Prevalence and burden of difficult-to-treat and severe asthma in Australia: A national population survey.

BACKGROUND AND OBJECTIVE: Most evidence about difficult-to-treat and severe asthma (DTTA) comes from clinical trials and registries. We aimed to identify people with DTTA from a large nationally representative asthma population and describe their characteristics and healthcare utilization compared with people whose asthma was not 'difficult-to-treat'. METHODS: We conducted a cross-sectional survey of Australians aged ≥18 years with current asthma from large web-based survey panels. Enrolment was stratified by gender, age-group and state/territory based on national population data for people with asthma. Difficult-to-treat or severe asthma was defined by poor symptom control, exacerbations and/or oral corticosteroid/biologic use despite medium/high-dose inhaled therapy. Outcomes included exacerbations, healthcare utilization, multimorbidity, quality of life and coronavirus disease of 2019 (COVID-19)-related behaviour. Weighted data were analysed using SAS version 9.4. RESULTS: The survey was conducted in February-March 2021. The weighted sample comprised 6048 adults with current asthma (average age 47.3 ± SD 18.1 years, 59.9% female), with 1313 (21.7%) satisfying ≥1 DTTA criteria. Of these, 50.4% had very poorly controlled symptoms (Asthma Control Test ≤15), 36.2% were current smokers, and 85.4% had ≥1 additional chronic condition, most commonly anxiety/depression. More than twice as many participants with DTTA versus non-DTTA had ≥1 urgent general practitioner (GP) visit (61.4% vs. 27.5%, OR 4.8 [4.2-5.5, p < 0.0001]), or ≥1 emergency room visit (41.9% vs. 17.9%, OR 3.8 [3.3-4.4, p < 0.0001]) in the previous 12 months. CONCLUSION: Our findings emphasize the burden of uncontrolled symptoms, current smoking, multimorbidity and healthcare utilization in people with DTTA in the community, who may be under-represented in registries or clinical trials.

The carbon footprint of as-needed budesonide/formoterol in mild asthma: a post hoc analysis.

INTRODUCTION: The use of pressurised metered-dose inhalers (pMDIs) and asthma exacerbations necessitating healthcare reviews contribute substantially to the global carbon footprint of healthcare. It is possible that a reduction in carbon footprint could be achieved by switching patients with mild asthma from salbutamol pMDI reliever-based therapy to inhaled corticosteroid-formoterol dry powder inhaler (DPI) reliever therapy, as recommended by the Global Initiative for Asthma. METHODS: This post hoc analysis included all 668 adult participants in the Novel START trial, who were randomised 1:1:1 to treatment with as-needed budesonide/formoterol DPI, as-needed salbutamol pMDI or maintenance budesonide DPI plus as-needed salbutamol pMDI. The primary outcome was carbon footprint of asthma management, expressed as kilograms of carbon dioxide equivalent emissions (kgCO2e) per person-year. Secondary outcomes explored the effect of baseline symptom control and adherence (maintenance budesonide DPI arm only) on carbon footprint. RESULTS: As-needed budesonide/formoterol DPI was associated with 95.8% and 93.6% lower carbon footprint compared with as-needed salbutamol pMDI (least-squares mean 1.1 versus 26.2 kgCO2e; difference -25.0, 95% CI -29.7 to -20.4; p<0.001) and maintenance budesonide DPI plus as-needed salbutamol pMDI (least-squares mean 1.1 versus 17.3 kgCO2e; difference -16.2, 95% CI -20.9 to -11.6; p<0.001), respectively. There was no statistically significant evidence that treatment differences in carbon footprint depended on baseline symptom control or adherence in the maintenance budesonide DPI arm. CONCLUSIONS: The as-needed budesonide/formoterol DPI treatment option was associated with a markedly lower carbon footprint than as-needed salbutamol pMDI and maintenance budesonide DPI plus as-needed salbutamol pMDI.

Burden of Uncontrolled Severe Asthma With and Without Elevated Type-2 Inflammatory Biomarkers.

BACKGROUND: Many patients with asthma have type-2 airway inflammation, identified by the presence of biomarkers, including history of allergy, high blood eosinophil (EOS) count, and high fractional exhaled nitric oxide levels. OBJECTIVE: To assess disease burden in relation to type-2 inflammatory biomarker status (history of allergy, blood EOS count, and fractional exhaled nitric oxide level) in patients with uncontrolled and controlled severe asthma in the NOVEL observational longiTudinal studY (NOVELTY) (NCT02760329). METHODS: Asthma diagnosis and severity were physician-reported. Control was defined using Asthma Control Test score (uncontrolled <20, controlled ≥20) and/or 1 or more severe physician-reported exacerbation in the previous year. Biomarker distribution (history of allergy, blood EOS count, and fractional exhaled nitric oxide level), symptom burden (Asthma Control Test score, modified Medical Research Council dyspnea scale), health status (St George's Respiratory Questionnaire score), exacerbations, and health care resource utilization were assessed. RESULTS: Of 647 patients with severe asthma, 446 had uncontrolled and 123 had controlled asthma. Among those with uncontrolled asthma, 196 (44%) had 2 or more positive biomarkers, 187 (42%) had 1 positive biomarker, 325 (73%) had low blood EOS, and 63 (14%) were triple-negative. Disease burden was similarly high across uncontrolled subgroups, irrespective of biomarker status, with poor symptom control (Asthma Control Test score 14.9-16.6), impaired health status (St George's Respiratory Questionnaire total score 46.7-49.4), clinically important breathlessness (modified Medical Research Council grade ≥2 in 47.3%-57.1%), and 1 or more severe exacerbation (70.6%-76.2%). CONCLUSIONS: Type-2 inflammatory biomarkers did not differentiate disease burden in patients with severe asthma. Patients with low type-2 inflammatory biomarker levels have few biologic therapy options; their needs should be addressed.

Respiratory Symptoms, Disease Burden, and Quality of Life in Australian Adults According to GOLD Spirometry Grades: Data from the BOLD Australia Study.

Purpose: Population data on the burden of chronic obstructive pulmonary disease (COPD) are often based on patient-reported diagnoses of COPD, emphysema or chronic bronchitis, without spirometry. We aimed to investigate the relationship between health burden, quality of life and severity of airway obstruction in Australian adults aged ≥40 years. Methods: We used data from the BOLD Australia study, which included randomly selected adults aged ≥40 years from six study sites to reflect the sociodemographic and geographic diversity of the Australian population (n = 3522). Participants with post-bronchodilator airflow limitation (ratio of forced expiratory volume in 1 second FEV1 to forced vital capacity <0.7) were grouped by GOLD spirometry grades 1-4. Quality of life was assessed with Short Form 12 (SF-12) Health Survey Questionnaire. Health burden was assessed as lost time off work or social activities, and healthcare utilization. Results: Of the study sample, 2969 participants did not have airflow limitation, 294 (8.4%) were classified as GOLD Grade 1, 212 (6.0%) as GOLD 2 and 43 (1.2%) as GOLD 3-4. Participants with higher GOLD grades had more respiratory symptoms, more comorbidities and greater burden than those with lower GOLD grades. The scores of mental and physical subscales of SF-12 were lower, indicating worse quality of life, from the no airflow limitation group to the GOLD 3-4 group (P = 0.03 and P < 0.001, respectively). Conclusion: Greater airflow limitation is associated with greater burden and poor quality of life. Interventions to prevent, or reduce the level of, airflow limitation will reduce the symptom burden and improve quality of life for patients.

Risk factors and clinical characteristics of breathlessness in Australian adults: Data from the BOLD Australia study.

BACKGROUND: Breathlessness is a common symptom related to a significant health burden. However, the association of breathlessness with clinical characteristics, especially objective pulmonary test results is scarce. We aimed to identify the characteristics independently associated with breathlessness in Australian adults. METHOD: The analysis used data from BOLD Australia, a cross-sectional study that included randomly selected adults aged ≥40 years from six sites in Australia. Clinical characteristics and spirometry results were compared for breathlessness (modified Medical Research Council [mMRC] grade ≥2). RESULTS: Among all respondents (n = 3321), 252 participants (7.6%) reported breathlessness. The main univariate associations were obesity, chronic respiratory diseases, heart diseases and being Indigenous Australians (odds ratios [ORs] = 2.78, 5.20, 3.77 and 4.38, respectively). Participants with breathlessness had lower pre-and post-bronchodilator lung function than those without. Impaired spirometry results including FVC or FEV1 below 80% predicted, or FEV1/FVC < LLN were independently associated with breathlessness (adjusted ORs = 2.66, 2.94 and 2.34, respectively). CONCLUSIONS: Breathlessness is common among Australian adults and is independently associated with obesity, chronic respiratory diseases, heart diseases, being Indigenous Australians, and impaired spirometry. Multi-disciplinary assessment and comprehensive investigation is needed in clinical practice to address the many factors associated with breathlessness in the population.

Clinical characteristics of adults with self-reported diagnosed asthma and/or COPD: data from the BOLD Australia Study.

Background: Diagnosis of asthma and chronic obstructive pulmonary disease (COPD) in the community is variable, often without spirometry. Some studies report that adults with both diagnostic labels (asthma+COPD) have worse health outcomes than those with asthma or COPD only, but data for Australian adults are limited. We investigated the relationship between clinical characteristics and self-reported diagnoses of asthma, COPD and both. Method: We used data from the BOLD Australia study, which included randomly selected adults aged ≥40 years from six study sites. The BOLD questionnaires and spirometry test were used in all sites. Participants were grouped by self-reported diagnosis. Demographic and clinical characteristics and lung function were compared between groups. Results: Of the study sample (n=3522), 336 reported asthma only, 172 reported COPD only, 77 reported asthma+COPD and 2937 reported neither. Fewer than half of participants with a COPD diagnosis (with or without asthma) had airflow limitation. Participants with asthma+COPD had more respiratory symptoms and greater airflow limitation than those with either diagnosis alone. Having asthma+COPD was independently associated with a higher probability of having clinically important breathlessness (modified Medical Research Council score ≥2) than asthma only (adjusted OR 3.44, 95% CI 1.86-6.33) or COPD only (adjusted OR 3.28, 95% CI 1.69-6.39). Airflow limitation (Global Initiative for Chronic Obstructive Lung Disease 2 or higher, using post-bronchodilator forced expiratory volume in 1 s/forced vital capacity ratio <0.7) was similar between asthma only and COPD only, but twice as prevalent in asthma+COPD (adjusted OR 2.18 and 2.58, respectively). Conclusions: Adults with diagnoses of asthma+COPD have a higher symptom and disease burden than those with diagnoses of asthma only or COPD only. These patients should receive regular comprehensive reviews because of the substantially increased burden of having both diagnoses.

Symptom Burden, Health Status, and Productivity in Patients with Uncontrolled and Controlled Severe Asthma in NOVELTY.

Background: Few studies have quantified symptom burden, health status, and productivity in patients with uncontrolled and controlled severe asthma. Up-to-date, real-world, global evidence is needed. Objective: To quantify symptom burden, health status, and productivity in patients with uncontrolled and controlled severe asthma using baseline data from the NOVEL observational longiTudinal studY (NOVELTY; NCT02760329). Methods: NOVELTY included patients aged ≥18 years (or ≥12 years in some countries) from primary care and specialist centres in 19 countries, with a physician-assigned diagnosis of asthma, asthma+chronic obstructive pulmonary disease (COPD), or COPD. Disease severity was physician-assessed. Uncontrolled severe asthma was defined by an Asthma Control Test (ACT) score <20 and/or severe physician-reported exacerbations in the previous year; controlled severe asthma required an ACT score ≥20 and no severe exacerbations. Assessment of symptom burden included Respiratory Symptoms Questionnaire (RSQ) and ACT score. Assessment of health status included St George's Respiratory Questionnaire (SGRQ), EuroQoL 5 Dimensions 5 Levels Health Questionnaire (EQ-5D-5L) index value, and EQ-5D-5L Visual Analog Score (EQ-VAS). Assessment of productivity loss included absenteeism, presenteeism, overall work impairment, and activity impairment. Results: Of 1652 patients with severe asthma, asthma was uncontrolled in 1078 (65.3%; mean age 52.6 years, 65.8% female) and controlled in 315 (19.1%; mean age 55.2 years, 56.5% female). With uncontrolled versus controlled severe asthma, symptom burden was higher (mean RSQ score 7.7 vs 2.5), health status more impaired (mean SGRQ total score 47.5 vs 22.4; mean EQ-5D-5L index value 0.68 vs 0.90; mean EQ-VAS score 64.1 vs 78.1), and productivity lower (presenteeism 29.3% vs 10.5%). Conclusion: Our findings highlight the symptom burden of uncontrolled severe asthma compared with controlled severe asthma and its impact on patient health status and productivity, and support the need for interventions to improve control of severe asthma.

Questions in Mild Asthma: An Official American Thoracic Society Research Statement.

Background: Patients with mild asthma are believed to represent the majority of patients with asthma. Disease-associated risks such as exacerbations, lung function decline, and death have been understudied in this patient population. There have been no prior efforts from major societies to describe research needs in mild asthma. Methods: A multidisciplinary, diverse group of 24 international experts reviewed the literature, identified knowledge gaps, and provided research recommendations relating to mild asthma definition, pathophysiology, and management across all age groups. Research needs were also investigated from a patient perspective, generated in conjunction with patients with asthma, caregivers, and stakeholders. Of note, this project is not a systematic review of the evidence and is not a clinical practice guideline. Results: There are multiple unmet needs in research on mild asthma driven by large knowledge gaps in all areas. Specifically, there is an immediate need for a robust mild asthma definition and an improved understanding of its pathophysiology and management strategies across all age groups. Future research must factor in patient perspectives. Conclusions: Despite significant advances in severe asthma, there remain innumerable research areas requiring urgent attention in mild asthma. An important first step is to determine a better definition that will accurately reflect the heterogeneity and risks noted in this group. This research statement highlights the topics of research that are of the highest priority. Furthermore, it firmly advocates the need for engagement with patient groups and for more support for research in this field.

Cluster Analyses From the Real-World NOVELTY Study: Six Clusters Across the Asthma-COPD Spectrum.

BACKGROUND: Asthma and chronic obstructive pulmonary disease (COPD) are complex diseases, the definitions of which overlap. OBJECTIVE: To investigate clustering of clinical/physiological features and readily available biomarkers in patients with physician-assigned diagnoses of asthma and/or COPD in the NOVEL observational longiTudinal studY (NOVELTY; NCT02760329). METHODS: Two approaches were taken to variable selection using baseline data: approach A was data-driven, hypothesis-free and used the Pearson dissimilarity matrix; approach B used an unsupervised Random Forest guided by clinical input. Cluster analyses were conducted across 100 random resamples using partitioning around medoids, followed by consensus clustering. RESULTS: Approach A included 3796 individuals (mean age, 59.5 years; 54% female); approach B included 2934 patients (mean age, 60.7 years; 53% female). Each identified 6 mathematically stable clusters, which had overlapping characteristics. Overall, 67% to 75% of patients with asthma were in 3 clusters, and approximately 90% of patients with COPD were in 3 clusters. Although traditional features such as allergies and current/ex-smoking (respectively) were higher in these clusters, there were differences between clusters and approaches in features such as sex, ethnicity, breathlessness, frequent productive cough, and blood cell counts. The strongest predictors of the approach A cluster membership were age, weight, childhood onset, prebronchodilator FEV1, duration of dust/fume exposure, and number of daily medications. CONCLUSIONS: Cluster analyses in patients from NOVELTY with asthma and/or COPD yielded identifiable clusters, with several discriminatory features that differed from conventional diagnostic characteristics. The overlap between clusters suggests that they do not reflect discrete underlying mechanisms and points to the need for identification of molecular endotypes and potential treatment targets across asthma and/or COPD.

Can we predict who will benefit most from biologics in severe asthma? A post-hoc analysis of two phase 3 trials.

BACKGROUND: Individualized prediction of treatment response may improve the value proposition of advanced treatment options in severe asthma. This study aimed to investigate the combined capacity of patient characteristics in predicting treatment response to mepolizumab in patients with severe asthma. METHODS: Patient-level data were pooled from two multinational phase 3 trials of mepolizumab in severe eosinophilic asthma. We fitted penalized regression models to quantify reductions in the rate of severe exacerbations and the 5-item Asthma Control Questionnaire (ACQ5) score. The capacity of 15 covariates towards predicting treatment response was quantified by the Gini index (measuring disparities in treatment benefit) as well as observed treatment benefit within the quintiles of predicted treatment benefit. RESULTS: There was marked variability in the ability of patient characteristics to predict treatment response; covariates explained greater heterogeneity in predicting treatment response to asthma control than to exacerbation frequency (Gini index 0.35 v. 0.24). Key predictors for treatment benefit for severe exacerbations included exacerbation history, blood eosinophil count, baseline ACQ5 score and age, and those for symptom control included blood eosinophil count and presence of nasal polyps. Overall, the average reduction in exacerbations was 0.90/year (95%CI, 0.87‒0.92) and average reduction in ACQ5 score was 0.18 (95% CI, 0.02‒0.35). Among the top 20% of patients for predicted treatment benefit, exacerbations were reduced by 2.23/year (95% CI, 2.03‒2.43) and ACQ5 score were reduced by 0.59 (95% CI, 0.19‒0.98). Among the bottom 20% of patients for predicted treatment benefit, exacerbations were reduced by 0.25/year (95% CI, 0.16‒0.34) and ACQ5 by -0.20 (95% CI, -0.51 to 0.11). CONCLUSION: A precision medicine approach based on multiple patient characteristics can guide biologic therapy in severe asthma, especially in identifying patients who will not benefit as much from therapy. Patient characteristics had a greater capacity to predict treatment response to asthma control than to exacerbation. TRIAL REGISTRATION: ClinicalTrials.gov number, NCT01691521 (registered September 24, 2012) and NCT01000506 (registered October 23, 2009).

Chronic Airways Assessment Test: psychometric properties in patients with asthma and/or COPD.

BACKGROUND: No short patient-reported outcome (PRO) instruments assess overall health status across different obstructive lung diseases. Thus, the wording of the introduction to the Chronic Obstructive Pulmonary Disease (COPD) Assessment Test (CAT) was modified to permit use in asthma and/or COPD. This tool is called the Chronic Airways Assessment Test (CAAT). METHODS: The psychometric properties of the CAAT were evaluated using baseline data from the NOVELTY study (NCT02760329) in patients with physician-assigned asthma, asthma + COPD or COPD. Analyses included exploratory/confirmatory factor analyses, differential item functioning and analysis of construct validity. Responses to the CAAT and CAT were compared in patients with asthma + COPD and those with COPD. RESULTS: CAAT items were internally consistent (Cronbach's alpha: > 0.7) within each diagnostic group (n = 510). Models for structural and measurement invariance were strong. Tests of differential item functioning showed small differences between asthma and COPD in individual items, but these were not consistent in direction and had minimal overall impact on the total score. The CAAT and CAT were highly consistent when assessed in all NOVELTY patients who completed both (N = 277, Pearson's correlation coefficient: 0.90). Like the CAT itself, CAAT scores correlated moderately (0.4-0.7) to strongly (> 0.7) with other PRO measures and weakly (< 0.4) with spirometry measures. CONCLUSIONS: CAAT scores appear to reflect the same health impairment across asthma and COPD, making the CAAT an appropriate PRO instrument for patients with asthma and/or COPD. Its brevity makes it suitable for use in clinical studies and routine clinical practice. TRIAL REGISTRATION: NCT02760329.

Budesonide/formoterol maintenance and reliever therapy versus fluticasone/salmeterol fixed-dose treatment in patients with COPD.

BACKGROUND: Maintenance and reliever therapy (MART) with inhaled corticosteroid (ICS)/formoterol effectively reduces exacerbations in asthma. We aimed to investigate its efficacy compared with fixed-dose fluticasone/salmeterol in chronic obstructive pulmonary disease (COPD). METHODS: Patients with COPD and ≥1 exacerbation in the previous 2 years were randomly assigned to open-label MART (Spiromax budesonide/formoterol 160/4.5 µg 2 inhalations twice daily+1 prn) or fixed-dose therapy (Diskus fluticasone propionate/salmeterol combination (FSC) 500/50 µg 1 inhalation twice daily+salbutamol 100 µg prn) for 1 year. The primary outcome was rate of moderate/severe exacerbations, defined by treatment with oral prednisolone and/or antibiotics. RESULTS: In total, 195 patients were randomised (MART Bud/Form n=103; fixed-dose FSC n=92). No significant difference was seen between MART and FSC therapy in exacerbation rates (1.32 vs 1.32 /year, respectively, rate ratio 1.05 (95% CI 0.79 to 1.39); p=0.741). No differences in lung function parameters or health status were observed. Total ICS dose was significantly lower with MART than FSC therapy (budesonide-equivalent 928 µg/day vs 1747 µg/day, respectively, p<0.05). Similar proportions of patients reported adverse events (MART Bud/Form: 73% vs fixed-dose FSC: 68%, p=0.408) and pneumonias (MART: 5% vs FSC: 1%, p=0.216). CONCLUSIONS: This first study of MART in COPD found that budesonide/formoterol MART might be similarly effective to fluticasone/salmeterol fixed-dose therapy in moderate to severe patients with COPD, at a lower daily ICS dosage. Further evidence is needed about long-term safety.

Key recommendations for primary care from the 2022 Global Initiative for Asthma (GINA) update.

The Global Initiative for Asthma (GINA) was established in 1993 by the World Health Organization and the US National Heart Lung and Blood Institute to improve asthma awareness, prevention and management worldwide. GINA develops and publishes evidence-based, annually updated resources for clinicians. GINA guidance is adopted by national asthma guidelines in many countries, adapted to fit local healthcare systems, practices, and resource availability. GINA is independent of industry, funded by the sale and licensing of its materials. This review summarizes key practical guidance for primary care from the 2022 GINA strategy report. It provides guidance on confirming the diagnosis of asthma using spirometry or peak expiratory flow. GINA recommends that all adults, adolescents and most children with asthma should receive inhaled corticosteroid (ICS)-containing therapy to reduce the risk of severe exacerbations, either taken regularly, or (for adults and adolescents with "mild" asthma) as combination ICS-formoterol taken as needed for symptom relief. For patients with moderate-severe asthma, the preferred regimen is maintenance-and-reliever therapy (MART) with ICS-formoterol. Asthma treatment is not "one size fits all"; GINA recommends individualized assessment, adjustment, and review of treatment. As many patients with difficult-to-treat or severe asthma are not referred early for specialist review, we provide updated guidance for primary care on diagnosis, further investigation, optimization and treatment of severe asthma across secondary and tertiary care. While the GINA strategy has global relevance, we recognize that there are special considerations for its adoption in low- and middle-income countries, particularly the current poor access to inhaled medications.

"As-Needed" Inhaled Corticosteroids for Patients With Asthma.

Prevention of severe asthma exacerbations is a primary management goal for asthma across the severity spectrum. Inhaled corticosteroids (ICSs) decrease the risk of asthma exacerbations, but patient adherence to ICS-containing medications as a daily maintenance therapy is poor, and many patients overuse short-acting beta2-agonist relievers; both are associated with increased risk of severe exacerbations and death. Airway inflammation also varies over time, influenced by exposures such as viral infections and allergen. As-needed ICS strategies, in which patients receive ICSs (or additional ICSs, if already taking controller therapy) whenever they take their reliever inhaler, empower patients to adjust their ICS intake in response to symptom fluctuation. These strategies can improve asthma morbidity outcomes, particularly by reducing severe exacerbations and reducing the risk of adverse effects of oral corticosteroids. In this review, the evidence for combination ICS-formoterol in a single inhaler, ICS and short-acting beta2-agonists in separate inhalers, and combination ICS-albuterol in a single inhaler is presented, along with practical considerations, evidence gaps, and implications for clinical practice for each strategy, presented by level of asthma severity and age group. Improving access to such strategies on a global scale is imperative to improve asthma outcomes and achieve equity across populations.

Diagnostic Performance of a Machine Learning Algorithm (Asthma/Chronic Obstructive Pulmonary Disease [COPD] Differentiation Classification) Tool Versus Primary Care Physicians and Pulmonologists in Asthma, COPD, and Asthma/COPD Overlap.

BACKGROUND: The differential diagnosis of asthma and chronic obstructive pulmonary disease (COPD) poses a challenge in clinical practice and its misdiagnosis results in inappropriate treatment, increased exacerbations, and potentially death. OBJECTIVE: To investigate the diagnostic accuracy of the Asthma/COPD Differentiation Classification (AC/DC) tool compared with primary care physicians and pulmonologists in asthma, COPD, and asthma-COPD overlap. METHODS: The AC/DC machine learning-based diagnostic tool was developed using 12 parameters from electronic health records of more than 400,000 patients aged 35 years and older. An expert panel of three pulmonologists and four general practitioners from five countries evaluated 119 patient cases from a prospective observational study and provided a confirmed diagnosis (n = 116) of asthma (n = 53), COPD (n = 43), asthma-COPD overlap (n = 7), or other (n = 13). Cases were then reviewed by 180 primary care physicians and 180 pulmonologists from nine countries and by the AC/DC tool, and diagnostic accuracies were compared with reference to the expert panel diagnoses. RESULTS: Average diagnostic accuracy of the AC/DC tool was superior to that of primary care physicians (median difference, 24%; 95% posterior credible interval: 17% to 29%; P < .0001) and was noninferior and superior (median difference, 12%; 95% posterior credible interval: 6% to 17%; P < .0001 for noninferiority and P = .0006 for superiority) to that of pulmonologists. Average diagnostic accuracies were 73%, 50%, and 61% by AC/DC tool, primary care physicians, and pulmonologists versus expert panel diagnosis, respectively. CONCLUSION: The AC/DC tool demonstrated superior diagnostic accuracy compared with primary care physicians and pulmonologists in the diagnosis of asthma and COPD in patients aged 35 years and greater and has the potential to support physicians in the diagnosis of these conditions in clinical practice.

Contribution of obesity to breathlessness in a large nationally representative sample of Australian adults.

BACKGROUND AND OBJECTIVE: Breathlessness is prevalent and associated with medical consequences. Obesity is related to breathlessness. However, the magnitude of its contribution has not been clearly documented. This investigation aimed to determine the contribution of obesity to breathlessness by estimating the population attributable fraction (PAF) in a representative sample of Australian adults. METHODS: A cross-sectional, nationally representative survey of Australian residents aged ≥18 years was conducted in October 2019. Breathlessness was defined as modified Medical Research Council (mMRC) dyspnoea scale grade ≥2. BMI was calculated from self-reported height and weight. Adjusted relative risks (aRRs) were estimated using a generalized linear model with Poisson distribution, adjusted for age group and/or participant-reported diagnosed illnesses. Adjusted PAFs were estimated using aRR and obesity prevalence in Australian adults. RESULTS: Among those who completed the National Breathlessness Survey, 9769 participants (51.4% female) were included in the analysis; 28.1% of participants were obese. The prevalence of breathlessness was 9.54%. The aRR of obesity for breathlessness was 2.04, adjusted for age. Adjusting for various co-morbid conditions, the aRR was slightly attenuated to around 1.85-1.98. The PAF, adjusted only for age, was 24.6% (95% CI 20.1-29.1) and after further adjustment for co-morbid conditions, the PAF ranged from 21.1% to 23.6%. Obesity accounted for a higher proportion of breathlessness in women than in men. CONCLUSION: Our results demonstrate that obesity accounts for around a quarter of breathlessness symptoms in Australian adults. This has important implications for health policy in light of the global trend in increasing obesity.