Currently the relationship between asthma and heart disease is unclear. Many doctors and scientists speculate that the lung inflammation that occurs in asthma increases a patients risk of developing heart disease such as a heart attack. Some studies have suggested that there is an association between asthma and heart disease, while others studies suggest that this association is only in those asthma patients that smoke, in patients that developed asthma as an adult, or in those with asthma caused by allergies. The differences in results may be because different populations have different risks or because previous studies have limitations in the way the study was carried out.
Recently a study looking at patients with a similar lung disease to asthma, but unlike asthma as it is caused by smoking (called chronic obstructive pulmonary disease, or COPD), found that certain inhaled treatments (long-acting bronchodilators) increase the risk of heart disease in a COPD population in Taiwan. These inhalers are also commonly used in asthma patients but no one has looked at the possible side-effects to the heart in asthma patients. We would like to look in a large UK nationwide population of asthma patients to see if they do have an increased risk of heart disease and if certain patients are at higher risk than others. As a comparison, we would also like to see if these inhalers increase the risk of heart disease in COPD patients in a UK population, as was found in the Taiwan population.
To determine the risk of cardiovascular disease in a general asthma cohort, annual incidence and prevalence rates will be calculated for each cardiovascular outcome (including ischaemic heart disease, heart failure and stroke) and stratified by clinical characteristics between 2004 and 2017. To compare CVD incidence and mortality rates to the general population a matched cohort of asthma patients and randomly identified patients from the total CPRD population will be obtained from CPRD between 2012 and 2017. A multivariate Poisson model, adjusting for cardiovascular risk factors, will be used to obtain rate ratios.
To determine any cardiovascular risk from incident long-acting bronchodilators (LAB) a nested case-control will be carried out from a cohort of incident LAB users. The cases will be acute cardiovascular events and controls will be matched 1:4 on disease risk score and cohort entry date. Conditional logistic regression will be used to estimate the association. Exposure (long acting bronchodilator) will be categorised by type of inhaler and duration of use. The same analysis will also be carried out in a COPD population to see if the findings in a UK population match those found in the Taiwanese population used in the original study.
1. Annual incidence and prevalence of cardiovascular disease (CVD) including ischaemic heart disease, cerebrovascular disease, arrhythmias and heart failure
2. Risk of CVD incidence and mortality in an asthma population compared to general UK population
3. Risk of CVD associated with incident and prevalent use of long-acting bronchodilators in asthma patients and COPD patients
Jennifer Quint - Chief Investigator - Imperial College London
Chloe Bloom - Corresponding Applicant - Imperial College London
HES Accident and Emergency;HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation