Prevalence, patient characteristics and treatment patterns of adult Atopic Dermatitis in UK primary care

Date of ISAC Approval: 
19/05/2020
Lay Summary: 
Atopic dermatitis (AD) or eczema is a long-lasting condition associated with red and itchy skin that tends to flare periodically. In many instances, AD begins in childhood, while severe cases may persist in adulthood. About one-third of adult cases develop in adulthood. AD is one of the most common non-communicable skin diseases which affects up to 20% of children and 2-8% of adults in most countries of the world. There is limited data on the number of adults living with AD in Europe, but studies suggest rates between 4.4% and 7.1% and trends of increasing occurrence. The purpose of this study is to determine how many adult patients live with moderate-to-severe atopic dermatitis as per Jan 1, 2020 in the UK population, how the occurrence of the disease has developed within the past 5 years and to examine the number of other diseases that may co-exist with AD. These data are based on patients seen in primary care. Also, the study aims to characterise patients with moderate-to-severe AD by age, gender, body mass index, what treatment they receive for the skin condition and counts of referrals from general practitioners to specialist/hospital care. The public health benefit and importance of the study is emphasized by the lack of knowledge on how many adults currently live with moderate to severe AD in the UK. Estimating the proportion of adults living with AD and assessing their severity of disease will help understanding the burden of disease of AD in the UK and how it has developed in recent time.
Technical Summary: 
The intention of this study is to provide reliable, current data on the prevalence and treatment patterns (topical and systemic treatment) of AD in the adult UK population. The study is cross-sectional, determining adult patients with AD in the CPRD by a validated algorithm combining diagnostic and treatment codes indicative for AD (index event) including historic data 2 years preceding the index event. The main outcome variables are counts and proportion of adult patients with AD including demographic data, comorbidities and treatment characteristics. The statistical analysis in the study is descriptive, using count and proportion of adult AD patients. The results are summarised as number (%) for categorical variables and mean (standard deviation) for continuous variables. No comparative analyses are performed. This study will generate evidence about the prevalence of adult AD in the UK based on recent data, representative for the UK population.
Health Outcomes to be Measured: 
- Point prevalence of AD in the adult population as per Jan 1, 2020 by 1) total prevalence 2) by age group and 3) by disease severity (moderate to severe) - 5-year prevalence of AD in the adult population during the Jan 1, 2015-Jan 1, 2020 - Age - Gender - BMI - Region - Time since diagnosis - AD type (based on 5 read codes used) - Co-morbidities - topical treatment (emollients, top. steroids, top. neuron inhib) - systemic treatment on drug level - referrals from primary to secondary care - time from diagnosis to referral
Collaborators: 

Dr Lill-Brith Von Arx - Chief Investigator - Eli Lilly & Co - UK
Dr Alexandra Celia Meeks - Collaborator - Eli Lilly & Co Ltd - US Headquarters
Dr Beatrice Gittens - Collaborator - Eli Lilly & Co Ltd - US Headquarters
Dr Lill-Brith Von Arx - Corresponding Applicant - Eli Lilly & Co - UK