The Agreement between Consumer-Driven Self-Assessment of Psoriasis Severity and Physician-Assessed Severity Based on Patient-Taken Photographs Is Weak: A Cross-Sectional Study

INTRODUCTION: Digital advancements have given access to huge amounts of real-world data (RWD) widely used for dermatological research.

OBJECTIVES: The objective of this study was 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 to 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 with 95% confidence intervals (CIs) were calculated.

RESULTS: In total, 187 patients (63% women) with mean age of 38 years were included. Self-assessment scores were higher than physicians' assessment scores for all groups, and scaling was closest to the physicians' assessment, while 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 to 0.82) for non-chronic patients. The agreement was better for men (0.53 [-0.02 to 0.98]) than for women (0.12 [-0.01 to 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.