Asthma is a chronic long-term condition affecting all age groups. It is characterised by a narrowing of the airways making it difficult to breathe. There is currently no cure, but simple treatments can help alleviate symptoms, keeping the asthma under control. However certain inflammatory conditions have been associated with asthma that makes it harder to manage, resulting in higher health care cost and poorer quality of life for the patient.
We want to understand the relationship between these conditions and asthma management: atopic dermatitis (a chronic skin condition associated with "flares" when the skin becomes very red and itchy), allergic rhinitis (typically a blocked or runny nose), chronic rhinosinusitis (where the nasal passages and sinuses become swollen and blocked), nasal polyps (small growths in the nose causing a blockage), urticaria (hives), allergic conjunctivitis (red, itchy, teary eyes caused by an airborne irritant), food allergy (when an individual has a harmful reaction to a food) and anaphylaxis (a serious allergic reaction which requires immediate medical intervention). All these conditions have a similar inflammatory pathway as asthma but how they co-occur and what their impact is on asthma management has not been previously studied within a real-world asthma population.
Asthma is a common long-term condition which is responsible for considerable morbidity, mortality and costs. There are several related conditions, involving type 2 inflammation which have been identified as affecting asthma outcomes. The nine T2 co-morbidities of interest are: eczema, allergic rhinitis, chronic rhinosinusitis, nasal polyps, urticaria, allergic conjunctivitis, food allergy, eosinophilic oesophagitis and anaphylaxis. Because of the common underlying disease process, it has been suggested that successful treatment of one might also improve related conditions.
The frequency with which these conditions co-occur in patients with asthma has not yet been described, nor has the relationship between co-morbidity patterns with asthma severity and asthma-related resource utilisation.
The aim of this study is to describe the frequency and interrelations of these conditions, and assess associations with asthma severity, asthma-related healthcare resource utilisation and costs, within a real-world asthma population.
The prevalence of each co-morbidities pattern will be measured, and associations between co-morbidities described using likelihood ratios and principal component analysis. This will be used to select a subset of patterns, in which patient characteristics, asthma severity, healthcare resource utilisation and cost will be compared using multivariable regression models, in all patients and stratified by asthma severity, co-morbidity severity and activity, blood eosinophil count and age.
Health Outcomes to be Measured:
- No health outcomes are measured, only co-morbidity co-occurrence are analysed
- Primary outcome: Asthma severity, measured with separate 3 indicators
- Number of severe asthma exacerbations (an asthma-related hospital admission and/or A&E attendance and/or an acute course of oral corticosteroids).
- Risk Domain Asthma Control (RDAC): Absence of severe asthma exacerbations, and no antibiotic prescribed with evidence of a lower respiratory consultation
- Overall asthma control: Achieving RDAC and a mean daily dosage of </=200 µg salbutamol or </=500 µg terbutaline used
- Secondary outcome: Asthma-related healthcare resource utilisation and costs, composed of
- Primary care consultations
- Prescribed medication
- Respiratory medication
- Chronic oral corticosteroids
- Outpatient visits
- Emergency room attendances
- Inpatient hospital admissions
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient