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.

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.

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.

Ultrafine particle exposure and biomarkers of effect on small airways in children.

The small size and large surface area of ultrafine particles (UFP) enhance their ability to deposit in the lung periphery and their reactivity. The Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH) cross-sectional study was conducted in 8-11-year-old schoolchildren attending 25 primary (elementary) schools, randomly selected from the Brisbane Metropolitan Area, Queensland, Australia. Main study findings outlined indirect evidence of distal airway deposition (raised C reactive protein) but as yet, there is no direct evidence in the literature of effects of UFP exposure on peripheral airway function. We present further UPTECH study data from two sensitive peripheral airway function tests, Oscillometry and Multiple Breath Nitrogen Washout (MBNW), performed in 577 and 627 children (88% and 96% of UPTECH study cohort) respectively: mean(SD) age 10.1(0.9) years, 46% male, with 50% atopy and 14% current asthma. Bayesian generalised linear mixed effects regression models were used to estimate the effect of UFP particle number count (PNC) exposure on key oscillometry (airway resistance, (Rrs), and reactance, (Xrs)) and MBNW (lung clearance index, (LCI) and functional residual capacity, (FRC)) indices. We adjusted for age, sex, and height, and potential confounders including socio-economic disadvantage, PM2.5 and NO2 exposure. All models contained an interaction term between UFP PNC exposure and atopy, allowing estimation of the effect of exposure on non-atopic and atopic students. Increasing UFP PNC was associated with greater lung stiffness as evidenced by a decrease in Xrs [mean (95% credible interval) -1.63 (-3.36 to -0.05)%] per 1000#.cm-3]. It was also associated with greater lung stiffness (decrease in Xrs) in atopic subjects across all models [mean change ranging from -2.06 to -2.40% per 1000#.cm-3]. A paradoxical positive effect was observed for Rrs across all models [mean change ranging from -1.55 to -1.70% per 1000#.cm-3] (decreases in Rrs indicating an increase in airway calibre), which was present for both atopic and non-atopic subjects. No effects on MBNW indices were observed. In conclusion, a modest detrimental effect of UFP on peripheral airway function among atopic subjects, as assessed by respiratory system reactance, was observed extending the main UPTECH study findings which reported a positive association with a biomarker for systemic inflammation, C-reactive protein (CRP). Further studies are warranted to explore the pathophysiological mechanisms underlying increased respiratory stiffness, and whether it persists through to adolescence and adulthood.

Prevalence and burden of breathlessness in Australian adults: The National Breathlessness Survey-a cross-sectional web-based population survey.

BACKGROUND AND OBJECTIVE: Chronic respiratory symptoms (in particular, breathlessness and cough) can cause physical, social and emotional distress, and may indicate the presence of an underlying disease that presages future poor health outcomes. Our aim was to investigate the burden of breathlessness in Australian adults, including breathlessness that may be undiagnosed, unlabelled or untreated. METHODS: The National Breathlessness Survey was a cross-sectional, web-based survey conducted in October 2019. Australian adults were randomly selected from a large web-based survey panel with recruitment stratified by age-group, gender and state of residence according to national population data. The main outcome measures were modified Medical Research Council (mMRC) dyspnoea scale, EuroQol visual analog scale, Dyspnoea-12 score and 4-item Patient Health Questionnaire (PHQ-4). RESULTS: Among all respondents (n = 10,072; 51.1% female; median age group 40-49 years), 9.5% reported clinically important breathlessness (mMRC dyspnoea grade ≥ 2, 2 = 'I walk slower than people of the same age on the level because of breathlessness or have to stop for breath when walking at my own pace on the level'). Among those with clinically important breathlessness, 49.1% rated their general health as fair or poor and 44.2% had at least moderate depression or anxiety symptoms (PHQ ≥ 6) but over half (50.8%) did not report a current respiratory or heart condition diagnosis. CONCLUSION: Breathlessness is common among Australian adults, and is associated with a substantial burden of ill health, including among people without a diagnosed respiratory or heart condition. The extent of underdiagnosis of these conditions or alternative causes of breathlessness requires further investigation.

Prevalence of chronic obstructive pulmonary disease with breathlessness in Australia: weighted using the 2016 Australian census.

Access to up-to-date Australian disease prevalence estimates assists health services and consumer organisations to plan and allocate resources. The Burden of Obstructive Lung Disease study was conducted between 2006 and 2012 and provided chronic obstructive pulmonary disease (COPD) (post-bronchodilator airflow limitation) prevalence estimates weighted to the 2006 Australian census. Using the 2016 Australian census, an updated prevalence estimate of all COPD is 8.30% (95% confidence interval = 6.59%-10.01%) for adults aged 40 or more years in Australia and includes 2.52% with mild breathlessness, 0.99% with moderate breathlessness and 0.91% with severe breathlessness.

Health System Costs of Treating Latent Tuberculosis Infection With Four Months of Rifampin Versus Nine Months of Isoniazid in Different Settings.

BACKGROUND: Four months of rifampin treatment for latent tuberculosis infection is safer, has superior treatment completion rates, and is as effective as 9 months of isoniazid. However, daily medication costs are higher for a 4-month rifampin regimen than a 9-month isoniazid regimen. OBJECTIVE: To compare health care use and associated costs of 4 months of rifampin and 9 months of isoniazid. DESIGN: Health system cost comparison using all health care activities recorded during 2 randomized clinical trials. (ClinicalTrials.gov: NCT00931736 and NCT00170209). SETTING: High-income countries (Australia, Canada, Saudi Arabia, and South Korea), middle-income countries (Brazil and Indonesia), and African countries (Benin, Ghana, and Guinea). PARTICIPANTS: Adults and children with clinical or epidemiologic factors associated with increased risk for developing tuberculosis that warranted treatment for latent tuberculosis infection. MEASUREMENTS: Health system costs per participant. RESULTS: A total of 6012 adults and 829 children were included. In both adults and children, greater health system use and higher costs were observed with 9 months of isoniazid than with 4 months of rifampin. In adults, the ratios of costs of 4 months of rifampin versus 9 months of isoniazid were 0.76 (95% CI, 0.70 to 0.82) in high-income countries, 0.90 (CI, 0.85 to 0.96) in middle-income countries, and 0.80 (CI, 0.78 to 0.81) in African countries. Similar findings were observed in the pediatric population. LIMITATION: Costs may have been overestimated because the trial protocol required a minimum number of follow-up visits, although fewer than recommended by many authoritative guidelines. CONCLUSION: A 4-month rifampin regimen was safer and less expensive than 9 months of isoniazid in all settings. This regimen could be adopted by tuberculosis programs in many countries as first-line therapy for latent tuberculosis infection. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research.

Tree pollen exposure is associated with reduced lung function in children.

BACKGROUND: Allergic disease is a recognized global epidemic and a significant cause of ill health and poor quality of life. The prevalence of pollen allergy is high throughout the world, and pollen exposure itself plays a role in emergency department presentations and hospitalizations for asthma. Lung function and airway inflammation are important measures of asthma activity and control. OBJECTIVE: To examine associations between exposure to multiple pollen types and lung function and markers of airway inflammation at 8 and 14 years of age, and to explore potential modification by residential greenness. METHODS: A cohort of high-risk children living in Sydney, Australia had spirometry and fractional exhaled nitric oxide (FeNO) measured at 8 and 14 years of age. Ambient pollen concentration on the day of lung function measurement and up to three days prior was used as the exposure measure. Residential greenness was derived from satellite imagery. We modelled the association between six pollen types and lung function and FeNO. We also assessed modifying effects of residential greenness. RESULTS: Casuarina, cypress and Pinus pollen in the air the day before measurement and 3 days prior respectively, were associated with reduced lung function in 8-year-olds. The pollen exposures were associated with decreases in FEV1 and FVC; however, the FEV1 /FVC ratio was not affected. Effect modification by greenness was not observed due to loss of power. CONCLUSIONS & CLINICAL RELEVANCE: Airborne tree pollen of cypress, Casuarina and Pinus and not grass in some regions may be detrimental to childhood lung function.

Weight Gain Trajectories from Birth to Adolescence and Cardiometabolic Status in Adolescence.

OBJECTIVE: To assess the influence of the trajectory of weight gain from birth to adolescence on cardiovascular and metabolic risk. We studied childhood body mass index (BMI) trajectories from birth to age 14 years and cardiometabolic risk factors at age 14 years. STUDY DESIGN: In total, 410 children with weight and height measurements were assessed from birth throughout childhood, from the Childhood Asthma Prevention Study, a prospective community-based cohort. BMI trajectory groups were determined by latent basis growth mixture models. Of these subjects, 190 had detailed cardiometabolic risk factors assessed at age 14 years. RESULTS: Three BMI trajectory groups were identified; normal BMI, "early rising" excess BMI from 2 years, and "late rising" excess BMI from 5 years. Differences were found between normal and excess BMI in children at 14 years of age. In addition, children with an early rising BMI trajectory had statistically significantly higher central adiposity and a more atherogenic lipoprotein profile at age 14 years than children with a late rising BMI trajectory (P < .05). No differences between BMI trajectory groups in vascular structure or function was identified at age 14 years. CONCLUSIONS: Earlier onset of an elevated BMI trajectory persisting from birth to age 14 years results in an unfavorable cardiometabolic risk profile at age 14 years, including central adiposity and more atherogenic lipoproteins, independent of achieved BMI.

Childhood fish oil supplementation modifies associations between traffic related air pollution and allergic sensitisation.

BACKGROUND: Studies of potential adverse effects of traffic related air pollution (TRAP) on allergic disease have had mixed findings. Nutritional studies to examine whether fish oil supplementation may protect against development of allergic disease through their anti-inflammatory actions have also had mixed findings. Extremely few studies to date have considered whether air pollution and dietary factors such as fish oil intake may interact, which was the rationale for this study. METHODS: We conducted a secondary analysis of the Childhood Asthma Prevention Study (CAPS) birth cohort, where children were randomised to fish oil supplementation or placebo from early life to age 5 years. We examined interactions between supplementation and TRAP (using weighted road density at place of residence as our measure of traffic related air pollution exposure) with allergic disease and lung function outcomes at age 5 and 8 years. RESULTS: Outcome information was available on approximately 400 children (~ 70% of the original birth cohort). Statistically significant interactions between fish oil supplementation and TRAP were seen for house dust mite (HDM), inhalant and all-allergen skin prick tests (SPTs) and for HDM-specific interleukin-5 response at age 5. Adjusting for relevant confounders, relative risks (RRs) for positive HDM SPT were RR 1.74 (95% CI 1.22-2.48) per 100 m local road or 33.3 m of motorway within 50 m of the home for those randomised to the control group and 1.03 (0.76-1.41) for those randomised to receive the fish oil supplement. The risk differential was highest in an analysis restricted to those who did not change address between ages 5 and 8 years. In this sub-group, supplementation also protected against the effect of traffic exposure on pre-bronchodilator FEV1/FVC ratio. CONCLUSIONS: Results suggest that fish oil supplementation may protect against pro-allergic sensitisation effects of TRAP exposure. Strengths of this analysis are that supplementation was randomised and independent of TRAP exposure, however, findings need to be confirmed in a larger experimental study with the interaction investigated as a primary hypothesis, potentially also exploring epigenetic mechanisms. More generally, studies of adverse health effects of air pollution may benefit from considering potential effect modification by diet and other factors. TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry. www.anzctr.org.au Registration: ACTRN12605000042640 , Date: 26th July 2005. Retrospectively registered, trial commenced prior to registry availability.

Impact of childhood asthma on growth trajectories in early adolescence: Findings from the Childhood Asthma Prevention Study (CAPS).

BACKGROUND AND OBJECTIVE: Understanding the associations between childhood asthma and growth in early adolescence by accounting for the heterogeneity of growth during puberty has been largely unexplored. The objective was to identify sex-specific classes of growth trajectories during early adolescence, using a method which takes the heterogeneity of growth into account and to evaluate the association between childhood asthma and different classes of growth trajectories in adolescence. METHODS: Our longitudinal study included participants with a family history of asthma born during 1997-1999 in Sydney, Australia. Hence, all participants were at high risk for asthma. Asthma status was ascertained at 8 years of age using data from questionnaires and lung function tests. Growth trajectories between 11 and 14 years of age were classified using a latent basis growth mixture model. Multinomial regression analyses were used to evaluate the association between asthma and the categorized classes of growth trajectories. RESULTS: In total, 316 participants (51.6% boys), representing 51.3% of the entire cohort, were included. Sex-specific classes of growth trajectories were defined. Among boys, asthma was not associated with the classes of growth trajectories. Girls with asthma were more likely than girls without asthma to belong to a class with later growth (OR: 3.79, 95% CI: 1.33, 10.84). Excluding participants using inhaled corticosteroids or adjusting for confounders did not significantly change the results for either sex. CONCLUSION: We identified sex-specific heterogeneous classes of growth using growth mixture modelling. Associations between childhood asthma and different classes of growth trajectories were found for girls only.

Absence of back to school peaks in human rhinovirus detections and respiratory symptoms in a cohort of children with asthma.

Much of what is known about the seasonality of human rhinovirus (hRV) infections has been learned from the study of acute asthma exacerbations presenting to emergency care, including those among children at the start of the school term. Much less is known about the patterns of hRVs in the community. In this study, viruses and day-to-day symptoms of asthma and colds were monitored twice weekly in 67 children with asthma aged 5-12 years, over a 15 month period in Sydney, Australia. Overall hRV was detected in 314/1232 (25.5%) of nasal wash samples and 142/1231 (11.5%) of exhaled breath samples; of these, 231 and 24 respectively were genotyped. HRVs were detected with similar prevalence rate throughout the year, including no peak in hRV prevalence following return to school. No peaks were seen in asthma and cold symptoms using twice-weekly diary records. However, over the same period in the community, there were peaks in asthma emergency visits both at a large local hospital and in state-wide hospitalizations, following both return to school (February) and in late autumn (May) in children of the same age. This study suggests that hRV infections are common throughout the year among children, and differences in virus prevalence alone may not account for peaks in asthma symptoms.

Rhinoviruses significantly affect day-to-day respiratory symptoms of children with asthma.

BACKGROUND: Viruses are frequently associated with acute exacerbations of asthma, but the extent to which they contribute to the level of day-to-day symptom control is less clear. OBJECTIVE: We sought to explore the relationship between viral infections, host and environmental factors, and respiratory symptoms in children. METHODS: Sixty-seven asthmatic children collected samples twice weekly for an average of 10 weeks. These included nasal wash fluid and exhaled breath for PCR-based detection of viral RNA, lung function measurements, and records of medication use and asthma and respiratory symptoms in the previous 3 days. Atopy, mite allergen exposure, and vitamin D levels were also measured. Mixed-model regression analyses were performed. RESULTS: Human rhinoviruses (hRVs) were detected in 25.5% of 1232 nasal samples and 11.5% of breath samples. Non-hRV viruses were detected in less than 3% of samples. hRV in nasal samples was associated with asthma symptoms (cough and phlegm: odds ratio = 2.0; 95% CI = 1.4-2.86, P = .0001; wheeze and chest tightness: odds ratio = 2.34, 95% CI = 1.55-3.52, P < .0001) and with cold symptoms, as reported concurrently with sampling and 3 to 4 days later. No differences were found between the 3 hRV genotypes (hRV-A, hRV-B, and hRV-C) in symptom risk. A history of inhaled corticosteroid use, but not atopic status, mite allergen exposure, or vitamin D levels, modified the association between viruses and asthma symptoms. CONCLUSION: The detection of nasal hRV was associated with a significantly increased risk of day-to-day asthma symptoms in children. Host, virus genotype, and environmental factors each had only a small or no effect on the relationship of viral infections to asthma symptoms.

Prevalence of airflow obstruction and reduced forced vital capacity in an Aboriginal Australian population: The cross-sectional BOLD study.

BACKGROUND AND OBJECTIVE: Mortality and hospital separation data suggest a higher burden of chronic obstructive pulmonary disease (COPD) in indigenous than non-indigenous subpopulations of high-income countries. This study sought to accurately measure the true prevalence of post-bronchodilator airflow obstruction and forced vital capacity reduction in representative samples of Indigenous and non-Indigenous Australians. METHODS: This study applies cross-sectional population-based survey of Aboriginal and non-Indigenous residents of the Kimberley region of Western Australia aged 40 years or older, following the international Burden Of Lung Disease (BOLD) protocol. Quality-controlled spirometry was conducted before and after bronchodilator. COPD was defined as Global initiative for chronic Obstructive Lung Disease (GOLD) Stage 2 and above (post-bronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV1 /FVC) ratio <0.7 and FEV1 < 80% predicted). RESULTS: Complete data were available for 704 participants. The prevalence of COPD, adjusted for age, gender and body weight in Aboriginal participants (7.2%, 95% confidence interval (CI) 3.9 to 10.4) was similar to that seen in non-Indigenous Kimberley participants (8.2%, 95% CI 5.7 to 10.7) and non-Indigenous residents of the remainder of Australia (7.1%, 95% CI 6.1 to 8.0). The prevalence of low FVC (<80% predicted) was substantially higher in Aboriginal compared with non-Indigenous participants (74.0%, 95% CI 69.1 to 78.8, vs 9.7%, 95% CI 7.1 to 12.4). CONCLUSIONS: Low FVC, rather than airflow obstruction, characterizes the impact of chronic lung disease previously attributed to COPD in this population subject to significant social and economic disadvantage. Environmental risk factors other than smoking as well as developmental factors must be considered. These findings require further investigation and have implications for future prevention of chronic lung disease in similar populations.

Assessing the performance of two lung age equations on the Australian population: using data from the cross-sectional BOLD-Australia study.

INTRODUCTION: Lung age, a simple concept for patients to grasp, is frequently used as an aid in smoking cessation programs. Lung age equations should be continuously updated and should be made relevant for target populations. We observed how new lung age equations developed for Australian populations performed when utilizing the Burden of Obstructive Lung Disease (BOLD)-Australia dataset compared to more commonly used equations. METHODS: Data from a cross-sectional population study of noninstitutionalized Australians aged ≥40 years with analysis restricted to Caucasians <75 years. Lung age calculated using equations developed by Newbury et al. and Morris and Temple was compared with chronological age by smoking status and within smoking status. RESULTS: There were 2,793 participants with a mean age of 57 (±10 SD) years. More than half (52%) ever smoked, and 10.4% were current smokers. Prevalence of chronic obstructive pulmonary disease stage I or higher was 13.4% (95% confidence interval = 12.2, 14.7). For both genders, newer Newbury equations estimated lung ages significantly higher than actual age across all smoking groups (p < .05). Morris and Temple equations resulted in lung age estimates significantly lower than chronological age for nonsmokers (p < .05) but no difference among current smokers. Both equations showed exposure to smoking had lung ages higher than never-smokers (p < .001). Lung age also increased with increased pack-years. CONCLUSIONS: This supports the use of updated equations suited to the population of interest. The Australian Newbury equations performed well in the BOLD-Australia dataset, providing more meaningful lung age profile compared to chronological age among smokers. Using equations not developed or ideally suited for our population is likely to produce misleading results.

Recruiting and retaining general practitioners to a primary care asthma-intervention study in Australia.

The need for more evidence-based interventions in primary care is clear. However, it is challenging to recruit general practitioners (GPs) for interventional research. This paper reports on the evaluation of three methods of recruitment that were sequentially used to recruit GPs for a randomised controlled trial of an asthma communication and education intervention in Australia. The recruitment methods (RMs) were: general practices were contacted by project staff from a Department of General Practice, University of Sydney (RM1); general practices were contacted by staff from an independent research organisation (RM2); and general practices were contacted by a medical peer (chief investigator) (RM3). A GP was defined as 'recruited' once they consented and were randomised to a group, and 'retained' if they provided baseline data and did not notify staff of their intention to withdraw at any time during the 12-month study. RM1 was used for the first 6 months, during which 34 (4%) GPs were recruited and 21 (62%) retained from a total of 953 invitations. RM2 was then used for the next 5 months, during which 32 (6%) GPs were recruited and 26 (81%) were retained. Finally over the next 7 months, RM3 recruited 84 (12%) GPs and retained 75 (89%) GPs. In conclusion, use of a medical peer as the first contact was associated with the highest recruitment and retention rate.

COPD in Never-Smokers: BOLD Australia Study.

Purpose: Tobacco smoking is the major risk factor for COPD, and it is common for other risk factors in never-smokers to be overlooked. We examined the prevalence of COPD among never-smokers in Australia and identified associated risk factors. Methods: We used data from the Australia Burden of Obstructive Lung Disease (BOLD) study, a cross-section of people aged ≥40 years from six sites. Participants completed interviews and post-bronchodilator spirometry. COPD was primarily defined as an FEV1/FVC ratio <0.70 and secondarily as the ratio less than the lower limit of normal (LLN). Results: The prevalence of COPD in the 1656 never-smokers who completed the study was 10.5% (95% CI: 9.1-12.1%) [ratio

Respiratory symptoms and illness in older Australians: the Burden of Obstructive Lung Disease (BOLD) study.

OBJECTIVE: To measure the prevalence of chronic obstructive pulmonary disease (COPD) among people aged 40 years or older in Australia. DESIGN, SETTING AND PARTICIPANTS: A cross-sectional study of people in the community aged ≥ 40 years, selected at random using electoral rolls, in six sites chosen to reflect the sociodemographic and geographic diversity of Australia, conducted between 2006 and 2010. Standardised questionnaires were administered by interview. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and the FEV1/FVC ratio were measured by spirometry, before and after bronchodilator administration. MAIN OUTCOME MEASURE: Prevalence of COPD, classified according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2006 criteria. RESULTS: Complete data were available for 1620 men (participation rate, 26%) and 1737 women (participation rate, 28%). The prevalence of GOLD Stage II or higher COPD (defined as post-bronchodilator FEV1/FVC ratio < 0.70 and FEV1 < 80% predicted) was 7.5% (95% CI, 5.7%-9.4%) among people aged ≥ 40 years, and 29.2% (95% CI, 18.1%-40.2%) among those aged ≥ 75 years. Among people aged ≥ 40 years, the prevalence of wheeze in the past 12 months was 30.0% (95% CI, 27.5%-32.5%), and prevalence of shortness of breath when hurrying on the level or climbing a slight hill was 25.2% (95% CI, 22.7%-27.6%). CONCLUSIONS: Symptoms and spirometric evidence of COPD are common among people aged 40 years or older and increase with age. Further research is needed to better understand the diagnosis and management of COPD in Australia, along with continuing efforts to prevent the disease.

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.