Alopecia Areata-Specific Patient-Reported Outcome Measures: A Systematic Review.

Importance: Alopecia areata (AA) has a high prevalence worldwide and causes considerable morbidity in patients. Patient-reported outcomes (PROs) have become an important component of clinical outcome assessment. The quality of existing AA-specific PRO measures (PROMs) has not been evaluated to date.

Objective: To identify and critically appraise the quality of the measurement properties of existing AA-specific PROMs and provide evidence-based recommendations on the most valid PROMs.

Evidence review: Using the predefined eligibility criteria, a systematic search was undertaken using 3 databases to screen the literature for available AA-specific PROMs after 2000. Original developmental studies and related validation studies that reported at least 1 measurement property of the primary PROM were retrieved. The Consensus Based Standards for the Selection of Health Measurement Instruments guidelines were used to examine the quality of the psychometric properties of retrieved PROMs. The quality of evidence was graded using the Grading of Recommendations Assessment, Development and Evaluation approach. Data were analyzed from April to July 2024.

Findings: A total of 15 articles were identified, including 8 developmental studies (describing 11 PROMs) and 7 validation studies. Three PROMs (Scale of Alopecia Areata Distress, Alopecia Areata Quality of Life Index, and Alopecia Areata Patients' Quality of Life) were AA-specific health-related quality-of-life instruments. Five instruments were single-item symptom-based PROMs (PRO measures for eyebrow, eyelash, nail appearance, and eye irritation, and Scalp Hair Assessment PRO). Three PROMs (Alopecia Areata Patient Priority Outcomes [AAPPO], Alopecia Areata Severity Self-Assessment, and Alopecia Areata Symptom Impact Scale) were based on both constructs. All PROMs were developed based on adult individuals. Seven PROMs (Scale of Alopecia Areata Distress, AAPPO, and all 5 symptom-based PROMs) featured very good development design. Content validity was the most frequently reported measurement property, rated to be sufficient for 8 PROMs. Internal consistency was reported for 5 PROMs with sufficient quality. AAPPO was the only PROM with high-quality evidence of sufficient structural validity and internal consistency. AAPPO was also the only PROM assessed for test-retest reliability, which was judged to be sufficient. No study reported measurement error.

Conclusions and relevance: This systematic review shows that there is still an unmet need for high-quality validation studies on the internal structure of AA-specific PROMs. Recommendations have been provided to help improve the rigor of the validation of AA-specific PROMs. Use of standards in psychometric testing of instruments could enhance the quality of instruments.