Socio-economic burden of asthma, allergy, and other atopic illnesses

Long-Term Outcomes of Pediatric Enterovirus Infection in Taiwan: A Population-Based Cohort Study

Introduction: The major burden of diseases in childhood has shifted from infectious diseases to chronic health conditions in recent decades. Although the rates of infectious diseases have decreased, the incidence of chronic diseases stemming from infectious agents continues to grow. Enterovirus is a major infectious disease of childhood and has been linked to numerous chronic diseases. We analyzed population-based data from Taiwan's National Health Insurance Research Database (NHIRD) to investigate the correlations between enterovirus infection and major chronic health conditions in children. Method: Children diagnosed with enterovirus (EV) infection during 1999-2003 were identified from the Longitudinal Health Insurance Database 2000 (LHID 2000), a subdataset of Taiwan's National Health Insurance Research Database (NHIRD). A total of 14,168 patients were selected after excluding patients with existing chronic diseases and missing data. Another 14,168 children matched by age and sex were selected as the control group. Five primary outcomes, including attention deficit and hyperactivity disorder (ADHD), epilepsy, asthma, allergic rhinitis, and atopic dermatitis, were recorded. Results: The risks of ADHD, asthma, allergic rhinitis, and epilepsy were significantly increased in the EV group compared with the control group. The risk of atopic dermatitis was significantly increased in the crude model. However, there were no significant differences in the adjusted model. The risks of ADHD, asthma, allergic rhinitis, and epilepsy were also significantly increased in patients with severe EV infection compared with patients with non-severe EV infection. Conclusion: Chronic diseases, such as ADHD, epilepsy, asthma, allergic rhinitis, and atopic dermatitis were shown to be associated with enterovirus infection during childhood. EV infection during early childhood might have long-term public health implications and thus prevention strategies should be implemented.

The Economic Burden of Asthma in the United States, 2008-2013

RATIONALE

Asthma is a chronic disease that affects quality of life, productivity at work and school, and healthcare use; and it can result in death. Measuring the current economic burden of asthma provides important information on the impact of asthma on society. This information can be used to make informed decisions about allocation of limited public health resources.

OBJECTIVES

In this paper, we provide a comprehensive approach to estimating the current prevalence, medical costs, cost of absenteeism (missed work and school days), and mortality attributable to asthma from a national perspective. In addition, we estimate the association of the incremental medical cost of asthma with several important factors, including race/ethnicity, education, poverty, and insurance status.

METHODS

The primary source of data was the 2008-2013 household component of the Medical Expenditure Panel Survey. We defined treated asthma as the presence of at least one medical or pharmaceutical encounter or claim associated with asthma. For the main analysis, we applied two-part regression models to estimate asthma-related annual per-person incremental medical costs and negative binomial models to estimate absenteeism associated with asthma.

RESULTS

Of 213,994 people in the pooled sample, 10,237 persons had treated asthma (prevalence, 4.8%). The annual per-person incremental medical cost of asthma was $3,266 (in 2015 U.S. dollars), of which $1,830 was attributable to prescription medication, $640 to office visits, $529 to hospitalizations, $176 to hospital-based outpatient visits, and $105 to emergency room visits. For certain groups, the per-person incremental medical cost of asthma differed from that of the population average, namely $2,145 for uninsured persons and $3,581 for those living below the poverty line. During 2008-2013, asthma was responsible for $3 billion in losses due to missed work and school days, $29 billion due to asthma-related mortality, and $50.3 billion in medical costs. All combined, the total cost of asthma in the United States based on the pooled sample amounted to $81.9 billion in 2013.

CONCLUSIONS

Asthma places a significant economic burden on the United States, with a total cost of asthma, including costs incurred by absenteeism and mortality, of $81.9 billion in 2013.

Lack of association between RAD50-IL13 polymorphisms and pediatric asthma susceptibility in Northeastern Han Chinese

OBJECTIVE

RAD50-IL13 region has been recently identified as one of critical asthma susceptibility loci in genome-wide association studies, yet the role of these genetic variants or single-nucleotide polymorphisms (SNPs) in the risk of developing asthma in Northeastern Han Chinese remains largely unknown.

METHODS

We conducted an association study by genotyping four SNPs (rs2244012 and rs6871536 in RAD50 as well as rs1295686 and rs1800925 in IL13) in 652 asthmatic children and age-matched 752 healthy controls from Northeastern Han Chinese to evaluate the asthma susceptibility with each individual SNP using SNaPshot genotyping method.

RESULTS

We did not find the allele or genotype frequency distribution of four SNPs in RAD50-IL13 region which was significantly different between asthmatic children and controls (p > 0.05).

CONCLUSIONS

Our findings first suggested that the variants in RAD50-IL13 region were not associated with asthma risk in Northeastern Han Chinese children.

Economic and health effect of full adherence to controller therapy in adults with uncontrolled asthma: a simulation study

BACKGROUND

Adherence to evidence-based controller treatments for asthma is disappointingly low in many jurisdictions. Quantifying the burden associated with suboptimal adherence in patients with uncontrolled asthma will help establish the priorities for policymakers.

OBJECTIVE

We sought to quantify the benefits in the United States of improving adherence to controller therapies in adults with uncontrolled asthma in terms of health care costs and quality-adjusted life years (QALYs).

METHODS

A Markov model of asthma was created to simulate the effect of treatment with controller medications on asthma control and exacerbations over a 10-year time horizon. Health care costs and QALYs associated with the current level of adherence (status quo) were compared with a hypothetical scenario in which each patient with uncontrolled asthma at baseline will be fully adherent to an evidence-based controller therapy (the full-adherence scenario). We also evaluated the cost-effectiveness of adherence interventions as a function of their costs and improvement in the adherence.

RESULTS

The status quo level of asthma management was associated with $2,786 costs and 7.55 QALYs over 10 years, whereas the corresponding values for the full-adherence scenario were $5,973 and 7.68, respectively. Consequently, the incremental cost-effectiveness ratio of the full-adherence versus the status quo was $24,515/QALY. To be cost-effective, a program that improves adherence by 50% should cost less than $130 ($450) per person annually at a willingness-to-pay value of $50,000/QALY ($100,000/QALY). Inclusion of productivity loss in the analysis resulted in the full-adherence scenario being cost-saving.

CONCLUSION

Considering the extent of suboptimal adherence, our study shows that attempts in improving adherence to evidence-based therapies in patients with uncontrolled asthma can be associated with significant return on investment.

Interleukin-13 genetic variants, household carpet use and childhood asthma

Interleukin (IL)-13 genetic polymorphisms have shown adverse effects on respiratory health. However, few studies have explored the interactive effects between IL-13 haplotypes and environmental exposures on childhood asthma. The aims of our study are to evaluate the effects of IL-13 genetic variants on asthma phenotypes, and explore the potential interaction between IL-13 and household environmental exposures among Taiwanese children. We investigated 3,577 children in the Taiwan Children Health Study from 14 Taiwanese communities. Data regarding children's exposure and disease status were obtained from parents using a structured questionnaire. Four SNPs were tagged accounting for 100% of the variations in IL-13. Multiple logistic regression models with false-discovery rate (FDR) adjustments were fitted to estimate the effects of IL-13 variants on asthma phenotypes. SNP rs1800925, SNP rs20541 and SNP rs848 were significantly associated with increased risks on childhood wheeze with FDR of 0.03, 0.04 and 0.04, respectively. Children carrying two copies of h1011 haplotype showed increased susceptibility to wheeze. Compared to those without carpet use and h1011 haplotype, children carrying h1011 haplotype and using carpet at home had significantly synergistic risks of wheeze (OR, 2.5; 95% CI, 1.4–4.4; p for interaction, 0.01) and late-onset asthma (OR, 4.7; 95% CI, 2.0–10.9; p for interaction, 0.02). In conclusions, IL-13 genetic variants showed significant adverse effects on asthma phenotypes among children. The results also suggested that asthma pathogenesis might be mediated by household carpet use.

Gene-gene and gene-environmental interactions of childhood asthma: a multifactor dimension reduction approach

Background

The importance of gene-gene and gene-environment interactions on asthma is well documented in literature, but a systematic analysis on the interaction between various genetic and environmental factors is still lacking.

Methodology/Principal Findings

We conducted a population-based, case-control study comprised of seventh-grade children from 14 Taiwanese communities. A total of 235 asthmatic cases and 1,310 non-asthmatic controls were selected for DNA collection and genotyping. We examined the gene-gene and gene-environment interactions between 17 single-nucleotide polymorphisms in antioxidative, inflammatory and obesity-related genes, and childhood asthma. Environmental exposures and disease status were obtained from parental questionnaires. The model-free and non-parametrical multifactor dimensionality reduction (MDR) method was used for the analysis. A three-way gene-gene interaction was elucidated between the gene coding glutathione S-transferase P (GSTP1), the gene coding interleukin-4 receptor alpha chain (IL4Ra) and the gene coding insulin induced gene 2 (INSIG2) on the risk of lifetime asthma. The testing-balanced accuracy on asthma was 57.83% with a cross-validation consistency of 10 out of 10. The interaction of preterm birth and indoor dampness had the highest training-balanced accuracy at 59.09%. Indoor dampness also interacted with many genes, including IL13, beta-2 adrenergic receptor (ADRB2), signal transducer and activator of transcription 6 (STAT6). We also used likelihood ratio tests for interaction and chi-square tests to validate our results and all tests showed statistical significance.

Conclusions/Significance

The results of this study suggest that GSTP1, INSIG2 and IL4Ra may influence the lifetime asthma susceptibility through gene-gene interactions in schoolchildren. Home dampness combined with each one of the genes STAT6, IL13 and ADRB2 could raise the asthma risk.

Asthma symptom burden: relationship to asthma severity and anxiety and depression symptoms

OBJECTIVE

The purpose of this work was to examine the relationship between youth-reported asthma symptoms, presence of anxiety or depressive disorders, and objective measures of asthma severity among a population-based sample of youth with asthma.

METHODS

We conducted a telephone survey of 767 youth with asthma (aged 11-17 years) enrolled in a staff model health maintenance organization. The Diagnostic Interview Schedule for Children was used to diagnose Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, anxiety and depressive disorders; the Child Health Status-Asthma questionnaire (modified) was used to assess asthma symptoms; and automated administrative data were used to measure asthma treatment intensity and severity. Analyses of covariance were performed to determine whether the number of anxiety and depressive symptoms was related to the number of asthma symptoms. Logistic regression analyses were used to evaluate the strength of association between individual symptoms of asthma and the presence of an anxiety or depressive disorder and objective measures of asthma severity.

RESULTS

After adjusting for demographic characteristics, objective measures of asthma severity, medical comorbidity, and asthma treatment intensity, youth with > or = 1 anxiety or depressive disorder (N = 125) reported significantly more days of asthma symptoms over the previous 2 weeks than youth with no anxiety or depressive disorders. The overall number of reported asthma symptoms was significantly associated with the number of anxiety and depressive symptoms endorsed by youth. In logistic regression analyses, having an anxiety or depressive disorder was also strongly associated with each of the 6 asthma-specific symptoms, as well as the 5 related nonspecific somatic symptoms contained in the Child Health Status-Asthma questionnaire.

CONCLUSIONS

The presence of an anxiety or depressive disorder is highly associated with increased asthma symptom burden for youth with asthma.

Do indoor pollutants and thermal conditions in schools influence student performance? A critical review of the literature

To assess whether school environments can adversely affect academic performance, we review scientific evidence relating indoor pollutants and thermal conditions, in schools or other indoor environments, to human performance or attendance. We critically review evidence for direct associations between these aspects of indoor environmental quality (IEQ) and performance or attendance. Secondarily, we summarize, without critique, evidence on indirect connections potentially linking IEQ to performance or attendance. Regarding direct associations, little strongly designed research was available. Persuasive evidence links higher indoor concentrations of NO(2) to reduced school attendance, and suggestive evidence links low ventilation rates to reduced performance. Regarding indirect associations, many studies link indoor dampness and microbiologic pollutants (primarily in homes) to asthma exacerbations and respiratory infections, which in turn have been related to reduced performance and attendance. Also, much evidence links poor IEQ (e.g. low ventilation rate, excess moisture, or formaldehyde) with adverse health effects in children and adults and documents dampness problems and inadequate ventilation as common in schools. Overall, evidence suggests that poor IEQ in schools is common and adversely influences the performance and attendance of students, primarily through health effects from indoor pollutants. Evidence is available to justify (i) immediate actions to assess and improve IEQ in schools and (ii) focused research to guide IEQ improvements in schools.

PRACTICAL IMPLICATIONS

There is more justification now for improving IEQ in schools to reduce health risks to students than to reduce performance or attendance risks. However, as IEQ-performance links are likely to operate largely through effects of IEQ on health, IEQ improvements that benefit the health of students are likely to have performance and attendance benefits as well. Immediate actions are warranted in schools to prevent dampness problems, inadequate ventilation, and excess indoor exposures to substances such as NO(2) and formaldehyde. Also, siting of new schools in areas with lower outdoor pollutant levels is preferable.

The costs of atopy and asthma in children: assessment of direct costs and their determinants in a birth cohort

The aim of this study was to estimate costs accrued by the health care of children with asthma in comparison to children with atopic eczema and seasonal rhinitis and to investigate cost determinants. From the multicenter cohort study (MAS-90), we selected children with an asthma, atopic eczema and/or seasonal rhinitis diagnosis during the first 8 years of life, and overall 8-year health care utilization was estimated retrospectively by reviewing medical records. Asthma treatment (n = 76) incurs an average cost of 627 US dollars per year, 44% due to hospital stays. Atopic eczema treatment (n = 91) cost on average 219 US dollars and seasonal rhinitis (n = 69) 57 US dollars per year. In asthma and atopic eczema, costs increase significantly with disease severity. Allergy diagnostics use accounts for only 1% of total costs. Costs for asthma and atopic eczema treatment are highest in those years when topical steroids are used for the first time, but decrease with every further year of steroid use. A remarkable 25% of asthmatic children with severe symptoms were not treated according to national guidelines, so that most steroid treatment was initiated during the first hospital stay. In the case of asthma, total direct costs increased until the 3rd year of the disease, and then decreased with further years of diagnosis, while steroid use continued to increase. These results indicate a 'learning effect' in the treatment of asthma and atopic eczema for each patient as well as considerable cost-saving potential by preventing severe asthma. Moreover, the importance of considering cost-driving factors and using cohort or longitudinal designs in cost-of-illness approaches is emphasized.

Asthma and allergy: the significance of chronic conditions for individual health behaviour

BACKGROUND

In health economics, health is regarded as part of an individual's human capital. As such it depreciates over time, and investments in health are made in order to keep the stock of health capital at the desired level. Using this framework for analysis of health-related behaviour and Swedish panel data, we examined whether the presence of asthma or allergy affects perceived health and investments in health.

METHODS

A set of panel data for approximately 3800 individuals interviewed repeatedly in 1980/81, 1988/89, and 1996/97 was created from the Swedish biannual survey of living conditions. Self-assessed health was chosen as the indicator of health capital and the reported number of sick days as the indicator of health investment. The presence of asthma or allergy, age, wage rate, wealth, marital status, number of children, exercise and smoking habits, gender, and geographic location of household were all chosen as explanatory variables. An ordered probit model was estimated for the health equation and a Poisson model for the investment equation.

RESULTS

We found that both asthmatics and those who suffer from allergy invested more in their health than the general population. We also found that asthmatics reported significantly lower self-assessed health than the general population, while those who suffered from allergy did not differ significantly from the general population regarding their self-assessed health.

CONCLUSION

The human capital approach was found suitable for studying the impact of asthma and allergy on individual health behaviour. Health policy measures, which reduce the individual's costs of investing in his or her health, would improve health levels. Because asthmatics were found less healthy than those suffering from allergy, the potential gains would be larger for patients with asthma than for patients with allergy. The issue of whether this would be a cost-effective policy or not would require a different design and, hence, could not be solved within the present study.

Health care utilization and cost in children with asthma and selected comorbidities

Children with asthma use significantly more health services than other children, yet the majority of their health care costs are for nonasthma services. The objective of this study was to measure the impact of asthma and specific upper respiratory comorbidities on the use and cost of health care by children. A population-based historical cohort study from January 1, 1992 to December 31, 1992 was conducted. Multiple visits for otitis media, sinusitis, and allergic rhinitis were considered comorbidities. The outcome measures were nonurgent outpatient care, pharmacy fills, urgent care visits, and hospital care along with the associated total costs. Children between ages 1 and 17 years were studied (n = 71,818). Children with asthma were more likely than children without asthma to have a comorbidity (26% vs. 9%). Children with multiple visits for otitis media, sinusitis, and allergic rhinitis were 1.8, 4, and 12 times more likely, respectively, to have a diagnosis of asthma in the same year. Children with asthma had a 47% probability of being in the highest total cost quintile compared to a 29% likelihood once adjusted for comorbidities. Visits for otitis media, sinusitis, and particularly allergic rhinitis appear to be overrepresented in children with asthma and contribute to their high utilization rate. Once a high-risk cohort is identified, the needs of those children can be addressed through targeted, organized systems of care that may include guidelines or other disease management strategies.

Hay fever, eczema, and wheeze: a nationwide UK study (ISAAC, international study of asthma and allergies in childhood)

OBJECTIVES

To describe the prevalence of atopic symptoms in children throughout the UK.

METHOD

A questionnaire survey of 12-14 year olds throughout England, Wales, Scotland, and the Scottish Islands using the international study of asthma and allergies in childhood (ISAAC) protocol.

RESULTS

A total of 27 507 (86%) children took part. Recent rhinoconjunctivitis was reported by 18.2%, with 6.2% reporting symptoms between March and September; 16.4% reported itchy flexural rash in the past 12 months. The prevalence of atopic symptoms was higher in girls and subjects born within the UK. The prevalence of severe wheeze was highest in subjects reporting perennial rhinoconjunctivitis, as opposed to summertime only symptoms. Winter rhinoconjunctivitis was associated with severe wheeze and severe flexural rash. One or more current symptoms were reported by 47.6% of all children and 4% reported all three symptoms.

CONCLUSION

In general, geographical variations were small but the prevalence of symptoms was significantly higher in Scotland and northern England. The study demonstrates the importance of atopic diseases both in their own right and in association with asthma.

Regulation of immune responses at mucosal surfaces: allergic respiratory disease as a paradigm

The epithelial surfaces of the respiratory tract represent a fragile interface between the immune system and the outside environment. In order to maintain local homeostasis, the adaptive immune system must continuously discriminate between innocuous antigens which are ubiquitous in the atmosphere, and antigens associated with microbial pathogens. Any breakdown in this discrimination process can potentially lead to chronic inflammatory disease. The mechanisms employed by the mucosal immune system to maintain this delicate balance are many and varied, and a comprehensive understanding of how they collectively operate would provide novel insight into a wide variety of diseases. This discussion reviews recent progress in this area, focusing on allergic respiratory disease as a model for the study of immune regulation at mucosal surfaces.

Health care utilization and cost among children with asthma who were enrolled in a health maintenance organization

OBJECTIVE

To measure the impact of asthma on the use and cost of health care by children in a managed care organization.

DESIGN

Population-based historical cohort study.

SETTING

A medium-sized staff model health maintenance organization in western Washington state.

SUBJECTS

All 71 818 children, between age 1 to 17 years, who were enrolled and used services during 1992.

OUTCOME MEASURES

Children were identified with one or more asthma diagnoses during 1992 using automated encounter data. Nonurgent outpatient visits, pharmacy fills, urgent care visits, and hospital days, as well as associated costs were measured. All services were categorized as asthma care or nonasthma care. Multivariate regression analysis was used to compute marginal cost for asthma (difference in total cost between children with asthma and other children using services, adjusted for covariates).

RESULTS

Treated prevalence of asthma was 4.9%. Children with asthma incurred 88% more costs ($1060.32 vs $563. 81/yr), filled 2.77 times as many prescriptions (11.59 vs 4.19/yr), made 65% more nonurgent outpatient visits (5.75 vs 3.48/yr), and had twice as many inpatient days (.23 vs .11/yr) compared with the general population of children using services. Asthma care represented 37% of all health care received by children with asthma, while the remaining 63% were for nonasthma services. Almost two-thirds of asthma-related costs were attributable to nonurgent outpatient care and prescriptions; only one third was attributable to urgent care and hospitalizations. Controlling for age, sex, and comorbidities, the marginal cost of asthma was $615.17/yr (95% confidence interval $502.73, $727.61), which includes asthma as well as nonasthma services. This marginal cost represents 58% of all health care costs for children with asthma.

CONCLUSIONS

Children with asthma use significantly more health services (and incur significantly more costs) than other children using services, attributable largely to asthma care. The majority of all health care costs for children with asthma were for nonasthma services. Urgent care visits and hospitalizations are less important components of asthma costs in this managed care organization than has been found in other national studies.

Ebastine. a review of its pharmacological properties and clinical efficacy in the treatment of allergic disorders

Ebastine is a long-acting nonsedating second generation histamine H1 receptor antagonist which binds preferentially to peripheral H1 receptors in vivo. It has shown antihistamine and antiallergic activity in healthy volunteers and patients with allergies, and protected against histamine-induced bronchoconstriction in patients with asthma. Significant symptom improvement is observed in patients with seasonal or perennial allergic rhinitis or chronic idiopathic urticaria following administration of ebastine 10 mg/day, or 20 mg/day in severe rhinitis. In clinical trials, the efficacy of ebastine 10 or 20 mg/day was generally similar to standard dosages of terfenadine, cetirizine, astemizole and loratadine in patients with seasonal allergic rhinitis, astemizole, terfenadine and ketotifen in patients with chronic idiopathic urticaria, and ketotifen, terfenadine, chlorpheniramine and mequitazine in patients with perennial allergic rhinitis. The most frequent adverse events reported during ebastine therapy are drowsiness, headache and dry mouth, the incidence being similar to that reported in placebo recipients. Serious adverse cardiac events, observed on rare occasions with some other histamine H1 receptor antagonists, have not been reported with ebastine, and there has been no evidence of QTc interval prolongation related to ebastine therapy. Thus, once-daily ebastine offers an effective and well-tolerated alternative to other second generation antihistamines in current use for the first-line treatment of seasonal and perennial allergic rhinitis and chronic idiopathic urticaria.

Environmental antigens and atopic disease: underlying mechanisms and prospects for therapy and prophylaxis

Natural exposure to non-pathogenic antigens, the so-called 'environmental antigens', experimentally elicits a characteristic pattern of T-cell immunity, involving selective suppression of the T-cell-dependent IgE responses that trigger allergic reactions. This 'immune deviation' results in the generation of long-lived T-cell memory, which confers active protection against allergic sensitization. Corresponding primary immune responses to environmental antigens in humans occur most frequently during infancy, and the development of allergic sensitization can be viewed as a failure of this natural immune-deviation process. In this article, potential strategies for primary prevention of allergic disease in infants involving, in particular, the exploitation of oral and mucosal tolerance to stimulate protective CD8+ T-cell-mediated immune deviation, are discussed.