Clinical and Economic Burden of Mild-to-Moderate Atopic Dermatitis in the UK: A Propensity-Score-Matched Case-Control Study.

INTRODUCTION The burden of mild-to-moderate atopic dermatitis (AD) in the United Kingdom (UK) is not well understood. Long-lasting AD flares may lead to systemic inflammation resulting in reversible progression from mild to more severe AD. This study aimed to assess the clinical and economic burden of mild-to-moderate AD in the UK. METHODS AD patients were identified in the Health Improvement Network (THIN) from 2013 to 2017 and propensity score matched to non-AD controls by demographics. Patients were identified based on continuous disease activity using validated algorithms and sufficient patient status to fully validate data integrity for the entire period. Mild-to-moderate AD patients were identified by using treatment as a surrogate. Demographics, clinical characteristics and healthcare resource use (HCRU) were obtained from THIN. Literature reviews were conducted to obtain additional outcomes. A cost-of-illness model was developed to extrapolate the burden in 2017 to the UK population and in subsequent years (2018-2022). RESULTS In 2017, the prevalence of mild-to-moderate AD in THIN was 1.28%. These patients reported higher comorbidity rates and significantly higher (p < 0.0001) HCRU, encompassing mean general practitioner visits (5.57 versus 3.59), AD-related prescriptions (5.85 versus 0.68) and total referrals (0.97 versus 0.82) versus matched non-AD controls. The model projected total HCRU and drug excess costs of €462.99M over the 5 years. The excess cost decreased to €417.35M after excluding patients on very potent topical corticosteroids, who most likely had at least moderate disease. The excess costs increased to €1.21B and €7.06B when considering comorbidity burden and productivity losses, respectively. CONCLUSION Mild-to-moderate AD patients had higher comorbidity burden, HCRU and cost compared with matched non-AD controls. Overall, UK country-based economic burden was high given partly the high prevalence of this disease. Moreover, productivity burden and comorbidities had considerable impact on the economic burden, which further suggests the importance of optimal disease management.