Residual disease associated with suboptimal treatment response in patients with psoriatic arthritis: a systematic review of real world evidence

Objective: This systematic literature review aimed to identify and summarise real-world observational studies reporting the type, prevalence and/or severity of residual symptoms and disease in adults with psoriatic arthritis (PsA) who have received treatment and been assessed against remission or low disease activity targets. Methods: Patients had received treatment and been assessed with treat-to-target metrics including minimal disease activity (MDA), Disease Activity Index in PsA (DAPSA) and others. MEDLINE, Embase® and the Cochrane Database of Systematic Reviews (CDSR) were searched using search terms for PsA, treatment targets and observational studies. Screening of search results was completed by two independent reviewers; studies were included if they reported relevant residual disease outcomes in adults with PsA who had received one or more pharmacological treatments for PsA in a real-world setting. Non-observational studies were excluded. Information from included studies was extracted into a prespecified grid by a single reviewer and checked by a second reviewer. Results: Database searching yielded 2,328 articles; 42 publications (27 unique studies) were included. 23 studies reported outcomes for MDA assessed patients, 14 studies reported outcomes for DAPSA assessed patients. Physician- and patient reported residual disease was less frequent and/or severe in patients reaching targets, but often not absent, including when patients achieved very low disease activity (VLDA) or remission. For example, studies reported 0–8% patients in DAPSA (or clinical DAPSA) remission had >1 tender joint, 25–39% had PASI >1, and 0–10% had patient reported pain >15. Residual disease was usually less frequent and/or severe among patients achieving MDA-assessed targets versus DAPSA­assessed targets, especially for skin outcomes. Conclusion: The findings demonstrate a need for further optimisation of care for patients with PsA.