Measurement properties of outcome measures for vitiligo. A systematic review.

OBJECTIVE To summarize and critically appraise the evidence on the measurement properties of clinician-, patient-, and observer-reported outcomes, measuring any construct of interest in patients with all types of vitiligo. DATA SOURCES Electronic databases including PubMed (1948 to July 2011), OVID EMBASE (1980 to July 2011), and CINAHL (EBSCOhost) (1982 to July 2011) were searched. STUDY SELECTION Two authors independently screened all records for eligibility. For inclusion, the study population had to include patients with vitiligo, for which outcome measures were developed or evaluated on their measurement properties. The initial search retrieved 1249 records, of which 14 articles met the inclusion criteria. DATA EXTRACTION Characteristics of the included instruments, study population, and results of the measurement properties were extracted. The Consensus-Based Standards for the Selection of Health Status Measurement Instruments (COSMIN) 4-point checklist, combined with quality criteria for measurement properties, was used to calculate the overall level of evidence per measurement property of each instrument. Independent extraction and assessment was performed by 2 authors. DATA SYNTHESIS Eleven different measurement instruments were identified. Strong evidence was found for a positive internal consistency of the Dermatology Life Quality Index. For other instruments, the evidence of measurement properties was limited or unknown. CONCLUSIONS Recommendations on the use of specific outcome measures for vitiligo should be formulated with caution because current evidence is insufficient owing to a low number of studies with poor methodological quality and unclear clinical relevance. To recommend outcome measures for vitiligo, further research on measurement properties of clinical relevant outcome measures for vitiligo according to COSMIN quality criteria is needed.