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The Short-Form 12 (SF-12) mental component score (MCS) and Short-Form 6-Dimensional (SF-6D) demonstrated good validity in assessing the quality of life (QoL) associated with atopic dermatitis (AD), according to study results published in the Journal of Investigative Dermatology.
A total of 602 of 2893 patients included in the study met the criteria for AD (prevalence, 7.39%; 95% CI, 5.81-8.97). At baseline, mean patient age was 52.0±16.3 years. The weighted mean Patient-Oriented Scoring Atopic Dermatitis (PO-SCORAD) was 27.5 (95% CI, 25.7-29.3), the Patient-Oriented Eczema Measure (POEM) was 7.5 (95% CI, 6.8-8.1), SF-12 MCS was 45.9 (95% CI, 45.0-46.9), physical-component score (PCS) was 53.0 (95% CI, 52.8- 53.3), SF-6D was 0.69 (95% CI, 0.68-0.71), and Dermatology Life Quality Index (DLQI) was 4.9 (4.2-5.5).
Strong correlations were found between the SF-12 MCS and SF-6D with regard to convergent validity, whereas moderate inverse correlations were found with the POEM, PO-SCORAD, PO-SCORAD-itch, PO-SCORAD-sleep, and numerical rating scale of pain (P <.0001 for all). Good discriminant validity was found for the MCS and SF-6D.
There were weak correlations and poor discriminant validity between the SF-12 PCS and AD severity assessments. The DLQI demonstrated better convergent and discriminant validity than the SF-12; however, both the SF-12 and DLQI had good internal consistency (Cronbach’s alpha: 0.89 and 0.94). The researchers found differential item functioning for items in the SF-12 and DLQI.
For moderate and severe AD, the optimal thresholds for SF-12 MCS were 46.6 (sensitivity, 60.2%; specificity, 62.6%) and 42.1 (sensitivity, 70.6%; specificity, 56.7%), respectively. For SF-6D, the optimal thresholds for moderate and severe AD were 0.67 (sensitivity, 67.3%; specificity, 66.7%) and 0.61 (sensitivity, 69.2%; specificity, 52.8%), respectively.
Study limitations include the lack of clinician-confirmed AD classification, as well as the lack of responsiveness, test-retest reliability or content validity assessments.
Based on their findings, the researchers suggest that both the “SF-12 MCS and SF-6D may be useful for the assessment of the burden of AD in clinical trials and practice.”
Disclosure: This study was sponsored by Sanofi Genzyme and Regeneron. Multiple authors disclosed affiliations with pharmaceutical companies. See the reference for complete disclosure information.
Reference
Silverberg JI, Gelfand JM, Margolis DJ, et al. Validation and interpretation of short form 12 and comparison with dermatology life quality index in atopic dermatitis in adults [published online April 19, 2019]. J Invest Dermatol. doi:10.1016/j.jid.2019.03.1152
