Impact of training on concordance among rheumatologists and dermatologists in the assessment of patients with psoriasis and psoriatic arthritis

Objective: To evaluate the impact of training on the reliability among dermatologists and rheumatologists in the assessment of psoriatic arthritis (PsA) patients. Methods: Overall, 9 hospital-based rheumatologists and 8 hospital-based dermatologists met in Reggio Emilia, Italy on October 2015 to assess 17 PsA patients. After 1 month, physicians underwent a 3-h training session by 4 recognized experts and then assessed 19 different PsA patients according to a modified Latin square design. Measures included tender (TJC) and swollen joint count (SJC), dactylitis, enthesitis, Schober test, psoriasis body surface area (BSA), Psoriasis Area and Severity Index (PASI), Nail Psoriasis Severity Index (NAPSI), and static physician's global assessment of PsA disease activity (sPGA). Variance components analyses were performed to estimate the intraclass correlation coefficient (ICC). Results: TJC and enthesitis-measured pre-training by dermatologists or rheumatologists revealed moderate-substantial agreement (ICC: 0.4-0.8). In contrast, SJC and Schober test showed fair (ICC: 0.2-0.4) and moderate agreement, respectively (ICC: 0.4-0.6), while poor agreement (ICC: 0-0.2) was represented by dactylitis. Moderate-substantial (ICC: 0.4-0.8) agreement was observed for most skin measures by dermatologists and rheumatologists, apart from BSA, where fair agreement (ICC: 0.2-0.4) was observed. Agreement levels were similar before and after training for arthritis measures. In contrast, levels of agreement after training for 3 of the 4 skin measures were increased for dermatologists and all 4 skin measures were increased for rheumatologists. Conclusions: Substantial to excellent agreement was observed for TJC, enthesitis, PASI, and sPGA. Rheumatologists benefited from training to a greater extent.