“Validation” of Outcome Measures in Dermatology

Abstract

Outcome measures are powerful tools in a clinician's arma- mentarium. These instruments capture clinical information and may supplement clinical judgment in order to optimize management approach, medical treatment, and referrals to other appropriate health-care providers. They may shed light on psychosocial issues while providing insight into gaps in understanding not previously considered by the clinician or the patient. These tools highlight variability between diseases when using the same scoring system and may influence clini- cal guideline recommendations. Additionally, these instru- ments may influence policy directed toward allocation of limited resources, playing a significant role in future strate- gies aimed at cost-effectiveness. BacKGrOund Scores, scales, profiles, and indexes are all examples of outcome measures. Outcome measures typically attempt to quantify either (i) clinical disease severity or (ii) patient- reported outcomes. Clinical disease severity-assessment tools gauge the global extent of disease, such as percentage of body surface area affected, physician global assessment, or the characteristics of isolated skin lesions. More disease- specific tools are the Psoriasis Area and Severity Index and the Scoring Atopic Dermatitis tool. Another group of tools focuses on patient-reported outcomes such as health- related quality of life (HRQoL), assessing the impact of a disease on patients' lives or evaluating treatment prefer- ence/satisfaction. These instruments may be generic, allow- ing comparison across diseases (e.g., SF-36), dermatology specific (e.g., Dermatology Quality of Life index or Skindex), disease specific, or concept specific (e.g., stigma- tization or anxiety). Figure 1 demonstrates the relationships among clinical disease severity measures, HRQoL tools, and therapeutic intervention data.