Prevalence and Predictors of Achieving Sustained Remission in Psoriatic Arthritis: A Swedish Nationwide Registry Study

Objective To estimate the prevalence and predictors of sustained remission (SR) in patients with psoriatic arthritis (PsA) receiving biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) in Sweden.

Methods All patients with PsA initiating b/tsDMARDs and who were registered in the national Swedish Rheumatology Quality Register (SRQ) from April 1999 to December 2019 were included. Data on disease/treatment characteristics at first b/tsDMARD (baseline) initiation and all subsequent visits were extracted from the SRQ. Remission was defined as Disease Activity Score in 28 joints based on C-reactive protein (DAS28-CRP) ≤ 2.6, Disease Activity Index for Psoriatic Arthritis in 28 joints (DAPSA28) ≤ 4 or the physician global assessment of disease activity (PGA) on a scale of 0 to 4 (remission = 0), and SR when these criteria persisted during ≥ 2 consecutive visits for ≥ 6 months. Baseline predictors of SR were explored using logistic regression analysis.

Results Data on 4669 patients with PsA with 48,773 visits were available. Eighty-one percent of patients achieved DAS28-CRP remission ever, and 54% achieved SR at least once. The corresponding percentages for DAPSA28 were 46% and 24% and for PGA were 69% and 38% for ever reaching remission and SR, respectively. Male sex was a positive predictor of reaching SR when measured by DAPSA28 and PGA but not by DAS28-CRP. Fewer swollen joints at baseline predicted SR according to all 3 remission criteria.

Conclusion A considerable proportion of patients with PsA receiving various b/tsDMARDs never achieved remission, and approximately half never achieved SR in this Swedish nationwide registry study. Fewer swollen joints at first b/tsDMARD initiation increases the likelihood of SR, regardless of remission criteria used. There was still a sex difference when measured with DAPSA28 and PGA, with men being more likely to reach SR.