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1.  Confirmatory Factor Analysis of the Pittsburgh Sleep Quality Index in Rheumatoid Arthritis Patients 
Behavioral sleep medicine  2013;12(1):1-12.
The purpose of this research was to evaluate the factor structure of the Pittsburgh Sleep Quality Index (PSQI) in rheumatoid arthritis (RA). The sample included 107 patients with RA, 88 females and seven males, with an average age of 56.09 years, recruited from the greater Southern California area. Confirmatory factor analysis evaluated single, two- and three-factor models. The single factor solution yielded a poor fit to the data. While the three-factor solution had the best fit, the two-factor solution, comprised of sleep efficiency and perceived sleep quality factors, was optimal because it had very good fit, and acceptable reliability for its individual factors. Clinical indices were consistently correlated with the sleep quality factor, but not with the sleep efficiency factor.
doi:10.1080/15402002.2012.720315
PMCID: PMC4285368  PMID: 23390921
sleep quality; rheumatoid arthritis; confirmatory factor analysis; PSQI
2.  Relationship between air pollution and positivity of RA-related autoantibodies in individuals without established RA: a report on SERA 
Annals of the rheumatic diseases  2013;72(12):10.1136/annrheumdis-2012-202949.
Introduction
Studies suggest that respiratory exposures including smoking, proximity to traffic and air pollution might be associated with development of rheumatoid arthritis (RA). RA-related autoantibodies are predictive of the development of RA.
Objective
We evaluated the relationship between RA-related autoantibodies and exposure to particulate matter (PM), a measure of air pollution of interest to health, in individuals without RA.
Methods
The Studies of the Etiology of Rheumatoid Arthritis (SERA) is a multicentre study following first-degree relatives (FDRs) of a proband with RA. FDRs are without the 1987 ACR (American College of Rheumatology) classifiable RA at enrolment and are followed for the development of RA-related autoimmunity. RA-related autoantibody outcomes as well as tender and swollen joint outcomes were assessed. Exposure to PM was assigned using ambient air pollution monitoring data and interpolated with inverse distance weighting spatial analyses using Geographic Information Systems. PM exposures were linked to FDR’s residential zip codes.
Results
RA-related autoantibodies as well as tender or swollen joints are not associated with ambient PM concentrations.
Discussion
While other respiratory exposures may be associated with increased risk of RA, our data suggest that ambient PM is not associated with autoantibodies and joint signs among individuals without RA, but at increased risk of developing RA.
doi:10.1136/annrheumdis-2012-202949
PMCID: PMC3818364  PMID: 23572338
3.  Prevalence of Axial Spondylarthritis in the United States: Estimates From a Cross-Sectional Survey 
Arthritis care & research  2012;64(6):905-910.
Objective
The US national prevalence of spondylarthritis (SpA) was estimated for 2 published sets of classification criteria: the Amor criteria and the European Spondylarthropathy Study Group (ESSG) criteria. These 2 SpA criteria sets have been the most widely utilized in previous population-based studies of SpA.
Methods
The US SpA prevalence estimates were based on a representative sample of 5,013 US adults ages 20 – 69 years who were examined in the US National Health and Nutrition Examination Survey (NHANES) 2009–2010.
Results
The overall age-adjusted prevalence of definite and probable SpA by the Amor criteria was 0.9% (95% confidence interval [95% CI] 0.7–1.1%), corresponding to an estimated 1.7 million persons (95% CI 1.4–2.1 million persons). The age-adjusted prevalence of SpA by the ESSG criteria was 1.4% (95% CI 1.0–1.9%), corresponding to an estimated 2.7 million persons (95% CI 1.9–3.7 million persons). There were no statistically significant sex differences in SpA prevalence. The SpA prevalence among non-Hispanic white persons was 1.0% (95% CI 0.7–1.5%) by the Amor criteria and 1.5% (95% CI 1.0–2.3%) by the ESSG criteria. SpA prevalence could not be reliably estimated in other race/ethnicity subgroups due to sample size imitations.
Conclusion
The SpA prevalence estimates are in the range of SpA prevalence estimates reported elsewhere in population-based surveys and it is likely that SpA may affect up to 1% of US adults, a prevalence similar to that reported for rheumatoid arthritis. The current US SpA prevalence estimates may be lower than the true value because the NHANES 2009–2010 data collection did not capture a complete set of the elements specified in the 2 SpA criteria sets.
doi:10.1002/acr.21621
PMCID: PMC4032290  PMID: 22275150
4.  The prevalence of inflammatory back pain: population-based estimates from the US National Health and Nutrition Examination Survey, 2009–10 
Annals of the rheumatic diseases  2012;72(3):369-373.
Objective
To estimate the current US inflammatory back pain (IBP) prevalence using four published case definitions.
Methods
Analysis of an IBP data collection instrument specifically designed for the 2009–10 National Health and Nutrition Examination Survey. Subjects were 5103 US adults ages 20–69 with complete data. IBP prevalence as determined by Calin et al criteria, European Spondylarthropathy Study Group (ESSG) criteria, and Berlin criteria 8a and 7b.
Results
Age-adjusted US prevalence of IBP by Calin criteria was 5.0% (95% CI 4.2% to 5.8%). Prevalence of IBP was 5.6% (95% CI 4.7% to 6.5%) by ESSG criteria, and 5.8% (95% CI 5.2% to 6.4%) and 6.0% (95% CI 4.9% to 7.1%) by Berlin Criteria 8a and 7b, respectively. IBP prevalence did not differ significantly by age groups or between men and women. IBP prevalence was significantly lower among non-Hispanic black persons compared with non-Hispanic white persons for the Calin and ESSG IBP criteria. For the ESSG and Berlin 7b criteria, non-Hispanic white persons had significantly higher IBP prevalences compared with Mexican Americans.
Conclusions
IBP is associated with spondyloarthritis. Awareness of the prevalence of IBP may be useful for planning future epidemiological studies as well as development and validation of diagnostic and classification criteria for specific clinically defined diseases.
doi:10.1136/annrheumdis-2012-201403
PMCID: PMC3954785  PMID: 22791746
5.  Anti-Cyclic Citrullinated Peptide Assays Differ in Subjects at Elevated Risk for Rheumatoid Arthritis and Subjects with Established Disease 
Arthritis and rheumatism  2013;65(9):2243-2252.
Objective
To compare commonly-available tests for antibodies to citrullinated protein antigens (ACPAs) for diagnostic accuracy and assay agreement in established rheumatoid arthritis (RA) and subjects at elevated risk for RA.
Methods
ELISA testing for anti-cyclic citrullinated peptide (anti-CCP) antibodies was performed using CCP2 (Axis-Shield) and CCP3.1 (IgA/IgG INOVA) in the following subjects: 1) probands with established RA (N=340) from the Studies of the Etiology of RA (SERA), 2) first degree relatives (FDRs) without RA (family members of SERA RA probands; N=681), 3) Department of Defense Serum Repository (DoDSR) RA cases with pre-diagnosis samples (N=83; 47/83 also had post-diagnosis samples), and 4) blood-donor and DoDSR controls (N=283).
Results
In established RA, CCP2 was more specific (99.2% vs. 93.1%, p<0.01), but less sensitive (58.7% vs. 67.4%, p=0.01) than CCP3.1, with specificity of CCP3.1 increasing to 97.2% if levels ≥3 times the standard cut-off level were considered. In all subjects, at standard cut-off levels, CCP3.1 positivity was more prevalent. In DoDSR cases, CCP2 was more specific than CCP3.1 for a future diagnosis of RA, and higher CCP levels trended towards greater specificity for disease onset within 2 years. At standard cut-off levels, assay agreement was good in established RA (kappa=0.76), but poor in FDRs without inflammatory arthritis (kappa=0.25).
Conclusion
Anti-CCP assays differ to an extent that may be meaningful in diagnosing RA in patients with inflammatory arthritis, and in evaluating the natural history of RA development in subjects at-risk for future RA. Mechanisms underlying these differences in test performance need further investigation.
doi:10.1002/art.38017
PMCID: PMC3776020  PMID: 23686569
Rheumatoid arthritis; autoantibodies; CCP; ACPA; preclinical
6.  The Epidemiology of Back Pain, Axial Spondyloarthritis and HLA-B27 in the United States 
The concept of inflammatory back pain (IBP) evolved in the 1970s, coincident with the discovery of the HLA-B27 association with ankylosing spondylitis (AS), leading to the development of criteria to determine the presence of IBP. The concept of IBP and it relationship with AS and axial spondyloarthritis (AxSpA) has further evolved, and an instrument developed (the Spondylitis Association of America Back Pain Tool), which was further modified and field tested for use in the 2009-2010 National Health and Nutrition Examination Survey (NHANES). This has shown the frequency of chronic back pain to have risen to 19.4%, with nearly one-third having IBP. The prevalence of AxSpA has been defined at 1.0-1.4% and AS at 0.52-0.55%. The national prevalence of HLA-B27 in the U.S. is 6.1%, and intriguing data from NHANES 2009 suggest a decreasing frequency with increasing age. From this arise new questions and a work agenda ahead.
PMCID: PMC4122314  PMID: 23841117
Epidemiology; Spondyloarthritis; HLA-B27; Back Pain; Ankylosing Spondylitis
7.  Relatives Without Rheumatoid Arthritis Show Reactivity to Anti-Citrullinated Protein/Peptide Antibodies Which are Associated with Arthritis-Related Traits: Studies of the Etiology of Rheumatoid Arthritis 
Arthritis and rheumatism  2013;65(8):1995-2004.
Objective
Examine anti-citrullinated protein/peptide antibodies (ACPA) reactivity and determine associations between ACPA and other rheumatoid arthritis (RA)-related autoantibodies and clinically-assessed swollen or tender joints in first-degree relatives (FDRs) without 1987 and 2010 American College of Rheumatology classified RA.
Methods
A bead-based assay measured 16 separate ACPA in sera from 111 FDRs (Ab+) who were positive on at least one visit for any of 5 RA-related autoantibodies (RF, anti-CCP2, and RF isotypes), and 99 FDRs (Ab−) who were never autoantibody positive. Cut-offs for positivity for each ACPA were determined using receiver operating characteristic curves of data from 200 RA cases and 98 blood-bank controls, wherein positivity for ≥ 9 ACPA had 92% specificity and 62% sensitivity for RA. In FDRs, we assessed ACPA reactivity and examined associations between ACPA (number positive and positivity for ≥ 9 ACPA) and RA-related characteristics.
Results
Four of 7 anti-CCP2 positive and 8% of anti-CCP2 negative FDRs were positive for ≥ 9 ACPA. After adjusting for age, gender, ethnicity and pack-years of smoking, increasing number of ACPA was directly associated with having ≥ 1 tender joint on exam (OR=1.18, 95% CI 1.04–1.34), with the greatest risk seen in FDRs positive for ≥ 9 ACPA (OR=5.00, 95% CI 1.37–18.18).
Conclusions
RA-free FDRs demonstrate reactivity to multiple ACPA, even in those negative for rheumatoid factor and anti-CCP2, and increasing ACPA may be associated with signs of joint inflammation. Prospective evaluation of the relationship between these findings and progression of classifiable RA is warranted.
doi:10.1002/art.38022
PMCID: PMC3729718  PMID: 23754702
pre-clinical RA; autoantibodies; ACPA; rheumatoid arthritis
8.  A Panel of Biomarkers Is Associated With Increased Risk of the Presence and Progression of Atherosclerosis in Women With Systemic Lupus Erythematosus 
Objective
An increased frequency of atherosclerosis (ATH) in systemic lupus erythematosus (SLE) is well-documented but not fully explained by the presence of traditional cardiac risk factors. Several nontraditional biomarkers, including proinflammatory high-density lipoprotein (piHDL) and leptin, have been individually associated with subclinical ATH in SLE. The aim of this study was to examine whether these and other biomarkers can be combined into a risk profile, the Predictors of Risk for Elevated Flares, Damage Progression, and Increased Cardiovascular Disease in Patients with SLE (PREDICTS), that could be used to better predict future progression of ATH.
Methods
In total, 210 patients with SLE and 100 age-matched healthy control subjects (all women) participated in this prospective cohort study. The longitudinal presence of carotid plaque and intima-media thickness (IMT) were measured at baseline and followup (mean ± SD 29.6 ± 9.7 months).
Results
At followup, carotid plaque was present in 29% of SLE patients. Factors significantly associated with plaque, determined using Salford Predictive Modeling and multivariate analysis, included age ≥48 years (odds ratio [OR] 4.1, P = 0.002), high piHDL function (OR 9.1, P < 0.001), leptin levels ≥34 ng/dl (OR 7.3, P = 0.001), plasma soluble TWEAK levels ≥373 pg/ml (OR 28.8, P = 0.004), and history of diabetes (OR 61.8, P < 0.001). Homocysteine levels ≥12 μmoles/liter were also a predictor. However, no single variable demonstrated an ideal combination of good negative predictive values (NPVs), positive predictive values (PPVs), sensitivity, and specificity. A high-risk PREDICTS profile was defined as ≥3 positive biomarkers or ≥1 positive biomarker plus a history of diabetes; for high-risk SLE patients, the PPV was 64%, NPV was 94%, sensitivity was 89%, and specificity was 79%. In multivariate analysis, SLE patients with the high-risk profile had 28-fold increased odds for the longitudinal presence of plaque (P < 0.001) and increased progression of IMT (P < 0.001).
Conclusion
A high-risk PREDICTS score confers 28-fold increased odds of the presence of any current, progressive, or acquired carotid plaque, both in patients with SLE and in control subjects, and is significantly associated with higher rates of IMT progression.
doi:10.1002/art.38204
PMCID: PMC4106468  PMID: 24449580
9.  Sputum Autoantibodies in Patients With Established Rheumatoid Arthritis and Subjects at Risk of Future Clinically Apparent Disease 
Arthritis and rheumatism  2013;65(10):2545-2554.
Objective
To evaluate the generation of rheumatoid arthritis (RA)–related autoantibodies in the lung.
Methods
Simultaneous collection of serum and induced sputum was performed in 21 healthy controls, 49 at-risk subjects without inflammatory arthritis but at risk of RA due to family history or seropositivity for anti–citrullinated protein antibodies, and 14 subjects with early RA. Samples were tested for anti–cyclic citrullinated peptide 2 (anti-CCP2), anti-CCP3, anti-CCP3.1, rheumatoid factor isotypes IgM, IgG, and IgA, and total IgM, IgG, and IgA.
Results
One or more autoantibodies were present in sputum of 39% of at-risk seronegative subjects, 65% of at-risk seropositive subjects, and 86% of subjects with early RA. In at-risk seronegative subjects, the rate of anti-CCP3.1 positivity and the median number of autoantibodies were elevated in sputum versus serum. In subjects with early RA, the rate of positivity for several individual autoantibodies and the median number of autoantibodies were higher in serum than in sputum. Results in at-risk seropositive subjects were intermediate between these groups. In at-risk subjects with autoantibody positivity in sputum, the ratios of autoantibody to total Ig were higher in sputum than in serum, suggesting that these autoantibodies are generated or sequestered in the lung.
Conclusion
RA-related autoantibodies are detectable in sputum in subjects at risk of RA and in subjects with early RA. In a subset of at-risk subjects, the presence of sputum autoantibodies in the absence of seropositivity, and the increased autoantibody-to–total Ig ratios in sputum, suggest that the lung may be a site of autoantibody generation in the early development of RA. These findings suggest an important role of the lung in the pathogenesis of RA.
doi:10.1002/art.38066
PMCID: PMC4066465  PMID: 23817979
10.  Multiple cytokines and chemokines are associated with rheumatoid arthritis-related autoimmunity in first-degree relatives without rheumatoid arthritis: Studies of the Aetiology of Rheumatoid Arthritis (SERA) 
Annals of the rheumatic diseases  2012;72(6):901-907.
Objective
We investigated whether rheumatoid arthritis (RA)-related autoantibodies were associated with systemic inflammation in a prospective cohort of first-degree relatives (FDRs) of RA probands, a population without RA but at increased risk for its future development.
Methods
We studied 44 autoantibody positive FDRs, of whom 29 were rheumatoid factor (RF) positive, 25 were positive for the high risk autoantibody profile (HRP), that is, positive for anti-cyclic citrullinated peptide and/or for at least two RF IgM, IgG or IgA isotypes, and nine FDRs who were positive for both; and 62 FDRs who were never autoantibody positive. Twenty-five cytokines/chemokines were measured using a bead-based assay in serum. As a comprehensive measure of inflammation, we calculated a Cytokine Score by summing all cytokine/chemokine levels, weighted by their regression coefficients for RA-autoantibody association. We compared C-reactive protein, individual cytokines/chemokines and Cytokine Score to the outcomes: positivity for RF and for the HRP using logistic regression.
Results
Adjusting for age, sex, ethnicity and ever smoking, the Cytokine Score and levels of IL-6 and IL-9 were associated with both RF and HRP. IL-2, granulocyte macrophage-colony stimulating factor (GM-CSF), and interferon (IFN)-γ were associated with HRP only. Associations between the Cytokine Score and RF and HRP positivity were replicated in an independent military personnel cohort.
Conclusions
In first-degree relatives of patients with RA, RA-related autoimmunity is associated with inflammation, as evidenced by associations with multiple cytokines and chemokines.
doi:10.1136/annrheumdis-2012-201505
PMCID: PMC3726193  PMID: 22915618
11.  The Prevalence of HLA–B27 in the US: Data From the US National Health and Nutrition Examination Survey, 2009 
Arthritis and rheumatism  2012;64(5):1407-1411.
Objective
To carry out the first large-scale population study of the prevalence of HLA–B27 in the US, which is needed for public health planning purposes because of recent improvements in medical therapy and diagnostic testing for ankylosing spondylitis (AS).
Methods
The national prevalence of HLA–B27 was determined as part of the 2009 US National Health and Nutrition Examination Survey (NHANES), a cross-sectional survey monitoring the health and nutritional status of the US civilian, noninstitutionalized population. DNA polymerase chain reaction analysis was conducted in samples from 2,320 adults ages 20–69 years from this nationally representative sample.
Results
The age-adjusted US prevalence of B27 was 6.1% (95% confidence interval [95% CI] 4.6–8.2). By race/ethnicity, the prevalence of B27 was 7.5% (95% CI 5.3–10.4) among non-Hispanic whites and 3.5% (95% CI 2.5–4.8) among all other US races/ethnicities combined. In Mexican Americans, the prevalence was 4.6% (95% CI 3.4–6.1). The prevalence of B27 could not be reliably estimated for other US racial/ethnic groups because of the low number of B27-positive individuals in those groups. For adults 50–69 years of age, the prevalence of B27 was 3.6% (95% CI 2.2–5.8), which suggested a decrease in B27 with age. These prevalence estimates took into account the NHANES survey design and are reviewed with respect to data from the medical literature.
Conclusion
Our findings provide the first US national prevalence estimates for HLA–B27. A decline in the prevalence of HLA–B27 with age is suggested by these data but must be confirmed by additional studies.
doi:10.1002/art.33503
PMCID: PMC4038331  PMID: 22139851
12.  The Effect of Rilonacept versus Placebo on Health-Related Quality of Life in Patients with Poorly Controlled Familial Mediterranean Fever 
BioMed Research International  2014;2014:854842.
Objective. To examine the effect of rilonacept on the health-related quality of life (HRQoL) in patients with poorly controlled familial Mediterranean fever (FMF). Methods. As part of a randomized, double-blinded trial comparing rilonacept and placebo for the treatment of FMF, patients/parents completed the modified Child Health Questionnaire (CHQ) at baseline, and at the start and end of each of 4 treatment courses, 2 each with rilonacept and placebo. Results. Fourteen subjects were randomized; mean age was 24.4 ± 11.8 years. At baseline the physical HRQoL score was significantly less (24.2 ± 49.5) but the psychosocial score was similar to the population norm (49.5 ± 10.0). There were significant improvements in most HRQoL concepts after rilonacept but not placebo. Significant differences between rilonacept and placebo were found in the physical (33.7 ± 16.4 versus 23.7 ± 14.5, P = 0.021) but not psychosocial scores (51.4 ± 10.3 versus 49.8 ± 12.4, P = 0.42). The physical HRQoL was significantly impacted by the treatment effect and patient global assessment. Conclusion. Treatment with rilonacept had a beneficial effect on the physical HRQoL in patients with poorly controlled FMF and was also significantly related to the patient global assessment. This trial is registered with ClinicalTrials.gov Identifier NCT00582907.
doi:10.1155/2014/854842
PMCID: PMC4131422  PMID: 25147819
13.  The Impact of TNF-inhibitors on radiographic progression in Ankylosing Spondylitis 
Arthritis and rheumatism  2013;65(10):2645-2654.
Introduction
We studied the effect of Tumor Necrosis Factor-Alpha (TNF)-inhibitors on progressive spine damage in Ankylosing Spondylitis (AS) patients.
Methods
All AS patients (satisfying the modified New York criteria) prospectively followed and with at least two sets of spinal radiographs at a minimum gap of 1.5 years were included (n=334). Patients received clinical standard of care, which included non-steroidal anti-inflammatory drugs and TNF-inhibitors. Radiographic severity was assessed by the modified Stokes Ankylosing Spondylitis Spine Score (mSASSS). Patients with a rate of progression more than 1 mSASSS unit/year were considered progressors. Univariable and multivariable regression analyses were done. Propensity score matching (PSM) and sensitivity analysis were performed. A zero-inflated negative binomial (ZINB) model was used to analyze the effect of TNF-inhibitor on change in mSASSS with varying follow-up periods. Potential confounders like Bath AS Disease Activity Index (BASDAI), ESR, CRP, HLA-B27, gender, age of onset, smoking and baseline damage were included in the model.
Results
TNF-inhibitor treatment was associated with a 50% reduction in the odds of progression (OR: 0.52; CI: 0.30-0.88; p=0.02). Patients with a delay in starting therapy of more than 10 years were more likely to progress compared to those who started earlier (OR=2.4; 95% CI: 1.09-5.3; p=0.03). In the ZINB model TNF-inhibitor use significantly reduced progression when the gap between x-rays was more than 3.9 years. The protective effect of TNF-inhibitors was stronger after propensity score matching.
Conclusions
TNF-inhibitors appear to reduce radiographic progression in AS, especially with early initiation and longer duration of follow up.
doi:10.1002/art.38070
PMCID: PMC3974160  PMID: 23818109
14.  FUNCTIONAL LIMITATIONS DUE TO AXIAL AND PERIPHERAL JOINT IMPAIRMENTS IN PATIENTS WITH ANKYLOSING SPONDYLITIS: ARE FOCUSED MEASURES MORE INFORMATIVE? 
Arthritis care & research  2013;65(4):607-614.
Objective
Functional limitations in ankylosing spondylitis (AS) may be due to peripheral joint or axial involvement. To determine if the Bath AS Functional Index (BASFI), an axial-focused measure, can detect limitations related to peripheral joint involvement equally well as the Health Assessment Questionnaire modified for the Spondyloarthropathies (HAQ-S), a peripheral arthritis-focused measure, and vice versa, we compared associations of each questionnaire with spinal and hip range of motion, peripheral arthritis, and enthesitis in patients with AS.
Methods
We examined patients every 4 to 6 months in this prospective longitudinal study. We used mixed linear models to examine associations between ten physical examination measures and the BASFI and HAQ-S.
Results
We studied 411 patients for a median of 1.5 years (3 visits). In multivariate analyses, cervical rotation, chest expansion, lateral thoracolumbar flexion, hip motion, tender joint count, and tender enthesis count were equally strongly associated with the BASFI and HAQ-S. Peripheral joint swelling was more strongly associated with the HAQ-S. Individual items of the BASFI were more likely than items of the HAQ-S to be associated with unrelated physical exam measures (e.g. association between difficulty rising from a chair and cervical rotation), which may have diminished the axial/peripheral distinction for the BASFI.
Conclusions
The BASFI and HAQ-S had similar associations with impairments in axial measures, while the HAQ-S had stronger associations with the number of swollen peripheral joints. The HAQ-S should be considered for use in studies focused on spondyloarthritis with peripheral joint involvement.
doi:10.1002/acr.21878
PMCID: PMC3567248  PMID: 23097327
Ankylosing spondylitis; functional limitations; metrology
15.  REGIONAL RADIOGRAPHIC DAMAGE AND FUNCTIONAL LIMITATIONS IN PATIENTS WITH ANKYLOSING SPONDYLITIS: DIFFERENCES IN EARLY AND LATE DISEASE 
Arthritis care & research  2013;65(2):257-265.
Objective
Radiographic damage and functional limitations both increase with the duration of ankylosing spondylitis (AS). We examined whether radiographic damage contributed more to functional limitations in late AS than in early AS, and if the strength of association varied with the anatomic region of damage.
Methods
In this cross-sectional study of 801 patients with AS, we examined associations of the lumbar modified Stoke AS Spine Score (mSASSS), cervical mSASSS, lumbar posterior fusion, cervical posterior fusion, and hip arthritis with the Bath AS Functional Index (BASFI) and the Health Assessment Questionnaire (HAQ-S).
Results
Higher lumbar and cervical mSASSS were associated with more functional limitations, but there was an interaction between mSASSS and the duration of AS such that the strength of their association with functional limitations decreased with increasing duration of AS. Cervical posterior fusion was associated with worse functioning independent of mSASSS. Hip arthritis was significantly associated with functional limitations independent of measures of spinal damage. Among patients with AS ≥ 40 years, the number of comorbid conditions accounted for most of the variation in functioning. Results were similar for both the BASFI and HAQ-S.
Conclusions
Although both radiographic damage and functional limitations increase over time in AS, the relative contribution of radiographic damage to functional limitations is lower among patients with longstanding AS than early AS, suggesting patients may accommodate to limited flexibility. Damage in different skeletal regions impacts functioning over the duration of AS. Functional limitations due to comorbidity supervene in late AS.
doi:10.1002/acr.21821
PMCID: PMC3541454  PMID: 23042639
Ankylosing spondylitis; radiographic damage; functional limitations
16.  The contribution of disease activity on functional limitations over time through psychological mediators: a 12-month longitudinal study in patients with ankylosing spondylitis 
Rheumatology (Oxford, England)  2011;50(11):2087-2092.
Objectives. To explore whether helplessness, internality and depression would mediate the relationship between disease activity and functional limitations in patients with AS in a 12-month longitudinal study.
Methods. A total of 294 participants with AS meeting modified New York criteria completed clinical and psychological assessments at 6-month intervals. Psychological measures evaluated helplessness, depression and internality. Path analysis evaluated the direct and indirect effects of baseline disease activity on 12-month functional limitations via the psychological measures of helplessness, internality and depression at 6 months.
Results. Baseline disease activity demonstrated direct and indirect effects on 12-month functional limitations. Helplessness and depression, but not internality, served as mediators of the relationship between disease activity and functional limitations.
Conclusion. Higher baseline disease activity predicted greater functional limitations at 12 months through helplessness and depression. Our findings suggest that helplessness and depression may constitute future treatment targets in reducing functional limitations in patients with AS.
doi:10.1093/rheumatology/ker274
PMCID: PMC3198906  PMID: 21875876
Ankylosing spondylitis; Disease activity; Functional limitations; Depression; Internality; Helplessness
17.  Porphyromonas gingivalis and Disease-Related Autoantibodies in Individuals at Increased Risk of Rheumatoid Arthritis 
Arthritis and rheumatism  2012;64(11):10.1002/art.34595.
Purpose
To examine the relationship of Porphyromonas gingivalis (Pg) with the presence of autoantibodies in individuals at risk for rheumatoid arthritis (RA).
Methods
Participants included: 1) a cohort enriched with HLA-DR4 and 2) those at risk for RA by virtue of having a first-degree relative with RA. None satisfied 1987 ACR RA classification criteria. Autoantibodies measured included anti-citrullinated protein antibody (ACPA) and rheumatoid factor (RF; nephelometry, IgA, IgM, IgG). Individuals were considered autoantibody positive (n = 113) with ≥ 1 positive autoantibody with individuals further categorized as `high-risk' (n = 38; positive ACPA or ≥ 2 RF assays). Autoantibody negative individuals served as comparators (n = 171). Antibody to Pg, P. intermedia (Pi), and F. nucleatum (Fn) were measured. Associations of bacterial antibodies with group status were examined using logistic regression.
Results
Anti-Pg concentrations were higher in high-risk (p = 0.011) and autoantibody positive group (p = 0.010) than in the autoantibody negative group. There were no group differences in anti-Pi or anti-Fn concentrations. After multivariable adjustment, anti-Pg concentrations (but not anti-Pi or anti-Fn) were significantly associated with autoantibody positive and high-risk status (p < 0.05).
Conclusion
Immunity to Pg, but not Pi or Fn, is significantly associated with the presence of RA-related autoantibodies in individuals at risk for RA. These results support the hypothesis that infection with Pg may play a central role in the early loss of tolerance to self-antigens in RA pathogenesis.
doi:10.1002/art.34595
PMCID: PMC3467347  PMID: 22736291
rheumatoid arthritis; periodontitis; Porphyromonas gingivalis; Prevotella intermedia; Fusobacterium nucleatum; rheumatoid factor; anti-citrullinated protein antibody
18.  CERVICAL VERTEBRAL SQUARING IN PATIENTS WITHOUT SPONDYLOARTHRITIS 
The Journal of rheumatology  2012;39(9):1900.
doi:10.3899/jrheum.120322
PMCID: PMC3461321  PMID: 22942307
Spondyloarthritis; squaring; vertebrae
19.  A Multidimensional Model of Fatigue in Patients with Rheumatoid Arthritis 
The Journal of rheumatology  2012;39(9):1807-1813.
Objective
To evaluate a multidimensional model testing disease activity, mood disturbance, and poor sleep quality as determinants of fatigue in patients with rheumatoid arthritis (RA).
Method
The data of 106 participants were drawn from baseline of a randomized comparative efficacy trial of psychosocial interventions for RA. Sets of reliable and valid measures were used to represent model constructs. Structural equation modeling was used to test the direct effects of disease activity, mood disturbance, and poor sleep quality on fatigue, as well as the indirect effects of disease activity as mediated by mood disturbance and poor sleep quality.
Results
The final model fit the data well, and the specified predictors explained 62% of the variance in fatigue. Higher levels of disease activity, mood disturbance, and poor sleep quality had direct effects on fatigue. Further, disease activity was indirectly related to fatigue through its effects on mood disturbance, which, in turn, was related to poor sleep quality. Mood disturbance also indirectly influenced fatigue through poor sleep quality.
Conclusion
The findings from this study confirmed the importance of a multidimensional framework in evaluating the contribution of disease activity, mood disturbance, and sleep quality to fatigue in RA using a structural equation approach. Mood disturbance and poor sleep quality played major roles in explaining fatigue along with patient-reported disease activity.
doi:10.3899/jrheum.111068
PMCID: PMC3735362  PMID: 22660801
Rheumatoid arthritis; Fatigue; Mood; Sleep disorders; Psychological factors
20.  Derivation and Validation of Systemic Lupus International Collaborating Clinics Classification Criteria for Systemic Lupus Erythematosus 
Arthritis and rheumatism  2012;64(8):2677-2686.
Objective
The Systemic Lupus Collaborating Clinics (SLICC) revised and validated the American College of Rheumatology (ACR) SLE classification criteria in order to improve clinical relevance, meet stringent methodology requirements and incorporate new knowledge in SLE immunology.
Methods
The classification criteria were derived from a set of 702 expert-rated patient scenarios. Recursive partitioning was used to derive an initial rule that was simplified and refined based on SLICC physician consensus. SLICC validated the classification criteria in a new validation sample of 690 SLE patients and controls.
Results
Seventeen criteria were identified. The SLICC criteria for SLE classification requires: 1) Fulfillment of at least four criteria, with at least one clinical criterion AND one immunologic criterion OR 2) Lupus nephritis as the sole clinical criterion in the presence of ANA or anti-dsDNA antibodies. In the derivation set, the SLICC classification criteria resulted in fewer misclassifications than the current ACR classification criteria (49 versus 70, p=0.0082), had greater sensitivity (94% versus 86%, p<0.0001) and equal specificity (92% versus 93%, p=0.39). In the validation set, the SLICC Classification criteria resulted in fewer misclassifications (62 versus 74, p=0.24), had greater sensitivity (97% versus 83%, p<0.0001) but less specificity (84% versus 96%, p<0.0001).
Conclusions
The new SLICC classification criteria performed well on a large set of patient scenarios rated by experts. They require that at least one clinical criterion and one immunologic criterion be present for a classification of SLE. Biopsy confirmed nephritis compatible with lupus (in the presence of SLE autoantibodies) is sufficient for classification.
doi:10.1002/art.34473
PMCID: PMC3409311  PMID: 22553077
21.  Inflammatory Back Pain 
doi:10.1016/j.rdc.2012.09.002
PMCID: PMC3501982  PMID: 23083751
22.  Airways abnormalities and rheumatoid arthritis-related autoantibodies in subjects without arthritis: early injury or initiating site of autoimmunity? 
Arthritis and Rheumatism  2011;64(6):1756-1761.
Objective
To evaluate the presence of pulmonary abnormalities in subjects with rheumatoid arthritis (RA)-related autoantibody (Ab) positivity without inflammatory arthritis (IA).
Methods
42 subjects without IA but with elevations of anti-cyclic citrullinated peptide antibodies and/or 2 or more rheumatoid factor isotypes (a profile that is 96% specific for RA), 15 Ab(−) controls and 12 patients with early established seropositive RA (<1 year duration) underwent spirometry and high-resolution computed tomographic (HRCT) lung imaging.
Results
The median age of Ab(+) subjects was 54 years-old, 52% were female and 38% were smokers (not significantly different than Ab(−) controls). No Ab(+) subject had IA on joint examination. On HRCT, 76% of Ab(+) subjects had airways abnormalities including bronchial wall thickening, bronchiectasis, centrilobular opacities and air trapping, compared to 33% of Ab(−) controls (p=0.005). The Ab(+) subjects had similar prevalence and type of lung abnormalities compared to patients with early RA. Two Ab(+) subjects with airways disease developed IA classifiable as articular RA ~13 months after lung evaluation.
Conclusion
Airways abnormalities that are consistent with inflammation are common in Ab(+) subjects without IA, and similar to airways abnormalities seen in early RA. These findings suggest that the lung may be an early site of autoimmune-related injury, and potentially a site of generation of RA-related autoimmunity. Further studies are needed to define the mechanistic role of lung inflammation in the development of RA.
doi:10.1002/art.34344
PMCID: PMC3319006  PMID: 22183986
Rheumatoid arthritis; etiology; autoantibodies; preclinical; lung disease
23.  Sex chromosome Aneuploides among Men with Systemic Lupus Erythematosus 
Journal of Autoimmunity  2011;38(2-3):J129-J134.
About 90% of patients with systemic lupus erythematosus (SLE) are female. We hypothesize that the number of X chromosomes, not sex, is a determinate of risk of SLE. Number of X chromosomes was determined by single nucleotide typing and then confirmed by karyotype or fluorescent in situ hybridization in a large group of men with SLE. Presence of an sry gene was assessed by rtPCR. We calculated 96% confidence intervals using the Adjusted Wald method, and used Bayes’ theorem to estimate the prevalence of SLE among 47,XXY and 46,XX men. Among 316 men with SLE, 7 had 47,XXY and 1 had 46,XX. The rate of Klinefelter’s syndrome (47,XXY) was statistically different from that found in control men and from the known prevalence in the population. The 46,XX man had an sry gene, which encodes the testes determining factor, on an X chromosome as a result of an abnormal crossover during meiosis. In the case of 46,XX, 1 of 316 was statistically different from the known population prevalence of 1 in 20,000 live male births. A previously reported 46,XX man with SLE had a different molecular mechanism in which there were no common gene copy number abnormalities with our patient. Thus, men with SLE are enriched for conditions with additional X chromosomes. Especially since 46,XX men are generally normal males, except for infertility, these data suggest the number of X chromosomes, not phenotypic sex, is responsible for the sex bias of SLE.
doi:10.1016/j.jaut.2011.10.004
PMCID: PMC3309073  PMID: 22154021
Systemic lupus erythematosus; Klinefelter’s syndrome; male 46; XX; female bias; X chromosome
24.  Is there a higher genetic load of susceptibility loci in familial ankylosing spondylitis? 
Arthritis care & research  2012;64(5):780-784.
Objective
Several genetic risk variants for ankylosing spondylitis (AS) have been identified in genome wide association studies. Our objective was to examine whether familial AS cases have a higher genetic load of these susceptibility variants.
Methods
Overall, 502 AS patients were examined, consisting of 312 who had first-degree relatives (FDR) with AS (familial) and 190 who had no FDR with AS or spondyloarthritis (sporadic). All patients and affected FDRs fulfilled the modified New York Criteria for AS. The patients were recruited from two U.S. cohorts (NASC and PSOAS) and from the United Kingdom- Oxford cohort. The frequencies of AS susceptibility loci in IL23R, IL1R2, ANTRX2, ERAP1, two intergenic regions on chromosomes 2p15 and 21q22, and HLA-B27 status as determined by the tag SNP rs4349859 were compared between familial and sporadic cases. Association between SNPs and multiplex status was assessed by logistic regression controlling for sibship size.
Results
HLA-B27 was significantly more prevalent in familial than sporadic cases of AS (p=0.0001, OR: 4.44, CI: (2.06–9.55)). Furthermore, the AS risk allele at chromosome 21q22 intergenic region showed a trend towards higher frequency in the multiplex cases (p=0.08). The frequency of the other AS risk variants did not differ significantly between familial and sporadic cases, either individually or combined.
Conclusions
HLA-B27 is more prevalent in familial than sporadic cases of AS, demonstrating higher familial aggregation of AS in patients with HLA-B27 positivity. The frequency of the recently described non-MHC susceptibility loci is not markedly different between the sporadic and familial cases of AS.
doi:10.1002/acr.21601
PMCID: PMC3335985  PMID: 22231927
25.  Are there gender differences in severity of ankylosing spondylitis? Results from the PSOAS cohort 
Annals of the Rheumatic Diseases  2006;66(5):633-638.
Objective
To examine the clinical and radiographic features in men and women in the Prospective Study of Outcomes in Ankylosing Spondylitis cohort, a large well‐defined cross‐sectional study of patients with AS, in order to understand the influence of gender in determining the severity of ankylosing spondylitis.
Methods
Extensive clinical assessments and spine radiographs were performed in 302 men and 100 women with AS of ⩾20 years duration. Radiographs were scored using the Bath Ankylosing Spondylitis Radiographic Index Spine (BASRI‐spine) score (range 2–12). Functional impairment was measured by the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Health Assessment Questionnaire for the Spondyloarthropathies (HAQ‐S).
Results
Radiographic severity was worse among men. The unadjusted median BASRI‐spine score for men was 10, compared with 6.5 for women (p<0.001). Functional disability, as measured by the BASFI and HAQ‐S, was not different between men and women. However, after adjusting for radiographic spinal damage, women were found to report worse functioning than men at any given level of radiographic damage. Women had a slightly earlier age of disease onset; however, disease duration was identical in both groups. Women more frequently reported family histories of AS in first‐degree relatives and were more likely to be treated with intra‐articular steroids, sulphasalazine and prednisone.
Conclusions
Among patients with longstanding AS, men have more severe radiographic changes; findings of treatment differences suggest that women may have more peripheral arthritis. At any given level of radiographic damage, self‐reported functional limitations were worse for women.
doi:10.1136/ard.2006.060293
PMCID: PMC1954622  PMID: 17127685

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