POS0004 WHAT DOES WORSENING IN DAPSA DISEASE ACTIVITY CATEGORIES MEAN FOR PATIENTS WITH PSORIATIC ARTHRITIS? AN ANALYSIS OF 222 PATIENTS

Abstract

BackgroundIn psoriatic arthritis (PsA), disease activity states have been defined using the DAPSA (Disease Activity index for Psoriatic Arthritis) score (1). The disease activity states have been validated using structural progression as the gold standard (2). However, the worsening in DAPSA states has not been compared to the patient’s perspective.ObjectivesTo assess the association between a worsening in disease activity (i.e., change in DAPSA disease activity category) versus the patient’s judgement of disease worsening.MethodsReFlap (NCT03119805) was a longitudinal study in 14 countries of consecutive adult patients with definite PsA and more than 2 years of disease duration. Patients were seen twice in the context of usual care, around 4 months apart (3). Worsening in disease activity between the 2 visits was defined as a transition to a more active disease category, based on the DAPSA categories [(remission, low disease activity (LDA), moderate disease activity (MDA) and high disease activity (HDA)] (1).This change was compared to (a) patient perceived-flares collected according to a patient-reported question: “At this time, are you having a flare of your psoriatic arthritis, if this means the symptoms are worse than usual?”; and (b) a worsening according to the MCID (Minimal Clinical Important Difference) question. The agreement between the definitions of worsening were calculated by frequency, Cohen’s kappa and prevalence adjusted bias adjusted kappa (PABAK). There was no imputation of missing data.ResultsOverall, 222 patients were analyzed: 127 (58.8%) were male, aged 53.5±12.3 years and with 10.8±8.3 years of disease duration. Disease activity was moderate: 35.9% had no current psoriasis skin lesions, mean tender joint count (TJC, 0-68) was 3.0±7.5, mean swollen joint count (SJC, 0-66) was 1.6±6.6, and mean DAPSA was 11.5±14.0.At 4.5±2.2 months follow-up, the proportion of DAPSA worsening was 40.1% [95% confidence interval, 33.9-46.7] (n=89). Most of the changes corresponded to patients going from remission to LDA (N=24, 27.0% of worsened patients) or from LDA to MDA (N=24, 27.0%).Patient-reported flares were reported in 27.0% [21.6-33.2] (n=60), and MCID worsening was reported in 14.0% [33.9-46.5] (n=31).Figure 1 shows the distribution of patients with worsening in DAPSA category, versus patient-defined worsening. Of the 89 patients who worsened according to DAPSA categories, 41 (46.1%) had self-perceived flares and 20 (22.5%) had worsening according to MCID. Among patients who worsened in DAPSA category, the mean change in DAPSA was higher in patients with self-perceived flares (increase of 22.2±15.0) than in patients without self-perceived flares (increase of 14.3±12.3). Of 133 patients with no worsening according to DAPSA, 114 (85.7%) had no self-perceived flares and 122 (91.7%) had no MCID worsening. The kappa [95% confidence interval] (PABAK) coefficients between DAPSA and either patient flare or MCID worsening were 0.34 [0.21-0.46] (0.40) and 0.16 [0.05-0.27] (0.28), respectively.Figure 1.Venn diagram for disease worsening between 2 visitsConclusionAfter 4 months of follow-up, 40.1% patients with long-standing PsA had a change in DAPSA category corresponding to more active disease. Most of these changes reflected transitions from remission to LDA, or from LDA to MDA. Among patients changing DAPSA category, only 46.1% reported themselves in flare at the second visit and only 22.5% reported themselves as worsened by MCID, leading to only fair (for flares) to low (for MCID worsening) agreement between the assessments of worsening. It is important to assess both disease activity, and the patient’s perspective of flare.