323 Onset of atopic comorbidities relative to atopic dermatitis diagnosis in a real-world setting using an Israeli claims database

Abstract

Abstract Patients with atopic dermatitis (AD) are more likely than the general population to have other type 2 associated conditions, for example, asthma, allergic rhinitis (AR) and food allergy (FA).1,2 Classically, the atopic march is thought to begin with AD and progresses to FA, asthma and AR,1,2 but this may be an oversimplification. This study aimed to describe the epidemiology of type 2 associated conditions included in the atopic march among patients newly diagnosed with AD in a large healthcare provider database in Israel. This retrospective cohort study was performed using the Maccabi Healthcare Services database in Israel, which includes over 2.5 million members. Based on the International Classification of Diseases, 9th revision (ICD-9) diagnosis codes, patients with diagnosed AD during 2000–2019 were identified. The earliest AD diagnosis was defined as the index date and patients had to have been enrolled for ≥12 months pre-index to exclude prevalent AD. Diagnosis data were obtained during 1998–2020 to describe the cumulative prevalence of asthma, AR and FA pre- and post-AD diagnosis (−1, 0, 1, 5, 10 and 20 years) using Kaplan–Meier analysis among patients aged <3, 3–5, 6–11, 12–17 and ≥18 years at AD diagnosis. The study included 243,687 patients (51.6% female) with AD. The median (interquartile range) age at AD diagnosis was 4.3 (1.1–22.8) years, with 43.9% and 72.7% of patients diagnosed before age 3 and 18 years, respectively. At AD diagnosis, 28.1% had a prior/concurrent diagnosis of asthma/AR/FA (asthma: 17.1%, AR: 12.8%, FA: 3.4%). Among patients diagnosed with AD at age <3 years, 16.2% had been diagnosed with asthma/AR/FA by/at the time of their AD diagnosis (asthma: 10.6%, AR: 2.2%, FA: 4.9%). In this youngest age group, the cumulative prevalences of asthma/AR/FA were 28.8%, 42.7%, 49.6% and 59.6% within 1, 5, 10 and 20 years post-AD diagnosis. Among patients diagnosed with AD in adulthood, 37.7% had been diagnosed with asthma/AR/FA by/at the time they were diagnosed with AD (asthma: 16.5%, AR: 29.7%, FA: 0.8%). It this oldest age group, the cumulative prevalences of asthma/AR/FA were 40.3%, 46.1%, 50.9% and 57.6% within 1, 5, 10 and 20 years post-AD diagnosis. The results of this real-world analysis are consistent with previous evidence that AD is primarily a childhood-onset disease. The sharpest increase in type 2 associated conditions was seen in the 5 years post-AD diagnosis among patients diagnosed with AD at age <3 years. Most adults newly diagnosed with AD who developed another type 2 associated condition had already done so prior to AD diagnosis, although it is possible that earlier AD diagnoses were not captured. Regardless of age at AD diagnosis, nearly 60% of patients with AD were estimated to have ≥1 of asthma/AR/FA within 20 years of their AD diagnosis.