Trabecular bone score as an assessment tool to identify the risk of osteoporosis in axial spondyloarthritis: a case-control study

Objectives

To compare the trabecular bone score (TBS) between patients with axial spondyloarthritis (axSpA) and matched normal controls and identify risk factors associated with a low TBS.

Methods

TBS and BMD were assessed in the two groups (axSpA and control) using DXA. Osteoporosis risk factors and inflammatory markers were also assessed. Disease activity and radiographic progression in the sacroiliac joint and spine were evaluated in the axSpA group. Multivariate linear regression analysis was performed to identify risk factors associated with TBS.

Results

In the axSpA group, 248 subjects were enrolled; an equal number of age- and sex-matched subjects comprised the control group. The mean TBS was 1.43 (0.08) and 1.38 (0.12) in the control and axSpA groups, respectively (P < 0.001); BMD at the lumbar spine did not differ between the two groups. The TBS was negatively correlated with ESR and CRP levels in the axSpA group only (P < 0.001 and P = 0.007, respectively). Syndesmophytes in the axSpA group was associated with lower TBS (P < 0.001) but higher lumbar BMD (P = 0.021) vs controls. In the multivariate analyses, ESR, CRP and spinal radiographic progression were significantly associated with TBS.

Conclusion

TBS assessments revealed poor bone quality in patients with axSpA compared with the matched controls. In axSpA, systemic inflammatory markers were negatively correlated with TBS and spinal radiographic progression and inflammatory markers were independently correlated with low TBS. TBS may, therefore, be a useful clinical tool to identify the risk of osteoporosis in patients with axSpA.

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

Objective.

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

Methods.

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

Results.

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

Conclusion.

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

Low Skeletal Muscle Mass is Associated with the Risk of Low Bone Mineral Density in Urban Dwelling Premenopausal Women

To evaluate the relationship between skeletal muscle mass and bone mineral density (BMD) and to determine the association between low skeletal muscle mass and low BMD in urban dwelling young adults. This study was based on data from the 2008-2011 Korea National Health and Nutrition Examination Surveys. The subjects were 1702 20-49-year-old men and 2192 premenopausal women (age 20-55 years). BMD at the lumbar spine, femoral neck, and total hip and the appendicular skeletal muscle mass (ASM) were measured by dual-energy X-ray absorptiometry. Skeletal muscle mass index (SMI) was defined as weight-adjusted ASM. Mildly and severely low muscle skeletal mass were defined as SMI that was 1-2 and >2 standard deviations below the sex-specific mean ASM of young adults, respectively. Low BMD was defined as T score of less than -1.0 at the lumbar spine, femoral neck, and/or total hip. After adjusting for confounders, skeletal muscle mass was positively associated with BMD at the lumbar spine, femoral neck, and total hip in both men and women. Mildly and severely low skeletal muscle mass increased the risk of low BMD in premenopausal women [OR (95% CI) = 1.4 (1.1-1.9) and 2.4 (1.2-4.6), respectively] but not men. In women, low skeletal muscle mass independently was associated with the risk of low BMD at the femoral neck and total hip but not the lumbar spine. Skeletal muscle mass was independently associated with BMD in urban dwelling young men and women, but low skeletal muscle mass was associated with the risk of low BMD in premenopausal women only.

Positive correlation between inflammation on sacroiliac joint MRI and serum C-terminal telopeptide of type-I collagen in ankylosing spondylitis but not in non-radiographic axial spondyloarthritis

OBJECTIVES

To identify the clinical disease activity scores and laboratory markers that best reflect magnetic resonance imaging (MRI)-determined sacroiliac joint (SIJ) inflammation in ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA).

METHODS

This cross-sectional study included all consecutive patients who presented with axial spondyloarthritis in 2013-2015. All underwent SIJ MRI. The bone marrow oedema in the inflammatory lesions on MRI was scored using the SPondyloArthritis Research Consortium of Canada (SPARCC) method. Bone-specific alkaline phosphatase (BALP), serum C-terminal telopeptide of type-I collagen (sCTX-I), and inflammatory markers were measured. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) were assessed. The correlations between the MRI-determined SIJ inflammation scores and disease activity scores and laboratory variables were evaluated.

RESULTS

Of the 81 patients with axSpA, 45 had AS and 36 had nr-axSpA. The AS and nr-axSpA groups did not differ in terms of disease activity scores, physical functional index, or MRI-determined SIJ inflammation. Erythrocyte sedimentation rate, C-reactive protein, and ASDAS correlated with MRI inflammatory scores in nr-axSpA but not in AS. sCTX-I correlated with MRI-determined SIJ inflammatory scores in AS only. BASDAI and BALP levels did not associate with MRI inflammatory scores in either group. Multivariate analysis showed that sCTX-I associated independently with MRI inflammatory score in AS (β=17.047, p=0.038).

CONCLUSIONS

Inflammatory markers and ASDAS correlated with active sacroiliitis on MRI in nr-axSpA only. In AS, only sCTX-I correlated with active inflammation on SIJ MRI. sCTX-I may be useful as a marker of objective inflammation in AS.

Gender-Specific Associations between Low Skeletal Muscle Mass and Albuminuria in the Middle-Aged and Elderly Population

Objective This study assessed gender-specific associations between low muscle mass (LMM) and albuminuria. Methods Data from the Korea National Health and Nutrition Examination Survey 2011 were employed. The study consisted of 1,087 subjects (≥50 years old). Skeletal muscle index (SMI) was defined as the weight-adjusted appendicular skeletal muscle mass. Mild LMM and severe LMM were defined as SMI that were 1-2 and >2 standard deviations below the sex-specific mean appendicular skeletal muscle mass of young adults, respectively. Increased albuminuria was defined as albumin-to-creatinine ratio ≥30mg/g Results Men with mild and severe LMM were significantly more likely to have increased albuminuria (15.2% and 45.45%, respectively) than men with normal SMI (9.86%, P<0.0001), but not women. Severe LMM associated independently with increased albuminuria in men (OR=7.661, 95% CI=2.72-21.579) but not women. Severe LMM was an independent predictor of increased albuminuria in hypertensive males (OR=11.449, 95% CI=3.037-43.156), non-diabetic males (OR=8.782, 95% CI=3.046-25.322), and males without metabolic syndrome (MetS) (OR=8.183, 95% CI=1.539-43.156). This was not observed in males without hypertension, males with diabetes or MetS, and all female subgroups. Conclusion Severe LMM associated with increased albuminuria in men, especially those with hypertension and without diabetes or MetS.

Severe bone marrow edema on sacroiliac joint MRI increases the risk of low BMD in patients with axial spondyloarthritis

To determine the association between inflammatory and structural lesions on sacroiliac joint (SIJ) MRI and BMD and to identify risk factors for low BMD in patients with axial spondyloarthritis (axSpA). Seventy-six patients who fulfilled the ASAS axSpA criteria were enrolled. All underwent SIJ MRI and BMD measurement at the lumbar spine, femoral neck, and total hip. Inflammatory and structural lesions on SIJ MRI were scored. Laboratory tests and assessment of radiographic and disease activity were performed at the time of MRI. The association between SIJ MRI findings and BMD was evaluated. Among the 76 patients, 14 (18%) had low BMD. Patients with low BMD showed significantly higher bone marrow edema (BME) and deep BME scores on MRI than those with normal BMD (p < 0.047 and 0.007, respectively). Inflammatory lesions on SIJ MRI correlated with BMD at the femoral neck and total hip. Multivariate analysis identified the presence of deep BME on SIJ MRI, increased CRP, and sacroiliitis on X-ray as risk factors for low BMD (OR = 5.6, 14.6, and 2.5, respectively). The presence of deep BME on SIJ MRI, increased CRP levels, and severity of sacroiliitis on X-ray were independent risk factors for low BMD.

Downregulation of Tryptophan-related Metabolomic Profile in Rheumatoid Arthritis Synovial Fluid

OBJECTIVE

Synovial fluid (SF) is one of the most important materials that reflect the pathophysiological process of arthritis. A metabolomic and lipidomic study of SF was performed with the aim of identifying tentative diagnostic markers or therapeutic candidates for rheumatoid arthritis (RA).

METHODS

SF was aspirated from 10 patients with RA and 10 patients with osteoarthritis (OA). RA SF and OA SF were collected and analyzed by ultraperformance liquid chromatography quadruple time-of-flight mass spectrometry. Associations among clinical variables, laboratory results, and metabolic profiles were investigated.

RESULTS

The metabolic pathways for carnitine, tryptophan, phenylalanine, arachidonic acid, and glycophospholipid were significantly upregulated in OA SF. The metabolic pathways for taurine, cholesterol ester, and the β-oxidation of pristine acid, linolenic acid, and sphingolipid were activated more in RA SF than in OA SF. In particular, the tryptophan pathway, which comprises kynurenine, indoleacetic acid, indole acetaldehyde, and N'-formylkynurenine, was downregulated. Interestingly, the levels of tryptophan metabolites kynurenine and N'-formylkynurenine, which are involved in immune tolerance, were significantly lower in RA SF compared with OA SF (p < 0.05), but the opposite pattern was observed for erythrocyte sedimentation rate (p < 0.01) and the levels of C-reactive protein (CRP; p < 0.01), rheumatoid factor (p < 0.01), and anticyclic citrullinated peptide antibody (p < 0.05). Kynurenine concentration correlated inversely with CRP concentration in RA SF but not in OA SF (r -0.65, p < 0.05).

CONCLUSION

Advances in metabolomic techniques enabled us to delineate distinctive metabolic and lipidomic profiles in RA SF and OA SF. RA SF and OA SF showed distinct metabolic profiles.

Fat Metaplasia on Sacroiliac Joint Magnetic Resonance Imaging at Baseline Is Associated with Spinal Radiographic Progression in Patients with Axial Spondyloarthritis

Objective

To study the relationship between inflammatory and structural lesions in the sacroiliac joints (SIJs) on MRI and spinal progression observed on conventional radiographs in patients with axial spondyloarthritis (axSpA).

Methods

One hundred and ten patients who fulfilled the ASAS axSpA criteria were enrolled. All underwent SIJ MRI at baseline and lumbar spine radiographs at baseline and after 2 years. Inflammatory and structural lesions on SIJ MRI were scored using the SPondyloArthritis Research Consortium of Canada (SPARCC) method. Spinal radiographs were scored using the Stoke AS Spinal Score (SASSS). Multivariate logistic regression analysis was performed to identify predictors of spinal progression.

Results

Among the 110 patients, 25 (23%) showed significant radiographic progression (change of SASSS≥2) over 2 years. There was no change in the SASSS over 2 years according to the type of inflammatory lesion. Patients with fat metaplasia or ankyloses on baseline MRI showed a significantly higher SASSS at 2 years than those without (p<0.001). According to univariate logistic regression analysis, age at diagnosis, HLA-B27 positivity, the presence of fat metaplasia, erosion, and ankyloses on SIJ MRI, increased baseline CRP levels, and the presence of syndesmophytes at baseline were associated with spinal progression over 2 years. Multivariate analysis identified syndesmophytes and severe fat metaplasia on baseline SIJ MRI as predictive of spinal radiographic progression (OR, 14.74 and 5.66, respectively).

Conclusion

Inflammatory lesions in the SIJs on baseline MRI were not associated with spinal radiographic progression. However, fat metaplasia at baseline was significantly associated with spinal progression after 2 years.

Radiographic Structural Damage Is Worse in the Dominant than the Non-Dominant Hand in Individuals with Early Rheumatoid Arthritis

Objective

The relationship between mechanical stress and radiographic progression in rheumatoid arthritis (RA) is unclear. The assumption is that mechanical stress is greater in the dominant hand. Therefore, the aim of the present study was to compare the presence and progression of erosions and joint space narrowing (JSN) in the dominant and non-dominant hand.

Methods

Data from 194 patients recently diagnosed with seropositive RA, and with hand radiographs taken at the time of diagnosis and at 2-year follow-up, were analyzed retrospectively. Radiographs were scored using the van der Heijde-modified Sharp Score (HSS) method. Each joint group within each hand was rated separately by two independent examiners in a double-blinded manner.

Results

One hundred and ninety-four patients were enrolled (80% female, 88% positive rheumatoid factor, 92% positive anti-citrullinated protein antibody, and 95.4% right-handed). The baseline, follow-up erosion and JSN HSS were significantly higher in the dominant hand than in the non-dominant hand. The annual rate of radiographic progression was also higher in the dominant hand. The erosive progression in the wrist joints varied significantly according to handedness, but the erosion in the proximal interphalangeal joints and metacarpophalangeal joints was similar in both hands. The radiographic progression was associated with the dominant hand, an abnormal baseline C-reactive protein level, and joint damage at baseline. There was no significant difference in bone mineral density between the right and left hands.

Conclusion

Radiological damage was worse and progressed faster in the dominant hand, suggesting that mechanical stress is associated with radiographic joint damage in early and active RA.

Survival and prognostic factors in patients with connective tissue disease-associated pulmonary hypertension diagnosed by echocardiography: results from a Korean nationwide registry

OBJECTIVES

Pulmonary arterial hypertension (PAH) is a major cause of mortality in connective tissue disease (CTD). The survival rates and mortality-predictive factors of a nationwide registry of Korean patients with CTD-PH measured by echocardiography were determined.

METHODS

Patients with CTD-PH were enrolled between April 2008 and December 2012. Hemodynamic parameters and clinical data (WHO-functional class [FC], organ involvement, laboratory tests and treatment agents) were recorded. Survival rates were calculated by using the Kaplan-Meier method. Mortality-associated factors were examined by Cox proportional hazards regression analysis.

RESULTS

In total, 174 incident PH cases (61 with systemic lupus erythematosus, 50 with systemic sclerosis, 10 with mixed CTD, 22 with rheumatoid arthritis (RA) and 31 with other CTDs) were diagnosed by Doppler echocardiography. Of these, 25 (14%) died during the 3.8 ± 2.7 year follow-up period after PH diagnosis. The 1- and 3-year survival rates were 90.7% and 87.3%, respectively. Compared to the other CTD-PHs, RA-PH had the lowest survival rates (56% 3 year survival; P = 0.022). Multiple regression analysis revealed that low diffusion capacity of carbon monoxide (DLCO), pleural effusion and diabetes mellitus were poor prognostic factors (P = 0.008, 0.04 and 0.009, respectively). Anti-UI-RNP (ribonucleoprotein) antibody positivity was protective (P = 0.022). In patients with WHO-FC III/IV, patients who received vasodilators had lower mortality than those who did not (P = 0.038).

CONCLUSIONS

In Korean patients with CTD-PH, the 3-year survival rate was 87%. Low diffusion capacity of carbon monoxide (DLCO), pleural effusion and diabetes mellitus were independent poor prognostic factors. Anti-UI-RNP antibody was protective. Prompt PAH-specific vasodilator therapy may improve the survival of patients with severe CTD-PH.

Low levels of serum uric Acid increase the risk of low bone mineral density in young male patients with ankylosing spondylitis

OBJECTIVE

Uric acid (UA) has antiosteoporotic effects in postmenopausal women. This study investigated the association between serum UA levels and bone mineral density (BMD) in young male patients with ankylosing spondylitis (AS).

METHODS

One hundred fifty patients who fulfilled the modified New York criteria for the classification of AS were analyzed. All patients were male and under 50 years of age. BMD, serum UA concentrations, clinical variables, and radiographic progression were assessed. The associations between UA and BMD at the lumbar spine and hip were evaluated using multiple linear regression analysis. Multivariate logistic regression analyses were performed to identify risk factors associated with low BMD.

RESULTS

Mean serum UA concentration in the 150 patients with AS was 5.5 ± 1.3 mg/dl. BMD at the lumbar spine, but not at the total hip and femoral neck, increased with increasing serum UA tertiles (p = 0.033). The significant positive association between serum UA and BMD at the lumbar spine remained after adjustment for confounding factors (β = 0.185, p = 0.014, adjusted R(2) = 0.310). Multiple logistic regression analyses showed that lower UA concentrations (OR 4.02, 95% CI 1.34-12.3) and body mass index and increased erythrocyte sedimentation rate were independently associated with the risk of low BMD.

CONCLUSION

Lower serum UA levels are associated with lower BMD in young male patients with AS. UA may be a novel predictive marker or therapeutic target in patients with AS.

Pulmonary hypertension in systemic lupus erythematosus: an independent predictor of patient survival

BACKGROUND/AIMS

We investigated whether transthoracic echocardiography-suspected pulmonary hypertension (PH) affects survival in systemic lupus erythematosus (SLE) patients and examined factors associated with PH occurrence and survival.

METHODS

This retrospective single-center study included 154 Korean SLE patients fulfilling the American College of Rheumatology criteria (January 1995 to June 2013). Student t test, Mann-Whitney U test, Kaplan-Meier curves, and log-rank tests were used for comparisons.

RESULTS

A total of 35 SLE patients with PH (SLE/PH+) and 119 without PH (SLE/PH-) were analyzed. Higher percentages of interstitial lung disease, Raynaud's phenomenon (RP), World Health Organization functional classification III/IV, and cardiomegaly were found in SLE/PH+ compared to SLE/PH-. Furthermore, the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index was significantly higher in SLE/PH+ (2.46 ± 1.245 vs. 1.00 ± 1.235), whereas survival rates were significantly higher in SLE/PH- in log-rank tests (p = 0.001). In multivariate analysis, the adjusted mortality hazard ratio (HR) for SLE/PH+ patients was 3.10. Subgroup analysis demonstrated a higher percentage of lupus nephritis in the SLE/PH+ patients who died (p = 0.039) and low complement-3 levels (p = 0.007). In univariate analysis, the mortality HR for SLE/PH+ patients with lupus nephritis was 4.62, whereas the presence of RP decreased the mortality risk in multivariate analysis; adjusted HR, 0.10.

CONCLUSIONS

PH is an independent factor predicting survival in SLE patients. The presence of lupus nephritis resulted in an increased trend for mortality, whereas coexistence of RP was associated with a better survival prognosis in SLE/PH+ patients.

Incidence and predictors of morphometric vertebral fractures in patients with ankylosing spondylitis

Introduction

Ankylosing spondylitis (AS) is associated with an increased incidence of vertebral fractures (VFs); however the actual incidence and predictors of morphometric VFs are unknown. The present study examined the incidence and predictors of new VFs in a large AS cohort.

Methods

In total, 298 AS patients who fulfilled the modified New York criteria were enrolled and spinal radiographs were evaluated biennially. Clinical and laboratory data and radiographic progression were assessed according to the Bath AS Disease Activity Index, erythrocyte sedimentation rate, C-reactive protein (CRP), and the Stoke AS spine score (SASSS). VF was defined according to the Genant criteria. The incidence of VFs at 2 and 4 years was evaluated using the Kaplan-Meier method. The age-specific standardized prevalence ratio (SPR) for AS patients in comparison with the general population was calculated.

Results

Of 298 patients, 31 (10.8%) had previous VFs at baseline. A total of 30 new VFs occurred in 26 patients over 4 years. The incidence of morphometric VFs was 4.7% at 2 years and 13.6% at 4 years. Multivariate logistic regression analysis showed that previous VFs at baseline and increased CRP levels at 2 years were predictors of new VFs (odds ratio (OR) =12.8, 95% confidence interval (CI) = 3.6-45.3 and OR = 5.4, 95% CI = 1.4–15.9). The age-specific specific standardized prevalence ratio of morphometric VFs in AS was 3.3 (95% CI 2.1–4.5).

Conclusions

The incidence of morphometric VFs increased in AS. Previous VFs and increased CRP levels predicted future VFs. Further studies are needed to identify the effects of treatment interventions on the prevention of new VFs.

Prevalence of systemic lupus erythematosus in South Korea: an administrative database study

Background

Systemic lupus erythematosus (SLE) is a rare autoimmune disease for which a population-based survey on the prevalence of the disease in South Korea has not yet been conducted. Our goal was to estimate the nationwide prevalence of SLE.

Methods

The International Classification of Diseases, Tenth Revision (ICD-10) code for SLE diagnosis—M32—was tentatively given when patients were suspected to have SLE before 2009. As such, the positive predictive value (PPV) of the M32 code shown in medical bills reflecting true SLE was uncertain. We attempted to estimate the prevalence of SLE in South Korea using national administrative database data from 2004–2006. We approximated the actual number of SLE patients by analyzing a list of SLE-coded patients provided by the National Health Insurance (NHI) and Health Insurance Review and Assessment Service. Prevalence was estimated by multiplying the PPV of the M32 diagnostic code by the number of patients receiving the code. The PPV was determined by three methods: direct investigation of the medical records of patients randomly selected from the SLE-coded patients list; assessment of all SLE patients treated at 56 selected hospitals in South Korea; and extrapolation from sub-groups at a single institute to the sub-groups of the national NHI data.

Results

The estimated number of national SLE cases was between 9000 and 11 000, depending on the method of ascertainment, corresponding to a prevalence of 18.8–21.7 per 100 000 people.

Conclusions

This is the first report of a nationwide prevalence survey of SLE in South Korea. National databases may serve as a resource for epidemiologic studies of rare autoimmune diseases like SLE.

Overflow proteinuria as a manifestation of unrecognized polymyositis

Polymyositis is a rare and gradually progressive autoimmune disease of skeletal muscle. Two main types of renal involvement have been described: acute tubular necrosis related to rhabdomyolysis and glomerulonephritis. However, cases of overflow proteinuria related to polymyositis have rarely been reported. Herein, we report a case of a 41-year-old male who presented with edema of both lower extremities. Laboratory studies revealed elevated creatine phosphokinase level, hypoalbuminemia, and a moderate amount of proteinuria, although albuminuria was not dominant. Urine electrophoresis showed an abnormally restricted zone in the β-fraction, which suggested overflow proteinuria of non-glomerular origin. Despite intravenous hydration, his serum creatine phosphokinase level did not decrease and his symptoms did not improve. Electromyography showed myopathy, and muscle biopsy revealed findings consistent with polymyositis. After corticosteroid therapy, his creatine phosphokinase level and proteinuria decreased and his clinical symptoms improved. This case demonstrates an atypical presentation of polymyositis manifested by overflow proteinuria.