How and what adverse events are reported and captured in randomized control trials of emollients in the treatment of eczema?

Background
Emollients are universally recommended for atopic dermatitis/eczema (“eczema”), to improve the skin barrier and reduce symptoms. However, our knowledge of the frequency and nature of adverse effects associated with their use is limited.

Objective
We sought to determine how well adverse events are reported in randomised controlled trials (RCTs) of emollients for eczema.

Methods
Medline was searched from inception (1946) to May 2022. Inclusion criteria: RCTs of moisturisers or emollients used as a leave-on treatment (as the intervention or control) in adults or children with eczema. Exclusion criteria: non-RCTs; patients with other diagnoses included; use of emollient as bath additives, soap substitutes, or as preventative; not published in English. References of eligible papers were reviewed for any additional, relevant research. Data were extracted into an Excel spreadsheet and analysed descriptively. An assessment of study quality was carried out using the JBI tool for RCTs.

Results
From 369 potential papers, 35 papers (reporting on 34 studies) were included. Most research was conducted in research centres or hospitals (unclear in 33%). 89% reported collecting data on adverse events related to emollient treatment use but the methods used were poorly reported (40% unclear). Four papers used patient questionnaires/diaries. However, it was unclear how and what was collected as only two studies showed the questionnaires used.

Conclusions
Reporting of adverse events related to emollient use in trials of patients with eczema is poor and inconsistent. Agreement should be reached on how and what adverse events should be collected, to standardise reporting across studies.