Patients with longstanding psoriatic arthritis can achieve DAPSA remission or low disease activity and it correlates to better functional outcomes: results from a Latin-American real-life cohort

Background Patients with psoriatic arthritis (PsA) experience reduced physical function and impaired quality of life. Better patient-reported functional outcomes are found when lower disease activity is achieved. Objectives To evaluate the variation of physical function by HAQ-DI over time in PsA patients treated with standard therapy in a real-life setting: to verify predictors of achieving a minimum clinically important difference (MCID) in function by HAQ-DI (ΔHAQ-DI ≤ − 0.35) and to measure the impact of achieving REM/LDA on long-term function by HAQ-DI. Methods This is a longitudinal analysis of a real-life retrospective cohort. Data from PsA patients with at least 4 years of follow-up in the PsA clinic from 2011 to 2019 were extracted from electronic medical records. The variations of physical function by HAQ-DI and disease activity by DAPSA over time were calculated. A multivariate hierarchical regression model was applied to verify predictors of MCID in HAQ-DI. A comparison of HAQ-DI variation between patients with DAPSA REM, LDA, moderate and high disease activity was made using the generalized estimating equation model (GEE), adjusted by Bonferroni test. The Spearman correlation method was applied to verify the correlation of ΔDAPSA and ΔHAQ-DI over time. Statistical analysis was performed in SPSS program version 21.0. Results Seventy-three patients were included in the analysis. Physical function measured by HAQ-DI was determined by PsA disease activity measured by DAPSA ( p < 0.000). A moderate and statistically significant correlation between ΔDAPSA and ΔHAQ-DI was observed (r s = 0.60; p < 0.001). Only patients in DAPSA REM demonstrated a constant decline in HAQ-DI scores during the follow-up. White ethnicity and older age at baseline were predictors for not achieving MCID in HAQ-DI [RR 0.33 (0.16–0.6795% CI p = 0.002) and RR 0.96 (0.93–0.9895% CI p < 0.000), respectively, while higher scores of HAQ-DI at baseline were predictors of achieving MCID [RR 1.71 (1.12–2.6095%CI p = 0.013)]. Conclusions In PsA, patients who maintained DAPSA REM/LDA over time had better long-term functional outcomes. Higher HAQ-DI scores at baseline, non-white ethnicity and younger age were predictors for achieving a clinical meaningful improvement of HAQ-DI.