Core outcome sets (COS), important outcomes that should be measured in clinical trials, are largely absent in atopic dermatitis (AD) research. This prevents the combining of evidence from systematic reviews of important therapeutic interventions for AD, leading to a lack of unbiased evidence to guide clinical practice.

The international Harmonising Outcome Measures for Eczema (HOME), established in 2010, aims to establish a complete COS for AD clinical trials. The HOME group’s core domain set for AD, established via an international panel of consumers and experts reaching at least 30% consensus, include:

·   Clinical signs assessed by a physician using a score


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·   Clinical symptoms

·   Long-term control flares

·   Quality of life

The HOME group’s roadmap for developing AD COS includes several steps for each core domain: identify instruments, evaluate the measurement properties and quality of validation studies for the identified instruments, and determine which instruments are preferred for COS.

1.  Symptoms

Identify instruments. Stand-alone measurements such as the visual analogue scale (VAS) or numeric rating scale (NRS), and those part of a composite measure (measuring clinical signs as well as patient-reported symptoms), such as the SCORing Atopic Dermatitis (SCORAD) index, were commonly used to measure AD symptoms.

Evaluate the measurement properties and quality of validation studies for the identified instruments. The following instruments had sufficient validations to consider for recommendation for the COS: Pediatric Itch Severity Scale (ISS), Patient-Oriented Eczema Measure (POEM), Patient-Oriented (PO-) SCORAD, Self-Administered Eczema Area Severity Index (SA-EASI), and Adapted SA-EASI.

Determine which instruments are preferred for COS. POEM was voted the most suitable instrument to measure AD symptoms, and was included in the COS.

2.  Signs

Identify instruments. EASI and SCOREAD were the most commonly used instruments to measure signs of AD in trials.

Evaluate the measurement properties and quality of validation studies for the identified instruments. EASI and SCOREAD were the most extensively studied instruments in validation studies, proving relevant to patients and providers for assessing disease severity.

Determine which instruments are preferred for COS. Consensus was reached to include EASI as the recommended instrument in the COS; however, SCOREAD remains a common instrument in AD trials alongside EASI.

3.  Quality of Life

Identify instruments. The most commonly used instruments to measure quality of life were the Dermatology Life Quality Index (DLQI) in adults, the Children’s Dermatology Life Quality Index (CDLQI) in children, the Infant’s Dermatitis Quality of Life Index (IDQOL) in infants, and the Dermatitis Family Impact (DFI) in caregivers.

Evaluate the measurement properties and quality of validation studies for the identified instruments. Two systematic reviews for adults, adolescents, children and infants measured 133 properties of 9 quality of life instruments.

Determine which instruments are preferred for COS. The HOME group voted to include the IDQOL, CDLQI and DLQI in the COS.

4.  Long-term Control

Identify instruments. This was assessed using of systematic reviews on long-term control measures used in RCTs and a review of AD flare definitions. In addition, qualitative studies were included to allow for the definition of the construct of interest.

Evaluate the measurement properties and quality of validation studies for the identified instruments. The HOME group focused on global measures of AD control when deciding on candidate instruments for long-term control, since they agreed that repeated measurement of the previous 3 core domains was not enough to capture long-term control, and that it should instead be a distinct domain that assessed with global measures of AD control recorded repeatedly over time.

Determine which instruments are preferred for COS. Recap of aAtopic eczema (RECAP) and Atopic Dermatitis Control Test (ADCT) were chosen to be included in the COS based on their good content validity, responsiveness, and promising results on all psychometric properties currently tested.

Once the instruments for each domain were chosen, the HOME group also established minimum cut-off points for each instrument to ensure they are used consistently throughout AD studies.

“We urge researchers, funders, regulators, commissioners of health care, patients and carers and all health care professionals dealing with AD to demand the use of the HOME COS so that all new evidence can be combined in a meaningful way for patient benefit,” the HOME group authors wrote.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference

Williams HC, Schmitt J, Thomas KS, , et al., on behalf of the HOME Initiative. The HOME core outcome set for clinical trials of atopic dermatitis.J Allergy Clin Immunol. Published online March 26, 2022. doi:1016/j.jaci.2022.03.017