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.

Relationship between life-time exposure to ambient fine particulate matter and carotid artery intima-media thickness in Australian children aged 11-12 years.

Long-term exposure to air pollutants, especially particulates, in adulthood is related to cardiovascular diseases and vascular markers of atherosclerosis. However, whether vascular changes in children is related to exposure to air pollutants remains unknown. This study examined whether childhood exposure to air pollutants was related to a marker of cardiovascular risk, carotid intima-media thickness (CIMT) in children aged 11-12 years old. Longitudinal Study of Australian Children (LSAC) recruited parents and their children born in 2003-4. Among the participants, CheckPoint examination was conducted when the children were 11-12 years old. Ultrasound of the right carotid artery was performed using standardized protocols. Average and maximum far-wall CIMT, carotid artery distensibility, and elasticity were quantified using semiautomated software. Annual and life-time exposure to air pollutants was estimated using satellite-based land-use regression by residential postcodes. A total of 1063 children (50.4% girls) with CIMT data, serum cholesterol, and modeled estimates of NO2 and PM2.5 exposure for the period 2003 to 2015 were included. The average and maximum CIMT, carotid distensibility, and elasticity were 497 µm (standard deviation, SD 58), 580 µm (SD 44), 17.4% (SD 3.2), and 0.48%/mmHg (SD 0.09), respectively. The life-time average concentrations of PM2.5 and NO2 were 6.4 µg/m3 (SD 1.4) and 6.4 ppb (SD 2.4), respectively. Both average and maximum CIMT were significantly associated with average ambient PM2.5 concentration (average CIMT: +5.5 µm per µg/m3, 95% confidence interval, CI 2.4 to 8.5, and maximum CIMT: +4.9 µm per µg/m3, CI 2.3 to 7.6), estimated using linear regression, adjusting for potential confounders. CIMT was not significantly related to NO2 exposure. Carotid artery diameter, distensibility, and elasticity were not significantly associated with air pollutants. We conclude that life-time exposure to low levels of PM2.5 in children might have measurable adverse impacts on vascular structure by age 11-12 years.

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.

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.

Risks associated with managing asthma without a preventer: urgent healthcare, poor asthma control and over-the-counter reliever use in a cross-sectional population survey.

OBJECTIVES: Overuse of asthma relievers, particularly without anti-inflammatory preventers, increases asthma risks. This study aimed to identify how many reliever-only users have urgent healthcare, explore their attitudes and beliefs about asthma and its treatment, and investigate whether purchasing over-the-counter relievers was associated with worse asthma outcomes than by prescription. DESIGN AND SETTING: Cross-sectional population-based Internet survey in Australia. PARTICIPANTS: Of 2686 participants ≥16 years with current asthma randomly drawn from a web-based panel, 1038 (50.7% male) used only reliever medication. MAIN OUTCOME MEASURES: Urgent asthma-related healthcare; Asthma Control Test (ACT); patient attitudes about asthma and medications; reliever purchase (with/without prescription). RESULTS: Of 1038 reliever-only participants, 23.3% had required urgent healthcare for asthma in the previous year, and only 36.0% had a non-urgent asthma review. Those needing urgent healthcare were more likely than those without such events to be male (56.5% vs 49.0%, p=0.003) and current smokers (29.4% vs 23.3%, p=0.009). Only 30.6% had well-controlled asthma (ACT ≥20) compared with 71.0% of those with no urgent healthcare (p<0.0001), and 20.8% used relievers regularly to prevent asthma symptoms (vs 5.5% of those without urgent healthcare). Those with urgent healthcare were more frustrated by their asthma and less happy with how they managed it, and they were less confident about their ability to manage worsening asthma, but just as likely as those without urgent healthcare to manage worsening asthma themselves rather than visit a doctor. Reliever-only users purchasing over-the-counter relievers were no more likely than those purchasing relievers by prescription to have uncontrolled asthma (35.9% vs 40.6%, p=0.23) but were less likely to have had a non-urgent asthma review. CONCLUSIONS: One-quarter of the reliever-only population had needed urgent asthma healthcare in the previous year, demonstrating the importance of identifying such patients. Their attitudes and beliefs suggest opportunities for targeting this population in the community.

Is higher population-level use of ICS/LABA combination associated with better asthma outcomes? Cross-sectional surveys of nationally representative populations in New Zealand and Australia.

BACKGROUND AND OBJECTIVE: New Zealand (NZ) and Australia (AU) have similarly high asthma prevalence; both have universal public health systems, but different criteria for subsidized medicines. We explored differences in asthma management and asthma-related outcomes between these countries. METHODS: A web-based survey was administered in AU (2012) and NZ (2013) to individuals aged ≥16 years with current asthma, drawn randomly from web-based panels, stratified by national population proportions. Symptom control was assessed with the Asthma Control Test (ACT). Healthcare utilization was assessed from reported urgent doctor/hospital visits in the previous year. RESULTS: NZ (n = 537) and Australian (n = 2686) participants had similar age and gender distribution. More NZ than Australian participants used inhaled corticosteroid (ICS)-containing medication (68.8% vs 60.9%; P = 0.006) but ICS/long-acting ß2 -agonist (LABA) constituted 44.4% of NZ and 81.5% of Australian total ICS use (P < 0.0001). Adherence was higher with ICS/LABA than ICS-alone (P < 0.0001), and higher in NZ than in AU (P < 0.0001). ACT scores were similar (P = 0.41), with symptoms well controlled in 58.6% and 54.4% participants, respectively. More NZ participants reported non-urgent asthma reviews (56.6% vs 50.4%; P = 0.009). Similar proportions had urgent asthma visits (27.9% and 28.6%, respectively, P = 0.75). CONCLUSION: This comparison, which included the first nationally representative data for asthma control in NZ, showed that poorly controlled asthma is common in both NZ and AU, despite subsidized ICS-containing medications. The greater use of ICS-alone in NZ relative to ICS/LABA does not appear to have compromised population-level asthma outcomes, perhaps due to better adherence in NZ. Different ICS/LABA subsidy criteria and different patient copayments may also have contributed to these findings.

Inappropriate prescribing of inhaled corticosteroids: are they being prescribed for respiratory tract infections? A retrospective cohort study.

BACKGROUND: Guidelines recommend regular use of inhaled corticosteroid (ICS)-containing medications for all patients with persistent asthma and those with moderate to severe chronic obstructive pulmonary disease. It is important to identify indicators of inappropriate prescribing. AIMS: To test the hypothesis that ICS are prescribed for the management of respiratory infections in some patients lacking evidence of chronic airways disease. METHODS: Medication dispensing data were obtained from the Australian national Pharmaceutical Benefits Scheme (PBS) for concessional patients dispensed any respiratory medications during 2008. We identified people dispensed only one ICS-containing medication and no other respiratory medications in a year, who were therefore unlikely to have chronic airways disease, and calculated the proportion who were co-dispensed oral antibiotics. RESULTS: In 2008, 43.6% of the 115,763 patients who were dispensed one-off ICS were co-dispensed oral antibiotics. Co-dispensing was seasonal, with a large peak in winter months. The most commonly co-dispensed ICS among adults were moderate/high doses of combination therapy, while lower doses of ICS alone were co-dispensed among children. In this cohort, one-off ICS co-dispensed with oral antibiotics cost the government $2.7 million in 2008. CONCLUSIONS: In Australia, many people who receive one-off prescriptions for ICS-containing medications do not appear to have airways disease. In this context, the high rate of co-dispensing with antibiotics suggests that ICS are often inappropriately prescribed for the management of symptoms of respiratory infection. Interventions are required to improve the quality of prescribing of ICS and the management of respiratory infections in clinical practice.

Cost is a major barrier to the use of inhaled corticosteroids for obstructive lung disease.

OBJECTIVE: To examine the effect of the level of patient copayment on the rate of purchase of inhaled corticosteroids (ICS) by patients with obstructive lung disease. DESIGN AND SETTING: Cross-sectional study of records of all prescriptions for ICS dispensed to general and concessional beneficiaries aged 15 years or over in the period January 2003 to December 2006. Data were obtained from the Pharmaceutical Benefits Scheme, which subsidises medication costs for all Australians. MAIN OUTCOME MEASURES: The number of prescriptions for ICS dispensed to government concession card holders compared with the number dispensed to general beneficiaries, expressed as a rate ratio. RESULTS: ICS prescriptions were dispensed to over 1.6 million people during the study period. Concession card holders were dispensed ICS prescriptions at a higher rate than general beneficiaries, both overall (43.7 v 9.1 ICS prescriptions per 100 person-years) and in all population subgroups. After adjusting for age, sex, remoteness category and socioeconomic status, people holding a concession card were dispensed over 2.5 times the number of ICS prescriptions (alone or in combination with a long-acting beta(2)-agonist) compared with general beneficiaries. Similar patterns were seen after adjusting for differences between the two groups in the prevalence of obstructive lung disease. CONCLUSIONS: As the patient copayment for general beneficiaries is over six times higher than for concession card holders, our findings imply that cost is a barrier to the purchase of ICS prescriptions for obstructive lung disease, independent of socioeconomic status.

Prevention of asthma during the first 5 years of life: a randomized controlled trial.

BACKGROUND: Early life exposures may be important in the development of asthma and allergic disease. OBJECTIVE: To test house dust mite (HDM) avoidance and dietary fatty acid modification, implemented throughout the first 5 years of life, as interventions to prevent asthma and allergic disease. METHODS: We recruited newborns with a family history of asthma antenatally and randomized them, separately, to HDM avoidance or control and to dietary modification or control. At age 5 years, they were assessed for asthma and eczema and had skin prick tests for atopy. RESULTS: Of 616 children randomized, 516 (84%) were evaluated at age 5 years. The HDM avoidance intervention resulted in a 61% reduction in HDM allergen concentrations (microg/g dust) in the child's bed but no difference in the prevalence of asthma, wheeze, or atopy (P > .1). The prevalence of eczema was higher in the active HDM avoidance group (26% vs 19%; P = .06). The ratio of omega-6 to omega-3 fatty acids in plasma was lower in the active diet group (5.8 vs 7.4; P < .0001). However, the prevalence of asthma, wheezing, eczema, or atopy did not differ between the diet groups (P > .1). CONCLUSION: Further research is required to establish whether other interventions can be recommended for the prevention of asthma and allergic disease. CLINICAL IMPLICATIONS: House dust mite avoidance measures and dietary fatty acid modification, as implemented in this trial during infancy and early childhood, did not prevent the onset of asthma, eczema, or atopy in high-risk children.