Heart failure (HF) is a common and costly condition affecting around 1 in 100 adults and using up 3-4% of the NHS budget. Patients can experience breathlessness, have swollen ankles and feel tired. HF can be effectively treated but getting a diagnosis is key to receiving life-saving medication.
The National Institute for Health and Care Excellence (NICE) recommend that people who see their GP with symptoms which might be due to HF should have a blood test to check for a protein called natriuretic peptide (NP) which goes up when the heart is under strain. If the natriuretic peptide level is above the cut-off recommended by NICE, the patient should be referred for a heart scan and specialist review to say whether they have HF, and if they need to start treatment.
We will use the Clinical Practice Research Datalink (CPRD) to look at the use of NP testing in UK general practice geographically and over time. We will also look at NP levels associated with a subsequent heart failure diagnosis (including with hospital admission) and if NP-level is related to survival. We hope this work will allow us to have a better understanding of NP-use in the community.
Heart failure (HF) is a common and costly condition affecting 1-2% of adults. Guidelines recommend GPs carry out a natriuretic peptide (NP) test to aid diagnosis in people with suspected HF. The aim of this study is to report the contemporary use of NP testing in UK general practice, determine the level of NP associated with a HF diagnosis and explore the association of baseline NP level and survival.
We will conduct an open retrospective cohort study using data from CPRD for the period between 1st January 2000 and 31st December 2018, linked to Hospital Episode Statistics and Office for National Statistics mortality data.
Our results will include: 1. Frequency of NP testing by year, geographical area and demographic details including age, sex, socioeconomic group; 2. NP levels associated with a HF diagnosis (including hospitalisation around time of diagnosis); 3. Guideline-defined thresholds for NP-testing to determine the proportion of patients meeting guideline recommendations for diagnosis; 4. Survival analysis to compare mortality by baseline NP level. We hope this work will allow us to have a better understanding of NP-use in the community for both diagnosis and prognosis.
Aim 1: Number of NP tests per 100 person-years, including the subtype (BNP/NT-proBNP) and NP level, in the primary care record (see Code List Appendix)
- Aims 2-3: Incident heart failure (primary) and hospitalisation around time of diagnosis (secondary).
Patients with a diagnosis of HF will be identified using diagnostic codes entered by GPs to record new diagnoses in the primary care (CPRD GOLD) medical record within 6 months of NP testing.
HF is a clinical syndrome and the diagnosis requires the presence of symptoms and objective evidence of a structural or functional abnormality of the heart. Patients with a clinical code of HF in their primary care record will be included. Patients with either an echocardiograph report or a record of HF in linked HES records within 3 months of the HF diagnostic code entry in the primary care record will be classified as being hospitalised around the time of diagnosis.
Echocardiograms will be identified using clinical codes and entity code 342. Two distinct types of HF are now recognised by researchers and the clinical community based on the left ventricular ejection fraction: HF with reduced Ejection Fraction (HFrEF) and HF with preserved Ejection Fraction (HFpEF). We will search for these codes in the patient record, and ejection fraction results from echocardiogram reports (entity 342) to establish whether it is possible to report HFrEF and HFpEF separately.
- Aim 4: Hospitalisation within 12 months.
Date and cause of hospitalisation will be taken from HES data.
- Aim 5: Time to death (all-cause mortality).
Date and cause of death will be taken from ONS mortality data. Secondary outcomes to be reported descriptively, will include primary cause of death and death due to HF (any position in the cause of death hierarchy)
Clare Taylor - Chief Investigator - University of Oxford
Clare Taylor - Corresponding Applicant - University of Oxford
Andrea Roalfe - Collaborator - University of Oxford
José M. Ordóñez-Mena - Collaborator - University of Oxford
Richard Hobbs - Collaborator - University of Oxford
Sarah Lay-Flurrie - Collaborator - University of Oxford
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation