Real-world validation of the minimal disease activity index in psoriatic arthritis: an analysis from a prospective, observational, biological treatment registry

Abstract

Objective: To describe the minimal disease activity (MDA) rate over time in patients with psoriatic arthritis (PsA) receiving antitumour necrosis factor agents, evaluate prognostic factors of MDA achievement and identify the most common unmet criteria among MDA achievers.

Design: Biologic Treatment Registry Across Canada (BioTRAC): ongoing, prospective registry of patients initiating treatment for rheumatoid arthritis, ankylosing spondylitis or PsA with infliximab (IFX), golimumab (GLM) or ustekinumab.

Setting: 46 primary-care Canadian rheumatology practices.

Participants: 223 patients with PsA receiving IFX (enrolled since 2005) and GLM (enrolled since 2010) with available MDA information at baseline, 6 months and/or 12 months.

Primary and secondary outcome measures: MDA was defined as ≥5 of the following criteria: 28-item tender joint count (TJC28) ≤1, 28-item swollen joint count (SJC28) ≤1, Psoriasis Area and Severity Index (PASI) ≤1 or body surface area≤3, Pain Visual Analogue Scale (VAS) ≤15 mm, patient's global assessment (PtGA) (VAS) ≤20 mm, Health Assessment Questionnaire (HAQ) ≤0.5, tender entheseal points ≤1. Independent prognostic factors of MDA achievement were assessed with multivariate logistic regression.

Results: MDA was achieved by 11.7% of patients at baseline, 43.5% at 6 months, 44.8% at 12 months and 48.8% at either 6 or 12 months. Among MDA achievers at 6 months, 75.7% had sustained MDA at 12 months. Lower baseline HAQ (OR=0.210; 95% CI: 0.099 to 0.447) and lower TJC28 (OR=0.880; 95% CI: 0.804 to 0.964), were significant prognostic factors of MDA achievement over 12 months of treatment. The most commonly unmet MDA criteria among MDA achievers was patient reported pain (25%), PtGA (15%) and PASI (12%).

Conclusions: Almost 50% of patients treated with IFX or GLM in routine clinical care achieved MDA within the first year of treatment. Lower baseline HAQ and lower TJC28, were identified as significant prognostic factors of MDA achievement. The most commonly unmet criteria in patients who achieved MDA were pain, PtGA and PASI.

Trial registration number: BioTRAC (NCT00741793).

Keywords: Psoriatic arthritis; golimumab; infliximab; minimal disease activity; real world; registry.

Conflict of interest statement

Competing interests: PR, MZ, AC, SK, LB, PB, BH, JK reports personal fees from Janssen during the conduct of the study. PR reports personal fees from Abbott, AbbVie, Amgen, BMS, Celgene, Novartis, Pfizer, Roche outside the submitted work. LB reports personal fees from Amgen, BMS, Roche, UCB, AbbVie, Pfizer, Merck, Sanofi, Celgene, Lilly, Novartis outside the submitted work. PB reports personal fees from AbbVie, Amgen, BMS, Pfizer, Roche outside the submitted work. BH reports personal fees from AbbVie, Amgen, BMS, Celgene, Pfizer, Roche, UCB outside the submitted work. JK reports personal fees from Abbott, AstraZeneca, BMS, Merck-Schering, Lilly, Pfizer, Wyeth, Roche, Takeda, UCB outside the submitted work. ER and EP report personal fees from Janssen as employees of JSS Medical Research, the CRO hired, during the conduct of the study. AJL, FN, BO and CT report personal fees as employees of Janssen during the conduct of the study.

© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Figures

Figure 1

Flow chart of the patient population over time. MDA, minimal disease activity.

Figure 2

MDA achievement, mMDA achievement, DAS28 remission, DAS28 deep remission and DAPSA remission over time. *The improvement in MDA achievement, mMDA achievement, DAS28 remission, DAS28 deep remission and DAPSA remission from baseline to 6 months and from baseline to 12 months was assessed with the McNemar test (p

Figure 3

(A) Proportion of met criteria among minimal disease activity (MDA) achievers. (B) Proportion of unmet disease criteria among MDA achievers. (C) Proportion of Unmet criteria among new MDA achievers. HAQ, health assessment questionnaire; PASI, psoriasis area and severity index; PtGA, patient’s global assessment; SJC28, 28-item swollen joint count, TJC28, 28-item tender joint count.