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1.  The Canadian systemic sclerosis oral health study: orofacial manifestations and oral health-related quality of life in systemic sclerosis compared with the general population 
Rheumatology (Oxford, England)  2014;53(8):1386-1394.
Objective. The aim of this study was to compare oral abnormalities and oral health-related quality of life (HRQoL) of patients with SSc with the general population.
Methods. SSc patients and healthy controls were enrolled in a multisite cross-sectional study. A standardized oral examination was performed. Oral HRQoL was measured with the Oral Health Impact Profile (OHIP). Multivariate regression analyses were performed to identify associations between SSc, oral abnormalities and oral HRQoL.
Results. We assessed 163 SSc patients and 231 controls. SSc patients had more decayed teeth (SSc 0.88, controls 0.59, P = 0.0465) and periodontal disease [number of teeth with pocket depth (PD) >3 mm or clinical attachment level (CAL) ≥5.5 mm; SSc 5.23, controls 2.94, P < 0.0001]. SSc patients produced less saliva (SSc 147.52 mg/min, controls 163.19 mg/min, P = 0.0259) and their interincisal distance was smaller (SSc 37.68 mm, controls 44.30 mm, P < 0.0001). SSc patients had significantly reduced oral HRQoL compared with controls (mean OHIP score: SSc 41.58, controls 26.67, P < 0.0001). Multivariate regression analyses confirmed that SSc was a significant independent predictor of missing teeth, periodontal disease, interincisal distance, saliva production and OHIP scores.
Conclusion. Subjects with SSc have impaired oral health and oral HRQoL compared with the general population. These data can be used to develop targeted interventions to improve oral health and HRQoL in SSc.
PMCID: PMC4103515  PMID: 24464709
systemic sclerosis; quality of life; oral health; dental caries; periodontal disease; Sjögren’s syndrome; tooth loss
2.  Relationship Between Disease Characteristics and Orofacial Manifestations in Systemic Sclerosis: Canadian Systemic Sclerosis Oral Health Study III 
Arthritis care & research  2015;67(5):681-690.
Systemic sclerosis (SSc; scleroderma) is associated with decreased saliva production and interincisal distance, more missing teeth, and periodontal disease. We undertook this study to determine the clinical correlates of SSc with these oral abnormalities.
Subjects were recruited from the Canadian Scleroderma Research Group cohort. Detailed dental and clinical examinations were performed according to standardized protocols. Associations between dental abnormalities and selected clinical and serologic manifestations of SSc were examined.
One hundred sixty-three SSc subjects were included: 90% women, mean ± SD age 56 ± 11 years, mean ± SD disease duration 14 ± 8 years, 72% with limited cutaneous disease, and 28% with diffuse cutaneous disease. Decreased saliva production was associated with Sjögren’s syndrome–related autoantibodies (β = −43.32; 95% confidence interval [95% CI] −80.89, −5.75), but not with disease severity (β = −2.51; 95% CI −8.75, 3.73). Decreased interincisal distance was related to disease severity (β = −1.02; 95% CI −1.63, −0.42) and the modified Rodnan skin thickness score (β = −0.38; 95% CI −0.53, −0.23). The number of missing teeth was associated with decreased saliva production (relative risk [RR] 0.97; 95% CI 0.94, 0.99), worse hand function (RR 1.52; 95% CI 1.13, 2.02), and the presence of gastroesophageal reflux disease (GERD; RR 1.68 [95% CI 1.14, 2.46]). No clinical or serologic variables were correlated with periodontal disease.
In SSc, diminished interincisal distance is related to overall disease severity. Decreased saliva production is related to concomitant Sjögren’s syndrome antibodies. Tooth loss is associated with poor upper extremity function, GERD, and decreased saliva. The etiology of excess periodontal disease is likely multifactorial and remains unclear.
PMCID: PMC4464822  PMID: 25303223 CAMSID: cams4711
3.  Systemic Sclerosis Classification Criteria: Developing methods for multi-criteria decision analysis with 1000Minds 
Journal of clinical epidemiology  2014;67(6):706-714.
Classification criteria for systemic sclerosis (SSc) are being developed. The objectives were to: develop an instrument for collating case-data and evaluate its sensibility; use forced-choice methods to reduce and weight criteria; and explore agreement between experts on the probability that cases were classified as SSc.
Study Design and Setting
A standardized instrument was tested for sensibility. The instrument was applied to 20 cases covering a range of probabilities that each had SSc. Experts rank-ordered cases from highest to lowest probability; reduced and weighted the criteria using forced-choice methods; and re-ranked the cases. Consistency in rankings was evaluated using intraclass correlation coefficients (ICC).
Experts endorsed clarity (83%), comprehensibility (100%), face and content validity (100%). Criteria were weighted (points): finger skin thickening (14–22), finger-tip lesions (9–21), friction rubs (21), finger flexion contractures (16), pulmonary fibrosis (14), SSc-related antibodies (15), Raynaud’s phenomenon (13), calcinosis (12), pulmonary hypertension (11), renal crisis (11), telangiectasia (10), abnormal nailfold capillaries (10), esophageal dilation (7) and puffy fingers (5). The ICC across experts was 0.73 (95%CI 0.58,0.86) and improved to 0.80 (95%CI 0.68,0.90).
Using a sensible instrument and forced-choice methods, the number of criteria were reduced by 39% (23 to 14) and weighted. Our methods reflect the rigors of measurement science, and serves as a template for developing classification criteria.
PMCID: PMC4134523  PMID: 24721558
Scleroderma; Systemic Sclerosis; Decision Analysis; Forced-Choice; Classification Criteria; Conjoint Analysis; Sensibility
4.  Classification Criteria for Systemic Sclerosis: An ACR-EULAR Collaborative Initiative 
Arthritis and rheumatism  2013;65(11):2737-2747.
The 1980 classification criteria for systemic sclerosis (SSc) lack sensitivity in early SSc and limited cutaneous SSc. A joint ACR-EULAR committee was established to develop new classification criteria for SSc.
Using consensus methods, 23 candidate items were arranged in a multi-criteria additive point system with a threshold to classify cases as SSc. The classification system was reduced by clustering items, and simplifying weights. The system was tested by: a) determining specificity and sensitivity in SSc cases and controls with scleroderma-like disorders; b) validating against the combined view of a group of experts on a set of cases with or without SSc.
Skin thickening of the fingers extending proximal to the MCPs is sufficient to be classified as SSc, if that is not present, seven additive items apply with varying weights for each: skin thickening of the fingers, finger tip lesions, telangiectasia, abnormal nailfold capillaries, interstitial lung disease or pulmonary arterial hypertension, Raynaud's phenomenon, and SSc-related autoantibodies. Sensitivity and specificity in the validation sample were 0.91 and 0.92 for the new classification criteria and 0.75 and 0.72 for the 1980 ARA classification criteria. All selected cases were classified in accordance with consensus-based expert opinion. All cases classified as SSc by the 1980 ARA criteria were classified with the new criteria, and several additional cases were now considered to be SSc.
The ACR-EULAR classification criteria for SSc performed better than the 1980 ARA Criteria for SSc and should allow for more patients to be classified correctly as SSc.
PMCID: PMC3930146  PMID: 24122180
Systemic Sclerosis; Scleroderma; Classification Criteria; Conjoint Analysis; Multi Criteria Additive Point System; Validation; ACR-EULAR
5.  An Assessment of the Measurement Equivalence of English and French Versions of the Center for Epidemiologic Studies Depression (CES-D) Scale in Systemic Sclerosis 
PLoS ONE  2014;9(7):e102897.
Center for Epidemiologic Studies Depression (CES-D) Scale scores in English- and French-speaking Canadian systemic sclerosis (SSc) patients are commonly pooled in analyses, but no studies have evaluated the metric equivalence of the English and French CES-D. The study objective was to examine the metric equivalence of the CES-D in English- and French-speaking SSc patients.
The CES-D was completed by 1007 English-speaking and 248 French-speaking patients from the Canadian Scleroderma Research Group Registry. Confirmatory factor analysis (CFA) was used to assess the factor structure in both samples. The Multiple-Indicator Multiple-Cause (MIMIC) model was utilized to assess differential item functioning (DIF).
A two-factor model (Positive and Negative affect) showed excellent fit in both samples. Statistically significant, but small-magnitude, DIF was found for 3 of 20 CES-D items, including items 3 (Blues), 10 (Fearful), and 11 (Sleep). Prior to accounting for DIF, French-speaking patients had 0.08 of a standard deviation (SD) lower latent scores for the Positive factor (95% confidence interval [CI]−0.25 to 0.08) and 0.09 SD higher scores (95% CI−0.07 to 0.24) for the Negative factor than English-speaking patients. After DIF correction, there was no change on the Positive factor and a non-significant increase of 0.04 SD on the Negative factor for French-speaking patients (difference = 0.13 SD, 95% CI−0.03 to 0.28).
The English and French versions of the CES-D, despite minor DIF on several items, are substantively equivalent and can be used in studies that combine data from English- and French-speaking Canadian SSc patients.
PMCID: PMC4103860  PMID: 25036894
6.  Effect of menopause on the modified Rodnan skin score in systemic sclerosis 
Arthritis Research & Therapy  2014;16(3):R130.
We aimed to evaluate the effect of menopause on skin thickening, as measured by the modified Rodnan skin score (mRSS), in women with systemic sclerosis (SSc).
We identified women with either limited or diffuse SSc, aged ≥ 18 years, enrolled within the Canadian Scleroderma Research Group (CSRG) cohort, between 2004 and 2011. As part of the CSRG cohort, subjects undergo annual assessments with standardized questionnaires and physical examinations. We performed multivariate regression analyses using generalized estimating equation (GEE) to determine the effect of menopause on the mRSS, adjusting for relevant covariates including notably age, follow-up time, and disease duration.
We identified 1070 women with SSc, contributing a total of 3546 observations over the study period. Of these women, at baseline, 65% had limited disease and 35% diffuse disease. In multivariate analyses, we observed a substantial effect of postmenopausal status on the mean mRSS in women with diffuse disease subtype [−2.62 units, 95% confidence interval (CI) -4.44, −0.80] and significant interaction between menopausal status and disease subtype (2.04 units, 95% CI 0.20, 3.88). The effect of postmenopausal status on the mean mRSS was smaller in women with limited SSc (−0.58, 95% CI −1.50, 0.34).
Our results suggest that menopause has a substantial effect on skin thickening in diffuse SSc, with postmenopausal status being associated with a lower mean mRSS compared to premenopausal status.
PMCID: PMC4095602  PMID: 24957704
7.  Systemic Sclerosis Immunoglobulin Induces Growth and a Pro-Fibrotic State in Vascular Smooth Muscle Cells through the Epidermal Growth Factor Receptor 
PLoS ONE  2014;9(6):e100035.
It has been suggested that autoantibodies in systemic sclerosis (SSc) may induce the differentiation of cultured fibroblasts into myofibroblasts through platelet-derived growth factor receptor (PDGFR) activation. The present study aims to characterize the effects of SSc IgG on vascular smooth muscle cells (VSMCs) and to determine if stimulatory autoantibodies directed to the PDGFR can be detected, and whether they induce a profibrotic response in primary cultured VSMCs.
Cultured VSMCs were exposed to IgG fractions purified from SSc-patient or control sera. VSMC responses were then analyzed for ERK1/2 and Akt phosphorylation, PDGFR immunoprecipitation, cellular proliferation, protein synthesis, and pro-fibrotic changes in mRNA expression.
Stimulatory activity in IgG fractions was more prevalent and intense in the SSc samples. SSc IgG immunoprecipitated the PDGFR with greater avidity than control IgG. Interestingly, activation of downstream signaling events (e.g. Akt, ERK1/2) was independent of PDGFR activity, but required functional EGFR. We also detected increased protein synthesis in response to SSc IgG (p<0.001) and pro-fibrotic changes in gene expression (Tgfb1 +200%; Tgfb2 −23%; p<0.001)) in VSMCs treated with SSc IgG.
When compared to control IgG, SSc IgG have a higher stimulation index in VSMCs. Although SSc IgG interact with the PDGFR, the observed remodeling signaling events occur through the EGFR in VSMC. Our data thus favour a model of transactivation of the EGFR by SSc-derived PDGFR autoantibodies and suggest the use of EGFR inhibitors in future target identification studies in the field of SSc.
PMCID: PMC4057313  PMID: 24927197
8.  The Comparability of English, French and Dutch Scores on the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F): An Assessment of Differential Item Functioning in Patients with Systemic Sclerosis 
PLoS ONE  2014;9(3):e91979.
The Functional Assessment of Chronic Illness Therapy- Fatigue (FACIT-F) is commonly used to assess fatigue in rheumatic diseases, and has shown to discriminate better across levels of the fatigue spectrum than other commonly used measures. The aim of this study was to assess the cross-language measurement equivalence of the English, French, and Dutch versions of the FACIT-F in systemic sclerosis (SSc) patients.
The FACIT-F was completed by 871 English-speaking Canadian, 238 French-speaking Canadian and 230 Dutch SSc patients. Confirmatory factor analysis was used to assess the factor structure in the three samples. The Multiple-Indicator Multiple-Cause (MIMIC) model was utilized to assess differential item functioning (DIF), comparing English versus French and versus Dutch patient responses separately.
A unidimensional factor model showed good fit in all samples. Comparing French versus English patients, statistically significant, but small-magnitude DIF was found for 3 of 13 items. French patients had 0.04 of a standard deviation (SD) lower latent fatigue scores than English patients and there was an increase of only 0.03 SD after accounting for DIF. For the Dutch versus English comparison, 4 items showed small, but statistically significant, DIF. Dutch patients had 0.20 SD lower latent fatigue scores than English patients. After correcting for DIF, there was a reduction of 0.16 SD in this difference.
There was statistically significant DIF in several items, but the overall effect on fatigue scores was minimal. English, French and Dutch versions of the FACIT-F can be reasonably treated as having equivalent scoring metrics.
PMCID: PMC3956818  PMID: 24638101
9.  New directions for patient-centred care in scleroderma: the Scleroderma Patient-centred Intervention Network (SPIN) 
Clinical and experimental rheumatology  2012;30(2 0 71):S23-S29.
Systemic sclerosis (SSc), or scleroderma, is a chronic multisystem autoimmune disorder characterised by thickening and fibrosis of the skin and by the involvement of internal organs such as the lungs, kidneys, gastrointestinal tract, and heart. Because there is no cure, feasibly-implemented and easily accessible evidence-based interventions to improve health-related quality of life (HRQoL) are needed. Due to a lack of evidence, however, specific recommendations have not been made regarding non-pharmacological interventions (e.g. behavioural/psychological, educational, physical/occupational therapy) to improve HRQoL in SSc. The Scleroderma Patient-centred Intervention Network (SPIN) was recently organised to address this gap. SPIN is comprised of patient representatives, clinicians, and researchers from Canada, the USA, and Europe. The goal of SPIN, as described in this article, is to develop, test, and disseminate a set of accessible interventions designed to complement standard care in order to improve HRQoL outcomes in SSc.
PMCID: PMC3925434  PMID: 22244687
scleroderma; psychosocial; health-related quality of life; patient-centred care
10.  The Scleroderma Patient-centered Intervention Network (SPIN) Cohort: protocol for a cohort multiple randomised controlled trial (cmRCT) design to support trials of psychosocial and rehabilitation interventions in a rare disease context 
BMJ Open  2013;3(8):e003563.
Psychosocial and rehabilitation interventions are increasingly used to attenuate disability and improve health-related quality of life (HRQL) in chronic diseases, but are typically not available for patients with rare diseases. Conducting rigorous, adequately powered trials of these interventions for patients with rare diseases is difficult. The Scleroderma Patient-centered Intervention Network (SPIN) is an international collaboration of patient organisations, clinicians and researchers. The aim of SPIN is to develop a research infrastructure to test accessible, low-cost self-guided online interventions to reduce disability and improve HRQL for people living with the rare disease systemic sclerosis (SSc or scleroderma). Once tested, effective interventions will be made accessible through patient organisations partnering with SPIN.
Methods and analysis
SPIN will employ the cohort multiple randomised controlled trial (cmRCT) design, in which patients consent to participate in a cohort for ongoing data collection. The aim is to recruit 1500–2000 patients from centres across the world within a period of 5 years (2013–2018). Eligible participants are persons ≥18 years of age with a diagnosis of SSc. In addition to baseline medical data, participants will complete patient-reported outcome measures every 3 months. Upon enrolment in the cohort, patients will consent to be contacted in the future to participate in intervention research and to allow their data to be used for comparison purposes for interventions tested with other cohort participants. Once interventions are developed, patients from the cohort will be randomly selected and offered interventions as part of pragmatic RCTs. Outcomes from patients offered interventions will be compared with outcomes from trial-eligible patients who are not offered the interventions.
Ethics and dissemination
The use of the cmRCT design, the development of self-guided online interventions and partnerships with patient organisations will allow SPIN to develop, rigourously test and effectively disseminate psychosocial and rehabilitation interventions for people with SSc.
PMCID: PMC3740254  PMID: 23929922
Rheumatology; Statistics & Research Methods; Rehabilitation Medicine; Mental Health
11.  Items for developing revised classification criteria in systemic sclerosis: results of a consensus exercise with the ACR/EULAR working committee for classification criteria in systemic sclerosis 
Arthritis care & research  2012;64(3):351-357.
Classification criteria for systemic sclerosis (SSc) are being updated.
To select a set of items potentially useful for the classification of SSc using consensus procedures including the Delphi and nominal group techniques (NGT).
Items were identified through two independent consensus exercises performed by the Scleroderma Clinical Trials Consortium (SCTC) and the EULAR Scleroderma Trials and Research Group (EUSTAR). The first-round items from both exercises were collated and redundancies were removed leaving 168 items. A 3-round Delphi exercise was performed using a 1–9 scale (1=completely inappropriate and 9=completely appropriate) and a consensus meeting using NGT. During the last Delphi, the items were ranked on a 1–10 scale.
Round 1: 106 experts rated the 168 items. Those with a median score <4 were removed, resulting in a list of 102 items. Round 2: The items were again rated for appropriateness and subjected to a consensus meeting using NGT by European and North American SSc experts (n=16), resulting in 23 items. Round 3: SSc experts (n=26) then individually scored each of the 23 items in a last Delphi round, using an appropriateness score (1–9) and ranking their 10 most appropriate items for classification of SSc. Presence of skin thickening, SSc-specific autoantibodies, abnormal nailfold capillary pattern and Raynaud’s phenomenon ranked highest in the final list that also included items indicating internal organ involvement.
The Delphi exercise and NGT resulted in a set of 23 items for classification of SSc which will be assessed for their discriminative properties in a prospective study.
PMCID: PMC3288452  PMID: 22052558
Delphi technique; nominal group technique; systemic sclerosis; scleroderma; classification; classification criteria
12.  Validation of potential classification criteria for systemic sclerosis 
Arthritis care & research  2012;64(3):358-367.
Classification criteria for systemic sclerosis (SSc) are being updated jointly by ACR and EULAR. Potential items for classification were reduced to 23 using Delphi and Nominal Group Techniques. We evaluated the face, discriminant and construct validity of the items to be further studied as potential criteria.
Face validity was evaluated using the frequency of items in patients sampled from the Canadian Scleroderma Research Group, 1000 Faces of Lupus, the Pittsburgh, Toronto, Madrid and Berlin CTD databases. SSc (n=783) were compared to 1071 patients with diseases similar to SSc (mimickers): SLE (n=499), myositis (n=171), Sjögren’s syndrome (n=95), Raynaud’s phenomenon (RP) (n=228), MCTD (n=29), and idiopathic PAH (n=49). Discriminant validity was evaluated using odds ratios (OR). For construct validity, empiric ranking was compared to expert ranking.
Compared to mimickers, SSc are more likely to have skin thickening (OR=427), telangiectasias (OR=91), anti-RNA polymerase III antibody (OR=75), puffy fingers (OR=35), finger flexion contractures (OR=29), tendon/bursal friction rubs (OR=27), anti-topoisomerase-I antibody (OR=25), RP (OR=24), finger tip ulcers/pitting scars (OR=19), anti-centromere antibody(OR=14), abnormal nailfold capillaries (OR=10), GERD symptoms (OR=8), and ANA, calcinosis, dysphagia, esophageal dilation (all OR=6), interstitial lung disease/pulmonary fibrosis (OR=5) and anti-PM-Scl antibody (OR=2). Reduced DLCO, PAH, and reduced FVC had OR<2. Renal crisis and digital pulp loss/acro-osteolysis did not occur in SSc mimickers (OR not estimated). Empiric and expert ranking were correlated (Spearman rho 0.53, p=0.01).
The candidate items have good face, discriminant and construct validity. Further item reduction will be evaluated in prospective SSc and mimicker cases.
PMCID: PMC3376721  PMID: 22052658
Systemic Sclerosis; Scleroderma; Classification Criteria; Validity; Bayesian
13.  Cross-Language Measurement Equivalence of the Center for Epidemiologic Studies Depression (CES-D) Scale in Systemic Sclerosis: A Comparison of Canadian and Dutch Patients 
PLoS ONE  2013;8(1):e53923.
Increasingly, medical research involves patients who complete outcomes in different languages. This occurs in countries with more than one common language, such as Canada (French/English) or the United States (Spanish/English), as well as in international multi-centre collaborations, which are utilized frequently in rare diseases such as systemic sclerosis (SSc). In order to pool or compare outcomes, instruments should be measurement equivalent (invariant) across cultural or linguistic groups. This study provides an example of how to assess cross-language measurement equivalence by comparing the Center for Epidemiologic Studies Depression (CES-D) scale between English-speaking Canadian and Dutch SSc patients.
The CES-D was completed by 922 English-speaking Canadian and 213 Dutch SSc patients. Confirmatory factor analysis (CFA) was used to assess the factor structure in both samples. The Multiple-Indicator Multiple-Cause (MIMIC) model was utilized to assess the amount of differential item functioning (DIF).
A two-factor model (positive and negative affect) showed excellent fit in both samples. Statistically significant, but small-magnitude, DIF was found for 3 of 20 items on the CES-D. The English-speaking Canadian sample endorsed more feeling-related symptoms, whereas the Dutch sample endorsed more somatic/retarded activity symptoms. The overall estimate in depression scores between English and Dutch was not influenced substantively by DIF.
CES-D scores from English-speaking Canadian and Dutch SSc patients can be compared and pooled without concern that measurement differences may substantively influence results. The importance of assessing cross-language measurement equivalence in rheumatology studies prior to pooling outcomes obtained in different languages should be emphasized.
PMCID: PMC3543260  PMID: 23326538
14.  Sexual Activity and Impairment in Women with Systemic Sclerosis Compared to Women from a General Population Sample 
PLoS ONE  2012;7(12):e52129.
Reports of low sexual activity rates and high impairment rates among women with chronic diseases have not included comparisons to general population data. The objective of this study was to compare sexual activity and impairment rates of women with systemic sclerosis (SSc) to general population data and to identify domains of sexual function driving impairment in SSc.
Canadian women with SSc were compared to women from a UK population sample. Sexual activity and, among sexually active women, sexual impairment were evaluated with a 9-item version of the Female Sexual Function Index (FSFI).
Among women with SSc (mean age = 57.0 years), 296 of 730 (41%) were sexually active, 181 (61%) of whom were sexually impaired, resulting in 115 of 730 (16%) who were sexually active without impairment. In the UK population sample (mean age = 55.4 years), 956 of 1,498 women (64%) were sexually active, 420 (44%) of whom were impaired, with 536 of 1,498 (36%) sexually active without impairment. Adjusting for age and marital status, women with SSc were significantly less likely to be sexually active (OR = 0.34, 95%CI = 0.28–0.42) and, among sexually active women, significantly more likely to be sexually impaired (OR = 1.88, 95%CI = 1.42–2.49) than general population women. Controlling for total FSFI scores, women with SSc had significantly worse lubrication and pain scores than general population women.
Sexual functioning is a problem for many women with scleroderma and is associated with pain and poor lubrication. Evidence-based interventions to support sexual activity and function in women with SSc are needed.
PMCID: PMC3522627  PMID: 23251692
15.  Are Scores on English and French Versions of the PHQ-9 Comparable? An Assessment of Differential Item Functioning 
PLoS ONE  2012;7(12):e52028.
Medical research increasingly utilizes patient-reported outcome measures administered and scored in different languages. In order to pool or compare outcomes from different language versions, instruments should be measurement equivalent across linguistic groups. The objective of this study was to examine the cross-language measurement equivalence of the Patient Health Questionnaire-9 (PHQ-9) between English- and French-speaking Canadian patients with systemic sclerosis (SSc).
The sample consisted of 739 English- and 221 French-speaking SSc patients. Multiple-Indicator Multiple-Cause (MIMIC) modeling was used to identify items displaying possible differential item functioning (DIF).
A one-factor model for the PHQ-9 fit the data well in both English- and French-speaking samples. Statistically significant DIF was found for 3 of 9 items on the PHQ-9. However, the overall estimate in depression latent scores between English- and French-speaking respondents was not influenced substantively by DIF.
Although there were several PHQ-9 items with evidence of minor DIF, there was no evidence that these differences influenced overall scores meaningfully. The PHQ-9 can reasonably be used without adjustment in Canadian English- and French-speaking samples. Analyses assessing measurement equivalence should be routinely conducted prior to pooling data from English and French versions of patient-reported outcome measures.
PMCID: PMC3522629  PMID: 23251676
16.  Immunosuppression for interstitial lung disease in systemic sclerosis – novel insights and opportunities for translational research 
PMCID: PMC3497900  PMID: 22865262
Immunosuppression; Interstitial lung disease; Outcomes research; Systemic sclerosis; Translational research
17.  Anti-Fibrillarin Antibody in African American Patients with Systemic Sclerosis: Immunogenetics, Clinical Features, and Survival Analysis 
The Journal of rheumatology  2011;38(8):1622-1630.
Anti-U3-RNP or anti-fibrillarin antibodies (AFA) are detected more frequently among African American (AA) patients with systemic sclerosis (SSc) compared to other ethnic groups and are associated with distinct clinical features. The current study examines the immunogenetic, clinical, and survival correlates of AFA in a large group of AA patients with SSc.
Overall, 278 AA SSc patients and 328 unaffected AA controls were enrolled from three North American cohorts. Clinical features, autoantibody profile, and HLA-class-II genotyping were captured. To compare the clinical manifestations, relevant clinical features were adjusted for disease duration. The Cox proportional hazards regression was used to determine the effect of AFA on survival.
Fifty (18.5%) AA patients had AFA. After Bonferroni correction, HLA-DRB1*08:04 was associated with AFA, compared to unaffected AA controls (OR=11.5, p<0.0001) and AFA negative SSc patients (OR=5.2, p=0.0002). AFA positive AA patients had younger age of disease onset, higher frequency of digital ulcers, diarrhea, pericarditis, higher Medsger Perivascular and lower Lung Severity Indices (p=0.004, p=0.014, p=0.019, p=0.092, p=0.006, and p=0.016, respectively). After adjustment for age at enrollment, AFA positive patients did not have different survival compared with patients without AFA (p=0.493).
These findings demonstrate strong association between AFA and HLA-DRB1*08:04 allele in AA patients with SSc. Moreover, AA SSc patients with AFA had younger age of onset, higher frequency of digital ulcers, pericarditis, and severe lower gastrointestinal involvement, but less severe lung involvement compared to AA patients without AFA. However, presence of AFA did not change survival.
PMCID: PMC3149738  PMID: 21572159
Scleroderma; GENISOS; anti-U3-RNP; digital ulcer; HLA DRB1; and Scleroderma Family Registry
18.  CD109, a TGF-β co-receptor, attenuates extracellular matrix production in scleroderma skin fibroblasts 
Arthritis Research & Therapy  2012;14(3):R144.
Scleroderma or systemic sclerosis (SSc) is a complex connective tissue disease characterized by fibrosis of skin and internal organs. Transforming growth factor beta (TGF-β) plays a key role in the pathogenesis of SSc fibrosis. We have previously identified CD109 as a novel TGF-β co-receptor that inhibits TGF-β signaling. The aim of the present study was to determine the role of CD109 in regulating extracellular matrix (ECM) production in human SSc skin fibroblasts.
CD109 expression was determined in skin tissue and cultured skin fibroblasts of SSc patients and normal healthy subjects, using immunofluorescence, western blot and RT-PCR. The effect of CD109 on ECM synthesis was determined by blocking CD109 expression using CD109-specific siRNA or addition of recombinant CD109 protein, and analyzing the expression of ECM components by western blot.
The expression of CD109 proteinis markedly increased in SSc skin tissue in vivo and in SSc skin fibroblasts in vitro as compared to their normal counterparts. Importantly, both SSc and normal skin fibroblasts transfected with CD109-specific siRNA display increased fibronectin, collagen type I and CCN2 protein levels and enhanced Smad2/3 phosphorylation compared with control siRNA transfectants. Furthermore, addition of recombinant CD109 protein decreases TGF-β1-induced fibronectin, collagen type I and CCN2 levels in SSc and normal fibroblasts.
The upregulation of CD109 protein in SSc may represent an adaptation or consequence of aberrant TGF-β signaling in SSc. Our finding that CD109 is able to decrease excessive ECM production in SSc fibroblasts suggest that this molecule has potential therapeutic value for the treatment of SSc.
PMCID: PMC3446527  PMID: 22694813
19.  Role overload, pain and physical dysfunction in early rheumatoid or undifferentiated inflammatory arthritis in Canada 
Inflammatory arthritis impairs participation in societal roles. Role overload arises when the demands by a given role set exceed the resources; time and energy, to carry out the required tasks. The present study examines the association between role overload and disease outcomes in early inflammatory arthritis (EIA).
Patients (n = 104) of 7.61 months mean duration of inflammatory arthritis completed self-report questionnaires on sociodemographics, disease characteristics and role overload. Pain was assessed using the Short Form McGill Pain Questionnaire (MPQ) and physical functioning was measured with the Medical Outcomes Study Short Form 36 (SF-36) physical functioning score. Role overload was measured by the Role Overload Scale. Patients indicated the number of social roles they occupied from a total of the three typical roles; marital, parental and paid work.
Participants’ mean age was 56 years and 70.2% were female. Role overload was not correlated to the number of social roles, however, it was positively associated with pain (p = 0.004) and negatively associated with physical functioning (p = 0.001). On multivariate analysis, role overload was negatively associated with physical functioning after controlling for the relevant sociodemographic variables.
This study identifies a possible reciprocal relationship between role overload and physical functioning in patients with EIA.
PMCID: PMC3428668  PMID: 22554167
Arthritis; Role overload; Physical functioning; Pain
20.  Loss of PPARγ expression by fibroblasts enhances dermal wound closure 
Peroxisome proliferator-activated receptor (PPAR)γ may be a key regulator of connective tissue deposition and remodeling in vivo. PPARγ expression is reduced in dermal fibroblasts isolated from fibrotic areas of scleroderma patients; PPARγ agonists suppress the persistent fibrotic phenotype of this cell type. Previously, we showed that loss of PPARγ expression in fibroblasts resulted in enhanced bleomycin-induced skin fibrosis. However, whether loss of PPARγ expression in skin fibroblasts affects cutaneous tissue repair or homeostasis is unknown.
Mice deleted for PPARγ in skin fibroblasts show an enhanced rate of dermal wound closure, concomitant with elevated phosphorylation of Smad3, Akt and ERK, and increased expression of proliferating cell nuclear antigen (PCNA), collagen, α-smooth muscle actin (α-SMA) and CCN2. Conversely, dermal homeostasis was not appreciably affected by loss of PPARγ expression.
PPARγ expression by fibroblasts suppresses cutaneous tissue repair. In the future, direct PPARγ antagonists and agonists might be of clinical benefit in controlling chronic wounds or scarring, respectively.
PMCID: PMC3348009  PMID: 22502865
21.  Sociodemographic and Disease Correlates of Body Image Distress among Patients with Systemic Sclerosis 
PLoS ONE  2012;7(3):e33281.
Body image concerns are infrequently studied in systemic sclerosis (SSc), even though significant visible disfigurement is common. The objective of this study was to identify sociodemographic and disease-related correlates of dissatisfaction with appearance and social discomfort among people with SSc.
SSc patients came from the 15-center Canadian Scleroderma Research Group Registry. Sociodemographic information was based on patient self-report. Disease characteristics were obtained via physician examinations. The Brief-SWAP was used to assess dissatisfaction with appearance and social discomfort. Structural equation models were conducted with MPlus to determine the relationship of dissatisfaction with appearance and social discomfort with age, sex, education, marital status, race/ethnicity, disease duration, skin involvement, telangiectasias, skin pigmentation changes, and hand contractures.
A total of 489 SSc patients (432 female, 57 male) were included. Extent of skin involvement was significantly associated with both dissatisfaction with appearance and social discomfort (standardized regression coefficients = 0.02, p = 0.001; 0.02, p = 0.020, respectively), as was skin involvement in the face (0.18, p = 0.016; 0.23, p = 0.006, respectively). Greater social discomfort was robustly associated with younger age (−0.017, p<0.001) and upper-body telangiectasias (0.32, p = 0.021). Dissatisfaction with appearance was associated with hand contractures (0.07, p = 0.036).
This study found that dissatisfaction with appearance and social discomfort were associated with numerous disfiguring characteristics of SSc, in addition to age. These results underline that there are multiple factors contributing to body image distress in SSc, as well as the need to attend to both disease and social contexts in understanding the impact of disfigurement among patients.
PMCID: PMC3311623  PMID: 22457749
22.  Clinical significance of antibodies to Ro52/TRIM21 in systemic sclerosis 
Autoantibodies to Ro52 recently identified as TRIM21 are among the most common autoantibodies in systemic autoimmune rheumatic diseases, but their clinical association remains poorly understood. We undertook this study to determine the clinical and serologic associations of anti-Ro52/TRIM21 antibodies in patients with systemic sclerosis (SSc).
Detailed clinical data and sera from 963 patients with SSc enrolled in a multicenter cohort study were collected and entered into a central database. Antibodies to Ro52/TRIM21 and other autoantibodies were detected with an addressable laser-bead immunoassay and different enzyme-linked immunosorbent assay (ELISA) systems. Associations between anti-Ro52/TRIM21 antibodies and clinical and other serologic manifestations of SSc were investigated.
Anti-Ro52/TRIM21 antibodies were present in 20% of SSc patients and overlapped with other main SSc-related antibodies, including anti-centromere (by immunofluorescence and centromere protein (CENP)-A and CENP-B ELISA), anti-topoisomerase I, anti-RNA polymerase III, and anti-Pm/Scl antibodies. Anti-Ro52/TRIM21 antibodies were strongly associated with interstitial lung disease (odds ratio (OR), 1.53; 95% confidence interval (CI), 1.11 to 2.12; P = 0.0091) and overlap syndrome (OR, 2.06; 95% CI, 1.01 to 4.19; P = 0.0059).
Anti-Ro52/TRIM21 antibodies were the second most common autoantibodies in this SSc cohort. In SSc, anti-Ro52/TRIM21 antibodies may be a marker of interstitial lung disease and overlap syndrome.
PMCID: PMC3446416  PMID: 22394602
23.  An International, Web-Based, Prospective Cohort Study to Determine Whether the Use of ACE Inhibitors prior to the Onset of Scleroderma Renal Crisis Is Associated with Worse Outcomes—Methodology and Preliminary Results 
Background. To describe the methodology of a study designed to determine whether systemic sclerosis (SSc) patients with incident scleroderma renal crisis (SRC) on angiotensin converting enzyme (ACE) inhibitors prior to the onset of SRC have worse outcomes. Methods. Prospective, international cohort study of SRC subjects identified through an ongoing web-based survey. Every second Friday afternoon, an e-mail was sent to 589 participating physicians to identify new cases of SRC. Death or dialysis at one year after the onset of SRC will be compared in patients exposed or not to ACE inhibitors prior to the onset of SRC. Results. Fifteen months after the start of the survey, we had identified 76 incident cases of SRC. Of these, 66 (87%) had a hypertensive SRC and 10 (13%) a normotensive SRC. Twenty-two percent (22%) of the patients were on an ACE inhibitor immediately prior to the onset of the SRC. To date, we have collected one-year follow-up data on approximately 1/3 of the cohort. Of these, over 50% have died or remain on dialysis at one year. Conclusion. An international, web-based cohort study design is a feasible method of recruiting a substantial number of patients to study an infrequent vascular manifestation of SSc.
PMCID: PMC2947816  PMID: 20936135

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