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 2328 articles, of which 42 publications (27 unique studies) were included in this systematic literature review. Twenty-three studies reported outcomes for MDA-assessed patients, and 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 that 0–8% patients in remission according to DAPSA (or clinical DAPSA) had > 1 tender joint, 25–39% had Psoriasis Area and Severity Index (PASI) score > 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 DAPSA-­assessed targets, especially for skin outcomes. CONCLUSION: The findings demonstrate a need for further optimisation of care for patients with PsA.