Characteristics and risk factors of pulmonary arterial hypertension in patients with primary Sjögren's syndrome

Pulmonary Hypertension in Connective Tissue Diseases Other than Systemic Sclerosis

Pulmonary hypertension (PH) is a known complication of certain connective tissue diseases (CTDs), with systemic sclerosis (SSc) being the most common in the Western world. However, PH in association with non-SSc CTD such as systemic lupus erythematous, mixed connective tissue disease, and primary Sjögren's syndrome constitutes a distinct subset of patients with inherently different epidemiologic profiles, pathophysiologic mechanisms, clinical features, therapeutic options, and prognostic implications. The purpose of this review is to inform a practical approach for clinicians evaluating patients with non-SSc CTD-associated PH.The development of PH in these patients involves a complex interplay between genetic factors, immune-mediated mechanisms, and endothelial cell dysfunction. Furthermore, the broad spectrum of CTD manifestations can contribute to the development of PH through various pathophysiologic mechanisms, including intrinsic pulmonary arteriolar vasculopathy (pulmonary arterial hypertension, Group 1 PH), left-heart disease (Group 2), chronic lung disease (Group 3), chronic pulmonary artery obstruction (Group 4), and unclear and/or multifactorial mechanisms (Group 5). The importance of diagnosing PH early in symptomatic patients with non-SSc CTD is highlighted, with a review of the relevant biomarkers, imaging, and diagnostic procedures required to establish a diagnosis.Therapeutic strategies for non-SSc PH associated with CTD are explored with an in-depth review of the medical, interventional, and surgical options available to these patients, emphasizing the CTD-specific considerations that guide treatment and aid in prognosis. By identifying gaps in the current literature, we offer insights into future research priorities that may prove valuable for patients with PH associated with non-SSc CTD.

Epidemiology of Sjögren's: A Systematic Literature Review

INTRODUCTION

Primary Sjögren's is a multi-system autoimmune disease affecting patients' physical, mental, and emotional wellbeing. The epidemiology of Sjögren's is not well understood, and up-to-date epidemiological evidence is needed to improve knowledge and awareness of Sjögren's among patients and healthcare professionals, and to ascertain the global burden of disease. The objective of this research was to conduct a de novo systematic literature review (SLR) to identify and synthesise evidence on global epidemiology of primary Sjögren's.

METHODS

This SLR was conducted in May 2021 by searching MEDLINE and Embase databases, relevant conference proceedings, websites of registries, and health technology assessment agencies and databases. Publications were systematically screened for English language articles reporting on the incidence, prevalence, age at symptom onset, and age at diagnosis for people with primary Sjögren's.

RESULTS

Of 3510 records identified, 68 publications were included, representing 62 unique studies. Studies reported on age at symptom onset (16/62; 25.8%) and age at diagnosis (43/62; 69.4%) more frequently than incidence (7/62; 11.3%) and prevalence (9/62; 14.5%). Primary Sjögren's was found to have the highest incidence and prevalence in females and in older age groups (incidence: ≥65 years; prevalence: ≥75 years). Average age at onset and diagnosis of primary Sjögren's ranged between 34-57 years and 40-67 years, respectively.

CONCLUSIONS

This SLR identified a paucity of incidence and prevalence data for primary Sjögren's, highlighting a need for further epidemiological studies. The global Sjögren's community must work together to follow the defined classification criteria of primary Sjögren's and reporting guidelines for incidence and prevalence data to allow for meaningful epidemiological comparisons across studies, settings, and countries.

Pulmonary hypertension in connective tissue diseases: What every CTD specialist should know - but is afraid to ask!

Pulmonary hypertension (PH) is a possible complication of connective tissue diseases (CTDs), especially systemic sclerosis (SSc), systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). It is defined by an elevation of the mean pulmonary arterial pressure above 20mmHg documented during a right heart catheterization (RHC). Due to their multiorgan involvement, CTDs can induce PH by several mechanisms, that are sometimes intricated: pulmonary vasculopathy (group 1) affecting arterioles (pulmonary arterial hypertension, PAH) and possibly venules (pulmonary veno-occlusive-like disease), left-heart disease (group 2), chronic lung disease (group 3) and/or chronic thromboembolic PH (group 4). PH suspicion is often raised by clinical manifestations (dyspnea, fatigue), echocardiographic data (increased peak tricuspid regurgitation velocity), isolated decrease in DLCO in pulmonary function tests, and/or unexplained elevation of BNP/NT-proBNP. Its formal diagnosis always requires a hemodynamic confirmation by RHC. Strategies for PH screening and RHC referral have been extensively investigated for SSc-PAH but data are lacking in other CTDs. Therapeutic management of PH depends of the underlying mechanism(s): PAH-approved therapies in group 1 PH (with possible use of immunosuppressants, especially in case of SLE or MCTD); management of an underlying left-heart disease in group 2 PH; management of an underlying chronic lung disease in group 3 PH; anticoagulation, pulmonary endartectomy, PAH-approved therapies and/or balloon pulmonary angioplasty in group 4 PH. Regular follow-up is mandatory in all CTD-PH patients.

Association of red cell distribution width with pulmonary arterial hypertension in patients with mixed connective tissue disease

BACKGROUND

Pulmonary arterial hypertension (PAH) is a severe complication of mixed connective tissue disease (MCTD) and contributes to increased morbidity and mortality. Still, the demographic characteristics and risk factors of PAH in MCTD remain poorly understood. This study explored risk factors for PAH development in MCTD.

METHODS

Data from patients with MCTD and PAH hospitalized from May 2009 to December 2022 in a single center were collected and compared with patients with MCTD without PAH. The variables were analyzed by logistic regression to identify the factors associated with PAH in patients with MCTD. The receiver-operating characteristic (ROC) curve was used to assess the diagnostic value of the identified factors.

RESULTS

Finally, 119 patients with MCTD were included; 46 had PAH. The mean age at PAH onset and diagnosis was 38.9 ± 13.4 and 39.9 ± 13.7 years, respectively. The median pulmonary arterial systolic pressure (PASP) was 67.0 mmHg. The median brain natriuretic peptide (BNP) level was 180.0 pg/ml at PAH diagnosis. Red cell distribution width (RDW) (OR: 2.128; 95% confidence interval: 1.497-3.026; P < 0.001) was associated with PAH in patients with MCTD. There was a positive correlation between RDW and PASP (r = 0.716, P < 0.001). At a cutoff of 15.2%, RDW had the best sensitivity (80.4%) and specificity (82.2%) for PAH.

CONCLUSION

RDW may serve as a sensitive index to predict PAH in patients with MCTD.

The Spectrum of Extraglandular Manifestations in Primary Sjögren's Syndrome

Extraglandular manifestations (EGMs) in primary Sjogren's syndrome (pSS) represent the clinical expression of the systemic involvement in this disease. EGMs are characterized by a wide heterogeneity; virtually any organ or system can be affected, with various degrees of dysfunction. The existing gaps of knowledge in this complex domain of extraglandular extension in pSS need to be overcome in order to increase the diagnostic accuracy of EGMs in pSS. The timely identification of EGMs, as early as from subclinical stages, can be facilitated using highly specific biomarkers, thus preventing decompensated disease and severe complications. To date, there is no general consensus on the diagnostic criteria for the wide range of extraglandular involvement in pSS, which associates important underdiagnosing of EGMs, subsequent undertreatment and progression to severe organ dysfunction in these patients. This review article presents the most recent basic and clinical science research conducted to investigate pathogenic mechanisms leading to EGMs in pSS patients. In addition, it presents the current diagnostic and treatment recommendations and the trends for future therapeutic strategies based on personalized treatment, as well as the latest research in the field of diagnostic and prognostic biomarkers for extraglandular involvement in pSS.

Soluble markers of B cell activation suggest a role of B cells in the pathogenesis of systemic sclerosis-associated pulmonary arterial hypertension

Introduction

Soluble markers of B cell activation are interesting diagnostic and prognostic tools in autoimmune diseases. Data in systemic sclerosis (SSc) are scarce and few studies focused on their association with disease characteristics.

Methods

1. Serum levels of 14 B cell biomarkers (β2-microglobulin, rheumatoid factor (RF), immunoglobulins (Ig) G, IgA, IgM, BAFF, APRIL, soluble (s)TACI, sBCMA sCD21, sCD23, sCD25, sCD27, CXCL13) were measured in SSc patients and healthy controls (HC). 2. Associations between these biomarkers and SSc characteristics were assessed. 3. The pathophysiological relevance of identified associations was explored by studying protein production in B cell culture supernatant.

Results

In a discovery panel of 80 SSc patients encompassing the broad spectrum of disease manifestations, we observed a higher frequency of RF positivity, and increased levels of β2-microglobulin, IgG and CXCL13 compared with HC. We found significant associations between several biomarkers and SSc characteristics related to disease phenotype, activity and severity. Especially, serum IgG levels were associated with pulmonary hypertension (PH); β2-microglobulin with Nt-pro-BNP and DLCO; and BAFF with peak tricuspid regurgitation velocity (TRV). In a validation cohort of limited cutaneous SSc patients without extensive ILD, we observed lower serum IgG levels, and higher β2-microglobulin, sBCMA, sCD23 and sCD27 levels in patients with pulmonary arterial hypertension (PAH). BAFF levels strongly correlated with Nt-pro-BNP levels, FVC/DLCO ratio and peak TRV in SSc-PAH patients. Cultured SSc B cells showed increased production of various angiogenic factors (angiogenin, angiopoietin-1, VEGFR-1, PDGF-AA, MMP-8, TIMP-1, L-selectin) and decreased production of angiopoietin-2 compared to HC.

Conclusion

Soluble markers of B cell activation could be relevant tools to assess organ involvements, activity and severity in SSc. Their associations with PAH could plead for a role of B cell activation in the pathogenesis of pulmonary microangiopathy. B cells may contribute to SSc vasculopathy through production of angiogenic mediators.

Cardiovascular Disease in Primary Sjögren's Syndrome: Raising Clinicians' Awareness

In the ever evolving landscape of systemic immune mediated diseases, an increased awareness regarding the associated cardiovascular system impairment has been noted in recent years. Even though primary Sjögren’s Syndrome (pSS) is one of the most frequent autoimmune diseases affecting middle-aged individuals, the cardiovascular profile of this specific population is far less studied, at least compared to other autoimmune diseases. Traditional cardiovascular risk factors and disease specific risk factors are inextricably intertwined in this particular case. Therefore, the cardiovascular risk profile in pSS is a multifaceted issue, sometimes difficult to assess. Furthermore, in the era of multimodality imaging, the diagnosis of subclinical myocardial and vascular damage is possible, with recent data pointing that the prevalence of such involvement is higher in pSS than in the general population. Nevertheless, when approaching patients with pSS in terms of cardiovascular diseases, clinicians are often faced with the difficult task of translating data from the literature into their everyday practice. The present review aims to synthesize the existing evidence on pSS associated cardiovascular changes in a clinically relevant manner.

Immunosuppressive therapy in patients with connective tissue disease-associated pulmonary arterial hypertension: A systematic review

OBJECTIVES

It is currently accepted that inflammation plays an important role in the pathogenesis of connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH). However, the efficacy of immunosuppressive therapy remains anecdotal. The objective of this systematic review was to evaluate the efficacy of immunosuppressive therapy in patients with CTD-PAH and to further assess whether response differs between CTD subtypes and clinical features.

METHODS

We systematically searched studies reporting the treatment response of immunosuppressants and biological agents in CTD-PAH from PUBMED, EMBASE, the Cochrane Library, and Scopus. Studies had to report treatment regime and response criteria. The risk of bias was assessed using the Newcastle-Ottawa scale.

RESULTS

Seven independent cohorts, 1 trial, and 1 case-series encompassing 439 patients with CTD-PAH were included. Patients were divided into 2 groups according to the therapeutic regimen. There were 146 patients in the immunosuppressants group with better heart function at baseline and 52.1% (76/146) of them were responders. There were 236 patients treated with immunosuppressants combined with PAH-specific therapy who showed more severity at baseline and 41.1% (97/236) of them were responders. Among different CTD subtypes, patients with systemic lupus erythematosus-associated PAH (SLE-PAH) showed a better response to immunosuppressants (response rate 48.1%). What is more, 1 randomized controlled trial showed the potential therapeutic value of rituximab (n = 57) in CTD-PAH patients.

CONCLUSIONS

Current studies support the use of immunosuppressive therapy in CTD-PAH, especially in SLE-PAH. Further studies on biological agents and the therapeutic effect of different immunosuppressants are still needed.

Recommendations for evaluation and diagnosis of extra-glandular manifestations of primary sjogren syndrome: results of an epidemiologic systematic review/meta-analysis and a consensus guideline from the Brazilian Society of Rheumatology (articular, pulmonary and renal)

Sjogren's Syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration of the exocrine glands and other organs, associated with sicca syndrome but also with systemic involvement with varying degrees of severity. Despite their importance, these systemic manifestations are not routinely evaluated and there is no homogenous approach to their diagnosis or evaluation. To close this gap, a panel of experts from the Brazilian Society of Rheumatology conducted a systematic review and meta-analysis on the identification of epidemiologic and clinical features of these manifestations and made recommendations based on the findings. Agreement between the experts was achieved using the Delphi method. The first part of this guideline summarizes the most important topics, and 11 recommendations are provided for the articular, pulmonary, and renal care of SS patients.

Cardiovascular Events, Sleep Apnoea, and Pulmonary Hypertension in Primary Sjögren's Syndrome: Data from the French Health Insurance Database

Primary Sjögren’s syndrome (pSS) is an autoimmune disease, associated with a high risk of lymphoma. Mounting evidence suggests that cardiovascular morbidity and mortality are higher in patients with pSS, although data are heterogeneous. The aim of this study was to assess whether pSS patients are at higher risk of hospitalisation for cardiovascular events (CVEs), venous thromboembolic events (VTEs), pulmonary hypertension (PH), and sleep apnoea syndrome (SAS). Through a nationwide population-based retrospective study using the French health insurance database, we selected new-onset pSS in-patients hospitalised between 2011 and 2018. We compared the incidence of CVEs (ischemic heart diseases (IHDs), strokes, and heart failure), SAS, VTEs, and PH with an age- and sex-matched (1:10) hospitalised control group. The calculations of adjusted hazard ratios (aHR) included available confounding factors. We studied 25,661 patients hospitalised for pSS compared with 252,543 matched patients. The incidence of hospitalisation for IHD, SAS, and PH was significantly higher in pSS patients (aHR: 1.20 (1.06–1.34); p = 0.003, aHR: 1.97 (1.70–2.28); p < 0.001, and aHR: 3.32 (2.10–5.25); p < 0.001, respectively), whereas the incidence of stroke, heart failure, and VTE was the same between groups. Further prospective studies are needed to confirm these results and to explore the pathophysiological mechanisms involved.

Diagnosis and management of lung involvement in systemic lupus erythematosus and Sjögren's syndrome: a literature review

Lung involvement in systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) has extensively been outlined with a multiplicity of different manifestations. In SLE, the most frequent finding is pleural effusion, while in pSS, airway disease and parenchymal disorders prevail. In both cases, there is an increased risk of pre-capillary and post-capillary pulmonary arterial hypertension (PAH) and pulmonary venous thromboembolism (VTE). The risk of VTE is in part due to an increased thrombophilic status secondary to systemic inflammation or to the well-established association with antiphospholipid antibody syndrome (APS). The lung can also be the site of an organ-specific complication due to the aberrant pathologic immune-hyperactivation as occurs in the development of lymphoma or amyloidosis in pSS. Respiratory infections are a major issue to be addressed when approaching the differential diagnosis, and their exclusion is required to safely start an immunosuppressive therapy. Treatment strategy is mainly based on glucocorticoids (GCs) and immunosuppressants, with a variable response according to the primary pathologic process. Anticoagulation is recommended in case of VTE and multi-targeted treatment regimens including different drugs are the mainstay for PAH management. Antibiotics and respiratory physiotherapy can be considered relevant complement therapeutic measures. In this article, we reviewed lung manifestations in SLE and pSS with the aim to provide a comprehensive overview of their diagnosis and management to physicians taking care of patients with connective tissue diseases.

Cardiac involvement in primary Sjӧgren's syndrome

Primary Sjӧgren's syndrome (pSS) is an autoimmune-mediated, inflammatory, and systemic connective tissue disease (CTD), especially in middle-aged women, which often involves multiple systems and organs of the body. In fact, the heart is an important target organ in patients with pSS. In recent years, it has been confirmed that the morbidity of cardiac involvement has increased in patients with pSS, and cardiovascular disease (CVD) is one of the main causes of death. The increased risk of CVD in pSS patients is associated with a great variety of risk factors, such as age, gender, hypertension, diabetes mellitus, dyslipidemia, disease duration, extra-glandular manifestations, therapeutic drugs of pSS, and so on. Early recognition and effective treatment of CVD may play a crucial role in improving adverse cardiovascular prognosis. Whereas cardiac involvement is closely related to patient prognosis and survival, the cardiac involvement of patients with pSS remains poorly studied. Therefore, this article reviews the cardiovascular risk factors, clinical manifestations of cardiac involvement, cardiovascular biomarkers, and therapeutic strategies of pSS patients.

Sjogren's Syndrome and Pulmonary Disease

Sjogren's syndrome is an autoimmune connective tissue disease targeting the exocrine glands and frequently affecting the respiratory system. The pulmonary disease is the most important extra-glandular manifestation as it carries most of the morbidity and mortality. Typically, it affects the small airways ranging from mild to severe respiratory symptoms. The upper airways are also commonly involved, predisposing sinusitis to occur more frequently than in the normal population. Lymphocytic interstitial pneumonia was initially thought to be the prevailing parenchymal disease; however, multiple cohorts report non-interstitial pneumonia to be the most frequent subtype of interstitial lung disease. In the review of high-resolution computed tomography scans, cystic lesions are commonly found and associate with both the small airways and parenchymal disease. Under their presence, amyloidosis or lymphomas should be considered in the differential. Overall, Sjogren's syndrome has a higher risk for lymphoma, and in lungs this condition should be thought of, especially when the images reveal pulmonary nodularity, lymphocytic interstitial pneumonia and lymphadenopathy. Although, pulmonary artery hypertension was traditionally and exceptionally linked with Sjogren's syndrome, together with systemic lupus erythematosus, they are now acknowledged to be the most common pulmonary vascular disease in east Asian populations, even over patients with systemic sclerosis. Although there are no controlled prospective trials to treat pulmonary disease in Sjogren's syndrome, the mainstay treatment modality still falls on glucocorticoid therapy (systemic and inhaled), combined with immune modulators or alone. Most of the evidence sustains successful outcomes based on reported cases or case series.

Primary Sjögren's Syndrome and Cardiovascular Disease

Sjögren's syndrome is a rheumatic autoimmune disease that primarily affects middle-aged women and runs a slowly progressing course with sicca symptoms being the prevalent manifestation. Premature atherosclerosis and increased cardiovascular (CV) morbidity and mortality are frequently encountered in rheumatic diseases characterized by significant systemic inflammation, such as the inflammatory arthritides, systemic vasculitides and systemic lupus erythematosus. In the same context, chronic inflammation and immune aberrations underlying Sjögren's syndrome are also reported to be associated with augmented risk of atherosclerosis. Increased CV disease (CVD) frequency has been found in recent meta-analyses. The involvement of the CV system is not a common feature of Sjögren's syndrome; however, specific manifestations, such as autoantibody-mediated heart block, pericarditis, pulmonary arterial hypertension and dysautonomia, have been described. This review focuses on studies addressing CV morbidity in Sjögren's syndrome and presents current data regarding distinct CV features of the disease.

Autoantibody clustering of lupus-associated pulmonary hypertension

Objective

To define the SLE phenotype associated with pulmonary hypertension using multiple autoantibodies.

Methods

207 (8%) patients with SLE with pulmonary hypertension, defined as a right ventricular systolic pressure greater than 40 mm Hg on transthoracic echocardiogram or as pulmonary artery dilatation on CT of the chest, were identified from the Hopkins Lupus Cohort (94.2% female; 56.5% African–American, 39% Caucasian; mean age 45.6 years). 53 patients were excluded from the clustering analysis due to incomplete autoantibody profiles. Agglomerative hierarchical clustering algorithm with Ward’s method was used to cluster the patients with pulmonary hypertension, based on their autoantibodies. Autoantibodies used in the clustering analysis included lupus anticoagulant, anticardiolipin, anti-beta 2 glycoprotein I, antidouble-stranded DNA, anti-Sm (anti-Smith), antiribonucleoprotein, false positive-rapid plasma reagin, anti-Ro, anti-La and hypocomplementaemia (C3 ever low or C4 ever low). The Dunn index was used to internally validate the clusters. Bootstrap resampling derived the mean Jaccard coefficient for each cluster. All analyses were performed in R V.3.6.1 using the packages cluster, fpc and gplots.

Results

A significantly higher prevalence of pulmonary hypertension in African–American patients with SLE, compared with Caucasian patients with SLE (11.5% vs 5.9%, p<0.0001), was found. Based on equivalent Dunn indices, the 154 patients with SLE-associated pulmonary hypertension with complete autoantibody data were divided into five clusters, three of which had mean Jaccard coefficients greater than 0.6. Hypocomplementaemia, renal disorder and age at diagnosis significantly differed across clusters. One cluster was defined by antiphospholipid antibodies. One cluster was defined by anti-Ro and anti-La. One cluster had low frequencies of all antibodies.

Conclusion

SLE-associated pulmonary hypertension disproportionately affects African–American patients. Pulmonary hypertension in SLE is defined by five autoantibody clusters. Antiphospholipid antibodies, anti-Ro and anti-La positivity, serological activity, and age at pulmonary hypertension diagnosis significantly differed across clusters, possibly indicating different pathophysiological mechanisms.

Autoimmune diseases in China

Autoimmune diseases, such as rheumatoid arthritis, systematic lupus erythematosus and Sjögren's syndrome, are a group of diseases characterized by the activation of immune cells and excessive production of autoantibodies. Although the pathogenesis of these diseases is still not completely understood, studies have shown that multiple factors including genetics, environment and immune responses play important roles in the development and progression of the diseases. In China, there are great achievements in the mechanisms of autoimmune diseases during the last decades. These studies provide new insight to understand the diseases and also shed light on the development of novel therapy.

Characteristics and risk factors for pulmonary arterial hypertension associated with primary Sjögren's syndrome: 15 new cases from a single center

AIM

This study aimed to retrospectively describe 15 new primary Sjögren's syndrome-pulmonary arterial hypertension (pSS-PAH) cases confirmed by right heart catheterization (RHC). Demographic and clinical characteristics were analyzed and risk factors for PAH in pSS were explored.

METHOD

We retrospectively described 15 new pSS-PAH cases confirmed by RHC referred to our institution between January 2013 and March 2018. We present PAH and pSS characteristics, hemodynamic evaluations, medical management, and outcomes. A matched case control study was carried out to determine the risk factors of PAH in pSS compared with pSS-non-PAH patients.

RESULTS

All patients were female with a mean age at PAH diagnosis of 52.9 ± 14.6 years. The delay between the first symptom and PAH diagnosis was 18.7 ± 19.7 months. The most common primary manifestation at PAH onset was exertional dyspnea (13/15). At diagnosis of PAH, PAH was severe with a mean pulmonary artery pressure of 48.8 ± 13.7 mm Hg (range, 27-72 mm Hg) and a mean cardiac index of 2.3 ± 0.6 L/min/m² (range, 1.47-3.41 L/min/m² ). Compared with the pSS-PAH without pericardial effusion, pSS-PAH with pericardial effusion had larger right arterial (53 [45-56.75] vs 38 [35.5-46.5], P = .018) and right ventricular sizes (47 [42.75-51.25] vs 36 [32.5-41], P = .007). Compared with the pSS non-PAH group, we identified 2 risk factors for PAH in pSS: pericardial effusion (odds ratio [OR] [95% CI], 14.29 [1.14-166.67], P = .039) and liver involvement (OR [95% CI], 14.71 [1.14-166.67], P = .035).

CONCLUSION

For pSS patients, PAH can be the first manifestation. We believe that systemic evaluation, especially in patients with pericardial effusion and liver involvement, is important to identify high-risk patients for PAH, improving their prognosis.

Pulmonary Involvement in Sjögren Syndrome

Sjögren syndrome (SS) is a progressive autoimmune disease characterized by dryness, predominantly of the eyes and mouth, caused by chronic lymphocytic infiltration of the lacrimal and salivary glands. Extraglandular inflammation can lead to systemic manifestations, many of which involve the lungs. Studies in which lung involvement is defined as requiring the presence of respiratory symptoms and either radiograph or pulmonary function test abnormalities quote prevalence estimates of 9% to 22%. The most common lung diseases that occur in relation to SS are airways disease and interstitial lung disease. Evidence-based guidelines to inform treatment recommendations for lung involvement are largely lacking.

Contribution of pulmonary function tests (PFTs) to the diagnosis and follow up of connective tissue diseases

Introduction

Connective Tissue Diseases (CTDs) are systemic autoimmune conditions characterized by frequent lung involvement. This usually takes the form of Interstitial Lung Disease (ILD), but Obstructive Lung Disease (OLD) and Pulmonary Artery Hypertension (PAH) can also occur. Lung involvement is often severe, representing the first cause of death in CTD. The aim of this study is to highlight the role of Pulmonary Function Tests (PFTs) in the diagnosis and follow up of CTD patients.

Main body

Rheumatoid Arthritis (RA) showed mainly an ILD with a Usual Interstitial Pneumonia (UIP) pattern in High-Resolution Chest Tomography (HRCT). PFTs are able to highlight a RA-ILD before its clinical onset and to drive follow up of patients with Forced Vital Capacity (FVC) and Carbon Monoxide Diffusing Capacity (DL_CO). In the course of Scleroderma Spectrum Disorders (SSDs) and Idiopathic Inflammatory Myopathies (IIMs), DL_CO appears to be more sensitive than FVC in highlighting an ILD, but it can be compromised by the presence of PAH. A restrictive respiratory pattern can be present in IIMs and Systemic Lupus Erythematosus due to the inflammatory involvement of respiratory muscles, the presence of fatigue or diaphragm distress.

Conclusions

The lung should be carefully studied during CTDs. PFTs can represent an important prognostic tool for diagnosis and follow up of RA-ILD, but, on their own, lack sufficient specificity or sensitivity to describe lung involvement in SSDs and IIMs. Several composite indexes potentially able to describe the evolution of lung damage and response to treatment in SSDs are under investigation. Considering the potential severity of these conditions, an HRCT jointly with PFTs should be performed in all new diagnoses of SSDs and IIMs. Moreover, follow up PFTs should be interpreted in the light of the risk factor for respiratory disease related to each disease.