Asthma is a very common disease and people with asthma, as with other obstructive respiratory diseases such as chronic obstructive pulmonary disease (COPD) suffer with episodes of acute deterioration termed exacerbations. In COPD, people who have exacerbations are at risk of having further exacerbations but it is not clear whether the same is true for people with asthma or if there are specific factors that affect the likelihood of having an exacerbation of asthma. This is important to recognise, not only for patients but also their health carers and employers.
In the UK, over 5.4 million people have asthma, and the condition accounts for over 65,000 hospital admissions and 1,000 deaths annually. People with asthma may experience periods of acute worsening of symptoms: cough, wheeze, breathlessness and sputum production. Asthma exacerbations range from mild attacks, which interrupt daily life and work productivity, to severe and life-threatening attacks. In other long term respiratory conditions such as COPD, people who have exacerbations are at risk of having further exacerbations. Whether or not this is true in asthma and whether there are specific factors that affect the likelihood of having an exacerbation of asthma has not been investigated. Using linked CPRD, HES, and ONS data, we will use conditional logistic regression to undertake a nested case control study in a cohort of asthma patients to determine what factors are associated with having an exacerbation.
Health Outcomes to be Measured:
Exacerbations as defined in CPRD, HES or ONS. All exacerbations will be used as a composite outcome and then severe exacerbations (those resulting in hospitalisation and death only) will be investigated separately. Exacerbations will be defined by LRTI codes, OCS prescription 5-14 days, OCS and antibiotics, hospital admission, A&E attendance, death, GP consultation out of hours based on previous work.
HES Accident and Emergency;HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation