Novel Heel Enthesitis Scoring System Reliable in SpA and PsA

The utility of an objective, reproducible enthesitis outcome measure in patients with spondyloarthritis (SpA) and psoriatic arthritis (PsA) is enhanced by the increasing numbers of novel therapeutic options available for individuals with these disorders. The OMERACT heel enthesitis magnetic resonance imaging (MRI) scoring system (HEMRIS) is a promising tool for use in clinical trials, according to the results of a recent study  published in The Journal of Rheumatology.

The investigators sought to develop and validate an enthesitis MRI scoring system for patients with SpA and PsA, in which the heel was used as the model. This was the first international consensus effort toward the development of a comprehensive MRI scoring system, combined with MRI definitions and reader rules, for enthesitis in patients with SpA and PsA. Consensus definitions of key pathologies in the disorders and 3 heel enthesitis multireader scoring exercises were performed, separated by discussion, training, and calibration. The definitions for soft tissue and bone pathologies were established.

At the final exercise, median pairwise single-measure intraclass correlation coefficients (ICCs; patient-level) for entheseal inflammation status and change scores were 0.83 and 0.82, respectively, for all readers.

Among radiologists and rheumatologists, ICCs were 0.91 and 0.84, respectively, and quadratic-weighted kappas (lesion-level) were 0.57 to 0.91 and 0.45 to 0.81, respectively.

The investigators concluded that the proposed definitions and heel enthesitis scoring system is reliable for use among trained readers. The heel enthesitis MRI score seems to be especially reliable if the mean score of 2 readers (as opposed to 1 reader) is used in the final study analysis. In fact, the average measure ICCs for 2 readers were distinctly higher (0.92-0.95 for inflammation total status/change score in last exercise) compared with single-measure ICCs. This finding is particularly relevant in real-life clinical trials, in which 2 independent readers typically score images.

Reference

Mathew AJ, Krabbe S, Eshed I, et al. The OMERACT MRI in enthesitis initiative: definitions of key pathologies, suggested MRI sequences and novel heel enthesitis scoring system (HEMRIS) [published online February 1, 2019]. J Rheumatol. doi: 10.3899/jrheum.181093