What are risk factors for subsequent fracture after vertebral augmentation in patients with thoracolumbar osteoporotic vertebral fractures

Background Due to its unique mechanical characteristics, the incidence of subsequent fracture after vertebral augmentation is higher in thoracolumbar segment, but the causes have not been fully elucidated. This study aimed to comprehensively explore the potential risk factors for subsequent fracture in this region. Methods Patients with osteoporotic vertebral fracture in thoracolumbar segment who received vertebral augmentation from January 2019 to December 2020 were retrospectively reviewed. Patients were divided into refracture group and non-refracture group according to the occurrence of refracture. The clinical information, imaging findings (cement distribution, spine sagittal parameters, degree of paraspinal muscle degeneration) and surgery related indicators of the included patients were collected and compared. Results A total of 109 patients were included, 13 patients in refracture group and 96 patients in non-refracture group. Univariate analysis revealed a significantly higher incidence of previous fracture, intravertebral cleft (IVC) and cement leakage, greater fatty infiltration of psoas (FIPS), fatty infiltration of erector spinae plus multifidus (FIES + MF), correction of body angle (BA), BA restoration rate and vertebral height restoration rate in refracture group. Further binary logistic regression analysis demonstrated previous fracture, IVC, FIPS and BA restoration rate were independent risk factors for subsequent fracture. According to ROC curve analysis, the prediction accuracy of BA restoration rate was the highest (area under the curve was 0.794), and the threshold value was 0.350. Conclusions Subsequent fracture might cause by the interplay of multiple risk factors. The previous fracture, IVC, FIPS and BA restoration rate were identified as independent risk factors. When the BA restoration rate exceeded 0.350, refractures were more likely to occur.

Experimental Study on the Initiation and Propagation of Multi-Cluster Hydraulic Fractures within One Stage in Horizontal Wells

Competitive propagation of fractures initiated from multiple perforation clusters is universal in hydraulic fracturing of unconventional reservoirs, which largely influences stimulation. However, the propagation mechanism of multi-fractures has not been fully revealed for the lack of a targeted laboratory observation. In this study, a physical simulation experiment system was developed for investigating the initiation and propagation of multi-cluster hydraulic fractures. Different from the traditional hydro-fracking test system, the new one was equipped with a multi-channel shunting module and a strain monitoring system, which could guarantee the full fracture extension at each perforation clusters and measure the internal deformation of specimens, respectively. Several groups of true tri-axial fracturing tests were performed, considering the factors of in situ stress, cluster spacing, pumping rate, and bedding structures. The results showed that initiation of multi-cluster hydraulic fractures within one stage could be simultaneous or successive according to the difference of the breakdown pressure and fracturing fluid injection. For simultaneous initiation, the breakdown pressure of the subsequent fracture was lower than or equal to the value of the previous fracture. Multiple fractures tended to attract and merge. For successive initiation, the breakdown pressures of fractures were gradually increasing. The subsequent fracture tended to intersect with or deviated from the previous fracture. Multiple fractures interaction was aggravated by the decrease of horizontal stress difference, bedding number and cluster spacing, and weakened by the increase of pump rate. The propagation area of multiple fractures increased with the pump rate, decreased with the cluster spacing. The strain response characteristics corresponded with the initiation and propagation of fracture, which was conducive to understanding the process of the fracturing. The test results provide a basis for optimum design of hydraulic fracturing.

Risk factor analysis of fragility fractures in rheumatoid arthritis: A 3-year longitudinal, real-world, observational, cohort study

Objectives To explore the risk factors for fragility fractures in rheumatoid arthritis (RA) patients using a 3-year longitudinal, observational cohort study. Methods This RA registry study included consecutive RA patients in the outpatient clinic of Chang Gung Memorial Hospital since September 1, 2014. The demographics, clinical characteristics, lifestyle, evidence of previous fracture, risk factors according to the Fracture Risk Assessment Tool (FRAX®), and the FRAX score of each participant were recorded. The participants were categorized into the new incident fracture (group A) and no incident fracture (group B) groups based on evidence or absence of new incident fractures and propensity score matching (age and gender, 1:2). Results Overall, 477 participants completed the 3-year observation period. After matching, 103 and 206 participants were allocated to groups A and B, respectively. The non-adjusted model revealed, presented as hazard ratio (HR) (95% confidence interval [CI]), that the presence of co-morbidity (1.80 [1.17–2.78], p = 0.008), Health Assessment Questionnaire Disability Index (1.35 [1.07–1.69], p = 0.010), lower baseline hip bone mineral density (0.11 [0.02–0.48], p = 0.004), longer disease duration (1.02 [1.00–1.04], p = 0.026), higher FRAX score of major fracture (1.03 [1.02–1.04], p<0.001) or hip fracture (1.03 [1.02–1.04], p<0.001), and previous fracture history (2.65 [1.79–3.94], p<0.001) were associated with new incident fracture. After adjustment, it was disclosed that a previous fracture is an independent risk factor for fragility fractures in RA patients (2.17 [1.20–3.90], p = 0.010). Conclusions In addition to aging and disease-related factors, previous fracture history is the most important risk factor for fragility fractures in RA patients.

Initiation of anti-osteoporotic drugs in high-risk female patients starting glucocorticoid treatment: a population study in Norway

Summary Glucocorticoid use is a risk factor for osteoporosis and fractures. We studied whether women initiating glucocorticoid treatment also started anti-osteoporotic treatment, according to clinical guidelines. Women with versus without previous fracture were twice as likely to start anti-osteoporotic treatment within 1 year after initiating glucocorticoid treatment, but the cumulative incidences were low 9.1% vs. 4.6%, respectively. Purpose Use of glucocorticoids (GC) is a risk factor for osteoporosis and fractures, and clinical guidelines suggest that preventive treatment with anti-osteoporotic drugs (AOD) should be considered when starting GC. Women with high risk of osteoporosis comprise those with previous fractures or a known inflammatory rheumatic disease, for whom the indication of AOD is even stronger. The purpose of these analyses was to investigate whether women initiating GC treatment also started AOD, especially those with high risk of osteoporosis. Methods We used data from the Norwegian Prescription Database to identify all women 55 years and older initiating GC treatment in Norway during 2010–2016 and to obtain information on use of AOD. Data from the Norwegian Patient Registry were used to obtain information on previous fractures and diagnoses. Results Among 105,477 women initiating GC treatment during 2010–2016, 3256 had started AOD and 79,638 had discontinued GC treatment after 1-year follow-up. Cumulative incidence of starting AOD after 1 year was 9.1% (95% CI: 7.9, 10.4) for women with vs. 4.6% (95% CI: 4.4%, 4.8%) for women without a previous fracture. Women with rheumatoid arthritis or another inflammatory rheumatic disease were more likely to start AOD than women with other indications. For the whole cohort, the probability of starting AOD treatment within 1 year after initiating GC increased on average 3% per year (HR = 1.03, CI: 1.01, 1.05) from 2010 to 2016. Conclusions Having had a previous fracture or an inflammatory rheumatic disease increased the probability of treatment with AOD. However, the proportions starting AOD were much lower than clinically indicated.

AB0901 PREVALENCE OF OSTEOPOROSIS IN ITALIAN POSTMENOPAUSAL WOMEN ACCORDING TO DEFRA ALGORITHM

Background:Osteoporosis is a recognized health problem and the burden of the disease is mostly associated with the occurrence of hip and vertebral fracture.Objectives:This study was aimed at evaluating the prevalence of osteoporosis in Italian postmenopausal women, defined by DeFRA calculation as a 10 years fracture risk equal or higher than 20%.Methods:This is a monocenter cohort study evaluating 1850 post-menopausal women aged 50 years and older. All the participants were evaluated as far as anthropometrics. Defra questionnaire was administered and calculated with bone mineral density (DXA) measured at lumbar spine and femoral neck.Results:The prevalence of osteoporosis as assessed by DeFRA was 29.8% in the whole population, according to literature. The frequency of a risk fracture equal or higher than 20% varied from 7.9% in the group aged 50-59 years to 35% in subjects aged >80. Among clinical risk factors for fracture, the presence of a previous fracture (spine primarily) was the most commonly observed.Conclusion:Our data showed that about one third of post-menopausal women aged 50 and older in Italy has osteoporosis on the basis of DeFRA algorithm, with a high 10 years fracture risk. A previous fracture is the most common risk factor. The data should be considered in relation to the need to increase prevention strategies and therapeutic intervention.Disclosure of Interests:None declared

OP0323 INCIDENCE OF CLINICAL FRAGILITY FRACTURES IN POSTMENOPAUSAL WOMEN WITH RHEUMATOID ARTHRITIS. A MULTICENTRIC CASE-CONTROL STUDY

Background:Incidence of clinical fractures in rheumatoid arthritis (RA) is not as well-known as hip or vertebral fracture incidence.Objectives:1. To estimate the incidence of clinical fragility fractures in a population of postmenopausal women diagnosed with RA and compare it with that of the general population; 2. To analyze the risk factors for fracture.Methods:330 postmenopausal women with RA from 19 Spanish Rheumatology Departments, randomly selected from the registry of RA patients in each center. The control group consisted of 660 Spanish postmenopausal women from the Camargo Cohort. Clinical fractures during the previous 5 years were recorded. Assessed risk factors for fracture were: sociodemographic characteristics, BMD and variables related to RA.Results:Median age of RA patients was 64 yrs. vs. 63 yrs. in controls (ns). Evolution of the disease was 8 yrs. 78% and 76% had RF and ACPA+, respectively. 69% of patients were in remission or low activity. 85% had received glucocorticoids and methotrexate and 40% at least one biological DMARD. We identified 105 fractures (87 fragility and 18 traumatic) in 75 patients. Fifty-four patients and 47 controls had at least one major fracture (MF) (p< 0.001). Incidence of MF was 3.55 per 100 patient-year in patients and 0.72 in controls. Risk factors for MF in RA patients were age, previous fracture, parental hip fracture, postmenopausal period, hip BMD and cumulative dose of glucocorticoids. In controls, risk factors were age, age at menopause and lumbar BMD.Among RA-associated factors, MFs were associated with erosions, disease activity and disability. Previous fracture in RA patients was a strong risk for MF (HR: 10.37 [95% CI: 2.95-36.41]).Conclusion:Between 3 and 4 of every 100 postmenopausal women with RA have a major fracture per year, four times more than the general population. Disease activity and disability associated with RA, the cumulative dose of glucocorticoids and mainly previous fracture are associated with the development of fragility fractures.References:NoneAcknowledgments:Funded in part by ISCIII (PI18/00762) that included FEDER funds from the EU.Disclosure of Interests:Carmen Gómez Vaquero: None declared, Jose Manuel Olmos: None declared, J. Luis Hernández: None declared, Dacia Cerda: None declared, Cristina Hidalgo: None declared, JA Martínez López: None declared, Luis Marcelino Arboleya Rodríguez: None declared, Javier Aguilar del Rey: None declared, Silvia Martinez Pardo: None declared, Inmaculada Ros: None declared, Xavier Surís: None declared, Dolors Grados Canovas: None declared, Chesús Beltrán Audera: None declared, Evelyn Suero-Rosario: None declared, Inmaculada Gómez Gracia: None declared, Asunción Salmoral: None declared, Irene Martín-Esteve: None declared, Helena Florez: None declared, Antonio Naranjo Grant/research support from: amgen, Consultant of: UCB, Speakers bureau: AMGEN, Santos Castañeda: None declared, Soledad Ojeda Speakers bureau: AMGEN, LILLY, GEBRO, S García Carazo: None declared, Alberto García-Vadillo: None declared, Laura López Vives: None declared, À Martínez-Ferrer: None declared, Helena Borrell Paños: None declared, Pilar Aguado: None declared, Raul Castellanos-Moreira: None declared, Cristian Tebé: None declared, Núria Guañabens: None declared