Development and Validation of the Morphea Activity Measure in Patients With Pediatric Morphea

Abstract

Morphea is an insidious inflammatory disorder of the skin and deeper tissues. Determining disease activity is challenging yet important to medical decision-making and patient outcomes. To develop and validate a scoring tool, the Morphea Activity Measure (MAM), to evaluate morphea disease activity of any type or severity that is easy to use in clinical and research settings. This pilot diagnostic study was conducted from September 9, 2019, to March 6, 2020, in 2 phases: development and validation. During the development phase, 14 morphea experts (dermatologists and pediatric dermatologists) used a Delphi consensus method to determine items that would be included in the MAM. The validation phase included 8 investigators who evaluated the tool in collaboration with 14 patients with pediatric morphea (recruited from a referral center [Medical College of Wisconsin]) during a 1-day in-person meeting on March 6, 2020. During the development phase, online survey items were evaluated by experts in morphea using a Likert scale (score range, 0-10, with 0 indicating not important and 10 indicating very important); agreement was defined as a median score of 7.0 or higher, disagreement as a median score of 3.9 or lower, and no consensus as a median score of 4.0 to 6.9. During the validation phase, reliability (interrater and intrarater agreement using intraclass correlation coefficients), validity (using the content validity index and κ statistics as well as correlations with the modified Localized Scleroderma Severity Index and the Physician Global Assessment of Activity using Spearman ρ coefficients), and viability (using qualitative interviews of investigators who used the MAM tool) were evaluated. Descriptive statistics were used for quantitative variables. Data on race and ethnicity categories were collected but not analyzed because skin color was more relevant for the purposes of this study. Among 14 survey respondents during the development phase, 9 (64.3%) were pediatric dermatologists and 5 (35.7%) were dermatologists. After 2 rounds, a final tool was developed comprising 10 items that experts agreed were indicative of morphea activity (new lesion in the past 3 months, enlarging lesion in the past 3 months, linear lesion developing progressive atrophy in the past 3 months, erythema, violaceous rim or color, warmth to the touch, induration, white-yellow or waxy appearance, shiny white wrinkling, and body surface area). The validation phase was conducted with 14 patients (median age, 14.5 years [range, 8.0-18.0 years]; 8 [57.1%] female), 2 dermatologists, and 6 pediatric dermatologists. Interrater and intrarater agreement for MAM total scores was good, with intraclass correlation coefficients of 0.844 (95% CI, 0.681-0.942) for interrater agreement and 0.856 (95% CI, 0.791-0.901) for intrarater agreement. Correlations between the MAM and the modified Localized Scleroderma Severity Index (Spearman ρ = 0.747; P < .001) and the MAM and the Physician Global Assessment of Activity (Spearman ρ = 0.729; P < .001) were moderately strong. In qualitative interviews, evaluators agreed that the tool was easy to use, measured morphea disease activity at a single time point, and should be responsive to changes in morphea disease activity over multiple time points. In this study, the MAM was found to be a reliable, valid, and viable tool to measure pediatric morphea activity. Further testing to assess validity in adults and responsiveness to change is needed.