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Reliability of skin‐type self‐assessment: agreement of adolescents’ repeated Fitzpatrick skin phototype classification ratings during a cohort study
Author(s) -
Magin P.,
Pond D.,
Smith W.,
Goode S.,
Paterson N.
Publication year - 2012
Publication title -
journal of the european academy of dermatology and venereology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.655
H-Index - 107
eISSN - 1468-3083
pISSN - 0926-9959
DOI - 10.1111/j.1468-3083.2011.04298.x
Subject(s) - medicine , skin type , phototype , cohort , kappa , cohen's kappa , reliability (semiconductor) , clinical psychology , dermatology , statistics , philosophy , linguistics , power (physics) , physics , quantum mechanics , mathematics
Background The Fitzpatrick Skin Phototype Classification (FSPC) is the most commonly used measure of skin type. In questionnaire‐based surveys, self‐rated FSPC is often used as a measure of respondents’ skin type. Objective The objective of this analysis was to assess test‐retest reliability of the self‐rated FSPC within a 12‐month cohort study that examined the psychological sequelae of acne. Methods Participants were students aged 14–17 years in four Australian secondary schools; two‐government system schools and two private schools. The primary outcomes were a number of psychological measures. The FSPC was assessed by a single concise questionnaire item. Test‐retest agreement (as measured by quadratic weighted kappa) of participants’ self‐rated FSPC at three time‐points (baseline, 6 and 12 months) was calculated. Results Of the 244 participating students, 209 students (86%) completed all three rounds of data collection. A further 26 students (11%) completed two rounds. Quadratic weighted kappa for Rounds 1 and 2 was 0.757 (95% CI 0.663–0.831). For Rounds 2 and 3 it was 0.805 (95% CI 0.659–0.893). Between Rounds 1 and 3 it was 0.767 (95% CI 0.698–0.832). This represents good‐to‐very‐good agreement. Skin type was retained as an independent variable in 8 of the16 regression models built to explain psychological outcomes in this study. Conclusion Skin type appears to be a significant factor in psychological morbidity in acne. The FSPC is a reliable method for assessing skin phenotype, even when elicited via a concise questionnaire item suitable for assessing skin type as a potential confounder in studies of other outcome factors.