PIK-III exerts anti-fibrotic effects in activated fibroblasts by regulating p38 activation.

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune-driven connective tissue disorder that results in fibrosis of the skin and internal organs such as the lung. Fibroblasts are known as the main effector cells involved in the progression of SSc through the induction of extracellular matrix (ECM) proteins and myofibroblast differentiation. Here, we demonstrate that 4'-(cyclopropylmethyl)-N2-4-pyridinyl-[4,5'-bipyrimidine]-2,2'-diamine (PIK-III), known as class III phosphatidylinositol 3-kinase (PIK3C3/VPS34) inhibitor, exerts potent antifibrotic effects in human dermal fibroblasts (HDFs) by attenuating transforming growth factor-beta 1 (TGF-ß1)-induced ECM expression, cell contraction and myofibroblast differentiation. Unexpectedly, neither genetic silencing of PIK3C3 nor other PIK3C3 inhibitors (e.g., SAR405 and Autophinib) were able to mimic PIK-III-mediated antifibrotic effect in dermal fibroblasts, suggesting that PIK-III inhibits fibroblast activation through another signaling pathway. We identified that PIK-III effectively inhibits p38 activation in TGF-ß1-stimulated dermal fibroblasts. Finally, PIK-III administration significantly attenuated dermal and lung fibrosis in bleomycin-injured mice.

Circulating cell adhesion molecules in systemic sclerosis: a systematic review and meta-analysis.

Introduction: Patients with systemic sclerosis (SSc) have an increased risk of endothelial dysfunction, atherosclerosis, and cardiovascular events compared to the general population. Therefore, the availability of robust circulating biomarkers of endothelial dysfunction and atherogenesis may facilitate early recognition and management of cardiovascular risk in SSc. We sought to address this issue by conducting a systematic review and meta-analysis of studies investigating various types of circulating cell adhesion molecules involved in endothelial dysfunction and atherogenesis (i.e., immunoglobulin-like vascular cell, VCAM-1, intercellular, ICAM-1, platelet endothelial cell, PECAM-1, neural cell, NCAM, Down syndrome cell, DSCAM, and endothelial cell-selective, ESAM, adhesion molecules, E-, L-, and P-selectin, integrins, and cadherins) in SSc patients and healthy controls. Methods: We searched PubMed, Scopus, and Web of Science from inception to 1 May 2024. Risk of bias and certainty of evidence were assessed using validated tools. Results: In 43 eligible studies, compared to controls, patients with SSc had significantly higher plasma or serum concentrations of ICAM-1 (standard mean difference, SMD=1.16, 95% CI 0.88 to 1.44, p<0.001; moderate certainty), VCAM-1 (SMD=1.09, 95% CI 0.72 to 1.46, p<0.001; moderate certainty), PECAM-1 (SMD=1.65, 95% CI 0.33 to 2.98, p=0.014; very low certainty), E-selectin (SMD=1.17, 95% CI 0.72 to 1.62, p<0.001; moderate certainty), and P-selectin (SMD=1.10, 95% CI 0.31 to 1.90, p=0.007; low certainty). There were no significant between-group differences in L-selectin concentrations (SMD=-0.35, 95% CI -1.03 to 0.32, p=0.31; very low certainty), whereas minimal/no evidence was available for cadherins, NCAM, DSCAM, ESAM, or integrins. Overall, no significant associations were observed between the effect size and various patient and study characteristics in meta-regression and subgroup analyses. Discussion: The results of this systematic review and meta-analysis suggest that specific circulating cell adhesion molecules, i.e., ICAM-1, VCAM-1, PECAM-1, E-selectin, and P-selectin, can be helpful as biomarkers of endothelial dysfunction and atherogenesis in the assessment of cardiovascular risk in SSc patients. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42024549710.

Development of a multivariable prediction model for progression of systemic sclerosis-associated interstitial lung disease.

OBJECTIVE: To develop a multivariable model for predicting the progression of systemic sclerosis-associated interstitial lung disease (SSc-ILD) over 52 weeks. METHODS: We used logistic regression models to analyse associations between candidate predictors assessed at baseline and progression of SSc-ILD (absolute decline in forced vital capacity (FVC) % predicted >5% or death) over 52 weeks in the placebo group of the SENSCIS trial. Analyses were performed in the overall placebo group and in a subgroup with early and/or inflammatory SSc and/or severe skin fibrosis (<18 months since first non-Raynaud symptom, elevated inflammatory markers, and/or modified Rodnan skin score (mRSS) >18) at baseline. Model performance was assessed using the area under the receiver operating characteristic curve (AUC). RESULTS: In the overall placebo group (n=288), the performance of the final multivariable model for predicting SSc-ILD progression was moderate (apparent AUC: 0.63). A stronger model, with an apparent AUC of 0.75, was developed in the subgroup with early and/or inflammatory SSc and/or severe skin fibrosis at baseline (n=155). This model included diffusing capacity of the lung for carbon monoxide (DLco) % predicted, time since first non-Raynaud symptom, mRSS, anti-topoisomerase I antibody status and mycophenolate use. CONCLUSION: Prediction of the progression of SSc-ILD may require different approaches in distinct subgroups of patients. Among patients with SSc-ILD and early and/or inflammatory SSc and/or severe skin fibrosis, a nomogram based on a multivariable model may be of value for identifying patients at risk of short-term progression.

PSGL-1, ADAM8, and selectins as potential biomarkers in the diagnostic process of systemic lupus erythematosus and systemic sclerosis: an observational study.

Background: Early diagnosis and treatment of Systemic lupus erythematosus (SLE) and Systemic sclerosis (SSc) present significant challenges for clinicians. Although various studies have observed changes in serum levels of selectins between healthy donors and patients with autoimmune diseases, including SLE and SSc, their potential as biomarkers has not been thoroughly explored. We aimed to investigate serum profiles of PSGL-1 (sPSGL-1), ADAM8 (sADAM8) and P-, E- and L-selectins (sP-, sE- and sL-selectins) in defined SLE and SSc patient cohorts to identify disease-associated molecular patterns. Methods: We collected blood samples from 64 SLE patients, 58 SSc patients, and 81 healthy donors (HD). Levels of sPSGL-1, sADAM8 and selectins were analyzed by ELISA and leukocyte membrane expression of L-selectin and ADAM8 by flow cytometry. Results: Compared to HD, SLE and SSc patients exhibited elevated sE-selectin and reduced sL-selectin levels. Additionally, SLE patients exhibited elevated sPSGL-1 and sADAM8 levels. Compared to SSc, SLE patients had decreased sL-selectin and increased sADAM8 levels. Furthermore, L-selectin membrane expression was lower in SLE and SSc leukocytes than in HD leukocytes, and ADAM8 membrane expression was lower in SLE neutrophils compared to SSc neutrophils. These alterations associated with some clinical characteristics of each disease. Using logistic regression analysis, the sL-selectin/sADAM8 ratio in SLE, and a combination of sL-selectin/sE-selectin and sE-selectin/sPSGL-1 ratios in SSc were identified and cross-validated as potential serum markers to discriminate these patients from HD. Compared to available diagnostic biomarkers for each disease, both sL-selectin/sADAM8 ratio for SLE and combined ratios for SSc provided higher sensitivity (98% SLE and and 67% SSc correctly classified patients). Importantly, the sADAM8/% ADAM8(+) neutrophils ratio discriminated between SSc and SLE patients with the same sensitivity and specificity than current disease-specific biomarkers. Conclusion: SLE and SSc present specific profiles of sPSGL-1, sE-, sL-selectins, sADAM8 and neutrophil membrane expression which are potentially relevant to their pathogenesis and might aid in their early diagnosis.

[Update on systemic sclerosis]. / Update zur systemischen Sklerose.

BACKGROUND: The updates to the European recommendations and the German guidelines for the treatment of systemic sclerosis are expected shortly, which are very good evidence-based guidelines for all those treating the disease; however, there are still disease manifestations with insufficient studies and current study results that were published after the review of the literature for the guidelines and might be of interest to the reader. OBJECTIVE AND METHODS: The aim of this work is to provide an overview of the publications in the last year that are interesting from the authors' point of view. The aim is to provide practically relevant information on the current state of knowledge that can supplement the guidelines. RESULTS: The pathogenesis of systemic sclerosis (SSc) is becoming better understood in its interplay between environmental factors and the development of autoantibodies. There have also been overviews of the manifestation and prognosis of cardiac involvement in the last year. The American Thoracic Society issued the first guidelines for the treatment of interstitial lung disease in SSc. There are an increasing number of studies that suggest that disease-modulating combination therapies, such as rituximab and mycophenolate mofetil (MMF) are beneficial. Work addressing the involvement of joints suggests that inflammatory changes are common. Current options for the treatment of gastrointestinal involvement are presented. CONCLUSION: The diagnosis and treatment of systemic sclerosis is making progress and many symptoms and complications are treatable. Nevertheless, much remains to be done to improve the quality of life of the patients.

Arrhythmia in patients with systemic sclerosis: incidence, risk factors and impact on mortality in a Swedish register-based study.

OBJECTIVES: The objectives of this study are to study the risk of developing cardiac arrhythmia and its subtypes over time in patients with systemic sclerosis (SSc), to assess potential risk factors for arrhythmia in SSc and to explore whether arrhythmia is associated with mortality. METHODS: We used nationwide Swedish registers to identify patients with incident SSc 2004-2019 and matched general population comparators (1:10). The primary outcome was incident arrhythmia. Follow-up started at the date of SSc diagnosis and ended at the primary outcome, death, emigration or 31 December 2019. We estimated the incidence of arrhythmia overall and stratified by subtype and explored the relative risk in relation to time since diagnosis using flexible parametric models. We used Cox regression to study risk factors for arrhythmia and the association of arrhythmia with mortality. RESULTS: We identified 1565 patients and 16 009 comparators. The overall incidence of arrhythmia was 255 (95% CI 221 to 295) and 119 (95% CI 112 to 127) per 10 000 person years in patients with SSc and comparators, respectively, corresponding to an IRR of 2.1 (95% CI 1.8 to 2.5). The greatest hazard difference between patients with SSc compared with the comparators was seen in the first year of follow-up (HR for arrhythmia 3.0; 95% CI 2.3 to 3.8). Atrial fibrillation and flutter were the most common arrhythmia subtypes. Male sex, index age and pulmonary arterial hypertension were significant risk factors for arrhythmia in SSc. Incident arrhythmia was significantly associated with mortality (HR 2.2; 95% CI 1.6 to 3.0). CONCLUSION: SSc is associated with higher incidence of cardiac arrhythmia compared with general population. Arrhythmia seems to be an early manifestation of SSc and is associated with higher mortality.

Characteristics and impact of infiltration of B-cells from systemic sclerosis patients in a 3D healthy skin model.

Introduction: In systemic sclerosis (SSc), B-cells are activated and present in the skin and lung of patients where they can interact with fibroblasts. The precise impact and mechanisms of the interaction of B-cells and fibroblasts at the tissular level are poorly studied. Objective: We investigated the impact and mechanisms of B-cell/fibroblast interactions in cocultures between B-cells from patients with SSc and 3-dimensional reconstituted healthy skin model including fibroblasts, keratinocytes and extracellular matrix. Methods: The quantification and description of the B-cell infiltration in 3D cocultures were performed using cells imagery strategy and cytometry. The effect of coculture on the transcriptome of B-cells and fibroblasts was studied with bulk and single-cell RNA sequencing approaches. The mechanisms of this interaction were studied by blocking key cytokines like IL-6 and TNF. Results: We showed a significant infiltration of B-cells in the 3D healthy skin model. The amount but not the depth of infiltration was higher with B-cells from SSc patients and with activated B-cells. B-cell infiltrates were mainly composed of naïve and memory cells, whose frequencies differed depending on B-cells origin and activation state: infiltrated B-cells from patients with SSc showed an activated profile and an overexpression of immunoglobulin genes compared to circulating B-cells before infiltration. Our study has shown for the first time that activated B-cells modified the transcriptomic profile of both healthy and SSc fibroblasts, toward a pro-inflammatory (TNF and IL-17 signaling) and interferon profile, with a key role of the TNF pathway. Conclusion: B-cells and 3D skin cocultures allowed the modelization of B-cells infiltration in tissues observed in SSc, uncovering an influence of the underlying disease and the activation state of B-cells. We showed a pro-inflammatory effect on skin fibroblasts and pro-activation effect on infiltrating B-cells during coculture. This reinforces the role of B-cells in SSc and provide potential targets for future therapeutic approach in this disease.

Can microvascular damage predict disease severity in patients with systemic sclerosis?

INTRODUCTION: Systemic sclerosis (SSc) is characterized by progressive fibrosis of the skin and internal organs, microvascular damage and cellular and humoral immunity abnormalities. Microvascular damage can be easily detected through nailfold videocapillaroscopy (NVC). MATERIALS AND METHODS: A retrospective study of patients with SSc and a NVC performed within the first 6 months after diagnosis was conducted. Visceral involvement in the first 3 years of the disease and NVC findings were collected. The severity of microvascular damage was classified into four categories, according to the worsening of the NVC patterns. The severity of organ involvement was assessed by the disease severity scale of Medsger for each organ and as a global measure of disease severity, the simple summation was used. RESULTS: A total of 86 patients with SSc were included. A moderate correlation was found between the severity of microvascular damage and the global measure of disease severity (r=0.55, p<0.001), the severity of peripheral vascular involvement (r=0.43, p<0.001) and the severity of skin involvement (r=0.34, p=0.001). The presence of a late scleroderma pattern in NVC were predictive in univariate analysis of digital ulcers (OR 6.03, 95% CI 1.52-23.86, p=0.01), muscular involvement (OR 13.09, 95% CI 1.09-156.78, p=0.04), calcinosis (OR 27.22, 95% CI 5.56-133.33, p<0.001) and worse global disease severity score (OR 1.67, 95% CI 1.17-2.38, p=0.005). Multivariate analysis adjusted for disease duration and gender confirmed late pattern as an independent predictor of calcinosis (OR 42.89, 95% CI 5.53-332.85, p<0.001). DISCUSSION AND CONCLUSION: In this study, the worsening of NVC pattern in SSc was associated with the overall disease severity, the severity of peripheral vascular involvement and extension of skin involvement. This study highlights the importance of NVC as a prognostic tool and a possible predictor of systemic visceral involvement.

Investigating the trajectory of functional disability in systemic sclerosis: group-based trajectory modelling of the Health Assessment Questionnaire-Disability Index.

OBJECTIVES: To identify the trajectories and clinical associations of functional disability in systemic sclerosis (SSc). METHODS: Australian Scleroderma Cohort Study (ASCS) participants meeting ACR/EULAR criteria for SSc recruited within 5 years of disease onset, with ≥2 Health Assessment Questionnaire-Disability Index (HAQ-DI) scores were included. Group based trajectory modelling (GBTM) was used to identify the number and shape of HAQ-DI trajectories. Between group comparisons were made using the chi-squared test, two-sample t-test or Wilcoxon rank-sum test as appropriate. Multiple logistic regression was used to identify features associated with trajectory group membership. Survival analyses were performed using Kaplan Meier and Cox proportional hazard modelling. RESULTS: We identified two HAQ-DI trajectory groups within 426 ASCS participants with incident SSc: low-stable disability (n=221, 52%), and high-increasing disability (n=205, 48%). Participants with high-increasing disability were older at disease onset, more likely to have diffuse SSc (dcSSc), cardiopulmonary disease, multimorbidity, digital ulcers, and gastrointestinal involvement (all p≤0.01), as was use of immunosuppression (p<0.01). Multimorbidity was associated with high-increasing trajectory group membership (OR3.1, 95%CI1.1-8.8, p=0.04); independently, multiple SSc features were also strongly associated including dcSSc (OR2.3, 95%CI1.3-4.2, p<0.01), proximal weakness (OR7.3, 95%CI2.0-27.1, p<0.01) and joint contractures (OR2.7, 95%CI1.3-5.3, p<0.01). High-increasing physical disability was associated with an almost two-fold increased risk of mortality (HR1.9, 95%CI1.0-3.8, p=0.05), and higher symptom burden. CONCLUSIONS: Two trajectories of functional disability in SSc were identified. Those with high-increasing functional disability had a distinct clinical phenotype and worse survival compared to those with low-stable functional disability. These data highlight the pervasive nature of physical disability in SSc, and its prognostic importance.

Systemic sclerosis and environment: an intriguing and still debated association.

Systemic sclerosis (SSc) is characterised by a heterogeneous clinical expression probably reflecting the different genetic background of each patient. Progress has been made in the definition of the principal pathogenetic events of the disease that can be summarised in endothelial damage and dysfunction, inflammation with activation of immune system and fibrosis. The aetiology of the disease still remains to be clarified and probably the first events are attributable to the repeated action of environmental stimuli in genetically predisposed subjects.The aim of the present manuscript is to review the most recent and relevant data regarding the association of SSc with environmental factors.

A randomised, parallel-group, double-blind, placebo-controlled phase 3 study to Determine the effectiveness of the type I interferon receptor antibody, Anifrolumab, In SYstemic sclerosis: DAISY study design and rationale.

OBJECTIVES: The type I interferon pathway is a promising target for treatment of patients with systemic sclerosis (SSc). Here, we describe the design of a multinational, randomised phase 3 study to Determine the effectiveness of the type I interferon receptor antibody, Anifrolumab, In SYstemic sclerosis (DAISY). METHODS: DAISY includes a 52-week double-blind, placebo-controlled treatment period, a 52-week open-label active treatment period, and a 12-week safety follow-up period. The patient population includes a planned 306 adults with limited or diffuse cutaneous active SSc who satisfied American College of Rheumatology/European Alliance of Associations for Rheumatology 2013 SSc criteria. Use of standard immunosuppressants, including mycophenolate mofetil, at a stable dose prior to randomisation is permitted in addition to weekly subcutaneous anifrolumab or placebo. Efficacy will be assessed at Week 52 via Revised-Composite Response Index in SSc (CRISS)-25 response (primary endpoint). Lung function and skin thickness will be assessed via change from baseline in forced vital capacity in patients with SSc-associated interstitial lung disease and modified Rodnan Skin Score, respectively (key secondary endpoints). CONCLUSIONS: The DAISY trial will evaluate the efficacy and safety of anifrolumab as a first-in-class treatment option for patients with both limited and diffuse cutaneous SSc and will provide insight into the contributions of type I interferon to SSc pathogenesis. Revised-CRISS-25 can account for improvement and worsening in a broad set of validated clinical measures beyond lung function and skin thickness, including clinician- and patient-reported outcomes, capturing the heterogeneity of SSc.

Systemic sclerosis is a chronic autoimmune disease that leads to inflammation and scarring of the skin and internal organs, especially the lungs. Systemic sclerosis and lupus are both associated with increased interferon signalling, which is usually triggered by viral infections, but is related to damaging inflammation in these diseases. Anifrolumab, a drug that blocks interferon signalling, is already used to treat patients with lupus (also known as SLE), so it could potentially be used to treat patients with systemic sclerosis. This publication details the DAISY study design and explains why it is needed. This study will follow 2 groups of 153 patients with systemic sclerosis over 2 years. During the first year, in addition to any standard immunosuppressant therapy, the groups will receive weekly injections of either anifrolumab or "dummy drug" (placebo). In the second year, all patients will receive anifrolumab with their standard immunosuppressant therapy. Multiple factors will be considered to evaluate the efficacy of anifrolumab treatment, including clinical measurements of skin thickness and lung function, and questionnaires completed by clinicians and patients to report on patient health and their everyday function during treatment. The DAISY study will investigate the efficacy and safety of anifrolumab treatment in a diverse group of patients with systemic sclerosis who currently have limited options for effective treatment. The study will evaluate the impact of anifrolumab treatment on multiple aspects of the disease, and how patients feel about their overall health-related quality of life.

Assessment of fertility and sexual dysfunction in women with systemic sclerosis: a narrative review of the literature.

OBJECTIVES: The aim of this work is to review the existing literature regarding sexual and reproductive function of women affected by systemic sclerosis and to establish the impact of the disease on the gynaecological-obstetrical field. METHODS: A systematic search has been conducted by means of PubMed, Cochrane, Google Scholar, until January 2024 by the keywords ''systemic sclerosis'', ''fertility'', "sexual dysfunction" and "pregnancy". RESULTS: Sexual dysfunction has been described in most of the studies. This could be related to dryness and dyspareunia, but also to the psychosocial impact of SSc on body and facial appearance, which impacts on social and sexual relationships. There is conflicting evidence regarding the influence of SSc and fertility. Before the 1980s pregnancies in these patients were rare. This could be linked to the satisfied reproductive desire before the onset of SSc, or to the fact that pregnancy was labelled as high-risk, leading to counsel against it in most patients. Recently, the evidence supporting infertility is conflicting. There is no certain theory on how the disease may interfere with reproductive function, but a possible linkage can be detected in a pro-inflammatory milieu which can impair the ovarian reserve. CONCLUSIONS: Women affected by SSc should be followed-up by a multidisciplinary team to prevent sexual dysfunction. Although there is no consensus on the impact of SSc on fertility, these patients should be provided with adequate pre-conceptional counselling and a strict follow-up in high-risk pregnancy units.

Gastrointestinal disorders in systemic sclerosis: cluster analysis and prognosis from a French prospective cohort.

OBJECTIVES: The gastrointestinal tract (GIT) is frequently involved in systemic sclerosis (SSc) and is responsible for alteration of quality of life. Many complications can occur, including chronic intestinal pseudo-obstruction, digestive haemorrhage and small-intestinal bacterial overgrowth. Since early development of organ failure is associated with poor prognosis, we need to identify risk factors associated with severe GIT involvement to prevent severe forms of the disease. METHODS: We conducted an observational prospective study, which included 90 SSc patients from December 2019 to September 2021. We collected questionnaires about digestive manifestations and quality of life, blood and stool samples, and performed imaging. At inclusion and throughout the study we assessed the occurrence of malnutrition and severe GIT disorders. We performed statistical analysis to highlight eventual risk factors associated with digestive manifestations, including hierarchical cluster analysis. RESULTS: A majority of our patients had gastro-oesophageal manifestations (93.3%), followed by intestinal manifestations (67.8%) and anorectal manifestations (18.9%). We found a correlation between anorectal disorders and cardiac disease, and between gastro-oesophageal involvement and impaired pulmonary function tests. Smoking was significantly associated with occurrence of severe GIT disorders. Malnutrition was frequent and associated with more cardiac and pulmonary disease. Cluster analysis identified three groups of patients, including one cluster with cardiac and digestive involvement. CONCLUSIONS: GIT manifestations are frequent and severe in SSc. Smoking appears to be associated with severe disease. Anorectal manifestations may be associated with cardiac disease, but we need more studies to validate these results.

Clinical and subclinical atherosclerosis in patients with systemic sclerosis: an observational, multicentre study of GIRRCS (Gruppo Italiano di Ricerca in Reumatologia Clinica e Sperimentale).

OBJECTIVES: Conflicting results about clinical and subclinical atherosclerosis in systemic sclerosis (SSc) and the associated risk factors have been reported. Hence, we aimed to determine the prevalence of clinical and subclinical atherosclerosis in a large number of Italian SSc patients and the associated risk factors. METHODS: This study included 613 SSc patients from 11 Italian tertiary Rheumatologic Units. All patients underwent full history taking, clinical examination, and relevant laboratory and radiological investigations. Doppler ultrasonography (US) of the common carotid and upper and lower limbs was performed to measure carotid and femoral intima-media thickness (cIMT and fIMT), and carotid and peripheral atheroma plaques. Doppler US of the brachial artery was performed to measure flow-mediated dilatation (FMD). RESULTS: Patients were mostly women (91.4%) with a median age of 61 years (range, 20-100); a median disease duration of 14 years (range, 0-77) from the onset of the first non-Raynaud's phenomenon (RP); 9.3% had a history of clinical atherosclerosis (9 stable/unstable angina, 21 myocardial infarctions, 24 heart failure, 3 strokes, 8 transient ischaemic attack, 6 intermittent claudication, 10 atrial thrombo-embolism). In 37.1% of patients, subclinical atherosclerosis was detected, after excluding those with a history of clinical atherosclerosis. The prevalence of clinical and subclinical atherosclerosis was higher than that reported by the European Society of Cardiology and observational studies that enrolled Italian healthy individuals as a control group, respectively. CONCLUSIONS: A higher prevalence of clinical and subclinical atherosclerosis was detected in SSc Italian patients and correlated with traditional and SSc-related risk factors.

The burden and determinants of fatigue in incident and prevalent systemic sclerosis.

OBJECTIVES: To investigate the burden and clinical associations of fatigue in systemic sclerosis (SSc) as measured by FACIT-Fatigue scores. METHODS: Australian Scleroderma Cohort Study participants with ≥1 FACIT-Fatigue score were included. Participants were divided into those with incident SSc (≤5 years SSc duration at recruitment and FACIT-Fatigue score recorded within 5 years of disease onset) or prevalent SSc (first FACIT-Fatigue score recorded >5 years after SSc onset). Generalised estimating equations were used to model change in FACIT-Fatigue scores over time, expressed as an increasing (improving) or decreasing (worsening) score. RESULTS: Of 859 participants, 215 had incident SSc and 644 prevalent SSc. First-recorded FACIT-Fatigue scores were similar in those with incident (37 units, IQR 25-45.5) and prevalent SSc (36 units, IQR 23-44; p=0.17), as were lowest-ever recorded FACIT-Fatigue scores (incident 23 units; prevalent 22 units, p=0.75). In incident SSc, higher skin scores (regression coefficient (RC) -1.5 units, 95%CI -2.3 to -0.8), PAH (RC -8.2, 95%CI -16.5 to 0.1) and reduced left ventricular function (RC -10.6, 95%CI -18.3 to -2.8) were associated with more severe fatigue. In prevalent SSc, higher skin scores (RC -0.6, 95%CI -1.3 to 0), gastrointestinal symptoms (RC -6.6, 95%CI -9.0 to -4.2), hypoalbuminaemia (RC -2.8, 95%CI -5.0 to -0.7), BMI<18.5kg/m2 (RC -6.3, 95%CI -10.3 to -2.2), raised CRP (RC -3.1, 95%CI -4.7 to -1.5), and anaemia (RC -1.7, 95%CI -3.5 to 0.1) were associated with more severe fatigue. CONCLUSIONS: The burden of fatigue is substantial in both incident and prevalent SSc. Cardiopulmonary and gastrointestinal involvement are associated with worse fatigue.

Primary biliary cholangitis has causal effects on systemic rheumatic diseases: a Mendelian randomization study.

BACKGROUND: An association has been observed between primary biliary cholangitis (PBC) and systemic rheumatic diseases (SRDs) in observational studies, however the exact causal link remains unclear. We aimed to evaluate the causal effects of PBC on SRDs through Mendelian randomization (MR) analysis. METHODS: The genome-wide association study (GWAS) summary data were obtained from MRC IEU OpenGWAS and FinnGen databases. Independent genetic variants for PBC were selected as instrumental variables. Inverse variance weighted was used as the main approach to evaluate the causal effects of PBC on Sjögren syndrome (SS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), mixed connective tissue disease (MCTD) and polymyositis (PM). Horizontal pleiotropy and heterogeneity were measured by MR‒Egger intercept test and Cochran's Q value, respectively. RESULTS: PBC had causal effects on SS (OR = 1.177, P = 8.02e-09), RA (OR = 1.071, P = 9.80e-04), SLE (OR = 1.447, P = 1.04e-09), SSc (OR = 1.399, P = 2.52e-04), MCTD (OR = 1.306, P = 4.92e-14), and PM (OR = 1.416, P = 1.16e-04). Based on the MR‒Egger intercept tests, horizontal pleiotropy was absent (all P values > 0.05). The robustness of our results was further enhanced by the leave-one-out method. CONCLUSIONS: Our research has provided new insights into PBC and SRDs, indicating casual effects on various SRDs.