Inflammation, bone loss and fracture risk in spondyloarthritis

Osteoporosis and fracture risk are multifactorial in patients with inflammatory rheumatic diseases

Patients with inflammatory rheumatic and musculoskeletal diseases (iRMDs) such as rheumatoid arthritis, connective tissue diseases, vasculitides and spondyloarthropathies are at a higher risk of osteoporosis and fractures than are individuals without iRMDs. Research and management recommendations for osteoporosis in iRMDs often focus on glucocorticoids as the most relevant risk factor, but they largely ignore disease-related and general risk factors. However, the aetiopathogenesis of osteoporosis in iRMDs has many facets, including the negative effects on bone health of local and systemic inflammation owing to disease activity, other iRMD-specific risk factors such as disability or malnutrition (for example, malabsorption in systemic sclerosis), and general risk factors such as older age and hormonal loss resulting from menopause. Moreover, factors that can reduce fracture risk, such as physical activity, healthy nutrition, vitamin D supplementation and adequate treatment of inflammation, are variably present in patients with iRMDs. Evidence relating to general and iRMD-specific protective and risk factors for osteoporosis indicate that the established and very often used term 'glucocorticoid-induced osteoporosis' oversimplifies the complex inter-relationships encountered in patients with iRMDs. Osteoporosis in these patients should instead be described as 'multifactorial'. Consequently, a multimodal approach to the management of osteoporosis is required. This approach should include optimal control of disease activity, minimization of glucocorticoids, anti-osteoporotic drug treatment, advice on physical activity and nutrition, and prevention of falls, as well as the management of other risk and protective factors, thereby improving the bone health of these patients.

Effects of Exercise Therapy in Axial Spondyloarthritis: A Systematic Review, Meta-analysis, and Meta-regression of Randomized Trials

OBJECTIVE

This study aimed to assess the effectiveness of exercise therapy for patients with axial spondyloarthritis (axSpA).

DATA SOURCES

We searched MEDLINE (via PubMed), Cochrane Library, Embase, Web of Science, Scopus, and SPORTDiscus for all relevant publications from database inception to March 2024, without language restriction.

STUDY SELECTION

We included randomized controlled trials (RCTs) of patients with axSpA in which ≥1 group received exercise therapy.

DATA EXTRACTION

Two independent reviewers assessed the quality of the literature using the Cochrane Collaboration Risk of Bias Tool 2.0. The outcomes were ankylosing spondylitis (AS) disease activity score (ASDAS), Bath AS disease activity index (BASDAI), Bath AS functional index (BASFI), Bath AS metrology index (BASMI), 6-minute walk test (6MWT), chest expansion capacity, peak oxygen consumption (VO2peak), pain, fatigue, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR).

DATA SYNTHESIS

A total of 20 RCTs, including 1670 patients, were included in this study. Compared with the control group, exercise therapy improved BASFI (weighted mean difference [WMD], -0.49; 95% confidence interval [CI], -0.65 to -0.32; I2=3.4%; P=.414), BASMI (WMD, -0.49; 95% CI, -0.87 to -0.11; I2=71.9%; P=.679), BASDAI (WMD, -0.78; 95% CI, -1.08 to -0.47; I2=55.9%; P=.021), ASDAS (WMD, -0.44; 95% CI, -0.64 to -0.24; I2=0.0%; P=.424), VO2peak (WMD, 3.16; 95% CI, 1.37-4.94; I2=0.0%; P=.873), 6MWT (WMD, 27.64; 95% CI, 12.04-43.24; I2=0.0%, P=.922), pain (standardized mean difference [SMD], -0.47; 95% CI, -0.74 to -0.21; I2=66.0%, P=.046), and fatigue (SMD, -0.49; 95% CI, -0.71 to -0.27; I2=0.0%; P=.446). However, no significant benefit was found in chest expansion, CRP, and ESR outcomes.

CONCLUSIONS

Exercise therapy is an effective strategy for improving disease control and symptom relief in patients with axSpA.

Association of trabecular bone score with disease parameters and vertebral fractures in axial spondyloarthritis

Objectives

We aimed to study trabecular bone score (TBS) association with disease parameters and vertebral fractures (VFs) in patients with axial spondyloarthritis.

Methods

Patients diagnosed with axial spondyloarthritis were included in this cross-sectional study. Dual-energy X-ray absorptiometry was used to measure BMD in the lumbar spine and TBS. Low TBS was defined as ≤1.31. The association between TBS and disease parameters including Ankylosing Spondylitis Disease Activity Score (ASDAS), BASDAI, BASFI and BASMI was studied using logistic regressions.

Results

Our study included 56 patients, with a mean age of 38.9 ± 13.5 years and a mean disease duration of 12.7 ± 7.7 years. Patients with low TBS were significantly older and had higher waist circumference and body mass index. These patients also showed greater clinical activity, as evidenced by higher ASDAS-CRP, BASFI and BASMI scores (P < 0.05). In multivariate logistic regression, low TBS was associated with all disease parameters, except for BASMI: BASDAI (OR [95% CI] = 3.68 [1.48-9.19], P = 0.005), ASDAS-CRP (OR [95% CI] = 2.92 [1.20-7.10], P = 0.018), BASFI (OR [95% CI] = 1.04 [1.01-1.08], P = 0.018), BASMI (OR [95% CI] = 1.36 [0.99-1.87], P = 0.062). However, no association was observed between TBS and VFs.

Conclusion

TBS was associated with active spondyloarthritis, suggesting increased bone fragility in these patients. However, TBS failed to demonstrate an association with VFs.

Iatrogenic vertebral fracture in ankylosed spine during liver transplantation: a case report and biomechanical study using finite element method

PURPOSE

The occurrence of an iatrogenic vertebral fracture during non-spinal digestive surgery is an exceptional event that has not been previously documented. Our study aims to explain the occurrence of this fracture from a biomechanical perspective, given its rarity. Using a finite element model of the spine, we will evaluate the strength required to induce a vertebral fracture through a hyperextension mechanism, considering the structure of the patient's spine, whether it is ossified or healthy.

METHODS

A 70-year-old patient was diagnosed T12 fracture during a liver transplantation on ankylosed spine. We use a finite element model of the spine. Different mechanical properties were applied to the spine model: first to a healthy spine, the second to a osteoporotic ossified spine. The displacement and force imposed at the Sacrum, the time and location of fractures initiation were recorded and compared between the two spine conditions.

RESULTS

A surgical treatment is done associating decompression with posterior fixation. After biomechanical study, we found that the fracture initiation occurred for the ossified spine after a sacrum displacement of 29 mm corresponding to an applied force of 65 N. For the healthy spine it occurred at a sacrum displacement of 52 mm corresponding to an applied force of 350 N.

CONCLUSION

The force required to produce a type B fracture in an ankylosed spine is 5 times less than in a healthy spine. These data enable us to propose several points of management to avoid unexpected complications with ankylosed spines during surgical procedures.

LEVEL OF EVIDENCE

IV.

The prevalence of vertebral fractures in diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis: A systematic review and meta-analysis

Background

Subjects with ankylosing spinal disorders, including diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) are more prone to vertebral fractures and frequently present with neurological deficit compared to the patients without an ankylosed spine. Moreover, prevalent vertebral fractures are an important predictor for subsequent fracture risk. However, the pooled fracture prevalence for DISH is unknown and less recent for AS. We aimed to systematically investigate the prevalence and risk of vertebral fractures in DISH and AS populations.

Methods

Publications in Medline and EMBASE were searched from January 1980 until July 2023 for cohort studies reporting vertebral fractures in AS and DISH. Data on prevalence were pooled with random effects modeling after double arcsine transformation. Heterogeneity was assessed with I2 statistics and we performed subgroup analysis and meta-regression to explore sources of heterogeneity.

Results

We included 7 studies on DISH (n = 1,193, total fractures = 231) with a pooled vertebral fracture prevalence of 22.6% (95%CI: 13.4%-33.4%). For AS, 26 studies were included (n = 2,875, total fractures = 460) with a pooled vertebral fracture prevalence of 15.2% (95%CI: 11.6%-19.1%). In general, fracture prevalence for AS remained similar for several study-level and clinically relevant characteristics, including study design, diagnostic criteria, spine level, and patient characteristics in subgroup analysis. AS publications from 2010 to 2020 showed higher fracture prevalence compared to 1990 to 2010 (18.6% vs. 11.6%). Fractures in DISH were most common at the thoracolumbar junction, whereas for AS, the most common location was the mid-thoracic spine.

Conclusions

Vertebral fractures are prevalent in AS and DISH populations. Differences in fracture distribution along the spinal axis exist between the 2 disorders. Additional longitudinal studies are needed for incident fracture assessment in patients with ankylosing spinal disorders.

Bone metabolism and inflammatory biomarkers in radiographic and non-radiographic axial spondyloarthritis patients: a comprehensive evaluation

Introduction

Axial spondyloarthritis (axSpA) is a heterogeneous disease that can be represented by radiographic axSpA (r-axSpA) and non-radiographic axSpA (nr-axSpA). This study aimed to evaluate the relationship between the markers of inflammation and bone turnover in r-axSpA patients and nr-axSpA patients.

Methods

A cross-sectional study included 29 r-axSpA patients, 10 nr-axSpA patients, and 20 controls matched for age and sex. Plasma markers related to bone remodeling such as human procollagen type 1 N-terminal propeptide (P1NP), sclerostin, tartrate-resistant acid phosphatase 5b (TRACP5b), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) were measured by an ELISA kit. A panel of 92 inflammatory molecules was analyzed by proximity extension assay.

Results

R-axSpA patients had decreased plasma levels of P1NP, a marker of bone formation, compared to controls. In addition, r-axSpA patients exhibited decreased plasma levels of sclerostin, an anti-anabolic bone hormone, which would not explain the co-existence of decreased plasma P1NP concentration; however, sclerostin levels could also be influenced by inflammatory processes. Plasma markers of osteoclast activity were similar in all groups. Regarding inflammation-related molecules, nr-axSpA patients showed increased levels of serum interleukin 13 (IL13) as compared with both r-axSpA patients and controls, which may participate in the prevention of inflammation. On the other hand, r-axSpA patients had higher levels of pro-inflammatory molecules compared to controls (i.e., IL6, Oncostatin M, and TNF receptor superfamily member 9). Correlation analysis showed that sclerostin was inversely associated with IL6 and Oncostatin M among others.

Conclusion

Altogether, different inflammatory profiles may play a role in the development of the skeletal features in axSpA patients particularly related to decreased bone formation. The relationship between sclerostin and inflammation and the protective actions of IL13 could be of relevance in the axSpA pathology, which is a topic for further investigation.

Probability of the 10-year Risk of Hip and Major Osteoporotic Fracture in Non-radiographic Axial Spondyloarthritis

BACKGROUND

Fracture risk in non-radiographic spondyloarthritis is underestimated. A reliable tool such as the Fracture Risk Assessment tool (FRAX) may assess this risk probability. This study aimed to assess the fracture risk by the FRAX score in patients with nr-axSpA and to determine factors associated with high fracture risk.

METHODS

We conducted a retrospective study of nr-axSpA patients meeting the Assessment of SpondyloArthritis International Society (ASAS) classification criteria for spondyloarthritis. All patients had Bone Mineral Density (BMD) by dual-energy X-ray absorptiometry (DEXA). The 10- year probability of major osteoporotic fracture (MOF) and hip fracture (HF) was calculated using the Fracture Risk Assessment Tool (FRAX).

RESULTS

Among 40 patients with nr-axSpA, 27 were women (67.5%). Their mean age was 43.7 ± 12.1 years. The mean disease duration was 3.15 ± 2.7 years. Eighteen patients (45%) had osteopenia, and 12 patients (30%) had osteoporosis. The median HF FRAX was 0% [0-1.2]. The median MOF FRAX was 0.5% [0.3-1.8]. MOF FRAX was positively correlated with age (p = 0.002), disease onset age (p = 0.006), disease duration (p = 0.024), and the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) (p < 0.0001), and negatively correlated with daily calcium intake (p < 0.0001). HF FRAX was positively correlated with mSASSS (p < 0.0001) and negatively correlated with daily calcium intake (p = 0.005).

CONCLUSION

Our study confirmed the frequency of bone loss during nr-axSpA and showed that osteoporotic risk fracture was related not only to traditional risk factors for osteoporosis but also to disease-related factors.

Inflammatory Processes Affecting Bone Health and Repair

PURPOSE OF REVIEW

The purpose of this article is to review the current understanding of inflammatory processes on bone, including direct impacts of inflammatory factors on bone cells, the effect of senescence on inflamed bone, and the critical role of inflammation in bone pain and healing.

RECENT FINDINGS

Advances in osteoimmunology have provided new perspectives on inflammatory bone loss in recent years. Characterization of so-called inflammatory osteoclasts has revealed insights into physiological and pathological bone loss. The identification of inflammation-associated senescent markers in bone cells indicates that therapies that reduce senescent cell burden may reverse bone loss caused by inflammatory processes. Finally, novel studies have refined the role of inflammation in bone healing, including cross talk between nerves and bone cells. Except for the initial stages of fracture healing, inflammation has predominately negative effects on bone and increases fracture risk. Eliminating senescent cells, priming the osteo-immune axis in bone cells, and alleviating pro-inflammatory cytokine burden may ameliorate the negative effects of inflammation on bone.

BushenHuoxue decoction suppresses M1 macrophage polarization and prevents LPS induced inflammatory bone loss by activating AMPK pathway

Abnormal bone metabolism and subsequence osteoporotic fractures are common complications of chronic inflammatory diseases. No effective treatment for these bone-related complications is available at present. The chronic inflammatory state in these diseases has been considered as a key factor of bone loss. Therefore, the combination of inflammation inhibition and bone loss suppression may be an important strategy for reducing bone damage associated with inflammatory diseases. Bushen Huoxue Decoction (BSHXD) is a traditional Chinese herbal compound that has demonstrated the ability to improve bone quality and increase bone density. However, the efficacy of BSHXD on inflammatory bone loss and its underlying mechanisms remain unclear. This study aimed to investigate whether BSHXD inhibits inflammatory bone loss in mice and its potential molecular mechanisms. In the present study, the effect of BSHXD on lipopolysaccharide (LPS)-induced M1 polarization of RAW264.7 macrophage and on local inflammatory bone loss model of mouse skull was determined. The results showed that after treating RAW264.7 cells with LPS for 24 h, the expression levels of IL-1β (39.42 ± 3.076 ng/L, p < 0.05), IL-6 (49.24 ± 1.766 mg/L, p < 0.05) and TNF-α (286.3 ± 27.12 ng/L, p < 0.05) were significantly increased. The addition of BSHXD decreased the expression levels of IL-1β, IL-6, and TNF-α to 31.55 ± 1.296 ng/L, 37.94 ± 0.8869 mg/L, and 196.4 ± 25.25 ng/L, respectively (p < 0.05). The results of immunofluorescence staining, Western blotting (WB) and flow cytometry indicated that the proportion of M1 macrophages in RAW264.7 cells treated with BSHXD for 24 h was significantly lower than that in the LPS group (13.36% ± 0.9829% VS 24.80% ± 4.619%, p < 0.05). The evidence from in-vitro experiments showed that the immunomodulatory ability of BSHXD may be associated with the activation of AMP-dependent protein kinase (AMPK) pathway in LPS-treated macrophages. In addition, the results of micro-CT, H&E staining, immunohistochemical staining and immunofluorescence staining of mouse skull further demonstrated that BSHXD treatment significantly alleviated LPS-induced local bone loss and inflammatory damage in mouse skull model. All results indicated that BSHXD significantly inhibited inflammatory factors release and M1 polarization of macrophage through AMPK signaling pathway. Therefore, BSHXD may be a promising drug for the treatment of inflammatory bone loss.

The risk of osteoporosis in patients with ankylosing spondylitis-A large retrospective matched cohort study

BACKGROUND

Ankylosing spondylitis (AS) is associated with increased bone turnover and systemic inflammation. Osteoporosis is common but frequently underappreciated in AS, studies regarding the incidence of osteoporosis in AS are limited and based on small cohorts. The aim of this study is to assess the risk of osteoporosis in patients with AS compared to matched controls.

METHODS

A population based retrospective cohort study using data retrieved from a large electronic medical record in Israel, the Clalit health services. Included patients that were diagnosed with AS from January 2002 to December 2018 were followed for development of osteoporosis. The incidence of osteoporosis was compared between AS and controls and a logistic regression model was used to assess the interaction between AS and osteoporosis.

RESULTS

The study included 5476 AS patients, and 27,657 age- and sex-frequency matched controls. The incidence of osteoporosis in AS patients was significantly higher than controls (4.7% vs 2.8%, p<0.001) in the whole cohort as well as when stratified by sex. Osteoporosis developed earlier in patients with AS versus controls (4.1 vs 5.2 years, p<0.001). In multivariate analysis and after adjustment to several potential confounders, AS was found to independently associated with osteoporosis (HR 1.83, 95%CI 1.58-2.11, p<0.0001).

CONCLUSIONS

Our study confirms the higher incidence and earlier development of osteoporosis in patients with AS. Such finding highlights the increased need of awareness and earlier detection of such comorbidity allowing prompt treatment to prevent undesired sequalae including increased risk of fractures.

Targeting STING: From antiviral immunity to treat osteoporosis

The cGAS-STING signaling pathway can trigger innate immune responses by detecting dsDNA from outside or within the host. In addition, the cGAS-STING signaling pathway has emerged as a critical mediator of the inflammatory response and a new target for inflammatory diseases. STING activation leads to dimerization and translocation to the endoplasmic reticulum Golgi intermediate compartment or Golgi apparatus catalyzed by TBK1, triggers the production of IRF3 and NF-κB and translocates to the nucleus to induce a subsequent interferon response and pro-inflammatory factor production. Osteoporosis is a degenerative bone metabolic disease accompanied by chronic sterile inflammation. Activating the STING/IFN-β signaling pathway can reduce bone resorption by inhibiting osteoclast differentiation. Conversely, activation of STING/NF-κB leads to the formation of osteoporosis by increasing bone resorption and decreasing bone formation. In addition, activation of STING inhibits the generation of type H vessels with the capacity to osteogenesis, thereby inhibiting bone formation. Here, we outline the mechanism of action of STING and its downstream in osteoporosis and discuss the role of targeting STING in the treatment of osteoporosis, thus providing new ideas for the treatment of osteoporosis.

Cardiovascular disease and bone health in aging female rheumatic disease populations: A review

Rheumatic diseases cover a wide spectrum of conditions, including primary and secondary degenerative joint diseases and autoimmune inflammatory rheumatic diseases. The risks of cardiovascular disease and osteoporosis and resultant fractures in aging female rheumatic disease populations, especially those with autoimmune rheumatic diseases, are increased. Changes in the immune system in aging populations need to be considered especially among patients with autoimmune rheumatic diseases. Immunosenescence is closely aligned to reduced adaptive immunity and increased non-specific innate immunity leading to chronic inflammation of inflammaging. The effective use of disease-modifying antirheumatic drugs to control autoimmune rheumatic diseases may also mitigate factors leading to cardiovascular disease and osteoporosis. Rheumatic diseases, which largely manifest as arthritis, predispose patients to premature joint degeneration and poor bone health and therefore have a higher risk of developing end-stage arthritis requiring joint arthroplasties sooner or more often than other patients without rheumatic disease.

Identification of gut dysbiosis in axial spondyloarthritis patients and improvement of experimental ankylosing spondyloarthritis by microbiome-derived butyrate with immune-modulating function

Introduction

Dysbiosis is an environmental factor that affects the induction of axial spondyloarthritis (axSpA) pathogenesis. In the present study, we investigated differences in the gut microbiota of patients with axSpA and revealed an association between specific gut microbiota and their metabolites, and SpA pathogenesis.

Method

Using 16S rRNA sequencing data derived from feces samples of 33 axSpA patients and 20 healthy controls (HCs), we examined the compositions of their gut microbiomes.

Results

As a result, axSpA patients were found to have decreased α-diversity compared to HCs, indicating that axSpA patients have less diverse microbiomes. In particular, at the species level, Bacteroides and Streptococcus were more abundant in axSpA patients than in HCs, whereas Faecalibacterium (F). prausnitzii, a butyrate-producing bacteria, was more abundant in HCs. Thus, we decided to investigate whether F. prausnitzii was associated with health conditions by inoculating F. prausnitzii (0.1, 1, and 10 μg/mL) or by administrating butyrate (0.5 mM) into CD4⁺ T cells derived from axSpA patients. The levels of IL-17A and IL-10 in the CD4⁺ T cell culture media were then measured. We also assessed osteoclast formation by administrating butyrate to the axSpA-derived peripheral blood mononuclear cells. The CD4⁺ IL-17A⁺ T cell differentiation, IL-17A levels were decreased, whereas IL-10 was increased by F. prausnitzii inoculation. Butyrate reduced CD4⁺ IL-17A⁺ T cell differentiation and osteoclastogenesis.

Discussion

We found that CD4⁺ IL-17A⁺ T cell polarization was reduced, when F. prausnitzii or butyrate were introduced into curdlan-induced SpA mice or CD4⁺ T cells of axSpA patient. Consistently, butyrate treatment was associated with the reduction of arthritis scores and inflammation levels in SpA mice. Taken together, we concluded that the reduced abundance of butyrate-producing microbes, particularly F. prausnitzii, may be associated with axSpA pathogenesis.

Metallothionein-1 is Positively Correlated with Inflammation and Ankylosing Spondylitis Activity

Introduction

Ankylosing spondylitis (AS) is a common form of chronic inflammatory rheumatic disease. Metallothionein-1 (MT-1) has been known to play an immunosuppressive role in various noninfectious inflammatory diseases, especially osteoarthritis and rheumatoid arthritis, thus inhibiting inflammation and pathogenesis in various diseases. However, whether MT-1 is related to AS is unclear. Here, we examined the levels of MT-1 in patients with AS and its correlation with the disease activity, complication, clinical indexes, and inflammatory cytokines and attempted to explain the effect of MT-1 on inflammation in AS.

Methods

The messenger RNA (mRNA) and protein expression of MT-1 in patients with AS were detected through real-time polymerase chain reaction and enzyme-linked immunosorbent assay. The associations between serum MT-1 protein level and clinical indexes or proinflammatory cytokines in AS were analyzed using the Spearman correlation test.

Results

The mRNAs and serum protein levels of MT-1 were significantly higher in patients with AS, especially in patients with active AS and patients with osteoporosis (OP) than in healthy controls (HCs), and no difference was observed between patients with inactive AS and HCs. Serum MT-1 levels positively correlated with disease activity, proinflammatory cytokines, and clinical indexes Ankylosing Spondylitis Disease Activity Score with C-Reactive Protein, C-reactive protein level, and erythrocyte sedimentation rate in patients with AS.

Conclusion

MT-1 expression was upregulated in patients with active AS but not in those with inactive AS and positively correlated with clinical indexes, especially in OP, as well as with proinflammatory cytokines tumor necrosis factor–alpha, interleukin (IL)-1β, and IL-6 in patients with AS.

Prevalence and Factors of Osteoporosis and High Risk of Osteoporotic Fracture in Patients with Ankylosing Spondylitis: A Multicenter Comparative Study of Bone Mineral Density and the Fracture Risk Assessment Tool

Background: We investigated the prevalence of and the factors associated with a high risk of osteoporotic fractures in Korean patients with ankylosing spondylitis (AS). Methods: This was a multicenter, retrospective study including 219 AS patients from five university hospitals; the control group was selected by matching age and sex with those of the AS patients. The fracture risk was evaluated based on bone mineral density (BMD) measured by dual-energy X-ray absorptiometry and the fracture risk assessment tool (FRAX) with/without BMD. Results: The mean age of the patients was 47.6 years, and 144 (65.8%) patients were men. According to the WHO criteria and FRAX with/without BMD, the candidates for pharmacological treatment were 44 (20.1%), 20 (13.2%), and 23 (15.1%) patients, respectively, significantly more than those in the healthy control group. Among them, the proportion of patients receiving osteoporosis treatment was 39.1–75%. In logistic regression analysis, menopause was an independent factor for the high risk of fracture according to the WHO criteria and FRAX with/without BMD. C-reactive protein level (odds ratio (OR) 3.8 and OR 6) and glucocorticoid use (OR 1.5 and OR 1.7) were associated with a high risk of osteoporotic fracture based on FRAX without BMD and osteoporosis diagnosed according to the WHO criteria. Conclusions: Our study suggests that both FRAX and WHO criteria may be complementary for treatment decisions to reduce osteoporotic fractures in patients with AS.

Effects of Biological/Targeted Therapies on Bone Mineral Density in Inflammatory Arthritis

Inflammatory arthritis has been reported to be associated with the development of osteoporosis. Recent research has investigated the mechanisms of bone metabolism in chronic inflammatory arthritis such as rheumatoid arthritis (RA) and spondyloarthritis (SpA). Progress in both animal and clinical studies has provided a better understanding of the osteoclastogenesis-related pathways regarding the receptor activator of nuclear factor-κB ligand (RANKL), anti-citrullinated protein antibodies (ACPAs), and Wnt signaling and Dickkopf-related protein 1 (Dkk-1). The complex interplay between inflammatory cytokines and bone destruction has been elucidated, especially that in the interleukin-17/23 (IL-17/23) axis and Janus kinase and signal transducer and activator of transcription (JAK-STAT) signaling. Moreover, advances in biological and targeted therapies have achieved essential modifications to the bone metabolism of these inflammatory arthritis types. In this narrative review, we discuss recent findings on the pathogenic effects on bone in RA and SpA. Proinflammatory cytokines, autoantibodies, and multiple signaling pathways play an essential role in bone destruction in RA and SpA patients. We also reviewed the underlying pathomechanisms of bone structure in biological and targeted therapies of RA and SpA. The clinical implications of tumor necrosis factor inhibitors, abatacept, rituximab, tocilizumab, Janus kinase inhibitors, and inhibitors of the IL-17/23 axis are discussed. Since these novel therapeutics provide new options for disease improvement and symptom control in patients with RA and SpA, further rigorous evidence is warranted to provide a clinical reference for physicians and patients.

Vitronectin-derived bioactive peptide prevents spondyloarthritis by modulating Th17/Treg imbalance in mice with curdlan-induced spondyloarthritis

Purpose

Spondyloarthritis (SpA) is a systemic inflammatory arthritis mediated mainly by interleukin (IL)-17. The vitronectin-derived bioactive peptide, VnP-16, exerts an anti-osteoporotic effect via β1 and αvβ3 integrin signaling. SpA is associated with an increased risk of osteoporosis, and we investigated the effect of VnP-16 in mice with SpA.

Methods

SpA was induced by curdlan in SKG ZAP-70^W163C mice, which were treated with vehicle, celecoxib, VnP-16, or VnP-16+celecoxib. The clinical score, arthritis score, spondylitis score, and proinflammatory cytokine expression of the spine were evaluated by immunohistochemical staining. Type 17 helper T cell (Th17) and regulatory T cell (Treg) differentiation in the spleen was evaluated by flow cytometry and in the spine by confocal staining. Splenocyte expression of signal transducer and activator of transcription (STAT) 3 and pSTAT3 was evaluated by in vitro Western blotting.

Results

The clinical score was significantly reduced in the VnP16+celecoxib group. The arthritis and spondylitis scores were significantly lower in the VnP-16 and VnP16+celecoxib groups than the vehicle group. In the spine, the levels of IL-1β, IL-6, tumor necrosis factor-α, and IL-17 expression were reduced and Th17/Treg imbalance was regulated in the VnP-16 alone and VnP-16+celecoxib groups. Flow cytometry of splenocytes showed increased polarization of Tregs in the VnP-16+celecoxib group. In vitro, VnP-16 suppressed pSTAT3.

Conclusions

VnP-16 plus celecoxib prevented SpA progression in a mouse model by regulating the Th17/Treg imbalance and suppressing the expression of proinflammatory cytokines.

Surgical Treatment of Spinal Fracture in a Patient With Ankylosing Spondylitis: An Opportunity To Correct Spinal Deformity Simultaneously With Fracture Fixation?

The objective of this case report is to describe the substantial sagittal correction of spinal hyperkyphosis alongside fracture fixation. In advanced ankylosing spondylitis (AS), the spine is usually fused, hyperkyphotic, and due to deformity, as well as improper bone remodeling, predisposed to fractures. These fractures, mostly unstable, require surgical treatment. The authors present fracture management with concomitant deformity correction at the fracture site and pedicle subtraction osteotomy (PSO) below the fracture, showing the benefits of performing the procedures with the patient in a sitting position.

A 58-year-old male with AS was diagnosed with a fracture of C6 and referred to the department of neurosurgery, Wroclaw University Hospital. For the last week, he had complained of worsening neck pain and exacerbation of spinal kyphosis, with no neurological deficits. The patient had a fully fused spine, significant hyperkyphosis prior to the injury, and a fracture with an additionally exacerbated deformity. The patient was offered operative treatment - spinal fusion and fracture reduction with hyperkyphosis correction. The procedure consisted of 1) partial, mostly closed correction at the fracture site, 2) PSO of C7 and C2-T3 pedicular fixation and fusion while sitting in the posterior approach. To enable closed reduction at the fracture site and avoid difficulties with positioning a prone patient with very severe hyperkyphosis and an unstable spine, the authors performed surgical procedures with the patient in a sitting position.

The authors obtained significant correction during the procedure by 74⁰, from 53.4⁰ of kyphosis to 24.3⁰ of lordosis measured between C2 and T1. The patient had several complications (transient weakness of the upper limb, pleural effusion, and delayed wound healing); however, all resolved and the patient was discharged within two weeks post the operation.

In patients with spinal hyperkyphosis with AS who sustain spinal fractures requiring operative treatment, it is worth considering simultaneous correction of the spinal deformity during surgical management of the fracture.

m6A Methylation Regulates Osteoblastic Differentiation and Bone Remodeling

Osteoporosis is a prevalent bone disease of the aging population, which is characterized by a decrease in bone mass because of the imbalance of bone metabolism. Although the prevention and treatment of osteoporosis have been explored by different researchers, the mechanisms underlying osteoporosis are not clear exactly. N6 methyladenosine (m6A) is a methylated adenosine nucleotide, which functions through its interaction with the proteins called “writers,” “readers” and “erasers.” The epigenetic regulation of m6A has been demonstrated to affect mRNA processing, nuclear export, translation, and splicing. At the cellular level, m6A modification has been known to affect cell proliferation, differentiation, and apoptosis of bone-related cells, such as bone marrow mesenchymal stem cells (BMSC), osteoblasts, and osteoclasts by regulating the expression of ALP, Runx2, Osterix, VEGF, and other related genes. Furthermore, PTH/Pth1r, PI3K‐Akt, Wnt/β‐Catenin, and other signaling pathways, which play important roles in the regulation of bone homeostasis, are also regulated by m6A. Thus, m6A modification may provide a new approach for osteoporosis treatment. The key roles of m6A modification in the regulation of bone health and osteoporosis are reviewed here in this article.

Advanced ankylosing spondylitis: a multisite, multimodality densitometric analysis for investigation of bone loss in the axial and appendicular skeleton

OBJECTIVE

The aim of this study was to investigate if there is a bias in bone mineral density measurements among major densitometric techniques across multiple skeletal sites.

METHODS

In 25 advanced ankylosing spondylitis patients, bone mineral density measurements were acquired in the lumbar spine, the hip, and the forearm.

RESULTS

In total, 60% of patients had a bone mineral density Z-score of -2 or less at one or more skeletal sites. Dedicated loss of cortical bone was identified at the distal forearm (60% of patients). Differences in bone mineral density measurements across all densitometric techniques were highly significant (p≤0.001). Bone loss was more striking in spinal trabecular bone by three-dimensional quantitative computed tomography [Z-score -2.1] versus dual-energy X-ray absorptiometry [Z-score 0]. A trabecular bone loss quantified by quantitative computed tomography was about twice as much as a cortical bone loss by single-energy X-ray absorptiometry (p=0.001).

CONCLUSIONS

Low bone mineral density is prevalent in advanced ankylosing spondylitis patients, predominating in the spine. Bone mineral density measurements have systematic differences when compared to each other. Knowledge of these offsets is useful for improved diagnosis of regional bone loss that allows for targeted treatment of osteoporosis. Three-dimensional quantitative computed tomography is more suitable for evaluating spinal osteoporosis in advanced ankylosing spondylitis than dual-energy X-ray absorptiometry, which rather underestimates bone loss.

Prevalence and Associated Factors of Low Bone Mineral Density in the Femoral Neck and Total Hip in Axial Spondyloarthritis: Data from the CASTRO Cohort

Studies on osteoporosis in axial spondyloarthritis (axSpA) have focused on the lumbar segment, and few studies have assessed bone mineral density (BMD) in the hip and femoral neck in these patients. The aim of this study was to evaluate the prevalence of low BMD and osteopenia in the total hip or femoral neck and the factors associated with these conditions in axSpA patients. This was a single-centre, observational, cross-sectional study among consecutive patients with axSpA according to the ASAS criteria from the CASTRO registry. All patients underwent total hip and femoral neck DXA BMD measurements. Low BMD was defined as a Z-score less than −1, and osteopenia was defined as a T-score less than −1. Multivariate logistic and generalised linear regressions were used to evaluate factors independently associated with low BMD and osteopenia in the hip or femoral neck and those associated with variability in BMD, respectively. A total of 117 patients were included, among which 30.8% were female and the mean age was 45 years. A total of 36.0% of patients had low BMD (28.1% in the total hip and 27.4% in the femoral neck), and 56.0% of patients had osteopenia (44.7% in the total hip and 53.8% in the femoral neck). A multivariate logistic regression showed that age, radiographic sacroiliitis and ASAS-HI were independently associated with low BMD in the total hip or femoral neck. Factors that were independently associated with osteopenia were Body Mass Index, disease duration, radiographic sacroiliitis and ASAS-HI. In conclusion, 36% of the patients with axSpA had low BMD in the total hip or femoral neck. A younger age and radiographic sacroiliitis were the most important factors associated with decreased BMD.

Microbial-derived antigens and metabolites in spondyloarthritis

Spondyloarthritis (SpA) is a group of chronic, immune-mediated, inflammatory diseases affecting the bone, synovium, and enthesis. Microbiome, the community of microorganisms that has co-evolved with human hosts, plays a pivotal role in human health and disease. This invisible "essential organ" supplies the host with a myriad of chemicals and molecules. In turn, microbial metabolites can serve as messengers for microbes to communicate with each other and in the cross-talk with host cells. Gut dysbiosis in SpA is associated with altered microbial metabolites, and an accumulated body of research has contributed to the understanding that changes in intestinal microbiota can modulate disease pathogenesis. We review the novel findings from human and animal studies to provide an overview of the contribution of individual microbial metabolites and antigens to SpA.

Management of cervical fractures in ankylosing spondylitis patients: immediate fixation effort via vertebroplasty with one-staged combined anterior and posterior fixation

The ankylosed spine is prone to fracture even as a result of minor trauma due to its changed biomechanical properties. Fractures in ankylosing spondylitis (AS) patients are highly unstable and surgical intervention for fixation is warranted. Implant failure rates are high and combined anterior and posterior fixation is required to enhance the fixation outcome. For fusion, anterior interbody fusion or posterior bone graft fusion is often adopted. Here, we introduce a new method which combines vertebroplasty with anterior and posterior approaches to improve pain control, facilitate the long-term fixation outcome and mechanics, and decrease perioperative risks with prompt stabilization, especially in patients with spine curve deformity. Here, we present two AS cases with cervical spine fracture treated with this new method.

Trabecular Bone Score (TBS) Predicts Fracture in Ankylosing Spondylitis: The Manitoba BMD Registry

INTRODUCTION

Ankylosing spondylitis (AS) is a chronic inflammatory disease of the spine characterized among other features by spinal boney proliferation, back pain, loss of flexibility, and increased fracture risk. Overlying bone limits the utility of bone mineral density (BMD) by dual X-ray absorptiometry (DXA) in the spine. Trabecular bone score (TBS) is a bone texture measurement derived from the spine DXA image that indicates bone quality and fracture risk independent of BMD.

METHODOLOGY

Using the Manitoba Bone Density Program database, patients with diagnosis codes for ankylosing spondylitis, baseline DXA and lumbar spine TBS were identified. Incident nontraumatic fractures (major osteoporotic [MOF], clinical spine, hip, and all fracture) were identified from population based databases. Cox-proportional hazard models are presented.

RESULTS

We identified 188 patients with diagnosed AS. TBS was lower in those with incident MOF (1.278 ± 0.126, compared to 1.178 ± 0.136, p < 0.001). Unadjusted TBS and FRAX-MOF-BMD adjusted predicted major osteoporotic fracture (N = 19) (hazard ratio [HR] 2.04, 95% confidence interval [CI]: 1.28-2.26, p = 0.003; HR 1.81, 95% CI: 1.11-2.96, p = 0.018). TBS unadjusted and FRAX-MOF-BMD adjusted also predicted clinical spine fracture (N = 7) (HR 2.50, 95% CI: 1.17-5.37; p = 0.019; HR 2.40 95% CI: 1.1-5.25; p = 0.028). Higher HRs were observed for prediction of hip fracture (N = 6), but these did not achieve statistical significance (FRAX-adjusted HR 1.74, 95% 0.73-4.17; p = 0.211). Unadjusted models show TBS was predictive of all fracture (N = 27) (HR 1.60, 95% CI: 1.08-2.39; p = 0.020), which was borderline significant after adjustment for FRAX-MOF-BMD (HR 1.51, 95% CI: 1.00-2.29; p = 0.052).

CONCLUSION

We report the first analysis of TBS for fracture prediction as an incident event in AS. TBS independently predicted major osteoporotic and clinical spine fracture in AS independent of FRAX.

Comorbidity management in spondyloarthritis

Comorbidities are defined as coexistent clinical disorders that appear as a consequence of persistent inflammatory activity and/or treatment. Comorbidities in spondyloarthritis (SpA) are frequent, contributing to a poorer quality of life, higher mortality and incremented healthcare costs. Several recommendations for the screening and management of these comorbidities have been developed in recent years with the aim of improving the different outcomes in these patients. Osteoporosis is the most prevalent comorbidity in patients with SpA, mainly caused by systemic inflammation and a lack of mobility, while cardiovascular diseases explain the increased mortality in patients with SpA with regard to the general population. Data from randomised controlled trials show a low incidence of infections in both patients with and without immunosuppressive treatment, and no evidence of a high incidence of malignant diseases has been demonstrated in these patients. Finally, concomitant fibromyalgia deserves attention, since its coexistence with SpA leads to a poorer treatment response and more switches of anti-TNF treatments. In this review, we show an update of the most common comorbidities in patients with SpA, and we discuss the latest evidence on the management of such comorbidities.

Absence of association between inflammatory dietary pattern and low trauma fractures: Results of the French cohort NutriNet-Santé

INTRODUCTION

The aim of our study was to assess the association between the Alternate Dietary Inflammatory Index (ADII) and the risk of fracture in a French cohort of women and men older than 50 years.

METHODS

A total of 15,096 participants were included from the French NutriNet-Santé cohort. The ADII score was calculated at inclusion. Incident low trauma fractures were retrospectively self-reported by participants on a specific additional questionnaire. Multivariate hazard ratio obtained from Cox proportional hazard regression models were used to characterize an association between ADII (in quartiles) and incident low trauma fractures.

RESULTS

In all, 12,046 participants (7607 (63.2%) women and 4439 (36.8%) men) were included in our study. For fractures, 806 (10.6%) and 191 (4.3%) low trauma fractures were recorded respectively in women and in men. Mean ADII was -1.23 (±3.13) for women and -0.87 (±3.64) for men. No association was detected between the ADII score and the risk of vertebral fracture (P=0.21), major osteoporotic fracture (P=0.93) and any low trauma fracture (P=0.72) in women nor in men (P=0.06 for major fracture and P=0.10 for low trauma fracture) after adjustment for sociodemographic, lifestyle variables and for bone treatments.

CONCLUSION

This study in postmenopausal women and men older than 50 years from the general population did not show any association between inflammatory dietary pattern measured using the ADII and the risk of incident low trauma fracture.

A posterior-only approach for ankylosing spondylitis (AS) with thoracolumbar pseudoarthrosis: a clinical retrospective study

Background

Surgical treatment has been recommended by most surgeons to treat pseudarthrosis in ankylosing spondylitis (AS). However, there is still some debate on the necessity of anterior fusion. There is very limited literature on the treatment and surgical outcomes of thoracolumbar pseudarthrosis in AS patients treated through a posterior-only approach.

Methods

From January 1, 2012 to December 31, 2017, a total of 42 cases diagnosed with thoracolumbar pseudarthrosis in AS patients with moderate kyphosis were included in this study. All of the patients received posterior-only kyphosis correction, internal fixation and fusion without anterior fusion, and underwent at least 2 years of follow-up. Clinical and radiographic results and complications were assessed.

Results

All of the patients were followed up for an average of 35.3 months (range, 24–48 months), and they achieved successful bone graft fusion at the pseudarthrosis sites. Satisfactory radiographic changes were achieved in these patients. The Cobb angles of global kyphosis (GK) were corrected from 53.2 ± 5.4 degrees preoperatively to 33.2 ± 4.3 degrees postoperatively, and to 36.1 ± 5.3 degrees at the latest follow-up. The Cobb angles of local kyphosis (LK) were corrected from 43.3 ± 4.6 degrees preoperatively to 26.8 ± 3.3 degrees postoperatively, and to 28.2 ± 3.6 degrees at the latest follow-up. The mean sagittal vertical axis (SVA) were corrected from 7.6 ± 4.2 cm preoperatively to 4.3 ± 2.1 cm postoperatively, and to 4.8 ± 2.3 cm at the latest follow-up. No serious neurological complication or deep wound infection was found in these 42 patients.

Conclusion

Posterior-only kyphosis correction and fixation without anterior fusion can achieve excellent bone fusion and satisfactory improvement in AS patients with thoracolumbar pseudarthrosis. This method may be a good choice for treating thoracolumbar pseudarthrosis in AS patients with moderate kyphosis.

Complete Fusion of Three Lumbar Vertebral Bodies in Ankylosing Spondylitis

Ankylosing spondylitis is a seronegative arthropathy of unknown etiology affecting mainly young adults. Acute or chronic changes of the spine such as sacroiliitis, spondylodiscitis, osteitis, ossification, and arthropathic lesions characterize the disease. Spinal involvement may accompany ossification of the ligaments, disc, end-plates and apophyseal structures, and seems to be bamboo spine. Here, we report a rare case describing the complete fusion of three lumbar vertebral bodies in ankylosing spondylitis. This rare case is presented alongside a literature review.

Perspective on skeletal health in inflammatory bowel disease

Osteopenia and osteoporosis are common features in inflammatory bowel disease (IBD), comprising both Crohn's disease and ulcerative colitis. Moreover, Crohn's disease is associated with increased fracture risk. The etiology of bone loss in IBD is multifactorial. It includes insufficient intake or absorption of calcium, vitamin D, and potassium; smoking; a low peak bone mass; a low body mass index; and decreased physical activity. In several studies, it has been shown that elevated concentrations of systemic and local pro-inflammatory cytokines, including tumor necrosis factor alpha (TNF-α), interferon-γ (IFNγ), interleukin (IL)-1β, IL-4, IL-5, IL-6, IL-13, and IL-17, present in IBD patients are potentially detrimental for bone metabolism and may be responsible for bone loss and increased fracture risk. This perspective aims to review the current literature on the role of inflammatory factors in the pathophysiology of skeletal problems in IBD and to suggest potential treatment to improve bone health, based on a combination of evidence and clinical and pathophysiological reasoning.

Baseline MRI inflammation is not a determinant of 5-year bone mineral density loss in patients with early spondyloarthritis

OBJECTIVE

The aim of this study was to assess the effect of baseline inflammation on Magnetic Resonance Imaging (MRI) on the change in Bone Mineral Density (BMD) over 5 years in patients with early spondyloarthritis (SpA).

METHODS

From the patients of the DESIR cohort (an early axial SpA cohort), patients with BMD data at both baseline and 5 years, and baseline spine and sacroiliac joints MRI were included. Inflammation was assessed with the SpondyloArthritis Research Consortium of Canada (SPARCC) spine score. Significant BMD loss was defined by a change of >0.03g/cm². No patients had received TNF blockers before inclusion in the cohort. Univariate and multivariable prognostic analyses were performed. An inverse propensity score weighting method was used to handle confounders.

RESULTS

One hundred and eighty-three patients were included (mean age 33.9±8.7 years, 58.5% men). A significant bone loss was reported in 51% (n=92) of patients at either lumbar spine or hip. Fourteen (7%) patients had low BMD (Z-score <-2) at the end of the follow-up vs. 28 (15%) at baseline. In multivariable analysis, age was a protective factor of 5 year-BMD loss at any site (OR=0.96, 95% CI [0.93-0.99]). Baseline MRI inflammation has no significant effect on BMD change at any site (OR=0.84, 95% CI [0.46-1.53]).

CONCLUSION

Half of patients with early SpA have a significant bone loss at either lumbar spine or hip over 5 years. Baseline MRI inflammation is not a determinant of this bone loss.

Repeating Measurement of Bone Mineral Density when Monitoring with Dual-energy X-ray Absorptiometry: 2019 ISCD Official Position

Bone mineral density (BMD) can be measured at multiple skeletal sites using various technologies to aid clinical decision-making in bone and mineral disorders. BMD by dual-energy X-ray absorptiometry (DXA) has a critical role in predicting risk of fracture, diagnosis of osteoporosis, and monitoring patients. In clinical practice, DXA remains the most available and best validated tool for monitoring patients. A quality baseline DXA scan is essential for comparison with all subsequent scans. Monitoring patients with serial measurements requires technical expertise and knowledge of the least significant change in order to determine when follow-up scans should be repeated. Prior ISCD Official Positions have clarified how and when repeat DXA is useful as well as the interpretation of results. The 2019 ISCD Official Positions considered new evidence and clarifies if and when BMD should be repeated. There is good evidence showing that repeat BMD measurement can identify people who experience bone loss, which is an independent predictor of fracture risk. There is good evidence showing that the reduction in spine and hip fractures with osteoporosis medication is proportional to the change in BMD with treatment. There is evidence that measuring BMD is useful following discontinuation of osteoporosis treatment. There is less documentation addressing the effectiveness of monitoring BMD to improve medication adherence, whether monitoring of BMD reduces the risk of fracture, or effectively discriminates patients who should and should not recommence treatment following an interruption of medication. Further research is needed in all of these areas.

Assessing bone impairment in ankylosing spondylitis (AS) using the trabecular bone score (TBS) and high-resolution peripheral quantitative computed tomography (HR-pQCT)

OBJECTIVES

To compare bone quality using the trabecular bone score (TBS) and bone microarchitecture in the distal tibia using high-resolution peripheral quantitative computed tomography (HR-pQCT) in ankylosing spondylitis (AS) patients and healthy controls (HC).

METHODS

Areal bone mineral density (aBMD) and TBS (TBS iNsight software) were evaluated using DXA (Hologic, QDR 4500); while volumetric bone mineral density (vBMD) and bone microarchitecture were analyzed in the distal tibia using HR-pQCT (Scanco) in 73 male patients with AS and 52 age-matched HC.

RESULTS

AS patients were a mean 41.6 ± 7.9 years old and had a mean disease duration of 16.4 ± 8.6 y, with a mean mSASSS 25.6 ± 16.4. No difference was observed in lumbar spine aBMD in AS patients and HC (p = 0.112), but total hip BMD (p = 0.011) and TBS (p < 0.001) were lower in AS patients. In the distal tibia, reduced trabecular volumetric density [Tb.vBMD (p < 0.006)] and structural alterations - trabecular thickness (Tb.Th), p = 0.044 and trabecular separation (Tb.Sp), p = 0.039 - were observed in AS patients relative to controls. Further analysis comparing TBS < 1.310 and TBS ≥ 1.310 in AS patients revealed a higher mean body mass index [BMI] (p = 0.010), lower tibia cortical vBMD [Ct.vBMD] (p = 0.007), lower tibia cortical thickness [Ct.Th]: (p = 0.048) in the former group. On logistic regression analysis, BMI (OR = 1.27; 95%IC = 1.08-1.50, p = 0.005), (VF 4.65; 1.13-19.1, p = 0.033) and tibial Ct.vBMD (0.98; 0.97-1.00, p = 0.007) were associated with a lower TBS (<1.310).

CONCLUSIONS

The present study demonstrates that TBS and HR-pQCT imaging are important technologies evaluating bone impairment in AS patients. Moreover, in these patients vertebral fractures were associated with lower TBS.

Should clinicians pay more attention to the potential underdiagnosis of osteoporosis in patients with ankylosing spondylitis? A national population-based study in Taiwan

OBJECTIVES

There are limited studies describing the association between ankylosing spondylitis (AS) and osteoporosis. We conducted a nationwide retrospective cohort study to investigate this epidemiologic evidence.

METHODS

Data were obtained from the Taiwan National Health Insurance Research Database (NHIRD). Of 10,290 participants, 2,058 patients with AS and 8,232 patients without AS were enrolled from the NHIRD between 2000 to 2013. Cumulative incidences of osteoporosis were compared between 2 groups. Cox regression model was used to estimate the hazard ratio (HR) of developing osteoporosis after controlling for demographic and other co-morbidities, and subgroup analyses were conducted to examine the risk factors for osteoporosis in AS patients.

RESULTS

The incidence rate ratio (IRR) of osteoporosis in AS patients was 2.17 times higher than that non-AS group (95% confidence interval [CI], 1.83-2.57). The adjusted HRs of osteoporosis for AS patients after controlling for demographic characteristics and comorbid medical disorders was 1.99 (95% CI 1.68-2.36). Among AS group, after adjustment for major comorbidities, old age (≥65 years, HR 4.32, 95% CI 3.01-6.18), female sex (HR 2.48, 95% CI 1.87-3.28), dyslipidemia (HR 1.44, 95% CI 1.01-2.06) were risk factors associated with osteoporosis.

CONCLUSIONS

This cohort study demonstrated that patients with AS had a higher risk of developing osteoporosis, especially in those aged over 65, female sex and with dyslipidemia in this patient group.

Comorbidities in spondyloarthritis including psoriatic arthritis

Comorbidities in spondyloarthritis (SpA) including psoriatic arthritis have to be differentiated to the concept of clinical features of SpA (e.g., uveitis, psoriasis, and inflammatory bowel disease). In addition to atherosclerosis-related cardiovascular diseases, the most frequent comorbidities in SpA are osteoporosis, fibromyalgia, and depression. Moreover, the current available drug therapies (e.g., NSAIDs, corticosteroids, and biologics) might increase the risk of some comorbidities such as infections and gastrointestinal disorders. Awareness about these comorbidities is crucial to improve their screening and management. For this purpose, any systematic periodical review should integrate a program (ideally internationally standardized) focused on comorbidities.

Low incidence of vertebral fractures in early spondyloarthritis: 5-year prospective data of the DESIR cohort

OBJECTIVES

An increased risk of vertebral fractures (VFs) has been reported in spondyloarthritis (SpA). Our hypothesis is that the prevalence of VFs is lower than reported in previous studies, especially in early SpA. This study aimed at assessing the incidence of radiographical VFs over 5 years in early axial SpA.

METHODS

The DESIR (DEvenir des Spondylarthropathies Indifférenciées Récentes) cohort, which included patients with inflammatory back pain highly suggestive of axial SpA, is the basis of this study. All radiographs of the DESIR cohort had been assessed at a central facility, by one investigator specialised in the field of the diagnosis of VFs according to Genant's method. We assessed the prevalence and incidence of VFs and vertebral deformities at baseline and over 5 years.

RESULTS

Five-year X-rays were available for 432 patients (mean age 34.3±8.7 years, 53% women). Diagnosis of VF was doubtful and needed adjudication for 19 patients (4.4%). 13 patients had prevalent VFs (3.0%) which were located at the thoracic spine (12 were grade 1). At 5 years, five patients had an incident VF (1.15%); seven vertebrae were fractured, mostly located at the thoracic spine (n=6/7), and of grade 1 (n=6/7).

CONCLUSION

In the DESIR cohort, a population of early SpA, we found a low prevalence and incidence of VFs (3.0% and 1.15 %), respectively. This confirms our hypothesis that the actual prevalence and incidence of VFvertebral fracture in SpA is lower than that reported in the previous studies.

Monocytes from male patients with ankylosing spondylitis display decreased osteoclastogenesis and decreased RANKL/OPG ratio

The present study investigates the osteoclastogenic capacity of peripheral blood mononuclear cells (PBMCs) in male patients with ankylosing spondylitis (AS). We demonstrated that monocytes from these patients display a lower capacity to generate osteoclasts compared to cells from healthy controls, and osteoclastogenesis was negatively correlated with disease duration.

INTRODUCTION

Ankylosing spondylitis (AS) is a disease characterized by new bone growth that leads to syndesmophyte formation but AS patients frequently present with low bone mineral density/fractures. Osteoclastogenesis in AS patients is poorly studied and controversial. The aim of this study is to determine if the osteoclastogenic capacity of PBMCs is different in AS patients compared to controls and the relationship between osteoclastogenesis and clinical/laboratory parameters.

METHODS

PBMCs from 85 male AS patients and 59 controls were tested for CD16+ cells and induced to differentiate into osteoclasts over 3 weeks in vitro. Serum levels of RANKL, osteoprotegerin (OPG), C-terminal telopeptide of type I collagen (CTX), and amino-terminal pro-peptide of type I collagen (P1NP) were also evaluated.

RESULTS

PBMCs from AS patients had fewer CD16+ cells and produced fewer osteoclasts compared to controls. Apoptosis occurred less frequently in osteoclasts obtained from AS patients than in osteoclasts from the controls. A lower RANKL/OPG and CTX/P1NP were observed in AS patients compared to controls. AS patients taking NSAIDs presented no difference regarding the number of OCs produced and the percentage of CD16+ cells compared to controls. However, patients taking TNF inhibitors (TNFi) presented lower OC numbers than controls. A negative correlation was demonstrated between the number of osteoclasts generated from PBMCs of AS patients and disease duration.

CONCLUSION

Monocytes from male AS patients display a lower capacity to generate osteoclasts in vitro compared to cells from controls. Osteoclastogenesis was negatively correlated with disease duration. This finding supports the idea that osteoclasts play a role in the physiopathology of bone disease in AS patients.

Spine Fractures in Ankylosing Diseases: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)

STUDY DESIGN

Review of literature and case series.

OBJECTIVES

Update and review of current treatment concepts for spine fractures in patients with ankylosing spinal disorders.

METHODS

Case presentation and description of a diagnostic and therapeutic algorithm for unstable spinal injuries with an underlying ankylosing spinal disorder (ASD) of the cervical and thoracolumbar spine.

RESULTS

Nondisplaced fractures can be missed easily using conventional X-rays. Thus, computed tomography (CT) scans are recommended for all trauma patients with ASD. In doubt or presence of any neurologic involvement additional magnetic resonance imaging (MRI) scans should be obtained. Spine precautions should be maintained all times and until definitive treatment (<24 h). Nonoperative fracture treatment is not recommended given the mechanical instability of the most commonly seen fracture patterns (AOSpine B- and C-type, M2) in patients with ASD and inherent high risk of secondary neurologic deterioration. For patients with ankylosing spondylitis (AS) or diffuse idiopathic hyperostosis (DISH) sustaining cervical spine fractures, a combined anterior-posterior instrumentation for fracture fixation is recommended. Closed reduction and patient positioning can be challenging in presence of preexisting kyphotic deformities. In the thoracolumbar (TL) spine, a posterior instrumentation extending 2 to 3 levels above and below the fracture level is recommended to maintain adequate reduction and stability until fracture healing. Minimally invasive percutaneous pedicle screws and cement augmentation can help to minimize the surgical trauma and strengthen the construct stability in patients with diminished minor bone quality (osteopenia, osteoporosis).

CONCLUSIONS

Current concepts, treatment options, and recommendations of the German Orthopedic Trauma Society-Spine Section for spinal fractures in the ankylosed spine have been outlined.

Comorbidities in Spondyloarthritis

Comorbidities in spondyloarthritis (SpA) add to the burden of disease by contributing to disease activity, functional and work disability, and mortality. Thus, awareness of comorbidities in SpA is crucial to improve their screening and management and to ultimately improve outcomes in those affected. Osteoporosis has been reported to be the most prevalent comorbidity in SpA, and its risk is increased in these patients, compared with the general population; the risk of vertebral fractures requires further evaluation. Cardiovascular risk is also increased in this population, both due to an increase of the traditional cardiovascular risk factors in these patients, but also due to the presence of inflammation. The role of non-steroidal anti-inflammatory drugs in this increased risk needs further elucidation, but there is consensus on the need to encourage smoking cessation and to perform periodic evaluation of cardiovascular risk in these patients, particularly in the case of change in treatment course. Concerning the risk of cancer, no increased risk inherent to SpA seems to exist. However, an increased neoplastic risk can occur due to SpA treatments, e.g., P-UVA. Data are sparse on the risk of infections compared with rheumatoid arthritis, but there appears to be no risk in the absence of TNF-inhibitor exposure. Regardless of which comorbidity, a gap exists between recommendations for their management and actual implementation in clinical practice, suggesting that there is still a need for improvement in this area. Systematic screening for these comorbidities should improve both short- and long-term outcomes in SpA patients.

Severity of Sacroiliitis and Erythrocyte Sedimentation Rate are Associated with a Low Trabecular Bone Score in Young Male Patients with Ankylosing Spondylitis

Objective.

To examine factors related to a low trabecular bone score (TBS) and the association between TBS and vertebral fractures in patients with ankylosing spondylitis (AS).

Methods.

One hundred patients (all male, aged < 50 yrs) who fulfilled the modified New York criteria for the classification of AS were enrolled. The TBS and bone mineral density (BMD) were assessed using dual-energy X-ray absorptiometry. Clinical variables, inflammatory markers, and the presence of vertebral fractures were also assessed. Sacroiliitis grade and spinal structural damage were measured using the modified New York criteria and the Stoke Ankylosing Spondylitis Spine Score (SASSS).

Results.

The mean TBS was 1.38 ± 0.13. The TBS showed a positive correlation with BMD at the lumbar spine, femoral neck, and total hip. TBS negatively correlated with SASSS, whereas BMD at the lumbar spine showed a positive correlation. A significant decrease in TBS values was observed in patients with spinal structural damage (p = 0.001). Univariate analysis identified disease duration, erythrocyte sedimentation rate (ESR), sacroiliitis grade, and SASSS as being associated with TBS. Multivariate analysis identified ESR and sacroiliitis grade as being independently associated with TBS (p = 0.006 and p < 0.001, respectively). Ten patients had morphometric vertebral fractures. The mean TBS was lower in patients with vertebral fractures than in age-matched patients without fractures (p = 0.028). Lower TBS predicted vertebral fractures (area under curve = 0.733, cutoff = 1.311).

Conclusion.

The TBS in young male patients with AS is associated with the ESR and severity of sacroiliitis. The TBS may be useful as a tool for assessing osteoporosis in AS.

Do biological disease-modifying antirheumatic drugs reduce the spinal fracture risk related to ankylosing spondylitis? A longitudinal multiregistry matched cohort study

OBJECTIVES

Ankylosing spondylitis (AS) is associated with an increased spinal fracture risk due to the loss of elasticity in spinal motion segments. With the introduction of biological disease-modifying antirheumatic drug (bDMARD) treatment for AS, the individual course of the disease has been ameliorated. This study aims to examine the association of bDMARD treatment and risk of spinal fracture.

DESIGN

Longitudinal population-based multiregistry observational matched cohort study.

SETTING

Swedish Patient Registry 1987-2014 and Swedish Prescribed Drugs Registry 2005-2014.

PARTICIPANTS

Included were patients ≥18 years of age receiving treatment at a healthcare facility for the primary diagnosis of AS. About 1352 patients received more than one prescription of bDMARD from 2005 to 2014. An untreated control group was created by propensity score matching for age, sex, comorbidity, antirheumatic prescriptions and years with AS (n=1352).

MAIN OUTCOME MEASURES

Spinal fracture-free survival.

RESULTS

No bDMARD treatment-related effect on spinal fracture-free survival was observed in the matched cohorts. Male gender (HR=2.54, 95% CI 1.48 to 4.36) and Charlson Comorbidity Index score (HR=3.02, 95% CI 1.59 to 5.75) contributed significantly to spinal fracture risk.

CONCLUSION

bDMARD had no medium-term effect on the spinal fracture-free survival in patients with AS.

TRIAL REGISTRATION NUMBER

NCT02840695; Post-results.

Which measuring site in ankylosing spondylitis is best to detect bone loss and what predicts the decline: results from a 5-year prospective study

BACKGROUND

Studies have shown increased prevalence of osteoporosis and increased risk for vertebral fractures in patients with ankylosing spondylitis (AS). Measurements of bone mineral density (BMD) in the lumbar spine anterior-posterior (AP) projection may be difficult to interpret due to the ligamentous calcifications, and the lateral projection might be a better measuring site. Our objectives were to investigate BMD changes after 5 years at different measuring sites in patients with AS and to evaluate disease-related variables and medications as predictors for BMD changes.

METHODS

In a longitudinal study, BMD in Swedish AS patients, 50 ± 13 years old, was measured with dual-energy x-ray absorptiometry (DXA) at the hip, the lumbar spine AP and lateral projections, and the total radius at baseline and after 5 years. Patients were assessed with questionnaires, blood samples, and spinal radiographs for grading of AS-related alterations in the spine with the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) and assessment of vertebral fractures by the Genant score. Multiple linear regression analyses were used to investigate predictors for BMD changes.

RESULTS

Of 204 patients included at baseline, 168 (82%) were re-examined after 5 years (92 men and 76 women). BMD decreased significantly at the femoral neck and radius and increased significantly at the lumbar spine, both for AP and lateral projections. Mean C-reactive protein during follow-up predicted a decrease in the femoral neck BMD (change in %, β = -0.15, p = 0.046). Use of bisphosphonates predicted an increase in BMD at all measuring sites (p < 0.001 to 0.013), except for the total radius. Use of tumor necrosis factor inhibitors (TNFi) predicted an increase in AP spinal BMD (β = 3.15, p = 0.012).

CONCLUSION

The current study (which has a long follow-up, many measuring sites, and is the first to longitudinally assess the lateral projection of the spine in AS patients) surprisingly showed that lateral projection spinal BMD increased. This study suggests that the best site to assess bone loss in AS patients is the femoral neck and that inflammation has an adverse effect, and the use of bisphosphonates and TNFi has a positive effect, on BMD in AS patients.

Utility of DXA for monitoring, technical aspects of DXA BMD measurement and precision testing

Monitoring a patient's bone mineral density (BMD) is one of the main reasons for dual-energy X-ray absorptiometry (DXA) referral. It is widely recommended by clinical guidelines, and the accepted standard in practice for managing patients with osteoporosis and other disorders. Clinicians and DXA providers must be familiar with the scientific rationale and procedures involved in measurement science to obtain accurate and reproducible results. Their importance is critical to maximise the value of scan acquisition and interpretation. Scanning individual patients, with different needs and disorders, requires excellence in training, experience, and is more complex than just simply 'measuring BMD'. Over the past 3 decades many studies have validated the importance of monitoring BMD for fracture risk assessment, and for patients on osteoporosis treatment. New DXA features enhance the value of DXA monitoring today. Quality BMD measurement remains an essential component of patient care in osteoporosis and other disorders, playing a critical role in informed decision making for clinicians assessing and managing their patients. In this article we describe some of the technical aspects of measurement and discuss the utility of DXA for monitoring patients in clinical practice.

Treatment of kyphosis in ankylosing spondylitis by osteotomy through the gap of a pathological fracture: a retrospective study

Background

Surgical interventions are commonly advocated for correcting kyphotic deformities and relieving severe back pain in ankylosing spondylitis (AS) patients. The aim of this study was to evaluate the clinical outcome of osteotomy performed through the gap of a pathological fracture for the treatment of kyphosis in ankylosing spondylitis and to introduce the key points of this novel surgical approach.

Methods

From January 1, 2010, to December 31, 2014, 13 consecutive AS patients who were treated with osteotomy through the fracture gap were retrospectively reviewed. Patients underwent the radiographic assessment of sagittal balance parameters. Visual analog scale (VAS) scores were used to assess improvement in back pain.

Results

The average follow-up time was 2 years and 1 month. The median operation time was 280 min (range, 220–460 min). The mean blood loss was 1100 mL (range, 820–1300 mL). No major acute complications such as death or complete paralysis occurred. There were no neurologic complications or cerebrospinal fluid leaks in any patient. One patient had postoperative wound infection, which subsided after a switch of antibiotics. The global kyphosis Cobb angle of patients decreased from the preoperative 55.8° ± 11.0° to 23.2° ± 6.7° (P < 0.001) after surgery. The C7 plumb line was used to assess global balance; its relationship with the posterosuperior corner of the sacrum decreased from 166 ± 37 mm to 111 ± 20 mm (P < 0.001). The thoracolumbar kyphosis Cobb angle decreased from 51.0° ± 9.9° to 21.6° ± 11.0° (P < 0.001). VAS scores for back pain decreased from 7.2 ± 1.2 to 2.1 ± 1.1 (P < 0.001). Lumbar lordosis increased from 5.7° ± 23.2° to 10.5° ± 29.2° (P = 0.001).

Conclusions

Osteotomy through the pathological fracture gap is a safe and effective surgical procedure for kyphosis correction and improvement of back pain in AS patients with pathological fractures. A significant kyphosis correction and improvement of back pain can be achieved with this surgical procedure.

Is there a relation between pre-sarcopenia, sarcopenia, cachexia and osteoporosis in patients with ankylosing spondylitis?

Background

Osteoporosis is a well-known complication of ankylosing spondylitis (AS). However, data about body composition modifications and muscle performance showed conflicting results. The aim of the study was to determine the prevalence and risk factors of pre-sarcopenia, sarcopenia and cachexia in patients with AS and analyze its relationship with bone loss and symptomatic and severity parameters of the disease.

Methods

Sixty-seven consecutive male patients with AS (mean age of 40.9 ± 11.0 years) and 67 healthy controls were studied. Body composition and bone mineral density (BMD) scans were obtained using DXA. The fat-free mass index (FFMI; fat-free mass divided by height squared) and the percent of fat mass (%FM) were calculated. Pre-sarcopenia was defined by low skeletal muscle mass (SMI <7.25 kg/m²), sarcopenia by the combined presence of the two following criteria: SMI <7.25 kg/m² and a low muscle strength (handgrip strength <30 kg) or a low muscle performance (timed get-up-and-go test >10 s) and cachexia by a BMI <20 kg/m² plus 3 from the 5 following parameters: anorexia, fatigue, handgrip strength <30 kg, CRP >5 mg/l, SMI <7.25 kg/m².

Results

Pre-sarcopenia, sarcopenia, cachexia, and osteoporosis prevalences were (50.4, 34.3, 11.9, and 16.0) respectively. Patients had a mean 3 kg significant decrease in FFM and a 1 kg/m² decrease in appendicular mass vs. healthy controls. Pre-sarcopenia, sarcopenia and cachexia were significantly associated to higher BASDAI levels and low BMD.

Conclusion

Our study showed that men with AS had a statistically significant reduction in total and appendicular lean mass that is related to higher disease activity and significantly associated to bone loss.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1155-z) contains supplementary material, which is available to authorized users.