Evaluation of skin ageing: a systematic review of clinical scales

Clinical scales are widely used in anti-ageing research and practice. More than 100 skin ageing scales exist, which makes it difficult to choose outcome measures and to compare study results. The objectives were to assess and evaluate the quality of measurement properties of available clinical skin ageing scales. A systematic review was conducted. Electronic databases including Medline (1970 to June 2013) and EMBASE (1974 to June 2013) were searched via Ovid SP. To enhance the sensitivity forward searches were conducted in Scopus and Web of Science. We identified 111 scales in 52 included publications. Thirty studies had good methodology for at least one measurement property. Forty-two scales were evaluated for their test-retest or interrater reliability. Nineteen showed high reliability coefficients. A further 15 instruments were partly supported by content and/or structural and/or criterion validity and/or hypotheses-testing evidence. The majority of existing clinical skin ageing scales were developed for evaluating facial characteristics. Many scales quantify similar constructs. In contrast to the high number of available scales there is limited evidence supporting their measurement properties. Recommendations for the use of specific skin ageing scales for clinical studies must be made with caution because of the high number of studies with poor methodology. Development of new instruments should be justified, and existing ones investigated for scale behaviour using appropriate methods. Future research should aim to select and/or adapt existing scales to identify the 'best' to improve clinical research and practice.