Atopic dermatitis (AD) is a chronic inflammatory disease that affects US children and adults, with a reported prevalence of 10%-13% and 7%, respectively [1-4]. Higher disease severity is associated with lower quality of life, worsened mental status, and higher use of health care resources [1,5]. This includes emergency department visits and hospitalizations as well as increased pharmaceutical and outpatient costs [6-8]. Consequently, effectively treating patients with AD has substantial clinical and economic implications.

Assessing the severity of AD is determined by the number of sites involved (eg, head and neck, upper extremities, or trunk and lower extremities), the lesion characteristics (eg, erythema, edema or papulation, and lichenification), as well as reported symptoms. Patients who have 10%-29% bodily involvement with notable signs of inflammation are classified as having moderate disease, and those with greater or equal to 30% bodily involvement are considered to have severe disease. This classification is important in the diagnosis and treatment of AD, thereby affecting therapeutic outcomes [9]. Treatment of AD with a systemic immunomodulating agent is indicated when the disease is considered moderate to severe [10]. A variety of systemic agents, including cyclosporine, azathioprine, methotrexate, mycophenolate mofetil, and systemic steroids, are used in practice without strict guidelines or recommendations to guide treatment choices [10,11]. In March 2017, dupilumab became the first biologic drug approved for the treatment of AD in adults, and in May 2020, it gained approval for use in children aged 6 years and older. Dupilumab blocks the interleukin (IL)-4 alpha receptor, inhibiting IL-4 and IL-13 signaling and preventing the release of type 2 cytokines that promote inflammation in AD [12]. Compared with the aforementioned systemic immunomodulating agents, dupilumab may be more effective as a long-term maintenance therapy and has the advantage of an overall improved side-effect profile, with no required drug-specific laboratory monitoring [11]. However, access to this immunomodulator may be limited by its novelty and cost (depending upon the dose, up to US $59,000/year for patients without insurance) [13].The disease burden of AD disproportionately affects non-Hispanic Black patients; the source of this disparity is multifactorial. Although the specific gene-environment interactions in the pathophysiology of AD are unknown, many factors—such as differences in environmental pollution, contact with tobacco smoke, hygiene practices, access to health care, diet, and exposure to disease—likely play a role [4,14,15]. Loss of function mutations in the filaggrin gene is linked with an increased risk of developing AD, oftentimes leading to persistent disease. Filaggrin loss-of-function mutations are less common in Black patients compared to White patients, yet Black patients are still more likely to experience persistent disease [16,17]. In addition, Black patients have lower skin ceramide/cholesterol ratios, attenuated T helper 1 and T helper 17 immunophenotypes, and higher serum immunoglobulin (Ig) E levels, which predisposes to skin breakdown, dysregulated immunity, and increased inflammation [18,19]. Despite higher AD disease severity and increased health care needs, Black patients are less likely to receive outpatient dermatologic care [3,20-22]. A prior investigation reporting on race- and ethnicity-related disparities in the treatment of AD found that Black patients had statistically significant lower odds of receiving dupilumab compared to White patients [23]. Previous research has also shown that Black patients with psoriasis are less likely than White patients to receive biologic treatment, independent of demographic or socioeconomic factors and comorbidities [24,25].

Data related to the prescription patterns of dupilumab for AD are needed to inform health equity and decision-making in everyday practice.

Summary statistics gathered based on the International Classification of Diseases, Tenth Revision billing codes are provided in Table 2. There were 249 dupilumab prescriptions among 6421 patients. Our cohort had a mean age of 53.2 (SD 17.9) years and was composed of mostly non-Hispanic (n=5491, 89%), White (n=4912, 79.3%), and female (n=3532, 57%) patients. The most common recent diagnosis was a general diagnosis of atopic dermatitis (n=3263, 50.8%), followed by vesicular eczema (n=1148, 17.9%), nummular eczema (n=1126, 17.5%), flexural eczema (n=763, 11.9%), and lastly, atopic neurodermatitis (n=12, 1.9%). Among those who received dupilumab, the mean age was 51.4 (SD 16.7) years and 58.6% (n=146) were female. Every patient who received a prescription had either multiple prescriptions, prescriptions for quantities greater than 1, or received refills. The majority of patients were White (n=179, 71.9%), followed by patients identifying as Black or African American (n=34, 13.7%) and “Other” races (n=13, 5.2%). Among the most common recent diagnoses, 85.8% (n=213) were general diagnoses of AD, and the remaining were diagnoses of atopic neurodermatitis (n=14, 5.6%), flexural eczema (n=5, 2.2%), nummular eczema (n=6, 2.2%), or vesicular eczema (n=11, 4.1%).

We assessed whether the proportion of patients who received dupilumab was different based on patient characteristics. Each patient characteristic (Table 3) was assessed using logistic regression with the binary outcome of receiving dupilumab or not receiving it. The P values associated with multilevel categorical characteristics (eg, race or diagnoses) were corrected for multiple testing using the False Discovery Rate (Benjamini-Hochberg correction) method. Reference levels included white race, non-Hispanic ethnicity, female sex, and AD as the first eligible diagnosis.

In our cohort, Black patients were approximately twice as likely to have received dupilumab for AD compared to White patients (odds ratio 2.352, 95% CI 1.58-3.39). Similarly, those diagnosed with atopic neurodermatitis were about twice as likely to have received dupilumab compared to those who were diagnosed with AD (odds ratio 1.87, 95% CI 1.01-3.22). Conversely, those with other eczema diagnoses, including flexural eczema, nummular eczema, or vesicular eczema, were less likely to have received dupilumab compared to those with a most recent diagnosis of atopic neurodermatitis.