Understanding clusters and mechanisms of complex multimorbidity in people with common allergic conditions

Multimorbidity is a term used to mean having two or more longterm physical or mental illnesses. Multimorbidity is important because it affects what happens to people throughout their life and how their doctors can treat them.
Conditions which can be associated with allergy, such as asthma and eczema, are very common particularly in children and young adults (at least 1 in 5 children), and are known to have major effects on quality of life and costs to the NHS. Previous work has shown people with allergic diseases are at risk of lots of different mental and physical health problems (multimorbidity), possibly due to their allergic disease. We don't yet understand how these diseases group together ("cluster") and why they occur.

Our work will help us understand how and why allergic diseases are associated with other mental and physical illnesses (multimorbidity) in order to work out how to treat people with allergic diseases better.
In this preparatory phase (also called a consolidator grant), we will first explore how allergic diseases occur in groups together with multiple other medical and psychiatric conditions and how these "clusters" develop over time. Some of these "clusters" will include conditions we already know can be associated with allergic diseases, but we also expect that we might find new associated diseases. We will do this analysis using data collected as part of usual healthcare, which has been stripped of identifiers (e.g., names). We have data collected on large numbers of people (for example 500,000 adults with eczema) over long periods of time with information about health issues, medications, doctors' visits and whether people smoke or drink alcohol.

This work will be complex, so we will need to run workshops involving different kinds of experts, such as data scientists, statisticians, doctors who treat patients with allergic diseases, and patient representatives. In this preparation phase, we will also spend time finalising the most important questions for the main body of work (focusing on working out why people with allergic diseases have other mental and physical conditions) and how we can answer those questions in the best possible way.

In the main body of work (also known as a "collaborative" grant), we will use advanced statistical techniques to understand why common allergic disorders are associated with other physical and mental health problems. We will look at factors in people's environment and lifestyle, or medications that doctors use to treat allergic conditions to see if these might play a role in these "clusters". This collaborative programme will help us move away from doctors focusing on only one problem at a time, to an approach that looks at all of the problems that people have that tend to cluster together. This "joined up" thinking will help us treat people better and might help us avoid some of those health problems in future.

Multimorbidity is a term used to describe people with two or more chronic physical or mental illnesses. Multimorbidity (i) reduces quality of life, (ii) complicates decision-making and (iii) incurs major health service costs.
Atopic allergic diseases, such as asthma and eczema, are amongst the commonest long-term conditions (1 in 5 children, up to 10% of adults), and are associated with adverse effects on quality of life and costs to individuals and health services. Our previous work (and that of others) has shown complex patterns of allergic disease comorbidity and increased risk of non-allergic comorbidity, including cardiovascular disease, fractures and mental health issues, supporting multimorbidity being an important, but poorly described concept, for these diseases. Multimorbidity may result from common biological mechanisms or treatment side-effects.
There is a need to better understand allergic and non-allergic disease comorbidities co-existing in clusters with allergic disease to help identify opportunities to prevent multimorbidity or reduce its impact.
Our objectives in the consolidator phase are to:
1. Identify clusters and trajectories to known and previously unidentified multimorbidity in people with allergic disorders using the Clinical Practice Research Datalink.
2. Engage a critical mass of inter-disciplinary expertise, including clinicians, data scientists, and patients to enhance the collaborative phase.
The Consolidator phase will provide the foundation for the Collaborative phase that will:
3. Investigate mechanisms driving associations between common allergic conditions and multimorbidity using classical statistical approaches and artificial intelligence and address determinants of multimorbidity in people with allergic diseases including environmental (e.g., pollution), lifestyle (e.g. smoking) and social factors (e.g. deprivation), and medications (e.g. corticosteroids).
4. Identify modifiable risk factors and "at-risk" subgroups.