Too Many Ways to Measure an Itch, Derm Study Finds

Dermatitis researchers use far too many instruments in measuring symptoms of skin ailments, a study found.

Symptoms of atopic ezcema/dermatitis (AD) were found in a systematic review of randomized controlled trials (RCTs) to be most often characterized from composite measures rather than stand-alone symptom severity rating instruments, and thirty different instruments were found to have been used across 378 trials.

The examination of how AD symptoms were assessed in RCTs reported from January 2000 to April 2014 was published by Louise A.A. Gerbens, MD, Department of Dermatology, Academic Medical Centre, University of Amsterdam, The Netherlands, and colleagues in the October issue of the British Journal of Dermatology. Reporting of Symptoms in Randomized Controlled Trials of Atopic Eczema Treatments: A Systematic Review

"As most RCTs on (AD) treatments aim to reduce symptoms and improve quality of life...assessing and reporting these outcomes is important," Gerbens and colleagues remark. "Our results show that although symptoms are reported in most RCTs, many of these patient-reported outcome measures are captured by the use of composite instruments that incorporate only one or two symptoms, and often do not report the symptom score separately."

The difficulty in evaluating treatments from trial results without comparable measures prompted the Core Outcome Measures in Effectiveness Trials (COMET) initiative in the UK, and its call for consensus-derived core outcomes. An initiative to establish such core outcomes for AD trials, the international Harmonizing Outcome Measures for Ezcema (HOME) was developed in Europe with participants from around the globe.

Four core domains for RCT trials with AD were developed by consensus in the HOME initiative: clinical signs, patient-reported symptoms, health-related quality of life, and long-term control. The HOME initiative is now in its next stage, identifying the instruments used in RCTs to measure each domain.

Symptoms were reported in 295 of the 378 RCTs (78%) examined by Gerbens and colleagues in the HOME initiative, and symptom change was the primary end point in 145 trials (50%). A stand-alone instrument to rate symptom severity was applied in 37% of the trials, while 63% used a composite instrument such as the Scoring Atopic Dermatitis (SCORAD) index. Only 23% of the RCTs reported the SCORAD symptom score separately.

"This systematic review demonstrates that symptoms, most frequently itch and sleep loss, are commonly reported in (AD) trials, but are measured using many different instruments," Gerbens and colleagues indicated.

Given the different outcomes and different outcome measures used in RCTs, they concluded, "standardization and validation of outcome domains and instruments is crucial."

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