Active AD Prevalent in 2.4% of the UK Adult Population

Active atopic dermatitis (AD) affected 2.4% of the adult UK population between 2015 and 2019, with females (58.2%) and those 82 years and older (4.4%-4.9%) more likely to receive this diagnosis, according to a study published in Skin Health and Disease.

Before this study, the researchers noted the limited data available on AD disease prevalence and treatment patterns in the UK population. Consequently, they conducted this study “to calculate the current prevalence of AD in the UK primary care adult population according to age group and by disease severity (mild to moderate to severe).”

More specifically, the study examined patient demographics and disease-related factors, such as type of AD, time since diagnosis, and comorbidities, in those with AD from 2015 to 2019. It also analyzed treatment and referral patterns for those with active AD in 2019, the index event defined as a physician visit or prescription between January 1, 2015, and January 1, 2020.

The researchers used the Clinical Practice Research Datalink (CPRD) database to create their study population. The CRPD is one of the UK’s largest primary care databases, as it contains medical records for over 11.3 million patients managed by 674 general practioners (GPs) and is representative of the UK general population’s demographics.

They identified patients with AD 18 years or older in the CRPD through an established algorithm based on diagnosis code and pharmaceutical treatment. Those with active AD were identified by an AD-related prescription or GP visit within the same year. Also, patients with moderate to severe AD were identified through either a referral to a specialist or a prescription for topical calcineurin inhibitors (TCIs), phototherapy, or systemic treatments; they noted that mild AD was identified if patients did not meet these criteria.

Through this study, the researchers found that, as of January 1, 2020, 72,013 adults in the UK had active AD, its prevalence remaining stable at 2.4% between 2015 and 2019. The mean (SD) age of those with active AD was 52.6 (21.0) years, and the mean disease duration was 9.4 (5.9) years. The researchers also found prevalence highest in those 82 years or older (4.4%-4.9%) and lowest in those aged 34 to 49 years (1.7%-1.8%). Additionally, most of the population had mild AD, as they only identified 7.5% to 8.3% of patients with moderate to severe AD; this amount decreased as the study progressed.

“There was a linear decrease each year in the CPRD population with AD and in the number of patients with moderate to severe AD (from 9098 in 2015 to 5988 in 2019),” the authors wrote.

In terms of treatment patterns, 86.3% of patients received topical regimens in 2019, making it the most popular therapy option; more patients with mild AD (79.5%) received topical corticosteroids than patients with moderate to severe AD (66.9%). Also, 36.7% of patients with moderate to severe AD were prescribed systemic agents, most frequently methotrexate (20.3%). Additionally, the researchers noted that 20.8% of patients with mild AD and 23.8% of those with moderate to severe AD were prescribed oral glucocorticoids.

The researchers found that 24,894 patients received a referral. Almost twice as many patients with moderate to severe AD vs mild AD received a referral of any type, including specialist referrals for AD (59.8% vs 32.3%, respectively). Most who received referrals (54.3%) were aged 50 to 81 years, and 17% were between 18 and 33 years. The researchers noted that the mean time between diagnosis and dermatology/immunopathology specialist referral for patients with moderate to severe AD was 8.2 (6.2) years.

Despite their findings, the researchers acknowledged that their study had imitations, one being that new biological treatments continue to be released. This means that referral and treatment patterns also continue to change; therefore, the researchers’ findings may be inaccurate. Consequently, for future research, they urged continued monitoring of AD disease management.

“The monitoring of prescribing and disease management patterns for AD in the UK primary care setting may help inform future AD treatment guidelines, ultimately leading to better patient outcomes,” the authors concluded.

Reference

Kleyn CE, McKenzie R, Meeks A, Gittens B, von Arx LB. Prevalence and treatment patterns of adult atopic dermatitis in the UK Clinical Practice Research Datalink. Skin Health Dis. 2023;3(4):e232. doi:10.1002/ski2.232