Reporting of concomitant and rescue topical therapies in randomized controlled trials evaluating a systemic treatment in atopic dermatitis: a scoping review.

Background: Randomized controlled trials (RCTs) evaluating new systemic treatments for atopic dermatitis (AD) have increased dramatically over the last decade. These trials often incorporate topical therapies either as permitted concomitant or rescue treatments. Differential use of these topicals postrandomization introduces potential bias as they may nullify or exaggerate treatment responses.

Objectives: To determine the proportion of RCTs that clearly report the allowance or prohibition of concomitant and rescue topical treatments; and to examine the reporting of specific key parameters for these topicals.

Methods: We included RCTs of systemic AD medication included in a recent living systematic review. Inclusion criteria were published RCTs evaluating systemic immunomodulatory treatments in AD. Only anti-inflammatory topical therapies were included treatments in this review; emollients were not considered.

Results: We screened 83 AD trials and included 67 RCTs published between 1991 and 2023. The majority adequately reported the allowance or prohibition of concomitant topical treatments (n = 64/67; 96%), but this clarity was less prevalent with regard to rescue topicals (n = 49/67; 73%). All trials that permitted concomitant treatments consistently reported the type, although details on potency (n = 31/35; 89%), duration (n = 19/35; 54%), application frequency (n = 12/35; 34%) and quantity (n = 2/35; 6%) were less frequently reported. Similarly, trials that allowed rescue treatments often specified the type (n = 31/34; 91%) but provided limited information on potency (n = 18/34; 53%), duration (n = 3/34; 9%), application frequency (n = 2/34; 6%) and quantity (n = 0/34; 0%). Notably, only 24% (n = 8/34) clearly reported the criteria for using rescue topical treatments, with the phrase 'at investigator's discretion' used in most cases (n = 21/34; 62%). In the multivariable logistic regression analysis including impact factor, the journal's policy on adhering to CONSORT guidelines, publication year, funding, number of patients randomized and blinding status, only publication year (≥ 2020) was associated with having better reporting for rescue topical treatments (adjusted odds ratio 9.55, 95% confidence interval 1.76-39.80).

Conclusions: While most clinical trials of systemic treatments in AD report concomitant topical treatments, reporting practices for rescue topicals are less consistent and inadequate. A standardized approach to reporting topical treatment in AD trials is needed to enhance transparency and interpretability.