expended in the care of patients with PH and MD in primary and secondary care.
In order to answer these questions, we intend to perform a study on the CPRD-HES linked data on patients diagnosed to have PH and MD. Through this, we can establish a trend in the prevalence and incidence of PH and MD, then determine their risk factor profile and demographic characteristics. We would then track patient records forwards to determine receipt of various medications used to treat PH and MD. Finally, we would like to determine the incidence of cardiovascular outcomes in that cohort, as well as the healthcare resource use in inpatient, outpatient, A&E and GP care.
Through our study, we hope to gain a clearer understanding of PH and MD in England, what treatment pathways patients with PH and MD undergo, and what outcomes they experience.
Health Outcomes to be Measured:
Epidemiologic experience (annual incidence of PH and MD, period prevalence of PH and MD, mean annual prevalence of PH and MD), demographic characteristics and clinical profile (age, sex, blood pressure on inclusion, low density lipoprotein (LDL) level, total cholesterol level, prevalence of co-morbidities including cardiovascular disease, familial hypercholesterolaemia, diabetes, chronic kidney disease), clinical outcomes (incidence of myocardial infarction, unstable angina, stable angina, stroke, transient ischaemic attack, cardiovascular events in aggregate), healthcare resource use (inpatient admissions, outpatient appointments, A&E attendances, GP appointments and associated tariffs)
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation