Session Type: Abstract Submissions (ACR)
Background/Purpose: A small number of prospective data have been published on the use of pQCT in large groups of pts with JIA and JSLE. Moreover, few studies have compared in groups of JIA an JSLE pts , homogenous for age and sex, the parameters of bone status using pQCT. Our aim is to evaluate, cross-sectionally and longitudinally, the prevalence of reduced bone mass and density and the differences on the biomechanical parameters, using pQCT, in two cohorts of patients with JIA and JSLE homogenous for age and sex.
Methods: 154 JIA pts (127 F, 27 M, median age 20.3 ± 7.9 yrs: 84 oligoarticular, 33 polyarticular, 10 systemic, 27 enthesitis-arthritis (ERA) onsets, and 56 JSLE pts (46 F, 10 M, median age 21.5 ± 6.1 yrs ) have been studied. The obtained data have been compared with age and sex matched control groups.
Results: JIA pts do not show any difference in comparison to controls as regard to cortical density (CrtBMD), except for systemic pts (p < 0.0001) while JSLE pts have a higher CrtBMD than controls and JIA pts (p < 0.005). Analyzing bone trabecular density (TrbBMD), all JIA pts regardless of type onsets (except for ERA), and JSLE pts have significant reduced values than controls, with no differences between JIA and JSLE. In addition, JIA pts show a significant reduced muscle area (muscle CSA) than JSLE and controls (p < 0.001). The difference is significant in systemic and polyarticular JIA pts, but no in oligo and ERA subsets. Conversely, fat area (fat CSA) is significantly increased in both JIA and JSLE pts when compared to controls (p < 0.001), with no differences in the two groups. The same results are observed evaluating the polar resistance to stress (SSIp). On longitudinal evaluation, the difference of CrtBMD, TrbBMD, muscle CSA e fat CSA are unchanged; in JSLE pts, SSIp is stable in comparison to JIA and controls without any difference among JIA pts and controls.
Conclusion: The pQCT evaluation of the main parameters of bone density and structure in adolescents and young adults with JIA and JSLE highlights significant differences between the two groups and JIA subtypes. These data might indicate a different pathogenesis of bone damage in the two entities, and suggest a different diagnostic and therapeutic approach to improve the bone mass peak in these patients.
M. L. Brandi,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/cross-sectional-and-longitudinal-comparison-of-bone-mass-status-using-pqct-in-a-large-cohort-of-juvenile-idiopathic-arthritis-and-juvenile-onset-systemic-lupus-erythematosus-patients/