Trends in the Epidemiology and Treatment of Atopic Dermatitis in the United Kingdom (UK)

Study Overview
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Brief Summary
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Atopic dermatitis, commonly called eczema, is one of the most frequently occurring skin conditions. It is estimated to affect around one fifth of children in developed countries and is also becoming increasingly common in less developed countries. Exact estimates of how common eczema is, vary considerably and there has not been an in-depth analysis of the number of people with eczema in the UK. It is also unclear which groups of people are most affected and which treatment options are being used. Most people with eczema are managed by their general practitioner (GP) with only a few people requiring specialist care. GP records therefore provide an excellent opportunity to explore how common eczema is and which treatments are being used currently. This study aims to provide accurate estimates of the number of people with current eczema (prevalence), number developing new onset eczema (incidence), and the pattern of common comorbidities in people with eczema. It also aims describe current treatment patterns by age groups and other factors. It also will look back over the last decade to identify how the number of people with eczema and treatments changing over time. The study will also explore patterns in the people most commonly affected and in the treatments used.

Detailed Description
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Objective This study aims to calculate current and accurate prevalence and incidence estimates for atopic dermatitis (AD) by age group and sociodemographic factors. It also aims to describe the burden of comorbidity in AD with a focus on atopic and mental health conditions. The study also aims to describe the health care resource utilisation of this cohort in terms of prescription use, primary care appointments, and specialist referrals. Method This study will define AD cases using a previously validated algorithm for case identification use clinical codes form primary care in the UK (Read codes). The study will analyse the population prevalence and incidence of AD using this definition over a 10-year period (2008-2018). Within this population the prevalence of autoimmune conditions (rheumatoid arthritis, inflammatory bowel disease, coeliac disease, type 1 diabetes, and multiple sclerosis) will be reported and compared with a cohort of individuals without a diagnosis of AD, matched by age and sex at GP practice level. In the same cohort, the annual use of topical and oral medications used for the treatment of AD, primary care appointments, and specialist referrals, overall and stratified by sociodemographic factors will also be reported.

Official Title
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The Epidemiology of Atopic Dermatitis, Associated Comorbidities, and Treatment Patterns in the United Kingdom (UK)

Conditions
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Atopic Dermatitis Eczema, Atopic Dermatitis, Eczema

Intervention / Treatment
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* Other: No intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All paediatric and adult patients registered with an Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) contributing GP practice during the study period (2008-2018) and with at least one year of follow-up. Exclusion Criteria: The presence of psoriasis, photodermatitis, or ichthyosis
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Prevalent case of atopic dermatitis<br>People with atopic dermatitis meeting the inclusion criteria and registered with one of the study practices for one or more years during the study period. | Other: No intervention<br>* Observational analysis of usual care only<br>|
| Controls<br>Age, gender and primary care practice-matched controls without a diagnosis of atopic dermatitis or another exclusion condition (psoriasis, photodermatitis, or ichthyosis) and registered with one of the study practices for one or more years during the study period. | Other: No intervention<br>* Observational analysis of usual care only<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The incidence of atopic dermatitis | Incidence of atopic dermatitis reported by predefined sociodemographic factors | Measure will be reported annually by year from 2008-2018 | 
| The prevalence of atopic dermatitis | Prevalence of atopic dermatitis reported by predefined sociodemographic factors | Measure will be reported annually by year from 2008-2018 | 
| The prevalence of diagnosed co-morbidities in people with and without atopic dermatitis | Co-morbidities to be reported comprise; asthma, allergic rhinitis (hay fever), depression, anxiety, attention deficit hyperactivity disorder (ADHD), cardiovascular diseases (CVD; comprising myocardial infarction, angina, heart failure, atrial fibrillation, and stroke), rheumatoid arthritis, inflammatory bowel disease (ulcerative colitis and Crohn's disease), type 1 and type 2 diabetes, multiple sclerosis (MS) and coeliac disease. The presence of these co-morbidities will be identified from existing primary care records. | Prevelence reported annually by year from 2008-2018 | 
| Annual rates of service utilisation (number of primary and secondary care visits) in people with atopic dermatitis | Service utilisation events comprise; primary care visits related to atopic dermatitis (prescription of treatment or coding of AD related problem), specialist care referrals to dermatology, and emergency admissions to dermatology. These events will also be reported separately. | Measures will be reported annually by year from 2008-2018 | 
| Annual prescription rates for atopic dermatitis related treatments | Treatment rates will be reported separately and comprise: emollients and soap substitutes, topical steroids, topical antimicrobial therapies, combination topical therapies, topical calcineurin inhibitors, and oral immune modulating treatments, and phototherapy. | Measures will be reported annually by year from 2008-2018 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to occurrence of moderate atopic dermatitis | The impact of sociodemographic predictors on time to first occurrence of moderate atopic dermatitis | Models will be devised using data from 2008-2018 | 
| Time to occurrence of severe atopic dermatitis | The impact of sociodemographic predictors on time to first occurrence of severe atopic dermatitis | Models will be devised using data from 2008-2018 | 
| Time to recurrence of active atopic dermatitis | The impact of sociodemographic predictors on time to first recurrence of atopic dermatitis in those with inactive disease | Models will be devised using data from 2008-2018 |