Background With expanding therapeutic possibilities for the treatment of psoriatic arthritis (PsA) it will be increasingly important to determine residual disease and define when to adjust treatment. The rationale behind treatment decisions in current daily clinical practice and the relation with residual disease activity has not been reported in literature.

Objectives To assess the current clinical practice on defining residual disease and the subsequent treatment decisions made in PsA patients.

Methods This cross sectional study included 142 consecutive PsA patients who visited the outpatient clinic. The treating rheumatologist scored disease activity and his opinion on the presence of residual disease and the subsequent treatment decisions made. Patients scored patient disease activity scores.

Results Of the 142 patients, 52 patients were considered without residual disease by the treating rheumatologist. These patients indeed show low disease activity on all measured domains, and all patients were considered in remission or low disease activity according to CDAI composite score.

90 of the 142 patients were considered to have residual active disease by their treating rheumatologist. Disease activity was present across all measured domains and 48/90 patients were considered in moderate (39) or high (9) disease activity defined by CDAI. There were no differences between the groups with or without residual disease activity in gender, disease duration, comorbidity, current treatment duration or number of previously used cDMARDS. Residual disease activity was more frequently reported in patients treated with a cDMARD only or a 2nd TNFi.

Of the 90 patients with residual disease, in 21 (23%) treatment adjustment was initiated. Treatment adjustments consisted of: addition or adjustment of analgesic treatment in 6 pts (29%); local or intramuscular corticosteroid therapy in 5 pts (24%); switch of cDMARD to another cDMARD in 4 pts (19%); referral to a paramedic in 2 pts (10%); switch to a 2nd or 3rd TNFi in a patient already using TNFi treatment in 2pts (10%); addition of a cDMARD to current TNFi 1 pt (5%); and start of a TNFi with current use of cDMARD only in 1pt (5%). Treatment changes were considered less frequent in those patients treated with a 2nd TNFi. No differences were seen in disease activity and demographics between those with or without a treatment adjustment.

Reasons not to adjust therapy mostly reported were: complaints were seen as only minor (39/69, 57%). The most frequent other reasons reported were: it was the patients' preference not to adjust medication (10/69, 14%); “we have no other options left” (5/69, 7%); lack of compliance (due to side effects) (5/69, 7%).

Conclusions Residual disease resulted in treatment adjustment in only a quarter of patients. Not adjusting treatment could not be explained by comorbidities, or a lack of treatment options in a majority of the patients. Our data indicate that future implementation of a treat-to-target approach in PsA does not only require a data-driven consensus on the optimal target to use but also active coaching of physicians and patients to promote treatment adjustments in clinical practice.

Disclosure of Interest L. Van Mens: None declared, S. Atiqi: None declared, I. Fluri: None declared, M. van de Sande Grant/research support from: Novartis, Eli Lilly, Boehringer Ingelheim; speakersfee: Benecke, Takeda, Tillotts, MSD, Cellgene, A. van Kuijk Grant/research support from: UCB, Pfizer, MSD, Janssen, Consultant for: Novartis, Celgene, D. Baeten Grant/research support from: Pfizer, MSD, AbbVie, UCB, Novartis, Janssen, Boehringer Ingelheim, Consultant for: Pfizer, MSD, AbbVie, UCB, Novartis, Janssen, Boehringer Ingelheim, Eli Lilly, Roche, BMS, Glenmark, Employee of: UCB, This work was financially supported by UCB in the context of an Investigator Initiated Study.