AB0725 Using a reduced joint count in measuring disease activity in psoriatic arthritis, is it legit?. (15th June 2017)

• Record Type: Journal Article
• Authors: Vis, M; Wervers, K; Tchetverikov, I; Gerards, A; Kok, M; Appels, C; Korswagen, L-A; Hazes, M; Veris, J; Groenendaal, H van; Luime, J
• Is Part Of: Annals of the rheumatic diseases. Volume 76(2017)Supplement 2
• Page Start: 1308
• Page End: 1308
• Publication Date: 2017-06-15
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2017-eular.6851
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: In Psoriatic arthritis (PsA) the pattern of joint involvement seems to be more heterogenic than Rheumatoid Arthritis (RA). Therefor the 66/68 joint count is frequently used in PsA scores. In this study we would like to investigate whether using less extensive joint counts influences PsA disease activity measures Objectives: To evaluate the effect of using a 28, 44 or 66/68 joint count on Minimal Disease Activity (MDA). Methods: Newly diagnosed PsA patients were included in the Dutch Early south-west Psoriatic Arthritis Registry (DEPAR) study between August 2013 and January 2017. Joint scores at baseline and 6 months were calculated using a 28, 44 and 66/68 joint count. Consecutively MDA was calculated using each of these joint counts. MDA is defined as minimal disease activity in 5 out of 7 domains (swollen joints, tender joints, PASI, patient vas pain, patient vas global, HAQ, enthesitis) Results: In total, 413 patients were included into the study, of which 320 had reached 6 months follow-up at the time of this abstract. Half of the patients were male (49%), and mean age was 50 years (SD 13.8). The percentage of patients with at least one involved joint (swollen or tender) at baseline decreased from 91% using the 66/68 score to 88% with 44 joints and then to 80% with a 28 joint count (Table 1 ). At 6 month these scores were 66% 63% and finally 56% respectively for the 66/68, 44 and 28 joint count. After 6 months, 96 patients (30%) had achieved MDA using the original 66/68 joint count. Using a 28 joint count, 10 more patients (10% of the MDA population) were classified as having achieved MDA. Conclusions: Using reduced joint count joints in PsA misclassifies around 10% of patients as having no joint involvement. It also misclassifies about 10% of the MDA population of having achieved MDA while they have not. Full 66/68 joint counts remain recommended for measuring disease activity in PsA. Disclosure of Interest: None declared