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Correlation and agreement of self‐assessed and objective skin disease severity in a cross‐sectional study of patients with acne, psoriasis, and atopic eczema
Author(s) -
Magin Parker J.,
Pond C. Dimity,
Smith Wayne T.,
Watson Alan B.,
Goode Susan M.
Publication year - 2011
Publication title -
international journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 93
eISSN - 1365-4632
pISSN - 0011-9059
DOI - 10.1111/j.1365-4632.2011.04883.x
Subject(s) - medicine , acne , psoriasis , atopic dermatitis , severity of illness , correlation , observational study , cross sectional study , depression (economics) , psoriasis area and severity index , anxiety , disease , dermatology , rank correlation , kappa , spearman's rank correlation coefficient , psychiatry , pathology , philosophy , statistics , geometry , mathematics , machine learning , computer science , economics , macroeconomics , linguistics
Background Previous studies have shown variable correlation of patients’ self‐assessed skin severity measures and clinician‐assessed objective measures of severity. But, generally, correlation has not been as good as might be expected for conditions in which the objective physical extent of skin disease is apparent to the sufferer to an extent that is not applicable in many other diseases. Methods This paper reports agreement and correlation of self‐assessed and objective severity measures in a study of 108 subjects with acne, psoriasis, or atopic eczema. The study was a cross‐sectional study examining psychological associations of these skin diseases. Objective severity was assessed with the Leeds technique (acne), the Psoriasis Area and Severity Index, and Six Area Six Sign Atopic Dermatitis instruments. Agreement is a more appropriate measure than correlation in this situation and was measured with weighted kappa, while correlation was measured with Spearman’s rank correlation. Results There was a modest correlation of ρ = 0.46 and similarly very modest agreement of 0.35 (weighted kappa) of self‐assessed and clinician‐assessed disease severity. Furthermore, self‐assessed (but not clinician‐assessed) severity was statistically associated with psychological morbidity in this study; i.e. – depression, anxiety, and overall psychological morbidity. Conclusions Clinicians should consider psychological sequelae of skin disease, not only in those with objectively more severe disease but in patients across the severity spectrum. Both observational and interventional studies of skin disease should include both clinician‐assessed and self‐assessed measures of severity among assessed variables.