Osteoporosis and ankylosing spondylitis

An effective strategy for treatment of severe kyphosis secondary to ankylosing spondylitis: one-level modified osteotomy combined with shoulders lifting correction method

BACKGROUND

Severe kyphosis is a common condition in patients with advanced ankylosing spondylitis (AS). Although two-level osteotomy may serve as a potential alternative, it is often associated with increased blood loss and elevated surgical risks. To date, the optimal treatment for the challenging condition remains unclear. This study aims to introduce an effective strategy for the treatment of severe kyphosis secondary to AS, using one-level modified osteotomy combined with shoulders lifting correction method.

METHODS

Seventy AS kyphosis who were treated with the strategy from 2012 to 2022, were reviewed retrospectively. All patients were followed up for a minimum duration of 2 years. Spinal and pelvic parameters were measured, including pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumber lordosis (LL), PI and LL mismatch (PI-LL), thoracic kyphosis, global kyphosis (GK), T1 pelvic angle (TPA), sagittal vertical axis (SVA), osteotomized vertebral angle (OVA), and chin-brow vertical angle (CBVA). Parameters of local osteotomized complex were measured and calculated, including the height of osteotomized complex and the length of spinal cord shortening. Clinical outcome was evaluated using Scoliosis Research Society-22 and Oswestry Disability Index scores.

RESULTS

Seventy patients with average age of 39.8 years were followed-up for 29.3 months. Average operation time was 373.5 min, and average blood loss was 751.0 ml. Postoperatively, sagittal balance was successfully restored. GK decreased from 90.6° to 35.6°, LL decreased from 8.0° to -35.1°, TPA decreased from 56.8° to 27.8°, and SVA decreased from 24.4 cm to 8.7 cm (P < 0.05). A harmonious and matched spinopelvic alignment was achieved. PT decreased from 37.2° to 26.3°, PI-LL decreased from 54.1° to 10.2°, and SS increased from 9.2° to 19.7°(P < 0.05). Horizontal vision was obtained with postoperative CBVA of 8.8°. Average OVA correction was up to 47.3°, and the spinal cord was shortened by 24.3 mm, with a shortening rate of 36.0%. All patients demonstrated a favorable clinical outcome. No permanent nerve damage, screw loosening, rod breakage and main vascular injury were observed. One case required revision surgery due to screw cap loosening and delayed union. Solid bone fusion was achieved in all other patients.

CONCLUSIONS

One-level modified osteotomy combined with shoulders lifting correction method is a safe and effective strategy for the treatment of severe AS kyphosis. This strategy offers a promising alternative for managing severe AS kyphosis, and may be particularly well-suited for individuals with concurrent osteoporosis.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Hounsfield units in assessing bone mineral density in ankylosing spondylitis patients with cervical fracture-dislocation

BACKGROUND

Cervical spine fracture-dislocations in patients with ankylosing spondylitis (AS) are mostly unstable and require surgery. However, osteoporosis, one of the comorbidities for AS, could lead to detrimental prognoses. There are few accurate assessments of bone mineral density in AS patients.

AIM

To analyze Hounsfield units (HUs) for assessing bone mineral density in AS patients with cervical fracture-dislocation.

METHODS

The HUs from C2 to C7 of 51 patients obtained from computed tomography (CT) scans and three-dimensional reconstruction of the cervical spine were independently assessed by two trained spinal surgeons and statistically analyzed. Inter-reader reliability and agreement were assessed by interclass correlation coefficient.

RESULTS

The HUs decreased gradually from C2 to C7. The mean values of the left and right levels were significantly higher than those in the middle. Among the 51 patients, 25 patients (49.02%) may be diagnosed with osteoporosis, and 16 patients (31.37%) may be diagnosed with osteopenia.

CONCLUSION

The HUs obtained by cervical spine CT are feasible for assessing bone mineral density with excellent agreement in AS patients with cervical fracture-dislocation.

Intermittent administration of PTH for the treatment of inflammatory bone loss does not enhance entheseal pathological new bone formation

OBJECTIVE

To investigate the effect of intermittent parathyroid hormone (iPTH) administration on pathological new bone formation during treatment of ankylosing spondylitis-related osteoporosis.

METHODS

Animal models with pathological bone formation caused by hypothetical AS pathogenesis received treatment with iPTH. We determined the effects of iPTH on bone loss and the formation of pathological new bone with micro-computed tomography (micro-CT) and histological examination. In addition, the tamoxifen-inducible conditional knockout mice (CAGGCre-ERTM; PTHflox/flox, PTH-/-) was established to delete PTH and investigate the effect of endogenous PTH on pathological new bone formation.

RESULTS

iPTH treatment significantly improved trabecular bone mass in the modified collagen-induced arthritis (m-CIA) model and unbalanced mechanical loading models. Meanwhile, iPTH treatment did not enhance pathological new bone formation in all types of animal models. Endogenous PTH deficiency had no effects on pathological new bone formation in unbalanced mechanical loading models.

CONCLUSION

Experimental animal models of AS treated with iPTH show improvement in trabecular bone density, but not entheseal pathological bone formation，indicating it may be a potential treatment for inflammatory bone loss does in AS.

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.

Construct length analysis of type B and C cervical and thoracolumbar fractures

Objectives

The purpose of this study is to identify if construct length affects the rate of surgical complications and instrumentation revision following surgical fixation of subaxial and thoracolumbar Type B and C fractures. This study evaluates the effect of ankylosing spondylitis/diffuse idiopathic skeletal hyperostosis (AS/DISH) within this population on outcomes.

Methods

Retrospective review of 91 cervical and 89 thoracolumbar Type B and C fractures. Groups were divided by construct length for analysis: short-segment (constructs spanning two or less segments adjacent to the fracture) and long-segment (constructs spanning more than two segments adjacent to the vertebral fracture).

Results

For cervical fractures, construct length did not impact surgical complications (P = 0.641), surgical hardware revision (P = 0.167), or kyphotic change (P = 0.994). For thoracolumbar fractures, construct length did not impact surgical complications (P = 0.508), surgical hardware revision (P = 0.224), and kyphotic change (P = 0.278). Cervical Type B fractures were nonsignificantly more likely to have worsened kyphosis (P = 0.058) than Type C fractures. Assessing all regions of the spine, a diagnosis of AS/DISH was associated with an increase in kyphosis (P = 0.030) and a diagnosis of osteoporosis was associated with surgical hardware failure (P = 0.006).

Conclusion

Patients with short-segment instrumentation have similar surgical outcomes and changes in kyphosis compared to those with long-segment instrumentation. A diagnosis of AS/DISH or osteoporosis was associated with worse surgical outcomes.

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.

Clinical features and outcomes of spine surgery in patients with ankylosing spondylitis

OBJECTIVES

The study aimed to comprehend the clinical features and outcomes of surgical treatments for spinal disorders in patients with ankylosing spondylitis (AS).

METHODS

This retrospective study enrolled patients with AS who underwent spine surgery between 2000 and 2019 in our facility.

RESULTS

Thirteen patients with AS underwent spine surgeries. The mean age was 56.2 years, and the mean disease duration was 25.1 years at the time of surgery. Nine patients had vertebral fracture, two had kyphotic deformity, and two had myelopathy due to the spinal ligament ossification. Fracture cases included five patients with secondary pseudarthrosis/delayed palsy due to conservative treatment failure. Spinal fixation was performed in all patients. Pedicle subtraction osteotomy for kyphosis and laminectomy for myelopathy were also conducted. All patients improved after surgeries. One patient with kyphotic deformity underwent additional surgery of bilateral hip prosthesis, which resulted in better spine alignment. Four cases of perioperative complications were observed.

CONCLUSION

Myelopathy was newly found as the aetiology requiring surgery in patients with AS. This summarized case series could help physicians to identify patients with surgically treatable spinal disorders among patients with AS.

Evaluation of cortical and trabecular bone structure of the mandible in patients with ankylosing spondylitis

This study aimed to examine the difference between the fractal dimension (FD) values of the mandibular trabecular bone and the panoramic mandibular index (PMI), mandibular cortical index (MCI) and mandibular cortical thickness (MCW) of patients with ankylosing spondylitis (AS) and healthy control group. A total of 184 individuals (92 cases, 92 controls), were examined in our study. PMI, MCI, and MCW values were calculated on panoramic images of all individuals. For FD values, the region of interest (ROI) was selected with the size of 100 × 100 pixels from the right-left gonial and interdental regions and 50 × 50 pixels from the condylar region. Degenerative changes in the temporomandibular joint (TMJ) region were recorded. PMI, MCI, and MCW values showed statistically significant differences between the groups (p = 0.000, p < 0.001). The radiological signs of mandibular cortical resorption were more severe in the case group than in the control group. PMI and MCW values were found to be lower in the case group than in the control group. It was determined that the number of C3 and C2 values, among the MCI values, was higher in the case group. Only the FD values of the ROI selected from the condyle region were found to be statistically significant and were lower in the case group (p = 0.026, p < 0.05). Degenerative changes in the TMJ region were significantly more frequent in the case groups (p = 0.000, p < 0.001). The fact that the mandibular cortex shows more resorptive features in individuals with AS may require further evaluation in terms of osteoporosis. Because of the low FD values of the condylar regions of these patients and the more frequent degenerative changes, the TMJ region should be followed carefully. Detailed examination of the mandibular cortex and condylar region is beneficial in patients with AS for screening and following osteoporotic changes in these individuals, which is essential for the patient's life quality.

Evaluation of temporomandibular joint components and mandibular bone structure in ankylosing spondylitis patients

OBJECTIVES

The study aimed to investigate the mandible and temporomandibular joint (TMJ) in patients with ankylosing spondylitis (AS) who had no signs or symptoms of TMJ-related disease and compare them with a control group.

STUDY DESIGN

In total, 128 panoramic radiographs (63 patients with AS, 65 controls) were evaluated. Fractal analysis was conducted on the mandibular condyle (ROI1), angle of the mandible (ROI2), and the area adjacent to the mental foramen (ROI3). Articular eminence inclination (AEI) values were measured. Klemetti index (KI) evaluation of the mandibular cortex was also performed.

RESULTS

Fractal dimension (FD) values were significantly lower in the patients with AS than the controls in ROI1 and ROI2 (P = .001), but there were no significant differences between groups for FD in ROI3, AEI, or KI (P ≥ .09). No significant differences were found in any parameters between patients with AS with different disease durations (P ≥ .06).

CONCLUSIONS

Patients with AS displayed significantly lower FD values in condyles and the angle of the mandible and slightly lower AEI values; therefore, they should be examined routinely for TMJ disorders. Clinicians should be aware of the possibility of secondary osteoporosis in patients with AS and consider its probable effects on the mandible.

Preoperative prediction of sagittal imbalance in kyphosis secondary to ankylosing spondylitis after one-level three-column osteotomy

Background

This study aimed to determine preoperative predictors for sagittal imbalance in kyphosis secondary to ankylosing spondylitis (AS) after one-level three-column osteotomy.

Methods

A total of 55 patients with AS who underwent one-level three-column osteotomy were enrolled. The patients were divided into two groups according to sagittal vertical axis (SVA) value at the final follow-up (group A: SVA > 5 cm; group B: SVA ≤ 5 cm). The radiographic measures included global kyphosis, lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), sacral slope, T1 pelvic angle (TPA), SVA, osteotomized vertebral angle and PI and LL mismatch (PI − LL). Postoperative clinical outcomes were evaluated using Scoliosis Research Society-22 questionnaire (SRS-22) and Oswestry Disability Index (ODI).

Results

Fifty-five AS patients had an average follow-up of 30.6 ± 10.2 months (range 24–84 months). Group A had larger preoperative and postoperative LL, PT, PI − LL, TPA and SVA values compared with group B (P < 0.05), and no significant differences were found in ODI and SRS-22 scores between the two groups (P > 0.05). Preoperative LL, PT, PI − LL, TPA, and SVA values were positively correlated with the follow-up SVA value (P < 0.05). Among them, TPA > 40.9°, PI − LL > 32.5° and SVA > 13.7 cm were the top three predictors with the best accuracy to predict sagittal imbalance. Immediate postoperative SVA value of ≤ 7.4 cm was a key factor in reducing the risk of sagittal imbalance during follow-up.

Conclusions

Preoperative TPA > 40.9°, PI − LL > 32.5° and SVA > 13.7 cm could predict sagittal imbalance in AS kyphosis after one-level three-column osteotomy, and additional osteotomies were recommended for this condition. Immediate postoperative SVA ≤ 7.4 cm was an optimal indicator for preventing sagittal imbalance.

Level of evidence

IV.

Sulfasalazine related nephrolithiasis in patients with rheumatoid arthritis and ankylosing spondylitis

Background Sulfasalazine (SSZ) is an anti-inflammatory and immunomodulatory drug used to treat many inflammatory diseases. Bacteria in the gut metabolize SSZ to active 5-aminosalicylic acid and inactive sulfapyridine. Sulfapyridine can crystallize in the kidney. We aimed to investigate the frequency of nephrolithiasis in patients who were diagnosed with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and who received SSZ treatment retrospectively. Material and Methods We retrospectively analyzed the files of AS and RA patients in the rheumatology outpatient clinic between 2009 and 2018. We identified patients who underwent kidney ultrasonography at least six months after initiation of SSZ. One hundred six patients and 50 healthy adults were included in the study. Results Only eight patients (6 AS, 2 RA) had nephrolithiasis on ultrasonography, but none in the control group (p=0.046). In logistic regression analysis, no correlation was found between gender, age, vitamin D, parathyroid hormone, and urinary calcium excretion with SSZ use (p>0.05). Conclusion Although, it is noteworthy that these patients are prone to stone formation for various reasons. Therefore, paying attention to the patient’s hydration while using these drugs may prevent such side effects.

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.

The Emerging Roles of Endocrine Hormones in Different Arthritic Disorders

The relationship between endocrine hormones and the spectrum of rheumatic conditions has long been discussed in the literature, focusing primarily on sexual hormones, such as estrogens, androgens, prolactin (PRL). Estrogens are indeed involved in the pathogenesis of the main inflammatory arthritis thanks to their effects on the immune system, both stimulatory and inhibitory. The PRL system has been discovered in synovial tissue of rheumatoid arthritis (RA) and psoriatic arthritis (PsA), patients and has been propose as a new potential therapeutic target. Besides sexual hormones, in the last years scientific interest about the crosstalk of immune system with other class of hormones has grown. Hormones acting on the bone tissue (i.e. parathyroid hormone, vitamin D) and modulators of the Wnt pathway (i.e. Dickkopf-1) have been demonstrated to play active role in inflammatory arthritis course, defining a new field of research named osteoimmunology. PTH, which is one of the main determinants of Dkkopf-1, plays a crucial role in bone erosions in RA and a correlation between PTH, Trabecular Bone Score (TBS) and disease activity has been found in ankylosing spondylitis (AS). In PSA is under studying the interaction among IL-17 and bone metabolism. The purpose of this review is to discuss and summarize the recent data about the interaction between endocrine hormone and immune system in the main rheumatic disorders, covering in particular the role of bone-related hormones and cytokines. We will describe this relationship from a biochemical, diagnostic and therapeutic perspective, with a particular focus on RA, PsA and AS.

Performance of bone mineral density and trabecular bone score in assessment of bone quality in Egyptian male patients with ankylosing spondylitis

Background

Osteoporosis is a common complication of ankylosing spondylitis (AS) even in the early stages of disease; however, previously published studies have demonstrated large discrepancies in the reported incidence of osteoporosis, based on measurement of bone mineral density (BMD). The aim of the present study was to compare bone quality using trabecular bone score (TBS) between AS patients and healthy controls and to evaluate factors associated with TBS in patients with AS.

Results

Ankylosing spondylitis patients had significantly lower BMD and T score at the neck of femur and lower total hip BMD than controls (BMD p = 0.010 and 0.032 respectively), (T score p = 0.006 and p = 0.025 respectively). The mean TBS was significantly lower in AS patients than in controls (p < 0.001). Lumbar spine TBS was directly correlated with BMI (p = 0.029) and BMD at the neck of femur (p = 0.016) and BMD of total hip (p = 0.007) while inversely correlated with the Bath AS Metrology Index (BASMI) (p = 0.026), the modified Stoke AS Spinal Score (mSASS) (p = 0.029), ESR (p = 0.031), and CRP (p = 0.033).

Conclusion

TBS evaluation detected lower bone quality in the lumbar spine in patients with AS when compared with matched controls, while lumbar BMD failed to identify it. These findings encourage the use of TBS as a beneficial tool to recognize the risk of axial osteoporosis as early as possible in AS patients. Also, we recommend its use for regular follow up of drug treatment for those patients.

Vitamin D levels in patients with ankylosing spondylitis: Is it related to disease activity?

Objective:

Ankylosing Spondylitis (AS) is an inflammatory rheumatic disease that mainly affects the axial spine. Osteopenia and osteoporosis are the main complications of AS. Vitamin D has functions on the immune system. In this study, we aimed to compare vitamin D levels and Bone Mineral Density (BMD) values between AS patients and controls.

Methods:

A total of 68 patients with axial AS and 34 healthy controls were enrolled in this study conducted between March 2018 and May 2018. Vitamin D concentrations, BMD values, disease activity, back mobility, functionality and radiologic damage were evaluated.

Results:

Vitamin D concentrations, the total BMD-femur and BMD-femur neck values were significantly lower in AS patients (p = 0.001, p = 0.011 and p = 0.003). No significant correlations were detected between vitamin D levels and BMD-femur total, BMD-femur neck values, disease activity, back mobility, functionality and radiologic damage scores (p > 0.05). Disease activity parameters were significantly and negatively correlated with total BMD-femur and BMD-femur neck values (p < 0.05).

Conclusion:

Our study demonstrates that AS patients have lower vitamin D levels, total BMD-femur and BMD-femur neck values. Higher disease activity increases bone loss in AS. Regular measurement of BMD and vitamin D should be kept in mind when planning a treatment in AS.

Evaluation of bone quality with trabecular bone score in active spondyloarthritis

OBJECTIVE

Many patients with spondyloarthritis (SpA) are at risk of fracture due to bone fragility, whereas their bone mineral density (BMD) is not significantly diminished. Other tools, such as trabecular bone score (TBS), evaluating other characteristics of bone tissue are therefore necessary in order to evaluate bone changes in these patients. Therefore we evaluated TBS as a bone quality marker, in a cohort of patients with SpA and investigated which clinical and biological factors were correlated with TBS values.

METHODS

Patients fulfilling ASAS criteria of SpA with a BMD assessment and visiting our department for initiation or switch of a biologic treatment were selected. The clinical and biological data were collected at the time of BMD measurement.

RESULTS

Ninety-five patients were included in the study, with a mean age of 40.2 and a mean disease duration of 8.2 years. Lumbar BMD T-score was <-1 and <-2.5 in 17% and 3% of patients, respectively. On average, TBS value was 1.34±0.12. Lumbar BMD was positively correlated with TBS (r=0.61), while disease duration, disease activity score and serum PTH levels were negatively correlated with TBS (r=-0.24, r=-0.33, and r=-0.27, respectively). These correlations persisted in a multivariate analysis. Furthermore, more than half of the patients with a BMD level above -2.5 T-score had a low TBS value.

CONCLUSION

Our results show that TBS provides information additional to BMD on the bone status of patients with SpA. They suggest that TBS may help in identifying those patients at risk of fracture.

Vertebral column decancellation: a new spinal osteotomy technique for correcting rigid thoracolumbar kyphosis in patients with ankylosing spondylitis

AIMS

The aim of this study is to introduce and investigate the efficacy and feasibility of a new vertebral osteotomy technique, vertebral column decancellation (VCD), for rigid thoracolumbar kyphotic deformity (TLKD) secondary to ankylosing spondylitis (AS).

PATIENTS AND METHODS

We took 39 patients from between January 2009 and January 2013 (26 male, 13 female, mean age 37.4 years, 28 to 54) with AS and a TLKD who underwent VCD (VCD group) and compared their outcome with 45 patients (31 male, 14 female, mean age 34.8 years, 23 to 47) with AS and TLKD, who underwent pedicle subtraction osteotomy (PSO group), according to the same selection criteria. The technique of VCD was performed at single vertebral level in the thoracolumbar region of AS patients according to classification of AS kyphotic deformity. Pre- and post-operative chin-brow vertical angle (CBVA), sagittal vertical axis (SVA) and sagittal Cobb angle in the thoracolumbar region were reviewed in the VCD and PSO groups. Intra- , post-operative and general complications were analysed in both group.

RESULTS

lf patients could lie on their backs and walk with horizontal vision and sagittal profile, radiographic parameters improved significantly post-operatively in both groups. No major acute complications such as death or complete paralysis occurred in either group. In the VCD group, five patients (12.8%) experienced complications such as severe CSF leak (n = 4), deep wound infection (n = 1) and in one patient a transient neurological deficit occurred. In the PSO group, eight patients (17.8%) suffered conditions such as severe CSF leak (n = 5), infections (n = 2) and sagittal translation at osteotomy site (n = 1). Scoliosis Research Society outcomes instrument (SRS-22) improved significantly in both groups. All patients achieved solid fusion at latest follow-up and no implant failures were noted in either group.

TAKE HOME MESSAGE

The VCD technique is a new, safe and effective strategy for correction of rigid TLKD in AS patients. The main advantage of the new correction mechanism is that it achieved a satisfactory correction by controlled anterior column opening and posterior column closing, avoiding the occurrence of sagittal translation. Cite this article: Bone Joint J 2016;98-B:672-8.

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.

Single anterior approach for cervical spine fractures at C5-T1 complicating ankylosing spondylitis

OBJECTIVES

To evaluate the outcomes of anterior approach for cervical spine fractures at C5-T1 in patients with ankylosing spondylitis (AS) and study the problems encountered in diagnosis and treatment.

PATIENTS AND METHODS

Ten patients with AS (all males; mean age 43.7±9.4 years) underwent anterior surgeries to treat fractures at C5-T1. Skull tractions were performed on patients with fracture dislocation preoperatively. After operation, all the patients wore a cervical collar for 3 months. Plain radiographs at follow-up were reviewed. If bone fusion could not be confirmed on plain radiograph, CT scan was employed. The pre- and postoperative neurological statuses were evaluated according to the Frankel grading system. Problems encountered in diagnosis and treatments were analyzed.

RESULTS

The mean follow-up was 41.2±22.7months. After operation, the displacements of fractures were significantly reduced(P<0.05). Bone fusions were observed in 9 patients at final follow-up. Frankel grades improved by 1.0±0.7 grade (P>0.05). Posterior complications occurred in four patients, including implants failure (n=1), subsidence of cage (n=1), hoarse voice (n=1) and pneumonias (n=2). The patient with implants failure required revision surgery and anterior-posterior fixation. Patient with subsidence of the titanium cage achieved bone fusion with prolonged cervical collar immobilization.

CONCLUSION

The diagnosis and treatment of cervical spine fractures at C5-T1 in AS patients are challenging, with high risk of neurological compromise and postoperative complications. The single anterior approach followed by postoperative immobilization with a cervical collar can yield acceptable results if the cases are properly selected.

Utility of DXA scanning and risk factors for osteoporosis in ankylosing spondylitis-A prospective study

BACKGROUND

Conventional DXA imaging of spine and hip to measure bone mineral density (BMD) has limitations in patients with ankylosing spondylitis (AS). We investigated the correlation of hip and spine BMD measurements in patients with AS to determine if hip DXA will prove clinically useful while avoiding the confounding effect of spinal disease. Also, we studied risk factors for osteoporosis (OP) and osteopenia in AS.

METHODS

We randomly identified patients from our validated AS registry ≥18 years of age who met the Modified New York Classification criteria for AS. BMD was measured and interpreted using ISCD 2007 guidelines and diagnosis of OP was based on WHO criteria. ESR, CRP, urinary N-telopeptide, and 25-hydroxy vitamin D were also measured. Correlation between the BMD (total hip and/or femoral neck) and lumbar spine was calculated. Statistical comparisons between the 2 sites, lumbar spine (AP) and hip (total hip and or femoral neck) were made using Bowker's test for symmetry and kappa statistics. Chi-square and odds ratio using logistic regression were used to assess the association of the purported risk factors for OP in these patients.

RESULTS

Frequency of OP among AS patients ≥50 years of age was 23%, and that of osteopenia was 41%. Among patients <50 years of age, the frequency of low bone mass for expected age (Z-score ≤-2.0) was 14.7%. There was moderate correlation (ρ = 0.59) and a fair agreement (κ = 0.26; 95% CI: 0.10-0.42) between the lowest T-values of hip and lumbar spine (AP view). OP was significantly associated with elevated CRP level [OR = 4.2 (95% CI: 1.13-15.9), p < 0.03] and African American race [OR = 7.2 (95% CI: 1.18-44.99), p < 0.03].

CONCLUSION

Our results demonstrated a moderate correlation and fair agreement between the T-scores of hip and the lumbar spine (AP view) in patients with AS, suggesting that DXA of the hip and the lumbar spine (AP view) may both be useful for OP and osteopenia screening in patients with AS without fused spines. We confirm the previous reports of an association of elevated CRP level with an increased risk of OP in patients with AS, but this is the first study to demonstrate that African American patients with AS may be at a higher risk of developing OP compared to Caucasians.

Sacroiliitis or insufficiency fracture?

Sacral stress fracture and sacroiliitis are two conditions that present with pain. Sacral stress fractures are a rare cause of lumbar and hip pain. Sacral insufficiency fractures are a type of sacral stress fractures. Sacroiliitis represents inflammation of the sacroiliac joints. Coexistence of sacroiliitis and sacral insufficiency fracture (SIF) has not been reported before. Case 1: A 39-year-old woman reporting inflammatory back pain. Imaging revealed bilateral chronic sacroiliitis and bilateral SIF. Case 2: A 31-year-old woman presenting with left hip and inguinal pain. Imaging revealed left sacroiliitis and ipsilateral SIF. Calcium and vitamin D supplementation together with nonsteroidal anti-inflammatory drug (NSAID) treatment were given. Sulfasalazine was added to the treatment of the second patient who developed peripheral arthritis during follow-ups. Early diagnosis is best made with magnetic resonance imaging (MRI) since roentgenograms may be negative initially. Furthermore, MRI findings of both entities share common features leading to a diagnostic dilemma. Interpretation of radiological findings assisted by detailed history and clinical findings is crucial for diagnosis and treatment.

Etanercept Increases Bone Mineral Density in Ankylosing Spondylitis, but Does Not Prevent Vertebral Fractures: Results of a Prospective Observational Cohort Study

OBJECTIVE

Ankylosing spondylitis (AS) is characterized by chronic inflammation leading to ankylosis, but also to low bone mineral density (BMD) and vertebral fractures (VFx). Treatment with tumor necrosis factor-α blockers decreases inflammation and has shown to be effective in increasing BMD. We studied the effects of etanercept (ETN) on BMD and VFx in patients with AS after 2 years of treatment. Further, we studied changes in bone turnover markers and radiological damage.

METHODS

Patients with active AS, treated with ETN for 2 years, were included. BMD lumbar spine and hip were measured at baseline and after 2 years, as well as radiological damage (modified Stoke Ankylosing Spondylitis Spinal Score with the addition of the thoracic spine), VFx (Genant method), and change in bone turnover markers.

RESULTS

Forty-nine patients with AS were included. After 2 years of ETN, hip BMD increased by 2.2% (p = 0.014) and lumbar spine BMD by 7.0% (p < 0.001). The Bath Ankylosing Spondylitis Disease Activity Index decreased significantly (p < 0.001), as well as C-reactive protein and erythrocyte sedimentation rate (p < 0.001). Despite ETN therapy, the number of patients with VFx more than doubled (from 6 to 15 patients, p = 0.003). Also, the radiological damage increased significantly over time (from 12.1 to 18.5, p < 0.001); however, no significant change in bone turnover markers was found.

CONCLUSION

This prospective longitudinal observational cohort study showed that after 2 years of ETN, BMD of the hip and spine increased significantly, but the number of patients with VFx and the severity of VFx increased as well. Besides that, radiological progression, including the thoracic spine, increased significantly. Thus, the favorable bone-preserving effect is accompanied by unfavorable outcomes on VFx and radiological damage.

Effect of Tumor Necrosis Factor Inhibitor Therapy on Osteoclasts Precursors in Ankylosing Spondylitis

Introduction

Ankylosing Spondylitis (AS) is characterized by excessive local bone formation and concomitant systemic bone loss. Tumor necrosis factor (TNF) plays a central role in the inflammation of axial skeleton and enthesis of AS patients. Despite reduction of inflammation and systemic bone loss, AS patients treated with TNF inhibitors (TNFi) have ongoing local bone formation. The aim of this study was to assess the effect of TNFi in the differentiation and activity of osteoclasts (OC) in AS patients.

Methods

13 AS patients treated with TNFi were analyzed at baseline and after a minimum follow-up period of 6 months. 25 healthy donors were recruited as controls. Blood samples were collected to assess receptor activator of nuclear factor kappa-B ligand (RANKL) surface expression on circulating leukocytes and frequency and phenotype of monocyte subpopulations. Quantification of serum levels of bone turnover markers and cytokines, in vitro OC differentiation assay and qRT-PCR for OC specific genes were performed.

Results

RANKL⁺ circulating lymphocytes (B and T cells) and IL-17A, IL-23 and TGF-β levels were decreased after TNFi treatment. We found no differences in the frequency of the different monocyte subpopulations, however, we found decreased expression of CCR2 and increased expression of CD62L after TNFi treatment. OC number was reduced in patients at baseline when compared to controls. OC specific gene expression was reduced in circulating OC precursors after TNFi treatment. However, when cultured in OC differentiating conditions, OC precursors from AS TNFi-treated patients showed increased activity as compared to baseline.

Conclusion

In AS patients, TNFi treatment reduces systemic pro osteoclastogenic stimuli. However, OC precursors from AS patients exposed to TNFi therapy have increased in vitro activity in response to osteoclastogenic stimuli.

Association between mean platelet volume and bone mineral density in patients with ankylosing spondylitis and diagnostic value of diffusion-weighted magnetic resonance imaging

[Purpose] The aim this study was to assess the relation between bone mineral density (BMD) and mean platelet volume (MPV) in ankylosing spondylitis (AS) patients, and evaluate the diagnostic role of the diffusion-weighted magnetic resonance imaging (MRI). [Subjects and Methods] Fifty patients diagnosed with AS were divided into two groups on the basis of BMD, a normal group (n=30) and an osteopenic (n=20) group. [Results] Duration of disease in the group with a normal BMD was 10.3±7.0 years, while it was 16.7±12.2 years in the osteopenia group. MPV was high in the osteopenia group, while no significant differences were observed between the groups in terms of apparent diffusion coefficient (ADC) and platelet distribution width (PDW). There was a positive correlation between MPV and duration of disease. Correlations between ADC value and the lumbar T score, femoral neck T score, and duration of disease were insignificant. A negative correlation was observed between BMD and disease duration. [Conclusion] Diffusion-weighted imaging provides valuable results in osteoporosis but is not a suitable technique for evaluating BMD in patients with AS because of the local and systemic inflammatory effects in the musculoskeletal system. The common pathophysiology of atherosclerosis and osteoporosis plays an important role in the negative correlation observed between MPV and BMD in patients with AS.

Clinical studies on bone-related outcome and the effect of TNF-α blocking therapy in ankylosing spondylitis

PURPOSE OF REVIEW

To provide an overview of clinical trials and observational studies investigating the effect of tumor necrosis factor-alpha (TNF-α) blocking therapy on bone formation and bone loss in patients with ankylosing spondylitis (AS).

RECENT FINDINGS

The effect of TNF-α blocking therapy on excessive bone formation or osteoproliferation remains inconclusive. Radiographic assessment of spinal osteoproliferation is complicated by the overall slow rate of progression and the high variability between individual AS patients. Multiple studies demonstrated that TNF-α blocking therapy results in a significant increase in bone mineral density (BMD) at the lumbar spine and hip. Based on bone turnover marker (BTM) analysis, this can mainly be explained by an increase in mineralization and decrease in bone resorption.

SUMMARY

Both osteoproliferation (e.g. syndesmophytes and ankylosis of vertebrae) and excessive bone loss resulting in osteoporosis and vertebral fractures are frequently present in AS. Previous studies showed that BMD increases during TNF-α blocking therapy. Long-term follow-up in a large cohort of patients is needed to investigate whether TNF-α blockers can consolidate or stop spinal osteoproliferation and prevent vertebral fractures. Future studies should focus on the effect of these agents on bone-related outcome in AS patients with early vs. advanced disease.

Bone microarchitecture in ankylosing spondylitis and the association with bone mineral density, fractures, and syndesmophytes

Introduction

Osteoporosis of the axial skeleton is a known complication of ankylosing spondylitis (AS), but bone loss affecting the peripheral skeleton is less studied. This study on volumetric bone mineral density (vBMD) and bone microarchitecture in AS was conducted to compare peripheral vBMD in AS patients with that in healthy controls, to study vBMD in axial compared with peripheral bone, and to explore the relation between vertebral fractures, spinal osteoproliferation, and peripheral bone microarchitecture and density.

Methods

High-resolution peripheral quantitative computed tomography (HRpQCT) of ultradistal radius and tibia and QCT and dual-energy x-ray absorptiometry (DXA) of lumbar spine were performed in 69 male AS patients (NY criteria). Spinal radiographs were assessed for vertebral fractures and syndesmophyte formation (mSASSS). The HRpQCT measurements were compared with the measurements of healthy controls.

Results

The AS patients had lower cortical vBMD in radius (P = 0.004) and lower trabecular vBMD in tibia (P = 0.033), than did the controls. Strong correlations were found between trabecular vBMD in lumbar spine, radius (r_S = 0.762; P < 0.001), and tibia (r_S = 0.712; P < 0.001).

When compared with age-matched AS controls, patients with vertebral fractures had lower lumbar cortical vBMD (-22%; P = 0.019), lower cortical cross-sectional area in radius (-28.3%; P = 0.001) and tibia (-24.0%; P = 0.013), and thinner cortical bone in radius (-28.3%; P = 0.001) and tibia (-26.9%; P = 0.016).

mSASSS correlated negatively with trabecular vBMD in lumbar spine (r_S = -0.620; P < 0.001), radius (r_S = -0.400; p = 0.001) and tibia (r_S = -0.475; p < 0.001) and also with trabecular thickness in radius (r_S = -0.528; P < 0.001) and tibia (r_S = -0.488; P < 0.001).

Adjusted for age, syndesmophytes were significantly associated with decreasing trabecular vBMD, but increasing cortical vBMD in lumbar spine, but not with increasing cortical thickness or density in peripheral bone. Estimated lumbar vBMD by DXA correlated with trabecular vBMD measured by QCT (r_S = 0.636; P < 0.001).

Conclusions

Lumbar osteoporosis, syndesmophytes, and vertebral fractures were associated with both lower vBMD and deteriorated microarchitecture in peripheral bone. The results indicate that trabecular bone loss is general, whereas osteoproliferation is local in AS.

Higher bone turnover is related to spinal radiographic damage and low bone mineral density in ankylosing spondylitis patients with active disease: a cross-sectional analysis

Introduction

Ankylosing spondylitis (AS) is characterized by excessive bone formation and bone loss. Our aim was to investigate the association of bone turnover markers (BTM) with spinal radiographic damage and bone mineral density (BMD) in AS patients with active disease.

Methods

201 consecutive AS outpatients of the Groningen Leeuwarden AS (GLAS) cohort were included. Serum markers of bone resorption (C-telopeptides of type-I collagen, sCTX) and bone formation (procollagen type-I N-terminal peptide, PINP; bone-specific alkaline phosphatase, BALP) were measured. Z-scores were used to correct for the normal influence that age and gender have on bone turnover. Radiographs were scored by two independent readers according to modified Stoke AS Spinal Score (mSASSS). The presence of complete bridging (ankylosis of at least two vertebrae) was considered as measure of more advanced radiographic damage. Low BMD was defined as lumbar spine and/or hip BMD Z-score ≤ −1.

Results

Of the 151 patients with complete data, 52 (34%) had ≥1 complete bridge, 49 (33%) had ≥1 syndesmophyte (non-bridging), and 50 (33%) had no syndesmophytes. 66 (44%) had low BMD. Patients with bridging had significantly higher sCTX and PINP Z-scores than patients without bridging (0.43 vs. −0.55 and 0.55 vs. 0.04, respectively). Patients with low BMD had significantly higher sCTX Z-score than patients with normal BMD (−0.08 vs. −0.61). After correcting for gender, symptom duration, and CRP, sCTX Z-score remained significantly related to the presence of low BMD alone (OR: 1.60), bridging alone (OR: 1.82), and bridging in combination with low BMD (OR: 2.26).

Conclusions

This cross-sectional study in AS patients with active and relatively long-standing disease demonstrated that higher serum levels of sCTX, and to a lesser extent PINP, are associated with the presence of complete bridging. sCTX was also associated with low BMD. Longitudinal studies are needed to confirm that serum levels of sCTX can serve as objective marker for bone-related outcome in AS.

Alendronate Effect on the Prevention of Bone loss in Early Stages of Ankylosing Spondylitis: A Randomized, Double-Blind, Placebo-Controlled Pilot Study

BACKGROUND

Ankylosing spondylitis (AS) is an inflammatory rheumatic disease that leads to a progressive ankylosis of vertebras and ossification of paravertebral ligaments. Bone loss and osteoporosis are amongst the important complications of AS, treatment of which is a challenging issue.

OBJECTIVES

This study aimed to clarify the effect of alendronate on the prevention of bone loss in patients with early AS.

PATIENTS AND METHODS

In a randomized, double-blind, placebo-controlled study, 24 patients with early stages of AS were recruited in Emam Reza Hospital, Tabriz University of Medical Sciences. The diagnostic criteria of early AS were Schober's index ≥ 5, normal hip joint in pelvic radiography, and absence or rarity of syndesmophytes in spine radiography (Taylor index ≤ 1). The participants were randomly allocated to the treatment and control groups and received 70 mg/week of alendronate and the same dose of placebo, respectively, for 12 months. Before and 12 months after the intervention, bone densitometry was performed from lumbar and pelvic region using the dual-energy X-ray absorptiometry (DEXA) method with Hologic QDR model instrument. Patients, physicians who prescribed the medications and those who interpreted the outcomes, and densitometry technicians were unaware of the assigned medication to each patient. Both groups received supplemental calcium (1000 mg/day) and vitamin D (400 mg/day).

RESULTS

After 12 months of treatment, hip and lumbar bone mineral density differences were not statistically significant between study groups (P = 0.061 and P = 0.112, respectively). No case of clinically apparent vertebral and nonvertebral fracture were observed in the treatment and control groups.

CONCLUSIONS

Our results suggested that applying alendronate was ineffective in preventing bone loss in patients with early stages of AS.

HLA-B27 alters the response to tumor necrosis factor α and promotes osteoclastogenesis in bone marrow monocytes from HLA-B27-transgenic rats

OBJECTIVE

To determine whether HLA-B27 expression alters the response of bone marrow monocytes from HLA-B27/human β2 -microglobulin-transgenic (B27-Tg) rats to tumor necrosis factor α (TNFα) and, if so, whether this affects the cells involved in bone homeostasis.

METHODS

Bone marrow monocytes were treated with RANKL or with TNFα to promote osteoclast formation. Osteoclasts were quantified by counting. Gene expression was measured using quantitative polymerase chain reaction analysis, and protein was detected by enzyme-linked immunosorbent assay, immunoblotting, or immunofluorescence. Effects of endogenously produced cytokines on osteoclast formation were determined with neutralizing antibodies.

RESULTS

TNFα treatment enhanced osteoclast formation 2.5-fold in HLA-B27-expressing cells as compared to wild-type or to HLA-B7/human β2 -microglobulin-expressing monocytes. TNFα induced ∼4-fold up-regulation of HLA-B27, which was associated with the accumulation of misfolded heavy chains, binding of the endoplasmic reticulum (ER) chaperone BiP, and activation of an ER stress response, which was not seen with HLA-B7. No differences were seen with RANKL-induced osteoclastogenesis. Enhanced interleukin-1α (IL-1α) production from ER-stressed bone marrow monocytes from B27-Tg rats was found to be necessary and sufficient for enhanced osteoclast formation. However, bone marrow monocytes from B27-Tg rats also produced more interferon-β (IFNβ), which attenuated the effect of IL-1α on osteoclast formation.

CONCLUSION

HLA-B27-induced ER stress alters the response of bone marrow monocytes from B27-Tg rats to TNFα, which is associated with enhanced production of IL-1α and IFNβ, cytokines that exhibit opposing effects on osteoclast formation. The altered response of cells expressing HLA-B27 to proinflammatory cytokines suggests that this class I major histocompatibility complex allele may contribute to the pathogenesis of spondyloarthritis and its unique phenotype through downstream effects involving alterations in bone homeostasis.

Circulating Levels of Soluble Receptor Activator of NF- κ B Ligand and Matrix Metalloproteinase 3 (and Their Antagonists) in Asian Indian Patients with Ankylosing Spondylitis

Background. Bone loss in ankylosing spondylitis may be related to inflammation. Data from previous studies on circulating levels of sRANKL, OPG, MMP3, and TIMP is inconsistent; thus this study is planned to look at this aspect in Asian Indian patients. Methods. Cross-sectional study included patients with ankylosing spondylitis and age- and gender-similar controls. Serum levels of sRANKL, OPG, MMP-3, and TIMP-1 were measured by ELISA. Results. Included 85 patients (M : F = 82 : 3) having mean age (±SD) 33.0 ± 10.0 years and disease duration 11.3 ± 7.3 years. BASDAI, BASFI, BASMI, and ESR were 4.0 ± 2.2, 3.9 ± 2.8, 3.0 ± 2.8, and 59.2 ± 31.2, respectively. Patients had higher mean (±SD) OPG level (649.7 ± 286.8, 389.3 ± 244.8 pg/mL, P < 0.001). However, there was no difference in sRANKL (349.2 ± 872.0, 554.7 ± 1850.1, P = ns). Serum MMP-3 (91.4 ± 84.7, 55.9 ± 37.1 ng/mL, P < 0.01) and TIMP-1 (520.6 ± 450.7, 296.5 ± 114.2 ng/mL, P < 0.001) levels were higher in patients; however, there was no difference in MMP-3/TIMP-1 ratio. Conclusion. Circulating levels of OPG were higher; however, there was no difference in sRANKL in Asian Indian ankylosing spondylitis patients. Although both MMP-3 and TIMP-1 were raised, their ratio was not different from that of controls.

Vertebral fractures in ankylosing spondylitis are associated with lower bone mineral density in both central and peripheral skeleton

OBJECTIVE

To study the prevalence and risk factors for vertebral fractures (VF) in ankylosing spondylitis (AS) and the relation between VF, measures of disease activity, and bone mineral density (BMD) in different measurement sites.

METHODS

Patients with AS (modified New York criteria) underwent examination, answered questionnaires, and gave blood samples. Lateral spine radiographs were scored for VF (Genant score) and syndesmophyte formation through modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). BMD was measured with dual-energy x-ray absorptiometry in the hip, radius, and lumbar spine in anteroposterior and lateral projections with estimation of volumetric BMD (vBMD).

RESULTS

Two hundred four patients (57% men) with a mean age of 50 ± 13 years and disease duration 15 ± 11 years were included. VF were diagnosed in 24 patients (12%), but were previously noted clinically in only 3 of the 24. Patients with VF were significantly older (p = 0.004), had longer disease duration (p = 0.011), higher Bath Ankylosing Spondylitis Metrology Index (p = 0.011), mSASSS (p = 0.035), and Bath Ankylosing Spondylitis patient global score-2 (BASG-2) (p = 0.032) and were more often smokers (p = 0.032). All women with a VF were postmenopausal. BMD was significantly lower at all measuring sites in the patients with VF. In logistic regression, high BASG-2, low BMD in femoral neck, and low lumbar vBMD were independently associated with presence of VF.

CONCLUSION

VF in AS are common but are often not diagnosed. VF are associated with advanced age, longstanding disease, impaired back mobility, syndesmophyte formation, and lower BMD in both the central and peripheral skeleton. BMD in the femoral neck, total hip, and estimated vBMD showed the strongest association with VF.

High prevalence of low bone mineral density in patients within 10 years of onset of ankylosing spondylitis: a systematic review

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease. Decreased bone mineral density (BMD) is a common complication of AS, with a prevalence range of 19 to 62 %. Many studies have shown decreased BMD in AS with long disease duration, but only a few studies investigated BMD in early AS. The prevalence of decreased BMD in early disease stages of AS has not yet been clearly described, and for that reason, we reviewed the literature which describes the prevalence of decreased BMD in AS patients with a short disease duration (<10 years). In this review, we included articles which used the modified New York criteria for the diagnosis of AS, included patients with a disease duration of less than 10 years, and used the WHO criteria for osteopenia and osteoporosis. Decreased BMD was defined as a T score < −1.0, including both osteopenia and osteoporosis. For this review, only articles that acquired BMD data of lumbar spine and femoral neck by DXA were used. The literature search provided us 35 articles of which 7 matched all our criteria, and they will be further outlined in this review. The overall prevalence of decreased BMD of the articles reviewed is 54 % (n = 229/424) for lumbar spine and 51 % (n = 224/443) for femoral neck. The prevalence of osteopenia vs. osteoporosis for lumbar spine is 39 vs. 16 % and for femoral neck, 38 vs. 13 %. This review showed a high total prevalence of 51–54 % decreased BMD and 13–16 % osteoporosis in AS with a short disease duration. This high prevalence was not to be expected in a relatively young and predominantly male population. Further research is needed to determine the clinical relevance of this low BMD by investigating the relation between low BMD and vertebral and nonvertebral fractures at this early stage in AS.

High frequency of vertebral fractures in early spondylarthropathies

We demonstrated that vertebral fractures (VF) are commonly found in early SpA. Patients with VF had lower lumbar BMD than patients without VF. VF remained frequently 'unrecognized' and untreated. VF have been associated with more back pain, reduced Qol, and increased risk of future fractures which stresses the importance of recognition also in early stage SpA.

INTRODUCTION

VF are a common complication of long-standing ankylosing spondylitis (AS). However, data of VF in early AS patients and in other spondylarthropathies (SpA) are scarce. Therefore we examined the prevalence of VF in early SpA patients and investigated the associations between VF and demographic and disease-related variables.

METHODS

SpA patients were included consecutively and radiographs of the spine were made. VF were assessed according to the method of Genant et al.: fractures were defined as reduction of ≥20% of the vertebrae. Descriptive statistics, t-tests and logistic regression analyses were used to study the relationship between VF and demographic and disease-related variables, radiographic damage and BMD.

RESULTS

A total of 113 early SpA patients were included with a disease duration of 7 months, a mean age of 37 years. Seventeen patients (15%) had at least one VF. Fourteen patients had one VF, three patients had two VF. Most VF were located at Th6-Th8. In patients with VF, bone mineral density (BMD) of lumbar spine was lower than BMD of patients without VF (t-test: p = 0.043). Axial Psoriatic Arthritis (PsA) was significantly associated with a higher risk for VF (odds ratio [OR]: 4.62, 95% confidence interval [CI] 1.15-18.58, p = 0.031). No significant associations were found with disease activity variables nor with radiographic severity.

CONCLUSION

In a group of 113 early, young SpA patients, 15% already had at least one VF. Most VF were asymptomatic, undetected by routine diagnostic procedures and located at the mid-thoracic spine. The VF were associated with low BMD of the lumbar spine and with axial PsA.

Serum leptin levels are associated with the presence of syndesmophytes in male patients with ankylosing spondylitis

The aim of this study is to clarify the association between serum leptin levels and the presence of syndesmophytes in male patients with ankylosing spondylitis (AS). Seventy-two male patients with AS and 20 age-matched healthy male controls were included. Patients were stratified by the presence of syndesmophytes. Serum leptin levels were measured and adjusted for body mass index (BMI). In addition, bone-specific alkaline phosphatase (BALP), osteocalcin, and telopeptide of type I collagen were determined. Patients with syndesmophytes were associated with older age (p < 0.001), longer disease duration (p = 0.003), and higher BMI (p = 0.038). Serum leptin levels and leptin per BMI (leptin/BMI) ratio were not different between AS patients and healthy controls. However, serum leptin/BMI ratio was significantly higher in patients with syndesmophytes compared to those without (p = 0.010). In multivariate analysis, higher serum leptin/BMI ratio remained significantly associated with the presence of syndesmophytes (p = 0.029). Moreover, serum leptin/BMI ratio was positively correlated with serum BALP (γ = 0.279, p = 0.039). However, there was no significant association between serum leptin/BMI ratio and bone mineral density. Serum leptin levels are elevated in male AS patients with syndesmophytes and were found to be correlated with bone formation marker, suggesting a potential role of leptin in new bone formation in AS.

Extra-articular manifestations of ankylosing spondylitis: prevalence, characteristics and therapeutic implications

Ankylosing spondylitis (AS) is the most frequent and most severe subtype of spondyloarthritis and can be an outcome of any of the other spondyloarthritis subtypes. It primarily affects the axial joints, most notably the sacroiliac joints. Other sites of involvement include the spine, peripheral joints, and entheses (capsules, ligaments, and tendons). Inflammatory enthesopathy progressing to ossification and ankylosis is the pathologic basis for the disease. Extra-articular manifestations vary widely in terms of both frequency and severity. The most common extra-articular manifestations are represented by uveitis, bowel disease, heart, lung, skin, bone and kidney involvement. This review focuses on prevalence and clinical characteristics of the most common extra-articular manifestations in AS, and discuss the diagnosis and therapeutic difficulties that rheumatologists faces when dealing with such manifestations. The advantages of treatment with non-steroidal anti-inflammatory drugs (NSAIDs), especially if continuous use is envisaged, should be weighted against possible gastrointestinal and cardiovascular disadvantages. In the presence of history of gastrointestinal complaints or a high cardiovascular risk, NSAIDs should be used with caution. TNF inhibition has demonstrated effectiveness in the treatment of AS symptoms and all currently available anti-TNF agents appear to have similar efficacy. However, the efficacy of anti-TNF agents varies in the presence of extra-articular manifestations. Etanercept appears to have very little effect on inflammatory bowel disease and limited efficacy on the course of uveitis probably inferior to the monoclonal antibodies infliximab and adalimumab.

Osteoporosis in psoriatic arthritis: is there any?

AIMS

Although considered as a feature of inflammatory rheumatic diseases, there is a lot of controversy around low bone mass in patients with psoriatic arthritis. The aim of this cross-sectional study was to analyze bone mineral density in patients with psoriatic arthritis, as well as to investigate its possible association with some measures of disease activity and functional capacity.

SUBJECTS AND METHODS

Sixty-nine patients with established psoriatic arthritis (mean age 56.20 ± 12.23 years) and who have not been treated with specific antiosteoporotic drugs were recruited from the out-patient clinic database. Bone mineral density was measured by dual-energy X-ray absorptiometry at the lumbar spine and at the left hip. Disease activity measures included: duration of morning stiffness, tender and swollen joint count, patient's and physician's global assessment, presence of dactylitis and enthesitis, ESR, CRP and Disease Activity Score 28. Health Assessment Questionnaire was used to assess functional status.

RESULTS

According to WHO definition, spinal osteoporosis was found in 7.2% of patients, total hip osteoporosis in 1.4% of patients and femoral neck osteoporosis in 2.9% of patients. There was no significant association of any of the measures of disease activity with BMD at any site. Higher HAQ scores were associated with lower total hip BMD.

CONCLUSIONS

In our sample of patients with psoriatic arthritis we did not find increased prevalence of osteoporosis. There was no association of BMD with indices of disease activity, while negative correlation was found between HAQ and total hip BMD.

Osteoimmunology and osteoporosis

The concept of osteoimmunology is based on growing insight into the links between the immune system and bone at the anatomical, vascular, cellular, and molecular levels. In both rheumatoid arthritis (RA) and ankylosing spondylitis (AS), bone is a target of inflammation. Activated immune cells at sites of inflammation produce a wide spectrum of cytokines in favor of increased bone resorption in RA and AS, resulting in bone erosions, osteitis, and peri-inflammatory and systemic bone loss. Peri-inflammatory bone formation is impaired in RA, resulting in non-healing of erosions, and this allows a local vicious circle of inflammation between synovitis, osteitis, and local bone loss. In contrast, peri-inflammatory bone formation is increased in AS, resulting in healing of erosions, ossifying enthesitis, and potential ankylosis of sacroiliac joints and intervertebral connections, and this changes the biomechanical competence of the spine. These changes in bone remodeling and structure contribute to the increased risk of vertebral fractures (in RA and AS) and non-vertebral fractures (in RA), and this risk is related to severity of disease and is independent of and superimposed on background fracture risk. Identifying patients who have RA and AS and are at high fracture risk and considering fracture prevention are, therefore, advocated in guidelines. Local peri-inflammatory bone loss and osteitis occur early and precede and predict erosive bone destruction in RA and AS and syndesmophytes in AS, which can occur despite clinically detectable inflammation (the so-called 'disconnection'). With the availability of new techniques to evaluate peri-inflammatory bone loss, osteitis, and erosions, peri-inflammatory bone changes are an exciting field for further research in the context of osteoimmunology.

Osteoporosis: a paradox in ankylosing spondylitis

Ankylosing spondylitis is a chronic and severe inflammatory disease of the axial skeleton and the joints. Inflammation is associated with trabecular bone loss leading to osteoporosis but also with corcal new bone formation leading to progressive ankylosis of the spine and sacroiliac joints. This results in an apparent paradox of bone formation and loss taking place at sites closesly located to each other. Osteoporosis can be explained by the impact of inflammation of the bone remodeling cycle. In contrast, new bone formation has been linked to aberrant acvaon of bone morphogenec protein and Wnt signaling. In this commentary, we review recent data on this bone paradox and highlight recent advances including the effect of current drug therapies and the idenfication of new therapeutic targets.

Relationship of bone mineral density with disease activity and functional ability in patients with ankylosing spondylitis: a cross-sectional study

In ankylosing spondylitis, inflammatory activity probably plays a key role in the pathophysiology of bone loss. The aim of the study was to investigate the relationship of bone mineral density (BMD) at the lumbar spine and hip region with some measures of disease activity and functional ability in patients with ankylosing spondylitis. In 80 patients with established ankylosing spondylitis, disease activity and functional ability were determined by C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath Ankylosing Spondylitis Functional Index (BASFI). Spinal pain and patient global health were assessed using horizontal visual analog scale. BMD was measured by dual-energy X-ray absorptiometry. There was a significant negative correlation of bone density T scores with acute-phase reactants (i.e., patients with lower T scores had higher level of CRP and ESR). That relationship was reflected more reliably at proximal femur sites than at the lumbar spine. There were also significant differences in ESR, BASDAI, BASFI, spinal pain and global health between three groups of patients according to WHO classification of osteoporosis (normal, osteopenic and osteoporotic). Significantly, more patients with osteopenia at the lumbar spine had lower BASDAI index than those with normal BMD (P = 0.030). Our results indicate an association of low BMD with high disease activity in patients with AS. Femoral BMD seems to be more associated with disease activity and functional ability than lumbar spine BMD.

Clinical Correlates of Urolithiasis in Ankylosing Spondylitis

Objective.

To determine the association between urolithiasis and syndesmophyte formation and the effect of urolithiasis on ankylosing spondylitis (AS) disease activity.

Methods.

In a longitudinal cohort of 504 patients with AS, we conducted an analysis of all patients with AS who have a history of urolithiasis. All patients met the modified New York criteria for AS. Demographics, clinical characteristics, extraarticular features, and comorbidities are systematically recorded in the database. We compared disease activity, functional indices, medical therapy and radiographic damage between AS patients with (Uro+) and without urolithiasis (Uro–) using the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS).

Results.

Thirty-eight patients with AS (7.5%) had a history of urolithiasis in our cohort. Seventy-six patients with AS who did not have urolithiasis, matched for age, sex, and ethnicity, were selected as controls. Patients who were Uro+ were more likely to have more functional disability, based on the Bath AS Functional Index (BASFI; mean 5.3 vs 3.6 in control group, p = 0.003). Trends were noted in the Uro+ group toward higher Bath AS Disease Activity Index (BASDAI; mean 4.9 vs 4.0, p = 0.09), more peripheral joint involvement (p = 0.075), and higher frequency of biologic therapy (p = 0.09). No significant difference was detected in mSASSS or the Bath AS Metrology Index (BASMI). Significant association with diabetes mellitus (DM; p = 0.016) and Crohn’s disease (p = 0.006) was noted in the Uro+ group.

Conclusion.

Although there is no acceleration of syndesmophyte formation or spinal mobility restriction, more functional disability was detected in the urolithiasis group. The higher risk with concomitant DM or Crohn’s disease should alert clinicians to these comorbidities in Uro+ patients with AS.

The relation between bone mineral density, bone turnover markers, and vitamin D status in ankylosing spondylitis patients with active disease: a cross-sectional analysis

SUMMARY

Osteoporosis is a well recognized complication of ankylosing spondylitis (AS). This study indicates that increased bone turnover, inflammation, and low vitamin D levels are important in the pathophysiology of AS-related osteoporosis, and that bone turnover markers (BTM) are valuable markers to detect bone loss in AS.

INTRODUCTION

The aim of this study was to elucidate the pathophysiology of AS-related osteoporosis by investigating the relation between bone mineral density (BMD), BTM, vitamin D, and clinical assessments of disease activity and physical function, as well as to identify parameters that are related to low BMD (osteopenia or osteoporosis) in AS patients with active disease.

METHODS

One hundred twenty-eight consecutive Dutch AS outpatients were included in this cross-sectional study. Bath AS Disease Activity Index (BASDAI), erythrocyte sedimentation rate (ESR), C-reactive protein, ASAS-endorsed disease activity score (ASDAS), Bath AS Functional Index (BASFI), bone formation markers procollagen type 1 N-terminal peptide (PINP) and osteocalcin (OC), bone resorption marker serum C-telopeptides of type I collagen (sCTX), 25-hydroxyvitamin D (25OHvitD), lumbar spine and hip BMD, and vertebral fractures were assessed. Z-scores of BTM were calculated using matched 10-year cohorts of a Dutch reference group to correct for the normal influence that age and gender have on bone turnover.

RESULTS

sCTX Z-score, OC Z-score, BASDAI, age, and gender were independently related to low BMD. In addition, PINP Z-score, ESR, 25OHvitD, age, and gender were independently related to sCTX and/or OC Z-score.

CONCLUSIONS

This study indicates that increased bone turnover, inflammation, and low vitamin D levels are important in the pathophysiology of AS-related osteoporosis. Furthermore, sCTX and OC Z-scores seem to be valuable markers to detect bone loss in AS patients in daily clinical practice where BMD of the lumbar spine, measured by DXA, may be overestimated due to osteoproliferation in patients with advanced AS.

Prevalence of vertebral fractures by semiautomated morphometry in patients with ankylosing spondylitis

OBJECTIVE

Ankylosing spondylitis (AS) is a chronic inflammatory disease mainly affecting the axial skeleton and characterized by ossification of the spinal disc, joints, and ligaments leading to progressive ankylosis. Vertebral osteoporosis is a recognized feature of AS. Studies have confirmed a moderate to high prevalence of vertebral fractures with extremely varying ranges in patients with AS. Our objective was to estimate the prevalence of vertebral fractures in a representative Spanish population of patients with AS using a validated semiquantitative method, MorphoXpress(®).

METHODS

Patients were randomly selected from the 10 initial participating centers of the Spanish National Registry of Spondyloarthropathies (REGISPONSER) by consecutive sampling. All patients fulfilled the New York modified criteria for AS and had a baseline thoracolumbar radiograph. A prevalent vertebral fracture was defined according to the Genant classification criteria.

RESULTS

The estimated prevalence of vertebral fractures was 32.4% (95% CI 25.5%-39.3%). The majority of fractures were localized in the thoracic segment (n = 100; 82.%) and were mild (n = 79; 64.8%). In logistic regression analysis, age (odds ratio per year 1.05, 95% CI 1.03-1.08, p < 0.001), disease duration (OR per year 1.03, 95% CI 1.01-1.06, p = 0.011), Bath Ankylosing Spondylitis Functional Index score (OR per score 1.16, 95% CI 1.03-1.30, p = 0.015), Bath Ankylosing Spondylitis Radiographic Index-TS (OR per score 1.25, 95% CI 1.12-1.39, p < 0.001), and wall-occiput distance (OR per cm 1.15, 95% CI 1.08-1.23, p < 0.001) were all associated with prevalent fracture.

CONCLUSION

Semiquantitative methods are needed to improve the diagnosis of vertebral fractures in AS in order to start early treatment and to avoid complications arising from osteoporosis.

Osteoporosis in ankylosing spondylitis

Osteoporosis (OP) is a frequent complication of ankylosing spondylitis (AS), even in early stages of the disease, and is associated with elevated levels of biochemical markers of bone turnover, proinflammatory cytokines, and acute-phase reactants. This suggests that systemic inflammatory mediators, such as interleukin-6 and tumor necrosis factor-alpha, may be involved. Various factors that conceivably work in conjunction with one another also cause bone loss in AS (eg, genetic polymorphisms of vitamin D, low levels of osteoprotegerin and sex steroid hormones, and impaired calcium and vitamin D absorption). Dual x-ray absorptiometry for assessing bone mineral density (BMD) has limitations in patients with AS because of unreliability of spinal measurements, particularly in advanced disease with new bone formation. Femoral neck BMD is reduced and correlates with increased risk of vertebral fractures. Hence, measurement of BMD at the femoral neck may provide the most accurate means of detecting osteopenia and OP and could assess fracture risk in AS patients. No guidelines are available for detection and treatment of OP in AS, and most patients are young men, who are less likely to be screened. The only evidence-based recommendation is that optimal control of disease activity in AS prevents bone loss. A recent study showed a beneficial effect of infliximab therapy on bone turnover markers and BMD in AS. Also, bisphosphonates may be useful in managing OP in AS.

Relationship Between Bone Mineral Density and Disease Activity in Patients with Ankylosing Spondylitis

Objective: This retrospective study was planned to determine the relationship between bone mineral density (BMD) and clinical, radiological and laboratory parameters in patients with ankylosing spondylitis (AS).

Materials and Methods: The study group consisted of 28 patients with a mean disease duration of 11.9±6.1 years. In addition to clinical and demographic variables, lumbar and femoral BMD were evaluated with dual energy X-ray absorbtiometry. Lumbar spine score (LSS) and sacroiliac score (SIS) were calculated by grading of standard radiographs. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level were determined as laboratory parameters.

Results: The rate of osteoporosis and osteopenia were 7.1% and 25% at the lumbar spine, and 14.2% and 17.8% at the femoral neck, respectively. LSS was significantly correlated with lumbar BMD (r=0.70, p<0.001), but not with femoral neck BMD (r=-0.11, p=0.55). SIS was negatively correlated with femoral neck BMD (r=-0.79, p<0.001), but not correlated with lumbar BMD (r=0.19, p=0.32). While lumbar BMD was positively correlated with disease duration (r=0.37, p=0.05), femoral neck BMD showed negative correlation with disease duration (r=-0.46, p=0.01). The evaluation of clinical paramaters and BMD showed that morning stiffness, spinal pain, ESR and CRP were not correlated with BMD. Only modified Schober's test was related to BMD on both lumbar spine and femoral neck.

Conclusion: Ankylosing spondylitis patients are at risk for developing osteoporosis. In advanced disease, the lumbar BMD is misleadingly high because of paravertebral calcification and ossification. Therefore, it is more rational to evaluate the BMD at the femoral neck. (Turk J Rheumatol 2010; 25: 24-8)

The relation between osteoporosis and vitamin D levels and disease activity in ankylosing spondylitis

In this study, the relation between osteoporosis and vitamin D and the disease activity in patients with ankylosing spondylitis (AS) was investigated. A hundred patients with AS and 58 healthy individuals were included in the study. In addition to the routine blood and urine tests, serum 25-(OH)D3, parathormone (PTH), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), total calcium, ionized calcium, and phosphorous levels of all participants were also measured. Bone mineral density (BMD) measurements were performed at the anterior-posterior and lateral lumbar and femur regions. Anterior-posterior and lateral thoracic and lumbosacral radiography was performed on all participants. The disease activity was evaluated by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), functional status by Bath Ankylosing Spondylitis Functional Index (BASFI), and mobility by Bath Ankylosing Spondylitis Metrology Index (BASMI). In the patient group, BMD values obtained from the lateral lumbar and femur regions and serum vitamin D levels were lower than the control group. A negative relation was determined between the lateral lumbar BMD values and ESR, CRP, and BASDAI scores of patients with AS. The ESR, CRP levels, and BASMI scores of the AS patients with osteoporosis were significantly higher, when compared to patients without osteoporosis. The negative correlation between serum 25-(OH)D3 level and ESR, CRP levels did not reach a statistically significant level in patients with AS; the positive correlation between PTH levels and ESR, and the negative correlation between CRP and BASDAI also did not reach a statistically significant level. Vitamin D deficiency in AS may indirectly lead to osteoporosis by causing an increase in the inflammatory activity. The present authors believe that it would be beneficial to monitorize vitamin D levels together with BMD measurements in order to determine the patients under osteoporosis risk.

Prevalence and risk factors of osteoporosis and vertebral fractures in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is characterized by inflammation of the entheses and paravertebral structures, leading in time to bone formation at those sites. As well, vertebral bone loss is also a recognized feature of AS Objective: To calculate the prevalence and risk factors of osteoporosis and vertebral fractures in patients with AS.

METHODS

Eighty patients with AS were enrolled in the study. Clinical, biological and radiological status was assessed by the Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), ESR and C-reactive protein (CRP), Bath AS Radiology Index (BASRI) and modified stoke AS spine score (mSASSS). BMD of the hip and spine was measured and vertebral fractures were defined using a combination of Genant semiquantitative (SQ) approach and morphometry by VFA (fracture vertebral assessment).

RESULTS

The years+/-11.8. The mean BMI was 22.8 kg/m(2)+/-4.1 and the mean disease duration was 10.8 years+/-6.6. Prevalence of osteoporosis was 25%. 18.8% of patients had a vertebral fracture (grades 2 and 3). Factors associated with osteoporosis were low weight and BMI and longer disease duration, higher ESR, CRP, BASFI and BASDAI. Vertebral fractures were associated with advanced age, longer disease duration, higher BASFI, BASRI and mSASSS and reduced BMD and T-score at the hip site, presence of osteoporosis at any site. Multiple logistic regression analysis (Table 4) revealed that parameters significantly associated with osteoporosis were BASDAI (OR=1.05, 95% confidence interval [CI]: 1.03-1.09); disease duration (OR=1.13, 95%CI: 1.03-1.25); and BMI (OR=0.82, 95%CI: 0.69-0.93). The presence of VFs (grades 2 and 3) were independently associated with disease duration (OR=1.50, 95%CI: 1.07-2.10); and mSASSS (OR=1.17, 95%CI: 1.05-1.30).

CONCLUSION

Osteoporosis is common in patients with AS and seems to be related to disease activity while vertebral fractures appear to be related to the duration and structural severity of the disease rather than BMD.