Predictors of Achieving Remission among Patients with Psoriatic Arthritis Initiating a Tumor Necrosis Factor Inhibitor

Abstract

Objective.To examine predictors of remission among patients with psoriatic arthritis (PsA) initiating a tumor necrosis factor (TNF) inhibitor.Methods.Patients with PsA enrolled in the Corrona Registry between 2005 and 2013 were followed from initiation of a TNF inhibitor (TNFi; etanercept, adalimumab, infliximab, certolizumab, or golimumab) to the visit closest to 12 months. Additional inclusion criteria included 3 tender or 3 swollen joints. Outcomes of interest were Clinical Disease Activity Index (CDAI) ≤ 2.8 (remission), low disease activity (LDA; CDAI ≤ 10), change in the modified Health Assessment Questionnaire (mHAQ) ≥ 0.35 and achievement of mHAQ < 0.30. Predictors were measured on or before TNFi initiation. Covariates significant in univariable logistic regression models and ≤ 5% missing values were included in a multivariable model and removed individually until all remaining variables were significant (p < 0.05).Results.Among 1832 TNFi initiations, 774 initiations (624 patients) met inclusion criteria. Median age at initiation was 52 years [interquartile range (IQR) 44–60], 56% were female, median PsA duration was 4 years (IQR 2–11), and median CDAI at baseline was 20 (IQR 14.5–28). Remission was achieved by 14% and LDA (or remission) by 37%. Achieving remission was positively associated with college education (OR 1.88, 95% CI 1.11–3.19) but negatively associated with female sex (0.62, 95% CI 0.40–0.97), obese body mass index (0.51, 95% CI 0.32–0.81), hypertension (0.55, 95% CI 0.32–0.95), previous biologic use (0.41, 95% CI 0.26–0.65), and baseline pain (0.80 per 10 mm visual analog scale, 95% CI 0.73–0.87). Predictors for LDA, mHAQ < 0.30, and mHAQ change were similar.Conclusion.Few patients with PsA in a US-based registry achieved remission by CDAI criteria. Female sex, obesity, comorbidities, and education influence achievement of remission on a TNFi.