Residual symptoms and disease burden among patients with psoriatic arthritis: is a new disease activity index required?

The aim of this study was to investigate residual symptoms or disease burden among patients with psoriatic arthritis (PsA) in remission or low disease activity (LDA) according to different outcome measures. A total of 126 patients with PsA were included and the following variables were assessed: Tender joint count (TJC), swollen joint count (SJC), patient's global assessment, physician's global assessment, pain, extra-articular manifestations, Psoriasis Area and Severity Index, Health Assessment Questionnaire, fatigue, Short Form-36, psoriatic quality of life, Hospital Anxiety and Depression Scale and C-reactive protein (CRP). Disease activity was measured using three different outcome measures including minimal disease activity (MDA), disease activity score for 28 joints (DAS28-CRP) and disease activity in psoriatic arthritis (DAPSA). The number (%) of patients who achieved remission or LDA was 9(14.1), 34(27.0) and 67(53.2) according to MDA, DAPSA and DAS28-CRP criteria, respectively, under usual care. SJC > 1 was seen in 3(8.8%) and 13(19.4%) of patients in remission or LDA as defined by the DAPSA and DAS28-CRP respectively. TJC > 1 was found at least 32.4% of patients with PsA in remission or LDA by any definition. 22.2-49.3% of patients with PsA in remission or LDA still suffered from clinically important fatigue. No patients in MDA had a substantial functional impairment while 2.9-19.4% of patients fulfilling remission or LDA according to the DAPSA and DAS28-CRP experienced functional disability. At least 22.2% of patients with PsA in remission or LDA by any description had higher risk for depression, and at least 11.1% for anxiety. Despite patients with PsA in remission or LDA by various definition, they may continue to experience pain, tender or swollen joints, fatigue, physiologic distress as well as functional impairment suggesting that there is a significant unmet need with regard to definition of remission or LDA in PsA.