TY - JOUR T1 - Validation of an Optical Pencil Method to Estimate the Affected Body Surface Area in Psoriasis JO - Actas Dermo-Sifiliográficas T2 - AU - Reolid,A. AU - Servitje,O. AU - Ginarte,M. AU - Pérez-Ferriols,A. AU - Vélez,A. AU - Aragües,M. AU - Pereiro,M. AU - Sánchez-Carazo,J.L. AU - Garrido,J. AU - Daudén,E. SN - 15782190 M3 - 10.1016/j.adengl.2020.01.001 DO - 10.1016/j.adengl.2020.01.001 UR - https://actasdermo.org/es-validation-an-optical-pencil-method-articulo-S1578219020300019 AB - BackgroundBody surface area (BSA) affected by psoriasis is one of the most often used measures for assessing severity, but this method has shortcomings. ObjectiveTo validate a new way to estimate BSA. Material and methodProspective, multicenter study in 56 patients with psoriasis. Each patient was evaluated by 2 dermatologists in 2 visits to the same hospital. Each dermatologist used 2 methods for estimating BSA: the traditional visual estimation in which the area of the palm equals 1% of the total body surface and an optical pencil (OP) method in which the affected area is drawn on a touch screen. Software in the application then calculates the BSA. ResultsOverall concordance between the 2 methods was acceptable according to an intraclass correlation coefficient (ICC) of 0.87. However, the limits of agreement were unacceptably large and there was systematic bias: traditional estimates were consistently greater than OP calculations. Concordance between the methods was better (ICC>0.8) on the trunk and lower extremities. Intraobserver reliability was excellent with both methods (ICCs, 0.97 and 0.98 for the traditional and OP estimates, respectively). Interobserver reliability was also high (ICCs, 0.91 and 0.94 for the traditional and OP methods), although the mean BSA differed significantly between observers. The ICCs were much lower for BSA estimates on the head. ConclusionsThis study to validate the OP method for estimating the affected BSA in patients with psoriasis shows good agreement between the OP and traditional approaches. The OP calculations also showed less variance and better interobserver reliability. ER -