Femoral bone mineral density is associated with vertebral fractures in patients with ankylosing spondylitis: a cross-sectional study

OBJECTIVE: To determine the association between vertebral fractures and clinical, laboratory, and radiological variables in patients with ankylosing spondylitis (AS). METHODS: Sixty-eight men with AS and 91 sex- and age-matched controls were consecutively enrolled. Vertebral fractures were assessed according to a visual semiquantitative grading system using plain radiographs of the lumbar spine obtained from patients with AS. Disease activity variables including C-reactive protein, erythrocyte sedimentation rate, finger-to-ground distance score, Schober's Index score, Bath Ankylosing Spondylitis Radiology Index for the spine (BASRI-s) score, and syndesmophyte score were identified. Assessments of bone mineral density (BMD) of the lumbar spine and the femur in patients and controls were performed using an anteroposterior dual energy x-ray absorptiometry technique. RESULTS: Eleven patients (16.2%) out of the total of 68 patients with AS had vertebral fractures; these were identified as wedge deformities (n = 5) or biconcave (n = 6) deformities. BMD levels of the lumbar spine and femur in patients were significantly reduced compared with those of age-matched controls. There were significant differences in the Schober's Index scores, finger-to-ground distance scores, BASRI scores of the lumbar spine, syndesmophyte scores, and intertrochanter values of BMD among AS patients both with and without vertebral fractures. Multiple logistic regression analyses revealed that intertrochanteric BMD values also were independently associated with vertebral fractures in AS (p = 0.041). CONCLUSION: We demonstrated evidence of a correlation between low femoral BMD levels and risk of vertebral fractures in patients with AS, especially at the intertrochanteric area. Longitudinal studies in a large population are required to determine the diagnostic implications of femur BMD for increased risk of vertebral fractures in AS.     

The prevalence of vertebral fractures in mild ankylosing spondylitis and their relationship to bone mineral density

OBJECTIVE: To determine bone mineral density (BMD) in patients with mild ankylosing spondylitis (AS), to establish the prevalence of vertebral fractures and fracture risk in these patients, and to determine the relationship between BMD and vertebral fractures. METHODS: Sixty-six men with mild AS were studied. BMD of the lumbar spine and femoral neck was measured by dual X-ray absorptiometry (DXA) and radiographs of the thoracic and lumbar spine were obtained in all subjects. From the radiographs, vertebral fractures were characterized by a morphometric technique using established criteria. Thirty-nine healthy male subjects aged 50-60 yr, recruited from primary care registers, had spinal radiographs performed and served as controls for vertebral fractures. RESULTS: In patients with AS, BMD was reduced in both the lumbar spine 0.97 (0.1) g/cm(2) [T score -1.10 (1.3), 95% confidence interval (CI) -0.50, +0.14] and femoral neck 0.82 (0.1) g/cm(2) [T score -1.40 (1.2), 95% CI -0.51, +0.09]. There was no correlation between BMD of either the lumbar spine or femoral neck and duration of disease in patients with AS. Eleven of 66 (16.7%) patients with AS had a vertebral fracture, compared with one of 39 (2.6%) controls; odds ratio 5.92 (95% CI 1.4, 23.8). AS patients with fractures were not significantly older (mean age 41.4 vs 37.8 yr, P=0.17), but had significantly longer disease duration (12.4 vs 9.3 yr, P<0.05) than patients without fractures. No significant difference was found in the visual analogue scores for pain in AS patients with fractures compared with those without. No significant correlation was observed between BMD of the lumbar spine or femoral neck and vertebral fractures in patients with AS. In addition, there was no significant difference in the lumbar spine or femoral neck BMD in AS patients with fractures compared with those without. CONCLUSIONS: Spinal and hip osteopenia and vertebral fractures are a feature of mild AS. However, there was no correlation between BMD and vertebral fractures in these patients. AS patients with mild disease had a higher risk of fractures compared with the normal population and this increased with the duration of disease.     

定量CT测量强直性脊柱炎患者髋臼骨密度

目的探讨定量CT（QCT）测量成年男性强直性脊柱炎（AS）患者髋臼骨密度（BMD）的价值,研究此类患者髋臼骨量变化。方法选取25例经临床确诊的成年男性AS患者为志愿者,年龄20-44岁,平均（28.6±7.1）岁。分别行双侧髋关节（50个）双能X线吸收仪（DXA）和QCT检查。按照全髋部DXA测定结果,将Z值≤-2.0S的27个髋关节设为试验组,Z值〉-2.0S的23个髋关节设为对照组,比较2组髋臼坐骨体、耻骨体和髂骨体BMD的差异。结果试验组耻骨体、坐骨体BMD值分别为（71.965±35.695）、（87.093±38.413）mg/cm^3,显著低于对照组的（110.526±62.466）、（121.883±39.380）mg/cm^3,差异有统计学意义（P〈0.05）,试验组髂骨体BMD（156.822±41.472）mg/cm^3与对照组（177.948±55.804）mg/cm^3差异无统计学意义（P〉0.05）;AS患者髋臼髂骨体BMD均显著高于坐骨体和耻骨体BMD（均P〈0.05）;AS患者坐骨体和耻骨体BMD差异无统计学意义（P〉0.05）。结论QCT可敏感地反映髋臼不同部位BMD变化。AS患者髋臼的坐骨体、耻骨体较髂骨体更易出现骨密度减低。     

Whole body and regional bone mineral density in ankylosing spondylitis

OBJECTIVE: To study the regional distribution of bone mass and look for factors leading to bone loss in ankylosing spondylitis (AS). METHODS: Thirty-nine patients, all men, aged 20 to 55 years and presenting with AS were studied. Four hundred sixteen gendarmes, all men aged 20 to 55 years, formed an age matched control population used to define standard values for bone mineral density (BMD) in men. The patients with AS and the controls underwent measurement of whole body BMD and regional BMD by dual-energy x-ray absorptiometry. RESULTS: AS was associated with spinal bone loss, with lumbar spine BMD (LSBMD) 1.085 +/- 0.178 g/cm2 in the AS group compared with 1.232 +/- 0.136 g/cm2 in the control group (p < 0.01). Whole body BMD and regional BMD of head, whole spine, pelvis, and legs were reduced, although this was not statistically significant. Using standard values for LSBMD from the controls, we found that 46% (18/39) of patients with AS had Z score < -1.5 SD. Biological markers of disease activity were higher in the subgroup of patients with low LSBMD than in the subgroup with normal LSBMD, with an erythrocyte sedimentation rate of 29.4 +/- 23.4 mm/h versus 12.1 +/- 10.8 mm/h (p < 0.05) and C-reactive protein at 24.8 +/- 18 mg/l versus 12.7 +/- 14.2 mg/l (p < 0.05). CONCLUSION: AS is associated with bone loss, mainly concerning the lumbar spine, in patients whose disease is biologically most active.     

Bone mineral density in ankylosing spondylitis

Summary Vertebral osteoporosis is a well-recognized feature of ankylosing spondylitis (AS) and also the vertebral compression fractures due to osteoporosis are a common but frequently unrecognized complication of AS. Both may contribute to the pathogenesis of spinal deformity and back pain. The aim of this study was to measure vertebral and femoral neck bone mass in patients with AS by dual photon absorptiometry, to determine the prevalence of compression fractures and to examine the relationship between bone density and disease severity. We found that the bone mass was diminished in the lumbar spine in moderate AS versus mild forms but the patients with advanced disease had the highest BMD values. Examination of spinal radiographs revealed compression and biconcave fractures in 9 (40.9%) cases. Neither the duration of the disease and the degree of sacroiliitis, nor the disease activity assessed by laboratory and clinical parameters was found to significantly affect the results.     

Biochemical markers of bone metabolism in mild ankylosing spondylitis and their relationship with bone mineral density and vertebral fractures.

OBJECTIVE: To determine the relationship of biochemical markers of bone metabolism in patients with mild ankylosing spondylitis (AS) with disease activity, bone mineral density (BMD), and vertebral fractures. METHODS: A total of 56 male patients with mild AS were studied. All patients had BMD measured by dual x-ray absorptiometry of the lumbar spine and hip and radiographs of the thoracic and lumbar spines. Radiographs of patients with AS were evaluated morphometrically and vertebral fractures were defined using established criteria. Serum osteocalcin, total and bone alkaline phosphatase (ALP, BALP, respectively), 25-hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), urinary deoxypyridinoline (Dpyr), and pyridinoline (Pyr) were measured in the patients with AS and compared with 52 age and sex matched controls. Thirty-nine healthy male subjects aged 50-60 years, recruited from primary care registers, had spinal radiographs and served as controls for vertebral fractures. RESULTS: Patients with AS had reduced BMD of the lumbar spine, 0.98 (0.1) g/cm2 [T score = -1.14 (1.2) and Z score = -1.01 (1.2)], and femoral neck, 0.83 (0.1) g/cm2 [T score = -1.44 (1.2) and Z score = -0.73 (1.1)]. Of the 56 patients with AS, 11 (19.6%) had a vertebral fracture, whereas only one of 39 control subjects did (2.6%). Patients with AS had significantly lower mean serum osteocalcin compared with controls [9.03 (2.7) microg/l vs 11.05 (2.33) microg/l; p < 0.001], and significantly higher mean serum ALP [73.09 (19.5) U/l vs 53.02 (16.7) U/l; p < 0.001] and BALP [38.54 (9.9) U/l vs 30.35 (8.28) U/l; p < 0.001]. There was no significant difference in the excretion of Dpyr and Pyr between patients with AS and controls [4.90 (3.9) nmol/mmol vs 4.00 (3.6) nmol/mmol, and 15.66 (10.8) nmol/mmol vs 12.24 (10.3) nmol/mmol, respectively]. There were no significant differences in the mean 25-OHD and PTH levels in patients with AS compared to controls [20.03 (1.6) micromol/l vs 18.9 (2.9) micromol/l and 3.31 (1.5) pmol/l vs 2.63 (0.4) pmol/l, respectively]. The biochemical markers of bone formation and resorption correlated well with inflammatory indices of disease activity (acute phase reactants), but not with BMD of the lumbar spine or femoral neck. No significant difference was seen in any marker of bone turnover when AS patients with vertebral fractures were compared with those without. CONCLUSION: Bone turnover in patients with mild AS is characterized by low serum osteocalcin and ALP in the presence of normal calciotropic hormones. Biochemical markers of bone metabolism do not correlate with BMD or vertebral fractures. The disparity between osteocalcin and alkaline phosphatase in patients with AS needs further evaluation.     

Bone mineral density and vertebral compression fracture rates in ankylosing spondylitis.

OBJECTIVE--To examine the relationship between disease severity and bone density as well as vertebral fracture risk in patients with ankylosing spondylitis (AS). METHODS--Measurements were taken for bone mineral density (BMD) and vertebral fracture rates in 87 patients with AS. BMD was measured at the hip (femoral neck -FN), lumbar spine (L1-L4-LS) and for the whole body using a hologic-QDR-1000/W absorptiometer. An algorithm based on normal female ranges of vertebral heights was used to define a fracture as occurring when two vertebral ratios were each three standard deviations below the calculated mean of the controls. RESULTS--Patients with AS had significantly lower FN-BMD in proportion to disease severity (based on a Schober index) and disease duration. LS-BMD was also reduced in early disease, but in patients with advanced AS it had increased considerably. Nine vertebral fractures (10.3%) were identified which was considerably higher than expected when compared with a fracture of 1.9% in a control population of 1035 females of a similar age range. Patients with AS with fractures were significantly older, more likely to be male, had longer disease duration and more advanced spinal limitation with less mobility. There was no significant reduction in lumbar spine or femoral neck bone density in the fracture group. CONCLUSIONS--Vertebral fractures that result from osteoporosis are a feature of longstanding AS. BMD used as a measure of osteoporosis of the spine in advanced AS is unreliable probably as a result of syndesmophyte formation and does not predict the risk of vertebral fracture. Alternative sites such as the neck of the femur should be used for sequential assessment of BMD in AS.     

强直性脊柱炎合并骨质疏松症患者临床特点、骨密度及骨代谢相关指标的研究

目的探索强直性脊柱炎(AS)患者合并骨质疏松症的发病机制及AS患者骨密度和骨代谢变化的相关因素。方法收集189例AS患者临床症状、体征、实验室检查、影像学检查结果,与健康对照组进行对照并进行相关性分析。结果 189例AS患者腰椎、股骨颈、Word’s三角、粗隆的骨密度均与骶髂关节相分级、急时相反应物红细胞沉降率(ESR)、C反应蛋白(CRP)呈负相关,P值分别<0.01、<0.05和<0.05。AS患者血清骨钙素(BGP)与枕墙距、骨特异性碱性磷酸酶(BALP)、Ⅰ型胶原羧基端前肽(CICP)、甲状旁腺激素(PTH)呈正相关,P值分别<0.05、<0.05、<0.01和<0.05。与ESR、Ⅰ型胶原羧基端交联肽(CTX)、尿脱氧吡啶啉(尿DPD)呈负相关,P值分别<0.01、<0.01和<0.05。PTH与年龄、尿DPD呈负相关,P值均<0.01。男性患者BALP较女性更低,P<0.01,其与枕墙距、CICP呈正相关,P值分别<0.05和<0.01,与CTX呈负相关,P<0.01。CICP与骶髂关节相分级、CTX、尿DPD呈负相关,P值分别<0.05、<0.01和<0.05;与BGP呈正相关,P<0.01。CTX与年龄呈负相关,P<0.01;与骶髂关节相分级呈正相关,P<0.01。HLA-B27阳性者CICP值低于阴性者,CTX值则高于阳性者,P值分别<0.05和<0.01。结论 AS患者BGP与BALP、PTH、CICP、CTX、尿DPD之间相互交织成网状对骨代谢造成影响,其启始的触发点为全身或局部的免疫反应,而HLA-B27通过抑制骨胶原蛋白的合成及促进其分解加速了骨破坏,其机理尚待进一步深入研究。     

Bone mineral density in women with ankylosing spondylitis

OBJECTIVE: To determine bone mineral density (BMD) in premenopausal women with early ankylosing spondylitis (AS). METHODS: Eighteen premenopausal women with AS without syndesmophytes, interapophysiary arthritis, and/or coxofemoral joint destruction were studied. BMD was analyzed at lumbar spine and femoral neck by dual energy x-ray absorptiometry (Hologic QDR 1000). Z scores and T scores related to the general Spanish population were recorded. Comparisons were performed using the Student t test. Pearson's correlation coefficients were used to study the correlation between BMD and the variables. Following the WHO classification, osteopenia was diagnosed in patients with T score between -1 and -2.5 and osteoporosis in those with T score < -2.5 at lumbar spine or femoral neck. RESULTS: The mean Z score for spine BMD was -0.19+/-0.7, and -0.03+/-0.85 for femoral neck BMD. There were no significant differences of Z score values compared to the general population. No significant correlation was found between BMD and disease duration, radiology sacroiliac score, and spine mobility. Densitometry showed osteopenia in 2 patients and osteoporosis in none. CONCLUSION: We found a slight reduction in BMD in premenopausal women with early AS, but the difference was not statistically significant. We discuss the factors related to its pathogenesis.     

Testosterone and testosterone free index in mild ankylosing spondylitis: relationship with bone mineral density and vertebral fractures.

OBJECTIVE: To determine the androgen status of men with mild ankylosing spondylitis (AS) and to evaluate the relationship of sex hormones with bone mineral density (BMD) and vertebral fractures. METHODS: Fifty-six male patients with mild AS were studied. All patients had BMD measured by dual x-ray absorptiometry (DXA) of the lumbar spine and hip, and had radiographs of the thoracic and lumbar spines. Radiographs were evaluated morphometrically, and vertebral fractures were defined using established criteria. Serum total testosterone, sex hormone binding globulin (SHBG), follicle stimulating hormone (FSH), and luteininzing hormone (LH) were measured in the patients with AS and 52 age matched controls. Testosterone free index (TFI) was calculated. RESULTS: There was a small, not significant reduction in serum total testosterone in patients with AS compared to controls [16.02 (5.0) vs 21.0 (6.2) nmol/l]. Serum SHBG was significantly lower in patients with AS [27.29 (10.6) vs 35.0 (13.0) nmol/l; p < 0.001] compared to controls. There was no significant difference in the mean TFI between patients and controls [58.7 (21.2) vs 60 (22.2) nmol/l; p > 0.05] or in the levels of LH and FSH. No significant correlation was found between sex hormones, BMD, and vertebral fractures in patients with AS. CONCLUSION: Sex hormones are not altered significantly in patients with mild AS and do not appear to be related to BMD or vertebral fractures. Osteopenia in men with mild AS is therefore unlikely to be secondary to hypogonadism.     

Bone loss is detected more frequently in patients with ankylosing spondylitis with syndesmophytes

OBJECTIVE: To define the relationship between bone growth (syndesmophytes) and bone loss (osteoporosis) in ankylosing spondylitis (AS). METHODS: Bone mineral density (BMD) at the spine, hip, and radius was measured by dual-energy x-ray absorptiometry (DEXA), dual-energy quantitative computed tomography (DEQCT), and peripheral quantitative computed tomography (pQCT) in 103 patients with AS. Radiographs of the lumbar spine were used to detect syndesmophytes. Patients were divided in 3 groups according to disease duration. RESULTS: Osteopenia at the hip and spine was found by DEXA in 56% and 41%, respectively, of the patients with disease duration < 5 years (n = 27), with an additional 11% and 15% having osteoporosis. In patients with a longer disease duration, > 10 years (n = 28), 29% were osteoporotic at the hip and only 4% at the lumbar spine. In contrast, using spinal DEQCT, 59% of patients with early disease were found to be osteopenic; 36% of patients with long-standing disease were osteopenic and 18% were osteoporotic. More than half the patients (55%) had syndesmophytes (n = 55). With spinal DEQCT there were more patients with syndesmophytes (63%) in the group with reduced bone density than in the group without (45%). This was similar with DEXA measurements at the hip, where 31% compared to 14% had osteoporosis, respectively. Osteocalcin was elevated in 34% of patients, but was not associated with disease activity or BMD. CONCLUSION: The majority of patients with AS had reduced bone density. The method of bone density measurement is critical and should be different depending on disease duration. The finding that more patients with syndesmophytes had reduced bone density than those without suggests that bone growth and bone loss occur in parallel, and the role of inflammation in this process warrants further investigation.     

Bone mineral density in young males with ankylosing spondylitis

Objective: To assess bone mineral density (BMD) abnormalities in young Indian males with ankylosing spondylitis (AS) and factors influencing this. Methods: Eighty AS male subjects were compared with 160 age/sex matched controls for BMD of lumbar spine and proximal femur. AS subjects were evaluated and followed up every 3 months for disease activity. BMD was estimated at spine and proximal femur using the dual‐energy X‐ray absorptiometry (DXA) technique. Results: All subjects were males with mean age of 32.9 ± 8.3 years and mean duration of disease was 8.1 ± 5.8 years. AS subjects had significantly lower BMD at the spine and femur as compared with controls (both P < 0.001). Using WHO standards, osteoporosis (OP) in spine and femur neck was seen in 28.75% (controls: 1.84%, P < 0.001) and 11.54% (controls: 1.23%, P < 0.001), respectively. No statistically significant difference in prevalence of OP was seen with disease duration, C‐reactive protein levels and disease activity indices (all P > 0.05). Syndesmophytes were seen in 22.5% (n = 18) of AS subjects. There was no significant difference between BMD values at spine in AS subjects with or without syndesmophytes (0.91 + 0.16 g/cm²vs. 0.90 + 0.14 g/cm², P = 0.79). Conclusion: OP is a significant complication in AS even in young males with early disease, and more prevalent in the spine compared to femur. In our study, BMD was not influenced by disease activity indices, inflammatory markers or total disease duration. Spinal BMD is the most sensitive site for defining OP in AS.     

Predisposition of six well-characterized microRNAs to syndesmophytes among Chinese patients with ankylosing spondylitis

Objectives: We quantified the expression of six well-characterized microRNAs (miRNAs) in peripheral blood mononuclear cells to see whether they can predispose to syndesmophytes in ankylosing spondylitis (AS) patients.

Methods: This is a cross-sectional study involving 46 AS patients (23/23 with/without syndesmophytes) and 22 healthy controls. miRNAs expression was quantified by real-time PCR.

Results: Six examined miRNAs were comparably expressed between AS patients without syndesmophytes and healthy controls (p?>?.05). Relative to AS patients without syndesmophytes, patients with syndesmophytes had significantly higher levels of miR-29a, miR-335-5p, miR-27a and let-7i (p?=?.001, .002, .013 and .029, respectively). Nine significant contributors associated with syndesmophytes in AS, including smoking, AS duration, human leukocyte antigen B27, erythrocyte sedimentation rate, C-reactive protein, miR-335-5p, miR-27a, miR-218 and sacroiliitis, were identified. The addition of miR-335-5p, miR-27a and miR-218 can significantly improve the accuracy of baseline risk factors. Based on the nine significant contributors, a nomogram was constructed, with good prediction accuracy (C-index: 0.86, p?Conclusion: We provide evidence for the predisposition of miR-335-5p, miR-27a and miR-218 to syndesmophytes in AS patients, indicating a contributory role of miRNAs in the pathogenesis of syndesmophytes. Further validation is warranted.     

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.     

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.     

Progression of radiographic damage in patients with ankylosing spondylitis: defining the central role of syndesmophytes

BACKGROUND: Structural changes such as erosions, syndesmophytes and ankylosis are characteristic of ankylosing spondylitis (AS). These can be quantified by the modified Stokes Anklylosing Spondylitis Spinal Score (mSASSS). It is unknown which radiographic feature is most relevant for the assessment of change and the prediction of future damage in AS. OBJECTIVES: To analyse radiographic progression in AS by using different assessments to define the most important changes. METHODS: Spinal radiographs of 116 patients with AS were scored by the mSASSS at baseline (BL) and after 2 years. Radiographic progression was assessed by differentiating (1) any change; (2) progression to syndesmophytes/ankylosis (definite change); and (3) changes exceeding the smallest detectable change (SDC) as predefined. A growth angle of 45 degrees was used to differentiate syndesmophytes from spondylophytes. RESULTS: Some radiographic progression after 2 years was detected in 42% of patients, novel syndesmophytes in 31% of patients, and, using the SDC (calculated at 2 mSASSS units) as cut-off, progression was seen in 28% of patients. Thus, in 74% of the patients changes were because of syndesmophytes and/or ankylosis. Using the predefined cut-off, only 12% of all syndesmophytes were spondylophytes. Patients with such changes were of older age. Definite radiographic progression was found in 44% of the patients with syndesmophytes/ankylosis at BL (n = 57) versus 19% (p = 0.03) of the patients without such changes (n = 59). CONCLUSIONS: Syndesmophytes and ankylosis are the most relevant structural changes in AS, and also in the mSASSS. Development of just one syndesmophyte within 2 years indicates progression of structural changes in AS; this is relevant for clinical practice. Syndesmophytes are the best predictors of radiographic progression.     

Bone mineral density, calcaneal ultrasound, and bone turnover markers in women with ankylosing spondylitis

OBJECTIVE: To assess bone mineral density (BMD) by dual energy x-ray absorptiometry (DEXA) and calcaneal quantitative ultrasound (QUS) in a cohort of pre- and postmenopausal women with ankylosing spondylitis (AS), and to determine any relationships with markers of bone turnover and disease activity or severity. METHODS: Fifty premenopausal and 16 postmenopausal women with AS were studied. Clinical and radiological status was assessed by the Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), Bath AS Metrology Index (BASMI), and Bath AS Radiology Index (BASRI). BMD of the hip and spine was measured by DEXA, and QUS measured at the heel. Serum osteocalcin (OC), bone-specific alkaline phosphatase (BALP), urinary D-pyridinoline crosslinks (D-PYR), and C-reactive protein (CRP) were assayed. RESULTS: Women with AS (n = 66) had reduced BMD at the hip compared to age and sex matched controls (n = 132). The mean t scores were -1.1 and -2.0, and z scores -0.4 and -0.37, for pre- and postmenopausal women, respectively. Four (6%) had osteoporosis and 34 (52%) had osteopenia according to the WHO definitions. Using a multiple regression model, femoral neck BMD was found to be significantly affected by age, body mass index, and the sacroiliac radiographic score. There were no significant correlations of BMD with disease duration or disease activity. QUS measures did not correlate with DEXA measures of BMD. Women with AS had significantly lower markers of bone formation, OC and BALP, and a trend to higher D-PYR than controls. Serum OC levels correlated negatively with femoral neck BMD, whereas D-PYR correlated with CRP levels. CONCLUSION: Women with AS have reduced hip BMD, 0.39 SD below age and sex matched controls. Bone turnover in women with AS is characterized by low OC and BALP.