Why statistics matter: limited inter-rater agreement prevents using the psoriasis area and severity index as a unique determinant of therapeutic decision in psoriasis.
Fiche publication
Date publication
septembre 2012
Auteurs
Membres identifiés du Cancéropôle Est :
Pr AUBIN François
Tous les auteurs :
Gourraud PA, Le Gall C, Puzenat E, Aubin F, Ortonne JP, Paul CF
Lien Pubmed
Résumé
Although the demand for evidence-based decisions is increasing in clinical practice, recent systematic reviews on the accuracy of existing psoriasis severity scales, including the Psoriasis Area and Severity Index (PASI), suggest that their validity is not fully characterized. We simulated the evaluation of PASI by two practitioners in 1,000 sets of 100 patients. PASI data from several practitioners who examined the same patients were used to generate PASI scores by two practitioners, in order to compare how well commonly used statistics assess the inter-rater agreement for the PASI. Because the PASI score has an asymmetric distribution, statistics such as Pearson's linear correlation coefficient "r" and Spearman's rank correlation coefficient overestimated the inter-rater agreement of PASI as compared with the intra-class correlation coefficient (ICC; r=0.8, rho=0.7, ICC=0.5). When restricting the analysis to patients with a PASI
Référence
J Invest Dermatol. 2012 Sep;132(9):2171-5