Tele-assessment of Psoriasis Area and Severity Index: A study of the accuracy of digital image capture

BACKGROUND: The implementation of remote Psoriasis Area and Severity Index (PASI) determinations would greatly enhance the delivery of specialist dermatological care to patients with severe psoriasis unable to attend face-to-face dermatological consultations. Here we investigate the feasibility of the remote determination of PASI scores by comparing the results of face-to-face with digital image assessment. METHODS: Twelve patients with confirmed psoriasis were recruited for the study. Initially, two dermatologists scored the PASI at the patients' usual scheduled face-to-face visits, at which time standardized digital images were obtained. PASI scoring based on digital images was then performed on two separate occasions by three dermatologists with a time-interval period between assessments, facilitating an assessment of score reproducibility. Linear weighted kappa statistics were applied to the PASI scores to ascertain agreement between sets of observations. RESULTS: While we found a moderate (κ = 0.51) agreement between the face-to-face scores, there was very good (κ = 0.83) agreement between the first round of telescores and moderate (κ = 0.60) agreement between the second round of telescores. Comparison between the face-to-face and telescores revealed good (κ = 0.67 and 0.63) agreement for the scorers respectively. CONCLUSION: We demonstrate that PASI scores can be determined with moderate to good accuracy by dermatologists using standardized digital images. Our results imply the implementation of a tele-PASI service may be a practical and effective adjunct to the dermatological care of patients with severe psoriasis where incapacity or distance prevent the realisation of face-to-face consultations.