The Incidence of Venous Thromboembolism in Atopic Dermatitis

Study Overview
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Brief Summary
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This study aims to investigate the incidence of venous thromboembolism in people who are diagnosed with atopic dermatitis.

Detailed Description
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The aim of this study is to examine whether venous thromboembolism is higher in people with atopic dermatitis compared and those without and to explore the risk in particular subgroups of people with AD such as those with higher body mass index or using oestrogen containing contraceptives. Such insights will be valuable for clinicians in advising patients with atopic dermatitis regarding venous thromboembolism prevention and detection and when selecting atopic dermatitis treatments.

Official Title
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The Incidence of Venous Thromboembolism in Atopic Dermatitis: A Matched Cohort Analysis in UK Primary Care

Conditions
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Venous Thromboembolism, Atopic Dermatitis, Pulmonary Embolism, Deep Vein Thrombosis, Allergic Rhinitis, Allergy to House Dust Mite, Allergy to Animal Dander, Food Allergy, Cows Milk Allergy

Intervention / Treatment
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* Other: Exposure of venous thromboembolism


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All eligible adult people (aged ≥ 18) registered with GP practices contributing data to OPCRD between January 1, 2010 and January 1, 2020, were eligible for inclusion in the study. Exclusion Criteria: People with less than 5 years potential follow up. People with atopic dermatitis that was not active atopic dermatitis during the study period. People without atopic dermatitis but diagnosed with other skin conditions.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cases<br>All adults with an episode of active atopic dermatitis at any point between 1st Jan 2010 to 1st Jan 2015 will be included for analysis. | Other: Exposure of venous thromboembolism<br>* Composite of pulmonary embolism and deep vein thrombosis<br>|
| Controls<br>Adults without atopic dermatitis or other skin conditions matched to cases by age, gender, and duration of practice registration. | Other: Exposure of venous thromboembolism<br>* Composite of pulmonary embolism and deep vein thrombosis<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diagnosis of venous thromboembolism after the start of follow-up for each person. | To describe the risk of venous thromboembolism (composite of pulmonary embolism and deep vein thrombosis) in people with active AD compared to a matched control population. | 10 years from index date | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diagnosis of pulmonary embolism and deep vein thrombosis individually after the start of follow-up for each person | To describe the risk of pulmonary embolism and deep vein thrombosis individually in people with active AD compared to a matched control population. | 10 years from index date | 
| Demographic sub-group analysis of risk of venous thromboembolism | To explore potential heterogeneity in the risk of venous thromboembolism across subgroups of people with atopic dermatitis: by gender, age groups (18-45, 45-65, 65+), obesity, baseline use of oestrogen containing contraceptives in females, atopic dermatitis severity and history of allergic conditions. | 10 years from index date | 
| Allergic condition sub-group analysis of risk of venous thromboembolism | To explore risk of VTE stratified by the presence, or absence of allergic conditions at baseline. Allergic conditions will comprise common allergies; allergic rhinitis, allergy to dust mites or animal dander, and food allergies e.g., nut, fruit, shellfish, eggs and cows' milk allergies. Medication and other allergies will not be included. | 10 years from index date |