Proposed Scoring System Predicts Enthesitis Outcome Measures in Psoriatic Arthritis

The Heel Enthesitis Scoring System (HEMRIS) represents a reliable enthesitis outcome measure for spondyloarthritis and psoriatic arthritis, according to study results recently published in The Journal of Rheumatology.

This study included consensus on major pathology definitions and 3 scoring exercises on heel enthesitis. The working group for the Outcome Measure in Rheumatology (OMERACT) Magnetic Resonance Imaging (MRI) in Arthritis Working Group performed a review of studies investigating the use of MRI in assessing enthesitis. The first exercise mostly involved qualitative training and education on pitfalls and principles. In exercises 2 and 3, reliability statistics, including average and pairwise single-measures intraclass correlation coefficients (ICC) by absolute agreement for patient level and squared weight Cohen K for lesion level, were evaluated. Exercise 3 included the calculation of standardized response mean.

Consensus was reached on bone and soft tissue pathology definitions. In exercise 3, entheseal inflammation status change ICC were 0.83/0.82 among all readers and 0.91/0.84 (quadratic-weighted lesion-level, 0.57-0.91/0.45-0.81) among rheumatologists and radiologists. Exercise 1 featured single-point heel images for initial learning and calibration; mean pairwise interreader ICC were 0.4 for inflammatory and 0.41 for structural variables. In exercise 2, reliability was improved by limiting analyses to 3 radiologists and 3 rheumatologists with the best ICC for inflammatory pathologies, for whom inflammation ICC was 0.85 and structural damage ICC was 0.68. In exercise 3, the same subset of readers demonstrated better reliability for both change in scores and baseline scores.

Limitations to this study included a variety of experience and backgrounds in the readers and the lack of an atlas of MRI enthesitis reference images.

The study researchers concluded, “Increasing the number of novel therapeutic options in [spondyloarthritis] and [psoriatic arthritis] increases the potential utility of an objective and reproducible enthesitis outcome measure. The proposed OMERACT MRI heel enthesitis scoring system (HEMRIS) is a promising tool for further refinement and validation through the OMERACT filter and for future use in clinical trials.”

Reference

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