The agreement between consumer-driven self-assessment of psoriasis severity and physician-assessed severity based on patient-taken photographs is weak: cross-sectional study.

INTRODUCTION:Digital advancements have given access to huge amounts of real-world data (RWD) widely used for dermatological research. OBJECTIVES:To investigate the agreement between consumer-driven self-assessed psoriasis severity and physician-assessed severity based on photographs. METHODS:Customer IDs in the Nøie database (Danish skincare company) from 2009 to 2022 with a smartphone photograph of psoriasis vulgaris on the body and a corresponding completed questionnaire were included. Smartphone photographs were evaluated by a physician assessing erythema, induration, and scaling on a scale from 0-4 based on Psoriasis Area Severity Index (PASI). Self-assessment was done on a scale from 0 to 10 and converted to 0-4 scale (0 converted to 0; 1-3 to 1; 4-6 to 2; 7-8 to 3; and 9-10 to 4). Intraclass correlation coefficients (ICC) with 95% confidence intervals (CI) were calculated. RESULTS:In total 187 patients (63% women) with mean age 38 years were included. Self-assessment scores were higher than physician-assessment scores for all groups, and scaling was closest to the physician-assessment whilst erythema and induration had a greater distance between the physicians' and patients' assessment. The correlation between self-assessed and physician-assessed psoriasis severity for all patients was 0.23 (95% CI 0.0-0.92); 0.34 (95% CI 0.0-0.95) for chronic patients, and 0.09 (-0.01-0.82) for non-chronic patients. The agreement was better for men 0.53 (-0.02-0.98) than for women 0.12 (-0.01-0.84). CONCLUSION:There was weak agreement between self-assessed psoriasis severity and photographically assessed severity by the physician. Consumer-driven RWD should be interpreted with caution.