AD indicates atopic dermatitis; Ph, phototherapy; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; UV, UV light therapy.
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Bhattacharya T, Silverberg JI. Efficacy of Systemic Treatments for Atopic Dermatitis in Racial and Ethnic Minorities in the United States. JAMA Dermatol. 2014;150(11):1232–1234. doi:10.1001/jamadermatol.2014.1674
Most evidence supporting systemic therapy for atopic dermatitis (AD) is derived from randomized clinical trials (RCTs) performed outside the United States, particularly in Europe. However, the US population vastly differs from that of Europe and other regions, with greater racial and ethnic diversity and heterogeneity. This is not a trivial point given recent studies demonstrating greater prevalence1 and severity of AD and quality-of-life impairment2 from AD in blacks. Furthermore, blacks have a distinct clinical presentation with a micropapular, perifollicular erythematous eruption.3 They also seem to have different genetic polymorphisms underlying their disease.4,5 Yet, little is known about the efficacy of systemic AD therapy in blacks. It is estimated that blacks will represent 13.4% of the US population in the year 2020.6 It is therefore imperative to determine which treatments work best in them and other sociodemographic groups. The aims of this study were to identify US studies involving systemic AD therapy and assess for racial differences in treatment responses.
We searched PubMed, EMBASE, Cochrane Library, and GREAT databases from 1898 to 2014 for all studies involving “atopic dermatitis,” “atopic eczema,” “phototherapy,” “UV,” “cyclosporine,” “cyclosporin,” “ciclosporin,” “azathioprine,” “methotrexate,” and “mycophenolate.” Only US studies were chosen. We anticipated a small number of studies and therefore decided a priori to include all studies irrespective of study design. Exclusion criteria included studies with fewer than 5 patients with AD and those without efficacy data. The study was approved by the institutional review board at Northwestern University.
A total of 18 studies in the United States concerning systemic AD therapy were identified, of which 9 were excluded (Figure). Of the 9 remaining, 3 were longitudinal prospective studies, and 6 were cross-sectional retrospective studies. The sample size of patients with AD ranged from 5 to 28. Overall, narrowband UV, low-dose UV-A and UV-B, cyclosporine, mycophenolate mofetil, and azathioprine all resulted in good clinical improvement and/or clearance (Table). Surprisingly, only 2 studies reported data on treatment responses in different races or ethnicities (Table). One study of cyclosporine showed that 1 black individual had poorer response than 5 white patients; however, her dose had been reduced owing to the adverse effect of hypertension. A retrospective study of treatment with azathioprine followed by mycophenolate mofetil reports that whites and nonwhites were equally likely to have switched from azathioprine to mycophenolate mofetil.
The present study highlights a major deficiency in the reporting of RCT outcomes for AD. There is a dearth of studies demonstrating efficacy of systemic therapy in different racial and ethnic subsets of either children or adults with AD in the United States. Furthermore, the results of our review raise intriguing questions about the generalizability of the results of the extant literature. A fundamental principle of all study designs is to determine whether the study cohort, and by extension the results of the study, is representative of the population. It is difficult to make such conclusions, because most studies did not describe their cohorts in much detail.
Most US studies have been retrospective cross-sectional studies with small sample sizes (the largest had 28 patients), and none were RCTs. These and other weaknesses limit their utility in guiding clinical decision-making for treating recalcitrant AD in racial and ethnic minorities in the United States. In addition, systemic AD treatments have a multitude of potentially serious adverse effects, including increased risk of infection and malignant disease; renal, hepatic, and neurological toxic effects; hypertension; and anemia and other hematologic abnormalities. Currently, we are lacking crucial data to allow for accurately weighing the benefits of treatment against the risks of adverse effects. It is imperative that large-scale RCTs of systemic treatment for AD that include racial and ethnic diversity be conducted in the United States.
Corresponding Author: Jonathan I. Silverberg, MD, PhD, MPH, Department of Dermatology, Northwestern University, 680 Lake Shore Dr, Ste 1400, Chicago, IL 60611 (email@example.com).
Published Online: September 10, 2014. doi:10.1001/jamadermatol.2014.1674.
Author Contributions: Dr Silverberg had full access to all the data in the study and takes responsibility for the integrity of the data and accuracy of the data analysis.
Study concept and design: Both authors.
Acquisition, analysis, or interpretation of data: Both authors.
Drafting of the manuscript: Silverberg.
Critical revision of the manuscript for important intellectual content: Both authors.
Statistical analysis: Silverberg
Study supervision: Silverberg.
Conflict of Interest Disclosures: None reported.