Ultrasound Composite Scores for the Assessment of Inflammatory and Structural Pathologies in Psoriatic Arthritis (PsASon-Score)

Anja Ficjan; Rusmir Husic; Judith Gretler; Angelika Lackner; Winfried B Graninger; Marwin Gutierrez; Christina Duftner; Josef Hermann; Christian Dejaco

Disclosures

Arthritis Res Ther. 2014;16(476) 

In This Article

Abstract and Introduction

Abstract

Introduction This study was performed to develop ultrasound composite scores for the assessment of inflammatory and structural lesions in Psoriatic Arthritis (PsA).

Methods We performed a prospective study on 83 PsA patients undergoing two study visits scheduled 6 months apart. B-mode and Power Doppler (PD) findings were semi-quantitatively scored at 68 joints (evaluating synovia, perisynovial tissue, tendons and bone) and 14 entheses. We constructed bilateral and unilateral (focusing the dominant site) ultrasound composite scores selecting relevant sites by a hierarchical approach. We tested convergent construct validity, reliability and feasibility of inflammatory and structural elements of the scores as well as sensitivity to change for inflammatory items.

Results The bilateral score (termed PsASon22) included 22 joints (6 metacarpophalangeal joints (MCPs), 4 proximal interphalangeal joints (PIPs) of hands (H-PIPs), 2 metatarsophalangeal joints (MTPs), 4 distal interphalangeal joints (DIPs) of hands (H-DIPs), 2 DIPs of feet (F-DIPs), 4 large joints) and 4 entheses (bilateral assessment of lateral epicondyle and distal patellar tendon). The unilateral score (PsASon13) compromised 13 joints (2 MCPs, 3 H-PIPs, 1 PIP of feet (F-PIP), 2 MTPs, 1 H-DIP and 2 F-DIPs and 2 large joints) and 2 entheses (unilateral lateral epicondyle and distal patellar tendon). Both composite scores revealed a moderate to high sensitivity (bilateral composite score 43% to 100%, unilateral 36% to 100%) to detect inflammatory and structural lesions compared to the 68-joint/14-entheses score. The inflammatory and structural components of the composite scores correlated weakly with clinical markers of disease activity (corrcoeffs 0 to 0.40) and the health assessment questionnaire (HAQ, corrcoeffs 0 to 0.39), respectively. Patients with active disease achieving remission at follow-up yielded greater reductions of ultrasound inflammatory scores than those with stable clinical activity (Cohen's d effect size ranging from 0 to 0.79). Inter-rater reliability of bi- and unilateral composite scores was moderate to good with ICCs ranging from 0.42 to 0.96 and from 0.36 to 0.71, respectively for inflammatory and structural sub-scores. The PsASon22 and PsASon13 required 16 to 26 and 9 to 13 minutes, respectively to be completed.

Conclusion Both new PsA ultrasound composite scores (PsASon22 and PsASon13) revealed sufficient convergent construct validity, sensitivity to change, reliability and feasibility.

Introduction

Current EULAR recommendations on the use of imaging techniques in rheumatoid arthritis (RA) recognize the high sensitivity of sonography to detect joint pathologies, suggesting the use of this technique for a more accurate assessment of patients' disease activity as compared to clinical examination alone.[1] In routine practice and clinical trials of psoriatic arthritis (PsA), disease activity is still monitored by RA-specific clinical composite scores.[2] These measures, however, are of questionable value for PsA because of the heterogeneous nature of the disease characterized by various articular and extra-articular manifestations.[3]

We recently reported good performance of sonography for the assessment of disease activity in PsA as determined by the investigation of 68 synovial sites and periarticular structures, as well as 14 entheses.[4] A comprehensive ultrasound assessment as performed in this study, however, is not feasible in daily routine practice, whereas a reduced ultrasound composite score might enable sonographic scoring of PsA patients in interventional trials and clinical practice.

A single ultrasound composite score has been developed for the assessment of PsA patients so far: the Italian so-called five-targets score focuses on joints, tendons, entheses, skin and nails; however, as only one site is assessed for each item, this index is of limited value to determine overall disease activity.[5] The German U7 score, primarily developed for RA, has occasionally been used to monitor disease activity in PsA patients in interventional studies; however, this score does not include important PsA manifestations such as enthesitis or distal interphalangeal joint (DIP) arthritis.[6,7]

The aim of this study was to develop ultrasound composite scores that (1) include all currently defined ultrasound pathologies of PsA, (2) are sensitive for detection of inflammation and structural damage as compared to the assessment of 68 joints and 14 entheses and (3) are feasible in clinical practice. We tested the construct validity, reliability and feasibility of inflammatory and structural elements of the new composite scores and investigated the sensitivity to change for the inflammatory items.

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