Recent advances in measuring the effects of diet on gastrointestinal physiology: Probing the "leaky gut" and application of real-time ultrasound.

There is a large pool of ideas in both mainstream and non-mainstream medicine on how diet can be manipulated in order to treat or prevent illnesses. Despite this, our understanding of how specific changes in diet influence the structure and function of the gastrointestinal tract is limited. This review aims to describe two areas that might provide key information on the integrity and function of the gastrointestinal tract. First, demystifying the "leaky gut syndrome" requires rational application and interpretation of tests of intestinal barrier function. Multiple ways of measuring barrier function have been described, but the inherent difficulties in translation from animal studies to humans have created misinterpretations and misconceptions. The intrinsic nature of intestinal barrier function is dynamic. This is seldom considered in studies of intestinal barrier assessment. To adequately understand the effects of dietary interventions on intestinal barrier function, background barrier function in different regions of the gut and the dynamic responses to stressors (such as psychological stress) should be assessed as a minimum. Second, intestinal ultrasound, which is now established in the assessment and monitoring of inflammatory bowel disease, has hitherto been poorly evaluated in assessing real-time intestinal function and novel aspects of structure in patients with disorders of gut-brain interaction. In conclusion, a more complete functional and structural profile that these investigations enable should permit a greater understanding of the effects of dietary manipulation on the gastrointestinal tract and provide clinically relevant information that, amongst other advantages, might permit opportunities for personalized health care delivery.

Understanding breathlessness burden and psychophysiological correlates in asthma.

BACKGROUND: Breathlessness is a disabling symptom, with complexity that is often under recognised and under treated in asthma. OBJECTIVE: To highlight the burden of breathlessness in people with severe compared with mild-to-moderate asthma and identify psychophysiological correlates of breathlessness. METHODS: This was a cross-sectional study of people with mild-to-severe asthma, who attended two in-person visits to complete a multidimensional assessment. The proportion of people with mild-to-moderate versus severe asthma who reported physically limiting breathlessness (modified Medical Research Council [mMRC] dyspnoea score ≥2) was compared. Psychophysiological factors associated with breathlessness in people with asthma were identified via a directed acyclic graph and explored with multivariate logistic regression to predict breathlessness. RESULTS: 144 participants were included, of which, 74 (51%) had mild-to-moderate asthma and 70 (49%) severe asthma. Participants were predominantly female (n=103, 72%) with a median (quartile 1, quartile 3) age of 63.4 (50.5,69.5) years and body mass index (BMI) of 31.3 (26.2, 36.0) kg/m2. The proportion of people reporting mMRC ≥2 was significantly higher in those with severe- (n=37, 53%) compared with mild-to-moderate (n=21, 31%) asthma (p=0.013). Dyspnoea-12 Total (8.00 [4.75, 17.00] versus 5.00 [2.00, 11.00], p=0.037) score was also significantly higher in the severe asthma group. Significant predictors of physically limiting breathlessness were: BMI, asthma control, exercise capacity, and hyperventilation symptoms. Airflow limitation and type-2 inflammation were poor breathlessness predictors. CONCLUSION: Over half of people with severe asthma experience physically limiting breathlessness despite treatment. Targeting psychophysiological factors, or traits, associated with breathlessness may help relieve this distressing symptom, which is of high priority to people with asthma.

Development of Novel High and Low Emulsifier Diets Based upon Emulsifier Distribution in the Australian Food Supply for Intervention Studies in Crohn's Disease.

BACKGROUND: The aims of this study were to develop and evaluate a high/low-emulsifier diet and compare emulsifier content with preclinical studies that have associated Crohn's disease with emulsifiers. METHODS: Supermarkets were audited with a seven-day high- (HED) and low-emulsifier diet (LED) meal plan developed. The emulsifier content of food was sought from food manufacturers, compared to acceptable daily intake (ADI), and doses were provided in trials. Nutritional composition analysis was completed. Healthy adults ate these diets for seven days in a randomized single-blinded cross-over feeding study to assess palatability, tolerability, satiety, food variety, dietary adherence, blinding and the ease of following the meal plan via visual analogue scale. RESULTS: A database of 1680 foods was created. There was no difference in nutritional content between the HED and LED, except HED had a higher ultra-processed food content (p < 0.001). The HED contained 41 emulsifiers, with 53% of the products able to be quantified for emulsifiers (2.8 g/d), which did not exceed the ADI, was similar to that in observational studies, and was exceeded by doses used in experimental studies. In ten participants, diets were rated similarly in palatability-HED mean 62 (5% CI 37-86) mm vs. LED 68 (54-82) mm-in tolerability-HED 41 (20-61) mm vs. LED 55 (37-73) mm-and in satiety HED 57 (32-81) mm vs. LED 49 (24-73) mm. The combined diets were easy to follow (82 (67-97) mm) with good variety (65 (47-81)) and excellent adherence. CONCLUSION: Nutritionally well-matched HED and LED were successfully developed, palatable and well tolerated.

Comparison of digitally-delivered gut-directed hypnotherapy program to an active control for irritable bowel syndrome.

OBJECTIVES: Gut-directed hypnotherapy (GDH) treats irritable bowel syndrome (IBS) but its accessibility is limited. This problem may be overcome by digital delivery. This study aimed to perform a randomised control trial comparing the efficacy of a digitally-delivered program with and without GDH in IBS. METHODS: Adults with IBS were randomized to a 42-session daily digital program with the GDH Program (Nerva) or without (Active Control). Questionnaires were completed to assess gastrointestinal symptoms via IBS-SSS, quality of life (IBS-QOL) and psychological symptoms (DASS-21) at regular intervals during the program and 6 months following conclusion on the intervention. The primary endpoint was the proportion of participants with ≥50-point decrease in IBS-SSS between the interventions at the end of the program. RESULTS: Of 240/244 randomized participants, 121 received GDH Program - median age 38 (range 20-65) years, 90% female, IBS-SSS 321 (IQR 273-367) - and 119 Active Control - 36 (21-65), 91% female, IBS-SSS 303 (255-360). At program completion, 81% met the primary endpoint with GDH Program versus 63% Active Control (p=0.002). IBS-SSS was median 208 (IQR 154-265) with GDH and 244 (190-308) with Control (p=0.004), 30% reduction in pain was reported by 71% compared with 35% (p<0.001), and IBS-QOL improved by 14 (6-25) compared with 7 (1-15), respectively (p<0.001). Psychological status improved similarly in both groups. CONCLUSIONS: A digitally-delivered GDH Program provided to patients with IBS was superior to the active control, with greater improvement in both gastrointestinal symptoms and quality of life and provides an equitable alternative to face-to-face behavioural strategies.

The treatable traits of asthma in pregnancy: a clinical audit.

Rationale: Poor asthma control in pregnancy is associated with adverse perinatal outcomes. Treatable traits improve patient outcomes but the pattern and prevalence of treatable traits in pregnant women with asthma is unknown. Whether treatable traits in pregnant women with asthma can be identified via a virtual care consult is also unknown. The objective of the present study was to assess the prevalence of treatable traits in pregnant women with asthma using a virtual model of care. Methods: Pregnant women with asthma (n=196) underwent an assessment by an asthma nurse educator and a respiratory physician via telehealth. In this clinical audit, 16 treatable traits were assessed including two traits in the pulmonary domain, five traits in the behavioural/risk factors domain and nine traits in the extrapulmonary domain. Results: Pregnant women with asthma had a mean±sd of 7.5±2.0 treatable traits per person including 1.0±0.7 treatable traits per person in the pulmonary domain, 3.5±1.56 in the extrapulmonary domain and 2±0.9 in the risk factor/behavioural domain. Treatable traits in the behavioural/risk factor domain were most prevalent and these included limited asthma knowledge (96%), inadequate inhaler technique (84%) and no written asthma action plan (80%). On average 3.8±1.24 interventions per person were delivered for a mean±sd of 7.5±2.0 treatable traits per person. Conclusion: Virtual antenatal asthma care is a feasible approach for assessing treatable traits in pregnant women with mild asthma. Pregnant women with asthma exhibit multiple management issues. Virtual models of care might increase asthma in pregnancy service uptake and acceptability.

Real-world biologics response and super-response in the International Severe Asthma Registry cohort.

BACKGROUND: Biologic asthma therapies reduce exacerbations and long-term oral corticosteroids (LTOCS) use in randomized controlled trials (RCTs); however, there are limited data on outcomes among patients ineligible for RCTs. Hence, we investigated responsiveness to biologics in a real-world population of adults with severe asthma. METHODS: Adults in the International Severe Asthma Registry (ISAR) with ≥24 weeks of follow-up were grouped into those who did, or did not, initiate biologics (anti-IgE, anti-IL5/IL5R, anti-IL4/13). Treatment responses were examined across four domains: forced expiratory volume in 1 second (FEV1) increase by ≥100 mL, improved asthma control, annualized exacerbation rate (AER) reduction ≥50%, and any LTOCS dose reduction. Super-response criteria were: FEV1 increase by ≥500 mL, new well-controlled asthma, no exacerbations, and LTOCS cessation or tapering to ≤5 mg/day. RESULTS: 5.3% of ISAR patients met basic RCT inclusion criteria; 2116/8451 started biologics. Biologic initiators had worse baseline impairment than non-initiators, despite having similar biomarker levels. Half or more of initiators had treatment responses: 59% AER reduction, 54% FEV1 increase, 49% improved control, 49% reduced LTOCS, of which 32%, 19%, 30%, and 39%, respectively, were super-responses. Responses/super-responses were more frequent in biologic initiators than in non-initiators; nevertheless, ~40-50% of initiators did not meet response criteria. CONCLUSIONS: Most patients with severe asthma are ineligible for RCTs of biologic therapies. Biologics are initiated in patients who have worse baseline impairments than non-initiators despite similar biomarker levels. Although biologic initiators exhibited clinical responses and super-responses in all outcome domains, 40-50% did not meet the response criteria.

Exploring Clinical Remission in Moderate Asthma - Perspectives from Asia, the Middle East, and South America.

INTRODUCTION: Clinical remission is a relatively new concept in asthma but recent research initiatives suggest it could be an ambitious and achievable therapeutic target for patients with asthma. METHODS: In this modified Delphi study (comprising two online surveys, completed either side of a virtual scientific workshop), the opinions of a panel of respiratory physicians were evaluated to summarize perspective statements on key therapeutic outcomes and criteria for on-treatment clinical remission in patients with moderate asthma. An agreement threshold was pre-defined as agreement by ≥ 75% of participants. RESULTS: Surveys 1 and 2 were completed by 20 and 18 participants, respectively. Most participants (95%) agreed with the concept of clinical remission in moderate asthma and that this should be a desirable treatment goal (90%). Based on a composite measure of 4-6 desirable therapeutic outcomes, current understanding of clinical remission was considered as 12 months with no exacerbations, no oral corticosteroids, no daytime or night-time asthma symptoms (Asthma Control Test score ≥ 20 or Asthma Control Questionnaire score ≤ 0.75), stable lung function, and no treatment-related adverse events. No agreement was reached on the role of relievers in defining therapeutic outcomes or on the wider use of biomarkers and airway hyperresponsiveness for defining asthma remission in clinical practice. CONCLUSIONS: In line with recent consensus statements from the United States and Europe, there was a high level of agreement on the elements of clinical remission among a panel of respiratory physicians from Asia, the Middle East, and South America. Extension of the concept of clinical remission to patients with moderate asthma was considered aligned with the potential of clinical remission as a goal of therapy.

Exploring Definitions and Predictors of Response to Biologics for Severe Asthma.

BACKGROUND: Biologic effectiveness is often assessed as response, a term that eludes consistent definition. Identifying those most likely to respond in real-life has proven challenging. OBJECTIVE: To explore definitions of biologic responders in adults with severe asthma and investigate patient characteristics associated with biologic response. METHODS: This was a longitudinal cohort study using data from 21 countries, which shared data with the International Severe Asthma Registry. Changes in four asthma outcome domains were assessed in the 1-year period before and after biologic initiation in patients with a predefined level of prebiologic impairment. Responder cutoffs were 50% or greater reduction in exacerbation rate, 50% or greater reduction in long-term oral corticosteroid daily dose, improvement in one or more category in asthma control, and 100 mL or greater improvement in FEV1. Responders were defined using single and multiple domains. The association between prebiologic characteristics and postbiologic initiation response was examined by multivariable analysis. RESULTS: A total of 2,210 patients were included. Responder rate ranged from 80.7% (n = 566 of 701) for exacerbation response to 10.6% (n = 9 of 85) for a four-domain response. Many responders still exhibited significant impairment after biologic initiation: 46.7% (n = 206 of 441) of asthma control responders with uncontrolled asthma before the biologic still had incompletely controlled disease postbiologic initiation. Predictors of response were outcome-dependent. Lung function responders were more likely to have higher prebiologic FeNO (odds ratio = 1.20 for every 25-parts per billion increase), and shorter asthma duration (odds ratio = 0.81 for every 10-year increase in duration). Higher blood eosinophil count and the presence of type 2-related comorbidities were positively associated with higher odds of meeting long-term oral corticosteroid, control, and lung function responder criteria. CONCLUSIONS: Our findings underscore the multimodal nature of response, showing that many responders experience residual symptoms after biologic initiation and that predictors of response vary according to the outcome assessed.

Probiotics: are they beneficial?

There are wide-ranging probiotic choices in Australasia. We reviewed the efficacy of probiotics for the management of gastrointestinal (GI) conditions in adults and assessed relevance to clinical practice. The benefits of probiotics were inconsistent, with a strong consensus reached for only a few of the indications. As different species/strains and combinations differ in efficacy, results cannot be extrapolated from one to another. This review endorses specific probiotics for limited indications. Efficacy of most marketed probiotic formulations remains unstudied and unproven, warranting further research.

Effect of fractional exhaled nitric oxide (FENO)-based asthma management during pregnancy versus usual care on infant development, temperament, sensory function and autism signs.

Asthma during pregnancy is associated with a range of adverse perinatal outcomes. It is also linked to increased rates of neurodevelopmental conditions in the offspring. We aimed to assess whether fractional exhaled nitric oxide (FENO)-based asthma management during pregnancy improves child developmental and behavioural outcomes compared to usual care. The Breathing for Life Trial was a randomised controlled trial that compared FENO-based asthma management during pregnancy to usual care. Participants were invited to the developmental follow-up, the Breathing for Life Trial - Infant Development study, which followed up infants at 6 weeks, 6 months and 12 months. The primary outcomes were measured in infants at 12 months using the Bayley-III: Cognitive, Language and Motor composite scores. Secondary outcomes included Bayley-III social-emotional and adaptive behaviour scores, autism likelihood and sensory and temperament outcomes. The exposure of interest was the randomised intervention group. Two hundred and twenty-two infants and their 217 participating mothers were recruited to the follow-up; 107 mothers were in the intervention group and 113 were in the control group. There was no evidence of an intervention effect for the primary outcomes: Bayley-III cognitive (mean = 108.9 control, 108.5 intervention, p = 0.93), language (mean = 95.9 control, 95.6 intervention, p = 0.87) and motor composite scores (mean = 97.2 control, 97.9 intervention, p = 0.25). Mean scores for secondary outcomes were also similar among infants born to control and FENO group mothers, with few results reaching p < 0.05. CONCLUSION:  In this sample, FENO-guided asthma treatment during pregnancy did not improve infant developmental outcomes in the first year of life. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: ACTRN12613000202763. WHAT IS KNOWN: • Maternal asthma during pregnancy has been associated with increased rates of neurodevelopmental conditions in offspring, including intellectual disability and autism. WHAT IS NEW: • This is the first study to examine how managing asthma during pregnancy via a FENO-guided algorithm or usual care affects infant developmental and behavioural outcomes. While the results of the study showed no impact of the intervention, and therefore do not support the integration of FENO-based management of asthma in antenatal settings for optimal infant development, they do send a positive message about the implications of active asthma management during pregnancy on infant developmental outcomes.

The illness burden of severe asthma contrasted to people with mild-to-moderate asthma: a qualitative study.

Background: Disabling symptoms of asthma including breathlessness, cough, wheeze and chest tightness largely impact quality of life; however, how these symptoms impact people with asthma of different severity levels remains unknown. This study aimed to compare and characterise patients' symptom experience and the burden caused, their quality of life, and the medication preferences of people with severe asthma against those of people with mild-to-moderate asthma. Methods: This was a multisite qualitative study involving two focus groups and semistructured interviews of adults with severe asthma undertaken in Australia and UK. Interviews were also undertaken in people with mild-to-moderate asthma. Audio recordings were transcribed and analysed thematically. Results: Participants in both severe asthma and mild-to-moderate asthma groups had a mean±sd age of 57±12 years. Between the severe asthma and mild-to-moderate asthma groups, 62% of participants were female and 86% lived with family. Themes were identified: 1) what is asthma and most bothersome symptoms: both groups reported breathlessness as the most bothersome symptom; 2) impacts on life: disease-related impact differed as people with severe asthma reported significant burden in their quality of life, which encompassed emotional, physical, social and financial wellbeing; and 3) personalised and responsive care: severe asthma interviewees preferred injectable biological therapy as a mode of treatment administration. Conclusions: People with asthma are burdened by breathlessness and cough and other disabling symptoms resulting in impaired quality of life. Understanding the experiences of people with asthma of different severities can improve the patient-clinician partnership.

Exploring Definitions and Predictors of Severe Asthma Clinical Remission Post-Biologic in Adults.

RATIONALE: There is no consensus on criteria to include in an asthma remission definition in real-life. Factors associated with achieving remission post-biologic-initiation remain poorly understood. OBJECTIVES: To quantify the proportion of adults with severe asthma achieving multi-domain-defined remission post-biologic-initiation and identify pre-biologic characteristics associated with achieving remission which may be used to predict it. METHODS: This was a longitudinal cohort study using data from 23 countries from the International Severe Asthma Registry. Four asthma outcome domains were assessed in the 1-year pre- and post-biologic-initiation. A priori-defined remission cut-offs were: 0 exacerbations/year, no long-term oral corticosteroid (LTOCS), partly/well-controlled asthma, and percent predicted forced expiratory volume in one second ≥80%. Remission was defined using 2 (exacerbations + LTOCS), 3 (+control or +lung function) and 4 of these domains. The association between pre-biologic characteristics and post-biologic remission was assessed by multivariable analysis. MEASUREMENTS AND MAIN RESULTS: 50.2%, 33.5%, 25.8% and 20.3% of patients met criteria for 2, 3 (+control), 3 (+lung function) and 4-domain-remission, respectively. The odds of achieving 4-domain remission decreased by 15% for every additional 10-years asthma duration (odds ratio: 0.85; 95% CI: 0.73, 1.00). The odds of remission increased in those with fewer exacerbations/year, lower LTOCS daily dose, better control and better lung function pre-biologic-initiation. CONCLUSIONS: One in 5 patients achieved 4-domain remission within 1-year of biologic-initiation. Patients with less severe impairment and shorter asthma duration at initiation had a greater chance of achieving remission post-biologic, indicating that biologic treatment should not be delayed if remission is the goal. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

People with Inflammatory Bowel Disease Prefer Cognitive Behavioral Therapy for Fatigue Management: A Conjoint Analysis.

BACKGROUND: Psychological interventions are a promising area for fatigue management in patients with inflammatory bowel disease (IBD). However, most interventions trialled to date have been pilots with limited direct input from patients about the type of intervention they want. Thus, this study aimed to explore patient preferences for a psychological IBD fatigue intervention. METHODS: An international online cross-sectional survey was conducted with adults with self-reported IBD. A conjoint analysis was employed to elicit, through a series of forced-choice scenarios, patient preferences for a fatigue intervention. For this study, the attributes manipulated across these forced-choice scenarios were type of intervention, modality of delivery, and duration of intervention. RESULTS: Overall, 834 people with IBD were included in analysis. Respondents ranked the type of psychological intervention as most important for overall preference (with cognitive-behavioral therapy (CBT) preferred over the other approaches), followed by modality of delivery, but placed very little importance on how long the intervention runs for. Patients with IBD appear to most strongly preference a short online CBT intervention for managing their IBD-related fatigue. CONCLUSION: This study helps provide therapists and program developers clear direction on patient preferences when it comes to developing new psychological programs that address fatigue in IBD.

Nutrition Assessment and Management in Celiac Disease.

Celiac disease (CeD) is the most common immune condition affecting the gastrointestinal tract; it is triggered by gluten and the only available treatment is a strict gluten-free diet (GFD). Therefore, for patients with CeD, adopting a GFD is not a lifestyle choice. The major problem is that a GFD is restrictive and, like all restrictive diets, it has the potential for adverse nutritional outcomes, especially if adopted for a long term. It is well known that GFD can be nutritionally inadequate and is frequently associated with vitamin and mineral deficiencies; it is also associated with excessive sugar and fat intake, particularly when gluten-free substitutes are consumed. Consequently, people with CeD are affected by higher rates of overweight and obesity and metabolic complications, such as fatty liver and cardiovascular disease. Therefore, assessment of nutritional status and diet quality at diagnosis and while on a long-term GFD is key in the management of CeD. This narrative review addresses nutritional considerations in CeD and management of common challenges associated with a GFD.

Clinical utility of C-reactive protein-to-albumin ratio in the management of patients with inflammatory bowel disease.

Background and Aim: C-reactive protein (CRP)-to-albumin ratio (CAR) is a novel score with prognostic value in inflammatory conditions. This study assessed the performance of CAR as an objective marker of disease activity and prediction of subtherapeutic infliximab trough levels in patients with inflammatory bowel disease (IBD). Methods: A retrospective study was conducted on three different patient cohorts with IBD: patients who had (i) fecal calprotectin (FC) measurements; (ii) Mayo Endoscopic Scores; and (iii) infliximab trough levels available. The relative performances of CAR, albumin, and CRP were compared in predicting disease activity (based on FC or Mayo Endoscopic Score) and infliximab trough levels. Results: In both the FC (n = 289) and endoscopy (n = 65) cohorts, albumin and CAR correlated with objective disease activity. CAR (area under the curve [AUC] 0.70) was only marginally better at detecting active disease, measured by FC, compared to CRP (AUC 0.68). A CAR >0.15 was able to detect Mayo 3 disease (AUC 0.83, sensitivity 81%, specificity 89%). Albumin (r = 0.38) and CAR (r = -0.42) correlated with infliximab trough levels (n = 204). The optimal CAR for detecting subtherapeutic infliximab trough levels was >0.08 (AUC 0.70, sensitivity 66%, specificity 64%). Both albumin and CAR were independent predictors of subtherapeutic infliximab trough levels but correlated poorly with infliximab trough levels longitudinally in the same patient. Conclusion: CAR was only a modest discriminator of subtherapeutic infliximab levels and offers little more than CRP in detecting active disease. CAR has potential to detect severe Mayo 3 disease and could be calculated in patients admitted with suspected acute severe ulcerative colitis.

Thoracic Society of Australia and New Zealand position statement: The safe clinical use of sputum induction for bio-sampling of the lower airways in children and adults.

Sputum induction is widely used in clinical settings for collection of biological samples from the lower airways. However, in recent years sputum induction has been associated with serious adverse events and even death. This position statement was commissioned by the Thoracic Society of Australia and New Zealand to address major adverse events of two deaths associated with sputum induction that have occurred in Australia in 2021, and outlines best practice for the safe use of sputum induction. The statement resulted from systematic literature searches by a multi-disciplinary group including respiratory physicians, nurses and physiotherapists (paediatric and adults focused). Consumers had input to an advanced draft of the position statement. The position statement covers indications for sputum induction, informed consent, scope of practice of personnel administering the procedure, infection control considerations, details about the sputum induction procedure, safety considerations and risk assessment in clinical settings.

Bacterial interactome disturbance in chronic obstructive pulmonary disease clinical stability and exacerbations.

RATIONALE: Our understanding of airway dysbiosis in chronic obstructive pulmonary disease (COPD) remains incomplete, which may be improved by unraveling the complexity in microbial interactome. OBJECTIVES: To characterize reproducible features of airway bacterial interactome in COPD at clinical stability and during exacerbation, and evaluate their associations with disease phenotypes. METHODS: We performed weighted ensemble-based co-occurrence network analysis of 1742 sputum microbiomes from published and new microbiome datasets, comprising two case-control studies of stable COPD versus healthy control, two studies of COPD stability versus exacerbation, and one study with exacerbation-recovery time series data. RESULTS: Patients with COPD had reproducibly lower degree of negative bacterial interactions, i.e. total number of negative interactions as a proportion of total interactions, in their airway microbiome compared with healthy controls. Evaluation of the Haemophilus interactome showed that the antagonistic interaction networks of this established pathogen rather than its abundance consistently changed in COPD. Interactome dynamic analysis revealed reproducibly reduced antagonistic interactions but not diversity loss during COPD exacerbation, which recovered after treatment. In phenotypic analysis, unsupervised network clustering showed that loss of antagonistic interactions was associated with worse clinical symptoms (dyspnea), poorer lung function, exaggerated neutrophilic inflammation, and higher exacerbation risk. Furthermore, the frequent exacerbators (≥ 2 exacerbations per year) had significantly reduced antagonistic bacterial interactions while exhibiting subtle compositional changes in their airway microbiota. CONCLUSIONS: Bacterial interactome disturbance characterized by reduced antagonistic interactions, rather than change in pathogen abundance or diversity, is a reproducible feature of airway dysbiosis in COPD clinical stability and exacerbations, which suggests that we may target interactome rather than pathogen alone for disease treatment.