The Prevalence and Clinical Burden of Primary Chylomicronaemia in the UK

Date of ISAC Approval: 
Lay Summary: 
Primary Chylomicronaemia (PC) is a genetic condition which is characterised by very high levels of a particular type of cholesterol (triglycerides) leading to frequent nausea, severe abdominal pain, regular hospitalisation with life threatening complications and can lead to further lifelong diseases including diabetes. A rare subtype of PC is called familial chylomicronaemia syndrome (FCS) and presents with severe complications early in life. Until now treatment options have been limited for individuals with PC, but recent breakthroughs mean new therapies are in development and may soon be available. Using routinely collected electronic health data from general practices, hospital admissions and death registry sources we aim to estimate the potential number of people in the United Kingdom with PC and its rarer subtype FCS, their rates of death compared with the general population and their usage of healthcare services. We also propose to estimate the risk of acute pancreatitis and abdominal pain in these patients compared to similar patients without the disease. We will also explore the risks of PC patients developing diabetes and heart diseases long term. With the findings of this study we aim to create an overall picture of the impact PC has on patients and healthcare services in the United Kingdom. This information will support the development and cost effectiveness analyses of new treatments for PC.
Technical Summary: 
Using linked electronic health records comprising of CPRD, hospital episode statistics (HES), and national mortality registry (ONS) data sources, the objectives of the study are to (1) identify preliminary estimates of cases with Primary chylomicronaemia (PC) through a set of descriptive analyses of patients in with elevated triglyceride levels (e.g. >8.4mmol/L) and the presence/absence of related conditions (acute pancreatitis and obesity), (2) develop a phenotype algorithm for identifying cases with PC and sub-phenotypes of differing specificity for PC by varying the threshold of triglyceride levels as well as age cut points and disease definitions. (3) evaluate the burden of PC in the UK through calculating prevalence, standard mortality ratios, and rates of primary and secondary healthcare usage, (4) estimate the risks of acute pancreatitis and abdominal pain in PC patients compared with age and gender matched controls without PC and (5) estimate the risks of type 1 and type 2 diabetes and 12 different cardiovascular endpoints in PC patients. For objectives (4) & (5) we will use Kaplan Meier plots to estimate cumulative incidence and Cox proportional hazards models, adjusted for confounders, to estimate hazard ratios of the endpoints.
Health Outcomes to be Measured: 
- Primary chylomicronaemia - Health service utilisation - All-cause mortality - Abdominal pancreatitis - Abdominal pain - Diabetes - Stable angina - Unstable angina - Myocardial infarction - Unheralded coronary heart disease death - Cardiac arrest/ sudden cardiac death - Heart failure - Transient ischaemic attack - Ischaemic stroke - Intracerebral haemorrhage - Subarachnoid haemmorhage - Peripheral arterial disease - Abdominal aortic aneurysm

Riyaz Patel - Chief Investigator - Barts Health and UCLH NHS Trusts
Arturo Gonzalez-Izquierdo - Collaborator - University College London (UCL)
Professor Harry Hemingway - Collaborator - University College London (UCL)
Laura Pasea - Collaborator - University College London (UCL)
Dr Spiros Denaxas - Corresponding Applicant - University College London (UCL)

HES Admitted;HES Outpatient;ONS;Practice IMD (Standard)