Session Type: Abstract Submissions (ACR)
Both the maturation of bone and its mineral density are affected by chronic inflammation in juvenile idiopathic arthritis (JIA). Bone age is in most cases assessed by a pediatric radiologist using a bone age standard atlas, usually the ‘Radiographic Atlas of Skeletal Development of the Hand and Wrist’ by Greulich and Pyle. Dual-energy X-ray densitometry (DXA) is the most commonly used method to assess bone density. Recently however, the old method of radiogrammetry has regained attention with the development of BoneXpert, an automated method of assessing bone age (BA) and bone density expressed in the Bone Health Index (BHI), using conventional hand X-rays. The objective of this study was to apply BoneXpert, measuring BA and BHI, in JIA patients prior to starting etanercept.
Radiographs of both right and left hand were collected for 63 patients (2 systemic JIA, 20 polyarthritis RF negative, 7 polyarthritis RF positive, 15 extendend oligoarthritis, 1 enthesitis related arthritis, 4 psoriatic arthritis) included in the Dutch Arthritis and Biologics in Children Register at start of etanercept. Because BoneXpert is developed for the use in children and has a bone age range of 2.5-17 years for boys and 2-15 years for girls, patients were selected within these age ranges. BA (Greulich and Pyle) and BHI were reported as standard deviations (SDS) from the reference population. Reproducibility of BoneXpert was assessed in all patients by calculating the BA and BHI twice for the left hand radiograph. Intraclass correlation coefficient (ICC) was used to determine the agreement between the two repeated measurements. Differences between patients and the reference population were tested with a one sample t-test. Patients for whom BoneXpert was not able to calculate BA or BHI were analysed separately.
For 52 patients (median age 10.0 IQR 6.5-11.3, 56% female), BoneXpert was able to calculate both BA and BHI. BA SDS (mean -0.47 ±1.32) and BHI SDS (mean -0.70 ±1.10) differed significantly (P<0.01) from the reference population. For 11 patients BoneXpert was not able to calculate either BA, BHI or both, most likely caused by a bone age close to the outer limits of BoneXpert. Reproducibility was excellent with an ICC ranging from 1.00 (for BA, BA SDS, BHI) to 0.84 (for BHI SDS).
BoneXpert is an easy to use and reproducible method for assessing BA and BHI in patients with JIA starting etanercept, provided that radiographs are of reasonable quality and patients’ BA is well within the age ranges of the program. The population investigated had a delayed bone maturation and lower bone density than healthy children as indicated by BoneXpert.
C. M. Nusman,
L. W. A. van Suijlekom-Smit,
Dutch Board of Health Insurances, Dutch Arthritis Association, Pfizer, Abbott,
M. A. J. van Rossum,
R. R. van Rijn,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/application-of-the-bonexpert-method-for-bone-age-and-bone-health-assessment-in-patients-with-juvenile-idiopathic-arthritis/