A formula for predicting emphysema extent in combined idiopathic pulmonary fibrosis and emphysema.

BACKGROUND: No single pulmonary function test captures the functional effect of emphysema in idiopathic pulmonary fibrosis (IPF). Without experienced radiologists, other methods are needed to determine emphysema extent. Here, we report the development and validation of a formula to predict emphysema extent in patients with IPF and emphysema. METHODS: The development cohort included 76 patients with combined IPF and emphysema at the Royal Brompton Hospital, London, United Kingdom. The formula was derived using stepwise regression to generate the weighted combination of pulmonary function data that fitted best with emphysema extent on high-resolution computed tomography. Test cohorts included patients from two clinical trials (n = 455 [n = 174 with emphysema]; NCT00047645, NCT00075998) and a real-world cohort from the Royal Brompton Hospital (n = 191 [n = 110 with emphysema]). The formula is only applicable for patients with IPF and concomitant emphysema and accordingly was not used to detect the presence or absence of emphysema. RESULTS: The formula was: predicted emphysema extent = 12.67 + (0.92 x percent predicted forced vital capacity) - (0.65 x percent predicted forced expiratory volume in 1 second) - (0.52 x percent predicted carbon monoxide diffusing capacity). A significant relationship between the formula and observed emphysema extent was found in both cohorts (R2 = 0.25, P < 0.0001; R2 = 0.47, P < 0.0001, respectively). In both, the formula better predicted observed emphysema extent versus individual pulmonary function tests. A 15% emphysema extent threshold, calculated using the formula, identified a significant difference in absolute changes from baseline in forced vital capacity at Week 48 in patients with baseline-predicted emphysema extent < 15% versus ≥ 15% (P = 0.0105). CONCLUSION: The formula, designed for use in patients with IPF and emphysema, demonstrated enhanced ability to predict emphysema extent versus individual pulmonary function tests. TRIAL REGISTRATION: NCT00047645; NCT00075998.

Cardiac sarcoidosis and neurosarcoidosis - multidisciplinary approach for diagnosis.

PURPOSE OF REVIEW: The current review aims to highlight the role of multidisciplinary approach in the diagnosis of patients with cardiac and neurosarcoidosis. Multidisciplinary approach integrates the available clinical information, imaging and histopathological results aiming to reach a definite or at least provisional diagnosis and allow appropriate management. Multidisciplinary approach is the reference standard for diagnosis of interstitial lung disease and should be strongly considered in complex clinical conditions such as cardiac sarcoidosis (CS) and neurosarcoidosis. RECENT FINDINGS: Histopathological confirmation of noncaseating granulomatous inflammation provides a definite diagnosis of sarcoidosis involving any organ. However, a provisional high confidence or even definite clinical diagnosis can be reached using multidisciplinary evaluation of all available evidence. The diagnosis of cardiac sarcoidosis and neurosarcoidosis requires the integration of different expertise based on the current diagnostic criteria sets. Identifying typical or at least compatible patterns on advanced imaging modalities (CMR and Fluro-Deoxy-Glucose Positron Emission Tomography (FDG-PET)) seems key for the diagnosis of CS, while a confident diagnosis of extra-cardiac disease supports an at least provisional diagnosis. Similarly, in neurosarcoidosis integrating compatible MRI appearances and cerebrospinal fluid results in patients with systemic sarcoidosis allows an at least provisional diagnosis. Exclusion of alternative differential diagnoses is crucial and requires high clinical suspicion, imaging review expertise and appropriate tests performance. SUMMARY: There have been considerable advances in the diagnostic approach of patients with cardiac and neurosarcoidosis. Multidisciplinary approach for both diagnosis and management is required to reach a confident clinical diagnosis and should be applied when possible.

Role of serial 18F-fludeoxyglucose positron emission tomography in determining the therapeutic efficacy of immunosuppression and clinical outcome in patients with cardiac sarcoidosis.

BACKGROUND: Myocardial inflammation and perfusion defects detected by 18F-fludeoxyglucose (FDG) and Rubidium-82 positron emission tomography (PET) may be associated with ventricular arrhythmias (VAs) in cardiac sarcoidosis (CS). The role of serial quantitative PET in determining the effect of treatment on myocardial inflammation and clinical outcomes is yet to be defined. METHODS: Newly diagnosed CS patients with active myocardial inflammation (maximum standardised uptake value (SUVmax) ≥ 2.5) were treated with immunosuppression, then underwent repeat FDG-PET, Rubidium-82, and echocardiographic imaging 6-12 months later. Serial changes in SUVmax, SUVmean, inflammatory extent, perfusion defect (PD) extent, metabolism/perfusion mismatch extent, global cardiac metabolic activity, and left ventricular ejection fraction (LVEF) were assessed. The primary endpoint was a composite of all-cause mortality, serious VA and heart-failure (HF) hospitalisation. Event data were recorded from the date of the second FDG-PET. RESULTS: The study population consisted of 113 patients (66% male, age: 55 ± 11 years, LVEF: 54 ± 13%). SUVmax reduced from 4.5 (interquartile range: 3.3-7.1) to 2.7 (2.2-3.6). Overall, 94 (83%) patients saw serial reduction in SUVmax, with 42 (37%) demonstrating complete response (SUVmax <2.5). Following a median of 46 (25-57) months, 28 (25%) patients reached the endpoint (8 deaths, 17 VAs, and 3 HF hospitalisations). PD extent (Hazard ratio 1.03, 95% confidence interval: 1.01-1.05; p = 0.035) was a significant predictor of outcome following treatment, even after accounting for LVEF and change in SUVmean. The risk of adverse events was the greatest in those with a pre-treatment or post-treatment PD extent of >10%. CONCLUSION: In our cohort with active CS, following a treatment-induced reduction in myocardial inflammation, PD extent was the main predictor of adverse events.

Sex disparities in cardiac sarcoidosis patients undergoing implantable cardioverter-defibrillator implantation.

INTRODUCTION: In patients with cardiac sarcoidosis (CS), implantable cardioverter-defibrillators (ICDs) are important for preventing sudden cardiac death. This study aimed to investigate sex disparities in CS patients undergoing ICD implantation. METHODS: The 2016-2020 National Inpatient Sample (NIS) database compared the characteristics and outcomes of males and females with CS receiving ICDs. RESULTS: Among 760 CS patients who underwent inpatient ICD implantation, 66.4% were male. Males were younger (55.0 vs. 56.9 years, p < .01), had higher rates of diabetes (31.7% vs. 21.6%, p < .01) and chronic kidney disease (CKD) (16.8% vs. 7.8%, p < .01) but lower prevalence of atrial fibrillation (AF) (11.9% vs. 23.5%, p < .01), sick sinus syndrome (4.0% vs. 7.8%, p = .024), ventricular fibrillation (VF) (9.9% vs. 15.7%, p = .02), and black ancestry (31.9% vs. 58.0%, p < .01). Unadjusted major adverse cardiovascular events (MACE), defined as a composite of in-hospital death, myocardial infarction (MI), and ischemic stroke, was higher in females (11.8% vs. 6.9%, p = .024), but when adjusted for age and tCharlson Comorbidity Index (CCI), females demonstrated significantly lower odds of experiencing MACE (aOR: 0.048, 95% CI: 0.006-0.395, p = .005). Incidence of acute kidney injury (AKI) post-ICD was significantly lower in females (15.7% vs. 23.8%, p = .01) as was the adjusted odds (aOR: 0.282, 95% CI: 0.146-0.546, p < .01). There was comparable mean length of stay and hospital charges. CONCLUSION: ICD utilization in CS patients is more common among males, who have a higher prevalence of diabetes and CKD but a lower prevalence of AF, sick sinus syndrome, and VF. Adjusted MACE and AKI were significantly lower in females.

Low bleeding rates following transbronchial lung cryobiopsy in unclassifiable interstitial lung disease.

BACKGROUND AND OBJECTIVE: Bronchoscopic transbronchial lung cryobiopsy (TBLC) is a guideline-endorsed alternative to surgical lung biopsy for tissue diagnosis in unclassifiable interstitial lung disease (ILD). The reported incidence of post-procedural bleeding has varied widely. We aimed to characterize the incidence, severity and risk factors for clinically significant bleeding following TBLC using an expert-consensus airway bleeding scale, in addition to other complications and diagnostic yield. METHODS: A retrospective cohort study of consecutive adult outpatients with unclassifiable ILD who underwent TBLC following multidisciplinary discussion at a single centre in the UK between July 2016 and December 2021. TBLC was performed under general anaesthesia with fluoroscopic guidance and a prophylactic endobronchial balloon. RESULTS: One hundred twenty-six patients underwent TBLC (68.3% male; mean age 62.7 years; FVC 86.2%; DLCO 54.5%). Significant bleeding requiring balloon blocker reinflation for >20 min, admission to ICU, packed red blood cell transfusion, bronchial artery embolization, resuscitation or procedural abandonment, occurred in 10 cases (7.9%). Significant bleeding was associated with traction bronchiectasis on HRCT (OR 7.1, CI 1.1-59.1, p = 0.042), a TBLC histological pattern of UIP (OR 4.0, CI 1.1-14, p = 0.046) and the presence of medium-large vessels on histology (OR 37.3, CI 6.5-212, p < 0.001). BMI ≥30 (p = 0.017) and traction bronchiectasis on HRCT (p = 0.025) were significant multivariate predictors of longer total bleeding time (p = 0.017). Pneumothorax occurred in nine cases (7.1%) and the 30-day mortality was 0%. Diagnostic yield was 80.6%. CONCLUSION: TBLC has an acceptable safety profile in experienced hands. Radiological traction bronchiectasis and obesity increase the risk of significant bleeding following TBLC.

Monitoring of Sarcoidosis.

This article focuses on the monitoring of pulmonary sarcoidosis. The monitoring of sarcoidosis is, in part, focused on serial change in major organ involvement but also includes diagnostic re-evaluation and review of change in quality of life. Recent criteria for progression of fibrotic interstitial lung disease are adapted to pulmonary sarcoidosis. The frequency and nature of monitoring are discussed, integrating baseline risk stratification and strategic treatment goals. Individual variables used to identify changes in pulmonary disease severity are discussed with a focus on their flaws and the need for a multidimensional approach. Other key monitoring issues are covered briefly.

Imaging of Pulmonary Sarcoidosis-A Review.

Sarcoidosis is the classic multisystem granulomatous disease. First reported as a disorder of the skin, it is now clear that, in the overwhelming majority of patients with sarcoidosis, the lungs will bear the brunt of the disease. This review explores some of the key concepts in the imaging of pulmonary sarcoidosis: the wide array of typical (and some of the less common) findings on high-resolution computed tomography (HRCT) are reviewed and, with this, the concept of morphologic/HRCT phenotypes is discussed. The pathophysiologic insights provided by HRCT through studies where morphologic abnormalities and pulmonary function tests are compared are evaluated. Finally, this review outlines the important contribution of HRCT to disease monitoring and prognostication.

Sarcoidosis Associated Pulmonary Hypertension.

In patients with sarcoidosis, the development of pulmonary hypertension is associated with significant morbidity and mortality. The global prevalence of sarcoidosis-associated pulmonary hypertension (SAPH) reportedly ranges between 2.9% and 20% of sarcoidosis patients. Multiple factors may contribute to the development of SAPH, including advanced parenchymal lung disease, severe systolic and/or diastolic left ventricular dysfunction, veno-occlusive or thromboembolic disease, as well as extrinsic factors such as pulmonary vascular compression from enlarged lymph nodes, anemia, and liver disease. Early diagnosis of SAPH is important but rarely achieved primarily due to insufficiently accurate screening strategies, which rely entirely on non-invasive tests and clinical assessment. The definitive diagnosis of SAPH requires right heart catheterization (RHC), with transthoracic echocardiography as the recommended gatekeeper to RHC according to current guidelines. A 6-min walk test (6MWT) had the greatest prognostic value in SAPH patients based on recent registry outcomes, while advanced lung disease determined using a reduced DLCO (<35% predicted) was associated with reduced transplant-free survival in pre-capillary SAPH. Clinical management involves the identification and treatment of the underlying mechanism. Pulmonary vasodilators are useful in several scenarios, especially when a pulmonary vascular phenotype predominates. End-stage SAPH may warrant consideration for lung transplantation, which remains a high-risk option. Multi-centered randomized controlled trials are required to develop existing therapies further and improve the prognosis of SAPH patients.

The role of infliximab in treating refractory cardiac sarcoidosis. Case series and systematic review of literature.

Cardiac sarcoidosis is associated with significant morbidity and mortality. Immunosuppressive treatment focuses on suppressing myocardial inflammation, which can lead to major adverse events especially when progressing to fibrosis. Conventional management usually includes steroids and steroid sparing agents such as methotrexate and azathioprine. Tumour necrosis factor alpha inhibitors are often reserved for those with a worsening clinical status and/or evidence of persistent inflammatory activity despite conventional therapy. Refractory cardiac sarcoidosis (CS) can be defined as the persistence or progression of active disease, evidenced either by lack of clinical response or persistence or progression of imaging abnormalities, despite being on conventional therapy. In the United Kingdom, tumour necrosis factor alpha inhibitors are currently not licensed for cardiac sarcoidosis as there are no randomised controlled trials to assess the efficacy of infliximab in this patient cohort. In this study, we present the outcomes of six patients treated with infliximab for refractory cardiac sarcoidosis at Royal Brompton Hospital and performed a systematic review of the existing literature on use of infliximab in cardiac sarcoidosis. We searched the Cochrane Library, OVID Medline, OVID Embase, Web of Science and Pubmed to identify 7 full-text studies assessing the role of infliximab in the management of cardiac sarcoidosis. Infliximab was found to play a vital role in stabilising refractory cardiac sarcoidosis by stemming clinical deterioration, arrythmia burden and even reducing steroids requirements. Further prospective trial data is necessary to validate these findings.

Racial disparities among patients with cardiac sarcoidosis and arrhythmias in the United States: A propensity matched-analysis from the national inpatient sample database 2016-2020.

BACKGROUND: Cardiac sarcoidosis (CS) is frequently associated with conduction abnormalities and arrhythmias. In this study, we aim to evaluate racial disparities in the frequency of arrhythmias, and associated co-morbidities, among patients with CS. METHODS: White and African American (AA) patients diagnosed with CS were identified and compared from the 2016-2020 National Inpatient Sample (NIS) database whilst adjusting for confounders via logistic regression models. RESULTS: A total of 7,935 patients with CS were included in the study. The propensity-matched sample comprised of 5,570 patients, of whom 2,785 were White and 2,785 were AA. AA patients had a longer mean length of hospital stay (LOS) (7.84 vs. 6.94, p<0.01), a higher mean Charlson Comorbidity Index (CCI) score (3.10 vs. 2.84, p<0.01), and significantly higher incidences of cardiogenic shock [(9.2% vs 6.3%, p<0.01), aOR 1.45 (95% CI 1.17-1.78), p<0.01] and acute kidney injury (AKI) [(34.3% vs. 26.9%, p<0.01), aOR 1.41 (95% CI 1.24-1.61), p<0.01]. From an arrhythmia perspective, AA CS patients were shown to have a lower frequency of: (1) ventricular tachycardia (32.5% vs. 37.9%, p<0.01), (2) ventricular fibrillation (5.4% vs.7.2%, p<0.01), (3) first-degree AV block (1.8% vs. 4.1%, p<0.01), (4) complete AV block (6.3% vs. 14.2%, p<0.01), and (5) atrial fibrillation (31.8% vs. 34.8%, p=0.016) when compared to Whites with CS. Mortality remained higher for AAs (3.8% vs. 2.7%, p=0.024). CONCLUSION: Our study demonstrates a higher incidence of cardiac arrhythmias among White patients but a higher incidence of cardiogenic shock, AKI, mean LOS, and mortality among AA patients with cardiac sarcoidosis.

Characteristics and clinical outcomes of patients with sarcoidosis admitted for ST-elevation myocardial infarction in the United States: a propensity matched analysis from the National Inpatient Sample.

Introduction: Sarcoidosis is a systemic inflammatory disorder characterised by non-caseating granulomas. Cardiac sarcoidosis (CS) normally causes conduction abnormalities, ventricular arrhythmias, and heart failure. Little is known about the characteristics and impact of sarcoidosis in patients admitted with ST-elevation myocardial infarction (STEMI). This study aims to fill this void. Material and methods: Utilising the National Inpatient Sample (NIS) database (2016-2020), individuals with STEMI were identified and categorised based on sarcoidosis presence whilst adjusting for confounders via logistic regression models. Results: Among 851,290 STEMI patients, 1215 had sarcoidosis. Before propensity matching, sarcoidosis patients were notably different in demographics and comorbidities compared to non-sarcoidosis patients. After propensity score matching (PSM), sarcoidosis patients were found to have a higher incidence of supraventricular tachycardia (SVT) (2.5% vs. 1.3%, p = 0.024) and acute kidney injury (AKI) (23.3% vs. 20.8%, aOR = 1.269, 95% CI: 1.02-1.58, p = 0.033) but a lower incidence of undergoing coronary artery bypass graft (CABG) (5.5% vs. 8.5%, aOR = 0.663; 95% CI: 0.472-0.931, p = 0.018), while no significant disparities were noted in PCI, cardiogenic shock, mortality, or mean length of stay (LOS). Conclusions: Using propensity-matched large real-world data of STEMI patients, sarcoidosis was associated with fewer cases of CABG and a greater incidence of AKI and SVT compared to non-sarcoidosis patients.

Comparing outcomes of an 'early' versus 'late' diagnosis of cardiac sarcoidosis following a baseline presentation of high-grade atrioventricular block.

BACKGROUND: There is a paucity of evidence on impact of a delay in Cardiac Sarcoidosis (CS) diagnosis after high-grade atrioventricular-block (AVB) and this study aims to fill this void. METHODS: Consecutive CS patients (n = 77) with high grade AVB referred to one specialist hospital in London between February 2007 to February 2023 were retrospectively reviewed. The median time from AVB to diagnosing CS (112 days) was used to define the Early (n = 38) and Late (n = 39) cohorts. The primary endpoint was a composite of all-cause mortality, cardiac transplantation, ventricular arrhythmic events or heart failure hospitalisation. Secondary endpoints included difference in maintenance prednisolone dose, need for cardiac device upgrade and device complications. RESULTS: The mean age of the cohort was 54.4 (±10.6) years of whom 64 % were male and 81 % Caucasian. After a mean follow up of 54.9 (±45.3) months, the primary endpoint was reached by more patients from the Late cohort (16/39 vs. 6/38, p = 0.02; multivariable HR 6.9; 95 %CI 1.5-32.2, p = 0.01). Early Group were more likely to have received an Implantable Cardioverter Defibrillator or Cardiac Resynchronisation Therapy-defibrillator as index device after AVB (19/38 vs. 6/39; p < 0.01) and had fewer device upgrades (19/38 vs. 30/39, p = 0.01) and a trend towards fewer device complications (1 vs. 5, p = 0.20). The maintenance dose of prednisolone was significantly higher in Late Group [20.7(±9.7) mg vs. 15.3(±7.9) mg, p = 0.02]. CONCLUSION: A late diagnosis of CS was associated with more adverse events, a greater probability of needing a device upgrade and required higher maintenance steroid dose.

Overnight desaturation in interstitial lung diseases: links to pulmonary vasculopathy and mortality.

Background: Overnight desaturation predicts poor prognosis across interstitial lung diseases (ILDs). The aim of the present study was to investigate whether nocturnal desaturation is associated with pulmonary vasculopathy and mortality. Methods: A retrospective single centre study of 397 new ILD patients was carried out including patients with idiopathic pulmonary fibrosis (IPF) (n=107) and patients with non-IPF fibrotic ILD (n=290). This is the largest study to date of the effect of significant nocturnal desaturation (SND) (≥10% of total sleep time with oxygen saturation ≤90% measured by pulse oximetry). Results: The prevalence of SND was 28/107 (26.2%) in IPF and 80/290 (27.6%) in non-IPF ILD. The prevalence of SND was higher in non-IPF ILDs than in IPF (p=0.025) in multivariate analysis. SND was associated with noninvasive markers of pulmonary hypertension (PH): tricuspid regurgitation velocity (TRV) (p<0.0001), brain natriuretic peptide (p<0.007), carbon monoxide transfer coefficient (p<0.0001), A-a gradient (p<0.0001), desaturation >4% in 6-min walking test (p<0.03) and pulmonary artery diameter (p<0.005). SND was independently associated with high echocardiographic PH probability in the entire cohort (OR 2.865, 95% CI 1.486-5.522, p<0.002) and in non-IPF fibrotic ILD (OR 3.492, 95% CI 1.597-7.636, p<0.002) in multivariate analysis. In multivariate analysis, SND was associated with mortality in the entire cohort (OR 1.734, 95% CI 1.202-2.499, p=0.003) and in IPF (OR 1.908, 95% CI 1.120-3.251, p=0.017) and non-IPF fibrotic ILD (OR 1.663, 95% CI 1.000-2.819, p=0.041). Separate models with exclusion of each one of the diagnostic subgroups showed that no subgroup was responsible for this finding in non-IPF ILDs. SND was a stronger marker of 5-year mortality than markers of PH. Conclusion: SND was associated with high echocardiographic probability and mortality and was a stronger predictor of mortality in IPF and non-IPF ILDs grouped together to power the study.

High-resolution CT phenotypes in pulmonary sarcoidosis: a multinational Delphi consensus study.

One view of sarcoidosis is that the term covers many different diseases. However, no classification framework exists for the future exploration of pathogenetic pathways, genetic or trigger predilections, patterns of lung function impairment, or treatment separations, or for the development of diagnostic algorithms or relevant outcome measures. We aimed to establish agreement on high-resolution CT (HRCT) phenotypic separations in sarcoidosis to anchor future CT research through a multinational two-round Delphi consensus process. Delphi participants included members of the Fleischner Society and the World Association of Sarcoidosis and other Granulomatous Disorders, as well as members' nominees. 146 individuals (98 chest physicians, 48 thoracic radiologists) from 28 countries took part, 144 of whom completed both Delphi rounds. After rating of 35 Delphi statements on a five-point Likert scale, consensus was achieved for 22 (63%) statements. There was 97% agreement on the existence of distinct HRCT phenotypes, with seven HRCT phenotypes that were categorised by participants as non-fibrotic or likely to be fibrotic. The international consensus reached in this Delphi exercise justifies the formulation of a CT classification as a basis for the possible definition of separate diseases. Further refinement of phenotypes with rapidly achievable CT studies is now needed to underpin the development of a formal classification of sarcoidosis.

Cluster analysis of blood biomarkers to identify molecular patterns in pulmonary fibrosis: assessment of a multicentre, prospective, observational cohort with independent validation.

BACKGROUND: Pulmonary fibrosis results from alveolar injury, leading to extracellular matrix remodelling and impaired lung function. This study aimed to classify patients with pulmonary fibrosis according to blood biomarkers to differentiate distinct disease patterns, known as endotypes. METHODS: In this cluster analysis, we first classified patients from the PROFILE study, a multicentre, prospective, observational cohort of individuals with incident idiopathic pulmonary fibrosis or non-specific interstitial pneumonia in the UK (Nottingham University Hospitals, Nottingham; and Royal Brompton Hospital, London). 13 blood biomarkers representing extracellular matrix remodelling, epithelial stress, and thrombosis were measured by ELISA in the PROFILE study. We classified patients by unsupervised consensus clustering. To evaluate generalisability, a machine learning classifier trained on biomarker signatures derived from consensus clustering was applied to a replication dataset from the Australian Idiopathic Pulmonary Fibrosis Registry (AIPFR). Biomarker associations with mortality and change in percentage of predicted forced vital capacity (FVC%) were assessed, adjusting for age, gender, baseline FVC%, and antifibrotic treatment and steroid treatment before and after baseline. Mortality risk associated with the clusters in the PROFILE cohort was evaluated with Cox proportional hazards models, and mixed-effects models were used to analyse how clustering was associated with longitudinal FVC% in the PROFILE and AIPFR cohorts. FINDINGS: 455 of 580 participants from the PROFILE study (348 [76%] men and 107 [24%] women; mean age 72·4 years [SD 8·3]) were included in the analysis. Within this group, three clusters were identified based on blood biomarkers. A basement membrane collagen (BM) cluster (n=248 [55%]) showed high concentrations of PRO-C4, PRO-C28, C3M, and C6M, whereas an epithelial injury (EI) cluster (n=109 [24%]) showed high concentrations of MMP-7, SP-D, CYFRA211, CA19-9, and CA-125. The third cluster (crosslinked fibrin [XF] cluster; n=98 [22%]) had high concentrations of X-FIB. In the replication dataset (117 of 833 patients from AIPFR; 87 [74%] men and 30 [26%] women; mean age 72·9 years [SD 7·9]), we identified the same three clusters (BM cluster, n=93 [79%]; EI cluster, n=8 [7%]; XF cluster, n=16 [14%]). These clusters showed similarities with clusters in the PROFILE dataset regarding blood biomarkers and phenotypic signatures. In the PROFILE dataset, the EI and XF clusters were associated with increased mortality risk compared with the BM cluster (EI vs BM: adjusted hazard ratio [HR] 1·88 [95% CI 1·42-2·49], p<0·0001; XF vs BM: adjusted HR 1·53 [1·13-2·06], p=0·0058). The EI cluster showed the greatest annual FVC% decline, followed by the BM and XF clusters. A similar FVC% decline pattern was observed in these clusters in the AIPFR replication dataset. INTERPRETATION: Blood biomarker clustering in pulmonary fibrosis identified three distinct blood biomarker signatures associated with lung function and prognosis, suggesting unique pulmonary fibrosis biomarker patterns. These findings support the presence of pulmonary fibrosis endotypes with the potential to guide targeted therapy development. FUNDING: None.