To study vertebral fracture (VF) prevalence and the scanographic bone attenuation coefficient of the first lumbar vertebra (SBAC-L1) on computed tomography scans (CT-scans) in systemic sclerosis patients. This monocentric retrospective study included patients followed from 2000 to 2014 and fulfilling ACR/EULAR 2013 criteria for systemic sclerosis and who underwent a thoracic or thoraco-abdomino-pelvic CT-scan during their follow-up. Clinical characteristics for sclerosis and osteoporosis risk factors were collected. For CT-scan, the VFs were determined according to Genant's classification, the SBAC-L1 was measured in Hounsfield Units (HU), and a SBAC-L1 ≤ 145 HU (fracture threshold) defined patients at VF risk. Predictive factors for SBAC-L1 ≤ 145 HU were studied. A total of 70 patients were included [mean age, 62.3 (± 15.6) years, women 88.5%, diffuse sclerosis 22.9% (n = 16)]. On CT-scans, three VFs were detected in three patients (4.3%). The mean SBAC-L1 was 157.26 HU (± 52.1), and 35 patients (50%) presented a SBAC-L1 ≤ 145 HU. In multivariate analysis, only age (especially patients older than 63 years, OR = 1.08, CI 95% 1.04-1.13, p = 0.001) and calcinosis (OR = 6.04, CI 95% 1.27-28.70, p = 0.02) were independently associated with a SBAC-L1 ≤ 145 HU. On a large sample of patients with systemic sclerosis, the VF prevalence on CT-scan was low (4.3%) while 50% of the patients presented a SBAC-L1 ≤ 145 HU. Interestingly, the presence of calcinosis, periarticular calcifications or acro-osteolysis was linked with low SBAC-L1 and should lead to an osteoporosis screening, especially for patients under 63 years old.

The objective of this study is to identify the prevalence of vertebral fractures (VFs) and to measure the scanographic bone attenuation coefficient of the first lumbar vertebra (SBAC-L1) based CT-scan, a biomarker of bone fragility in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) and in a control group. This monocentric and retrospective study included patients with RA and AS, based on ACR/EULAR or New-York criteria, respectively. A control group was constituted. All of the patients received a CT-scan. VFs were determined via CT-scans according to the Genant classification, and the SBAC-L1 was measured in Hounsfield units (HU). SBAC-L1 ≤145 HU (fracture threshold) defined patients at risk of VFs. 244 patients were included (105 RA, 83 AS, 56 controls). Of the 4.365 vertebrae studied, 66 osteoporotic VFs were found in 36 patients: 18 (17.1%) RA, 13 (15.7%) AS and 5 (8.9%) controls. The mean SBAC-L1 was 142.2 (±48.4) HU for RA, 142.8 (±48.2) for AS, both of which were significantly lower than that of the control group (161.8 (±42.7) HU). Of the 36 patients with VFs and rheumatism, 28% had a T-score ≤−2.5 SD and 71.4% a SBAC-L1 ≤145 HU. A T-score ≤−2.5 SD and a SBAC-L1 ≤145 HU were associated with VF (OR = 3.07 (CI 95%: 1.07; 8.81), and 2.31 (CI 95%: 1.06; 5.06)), respectively. The SBAC-L1 was significantly lower in the RA and AS groups than in the control group. Furthermore, SBAC-L1 ≤145 HU was associated with a higher risk of VFs, with an odds ratio similar to that of a DXA.

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BackgroundOsteoporosis screening is not systematic in sclerodermic patients but some studies demonstrated a similar risk between rheumatoid arthritis and systemic scleroderma.1,2,3 Thoracic and/or TAP (thoraco-abdomino-pelvic) CT (Computed Tomography) scans are classically performed in the follow-up of scleroderma, mainly to evaluate lung involvement.ObjectivesTo study vertebral fracture (VF) prevalence and the scanographic bone attenuation coefficient of the first lumbar vertebra (SBAC-L1) on CT scans in systemic scleroderma patients. Secondary objectives are to study specific risk factors of SBAC-L1 ≤145 Hounsfield Units (HU) and to evaluate SBAC-L1 measurements reliability.MethodsThis monocentric retrospective study included patients followed from 2000 to 2014 and fulfilling ACR/EULAR 2013 criteria for systemic scleroderma and who underwent a thoracic or TAP CT scan. Osteoporotic risk factors, Dual Energy X-ray Absorptiometry (DXA) measurements and clinical characteristics were collected. For CT scan, the VFs were determined according to Genant’s classification on sagittal sections. The SBAC-L1 was measured in Hounsfield Units (HU) on axial section of L1 in a Region of Interest drawed in trabecular bone. Intra- and inter-reader reliabilities for SBAC-L1 were calculated. An SBAC-L1 ≤145 HU (fracture threshold) was used to define patients at risk of VF.4 Predictive factors for VF or SBAC-L1 ≤145 HU were studied.ResultsA total of 70 patients were included (mean age: 62.3 (±15.6) years, women 88.5%, diffuse scleroderma 22.9% (n=16)) in the study. Sixty patients (85.7%) presented with at least one clinical risk factor for osteoporosis. Eighteen patients (25.7%) received vitaminocalcic supplementation and 10 (14.3%) received antiresorptive therapy. DXA was only performed on 30 patients (42.8%), and 5 (16.7%) of them presented a T-score ≤−2.5 DS. 3 VFs were detected in 3 patients (4.3%). The mean SBAC-L1 was 157.26 HU (±52.1), and 35 patients (50%) presented a SBAC-L1 ≤145 HU. SBAC-L1 measurements were highly reliable (Kappa >0.9 for both intra- and inter-reader reliability). For the univariate analysis, a SBAC-L1 ≤145 HU was significantly associated with age (OR=1.09, CI 95%: 1.04–1.13), calcinosis (OR=6.3, CI 95%: 1.61–24.75) and periarticular calcifications (OR=3.22, CI 95%: 1.06–9.77). For the multivariate analysis, age (especially patients older than 63 years), calcinosis and acro-osteolysis were independently associated with a SBAC-L1 ≤145 HU.ConclusionsOn a large sample of sclerodermic patients with clinical risks of osteoporosis, only 42.8% were screened for DXA and 16.7% of them were osteoporotic. The VF prevalence on CT scan was 4.3% and the SBAC-L1 measurement identified 50% of the population at the fracture threshold. The presence of calcinosis, periarticular calcifications or acro-osteolysis should lead to an osteoporosis screening, especially for patients under 63 years old.References[1] Avouac J. Arthritis Care Res (Hoboken). 2012Dec;64(12):1871–8.[2] Yuen SY. J Rheumatol. 2008June;35(6):1073–8.[3] Kili...

BackgroundScreening for osteoporosis is crucial in rheumatoid arthritis (RA) patients. Computed tomography (CT) attenuation assessment has been proved to be of interest in general population for detection of osteoporosis.ObjectivesTo assess the value of thoraco-abdomino-pelvic CT-derived bone mineral density (BMD) in L1, compared with dual energy X-ray absorptiometry (DXA) for osteoporosis screening in rheumatoid arthritis patients.MethodsConsecutive RA patients who underwent a CT-scan and a DXA within a two-year period are retrospectively included. CT sagittal images are evaluated from T4 to L5 for vertebral fractures according to Genant classification. CT attenuation values (in Hounsfield units [HU]) of trabecular bone in L1 are measured on axial images and compared to DXA results.ResultsOne hundred and five patients (mean age 61.1 years (±9.5), 78.1% women) were included. Twenty-eight patients (26.7%) have DXA-defined osteoporosis and 32 (30%) have osteoporotic fractures (vertebral and/or non-vertebral). According to CT assessment, mean (SD) vertebral L1 attenuation is 142.2 HU (±18.5). The diagnostic performance for vertebral CT-attenuation measurement was good, with an AUC of 0.67 for predicting osteoporotic fractures and of 0.69 for predicting vertebral fractures. Among 31 patients with osteoporotic fractures, 23 (74%) patients are categorised as osteoporotic with L1 CT-attenuation of 135 HU or less, whereas only 13 patients (42%) with DXA.ConclusionsThis technique offers a combined opportunistic screening for osteoporosis by assessing both vertebral fractures and bone density on routine CT-scans. This seems of particular interest in RA patients who are at high risk for osteoporosis.Disclosure of InterestNone declared