Spondyloarthritis Research Consortium of Canada sacroiliac joint inflammation and structural scores: change score reliability and recalibration utility in children

Abstract

Background: The SPARCC sacroiliac joint inflammation (SIS) and structural (SSS) scores are reliable measures to quantify abnormalities in the pediatric sacroiliac joint. We aimed to evaluate the utility of online calibration modules for the SIS and SSS and the reliability of their component change scores.Methods: Change score reliability of 6 raters was assessed by overall and pairwise intraclass correlation coefficients (ICCs) before and after the use of real-time iterative calibration (RETIC) modules for both the SIS and SSS comprised of 20 adult cases. Acceptable ICC for change scores was > 0.7 for SIS and > 0.5 for all SSS components. Sensitivity to change was assessed by the standardized response mean (SRM). Results: In scoring exercise 1, the SIS had acceptable reliability with a change score ICC of 0.80 and sclerosis was the only SSS lesion that met the acceptability threshold with a change score ICC of 0.52. After RETIC calibration, the SIS overall (ICC = 0.83) and mean pairwise (ICC = 0.83) change scores remained reliable with a large SRM (0.90). All SSS components except sclerosis met the overall and mean pairwise change score ICC acceptability thresholds-backfill: overall = 0.54, mean pairwise = 0.50; fat metaplasia: overall = 0.65, mean pairwise = 0.57; erosion: overall = 0.60, mean pairwise = 0.58; and ankylosis: overall = 0.96, mean pairwise = 0.96. The SSS RETIC module augmented the number of SSS components surpassing the acceptability threshold from 1 to 4. Sensitivity to change, as measured by the SRM, was large for erosion (0.96), moderate for backfill (0.55) and sclerosis (0.70), and small for fat metaplasia (0.36) and ankylosis (0.28).

Changes over time in inflammatory and structural lesions at the sacroiliac joint in children with spondyloarthritis exposed and unexposed to tumor necrosis factor inhibitor

“…Sclerosis and backfill had the lowest levels of agreement which can most likely be attributed to the low prevalence reported by any rater. The remaining SPARCC SIS and SSS components met the literature reported agreement of fair to excellent [ 20 – 22 ].…”

“…The SIS divides each sacroiliac joint into quadrants and scores presence, depth, and intensity of bone marrow edema (BME) on STIR MRI sequences and has been demonstrated to be reliable and valid in the pediatric population for both status and change scores [ 20 – 22 ]. Six consecutive semicoronal slices through the cartilaginous portion of the joint are scored for BME (total score 0–72).…”

“…The SSS assesses a spectrum of structural lesions of the SIJ on MRI including erosion, backfill, fat metaplasia, and ankylosis on 5 consecutive slices through the cartilaginous part of the joint and has been shown to be reliable for both status and change scores [ 20 , 22 ]. These components are scored 0–20 (backfill and ankylosis) or 0–40 (erosion and fat metaplasia).…”

“…Interpretation of ICCs were as follows: ICC < 0.40 was poor, 0.40 ≤ ICC < 0.75 was fair to good, and ICC ≥ 0.75 was excellent [ 24 ]. These interpretation thresholds were used in the evaluation of the SPARCC SIS and SSS status and change scores in pediatrics [ 20 – 22 ]. Spearman’s correlation was used to assess the relationship of change in pain score with change in SIS.…”

Imaging update in inflammatory arthritis

“…According to the Spondyloarthritis Research Consortium of Canada, inflammation and structural scores are practical and reliable to use for pediatric imaging, but they do not account for age-related maturational changes. 13,14 The MRI in JIA working group of Outcome Measures in Rheumatology and Clinical Trials (OMERACT) seeks to develop an MRI-based scoring system for the assessment of SIJ in JIA. 15 Different MRI features of SIJ inflammation defined in the revised preliminary JAMRIS-SIJ scoring system include BME, osteitis, joint space fluid, joint space enhancement, inflammation in an erosion cavity, capsulitis, and enthesitis.…”