Assessment of a medication-based asthma index for population research

Risk factors and clinical outcomes associated with fixed airflow obstruction in older adults with asthma

BACKGROUND

Asthma in older adults is associated with increased morbidity and mortality compared with asthma in younger patients. Fixed airflow obstruction (FAO) is associated with decreased survival in younger patients, but its significance remains unclear in older adults with asthma.

OBJECTIVE

To identify risk factors and outcomes related to FAO in older adults with asthma.

METHODS

Subjects older than 55 years with a physician diagnosis of persistent asthma were evaluated. Collected data included participant demographic information, medications, asthma exacerbations, Asthma Control Test (ACT) score, Asthma Quality of Life (AQLQ) score, comorbidities, spirometry, atopic status, and fractional exhaled nitric oxide. Clinical characteristics and outcomes associated with FAO (defined as post-bronchodilator ratio of forced expiratory volume in 1 second to forced vital capacity ≤70%) were assessed.

RESULTS

A total of 186 participants were analyzed (48 men and 138 women, mean age 66 years). FAO was demonstrated in 30% of participants. Using regression analysis, predictors of FAO included advanced age, African American race, male sex, and longer duration of asthma. In outcomes analysis, FAO was associated with worsened ACT and AQLQ scores; however, after controlling for confounding factors, logistic regression showed no association. No significant association was found between FAO and exacerbations, fractional exhaled nitric oxide, atopy, rhinitis, education level, depression, smoking, or body mass index.

CONCLUSION

Risk factors associated with FAO in older adults with asthma include advanced age, African American race, increased asthma duration, and male sex. Unlike younger patients, FAO is not independently associated with worsened asthma control, quality of life, or exacerbations in older patients with asthma.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01979055.

Assessment of asthma severity in adults with ever asthma: A continuous score

BACKGROUND

In epidemiological studies, continuous measures of asthma severity should be used to catch the heterogeneity of phenotypes. This study aimed at developing and validating continuous measures of asthma severity in adult patients with ever asthma from the general population, to be used in epidemiological studies.

METHODS

Respiratory symptoms, anti-asthmatic treatment and lung function were measured on 520 patients with ever asthma aged 20-64 years from the general Italian population (GEIRD study; 2007/2010). The variables that represent the same dimension of asthma severity were identified through an exploratory factor analysis and were summarized through a multiple factor analysis.

RESULTS

Only respiratory symptoms and anti-asthmatic treatment were summarized in a continuous score (STS). STS ranges from 0 (no symptoms/treatment) to 10 (maximum symptom frequency and treatment intensity). STS was positively correlated with the Global Initiative for Asthma classification of asthma severity computed on the 137 cases with a doctor's diagnosis (Spearman's coefficient = 0.61, p-value<0.0001) (concurrent validity). Furthermore, using a cohort of 1,097 European asthmatics (ECRHS II study; 1999/2002), increasing STS levels at baseline (1991/1993) were positively associated with long-term outcomes (hospitalization and lost workdays for breathing problems, asthma attack frequency and use of asthma controllers) (predictive validity). Finally, the STS scores computed from the GEIRD and ECRHS II data were comparable (Lin's coefficient = 0.95, p-value<0.0001) (replication analysis).

CONCLUSIONS

STS is a valid and replicable measure of asthma severity in adults, which could be used in association studies.

Asthma during pregnancy in a population-based study--pregnancy complications and adverse perinatal outcomes

Background

Asthma is one of the most common chronic diseases, and prevalence, severity and medication may have an effect on pregnancy. We examined maternal asthma, asthma severity and control in relation to pregnancy complications, labour characteristics and perinatal outcomes.

Methods

We retrieved data on all singleton births from July 1, 2006 to December 31, 2009, and prescribed drugs and physician-diagnosed asthma on the same women from multiple Swedish registers. The associations were estimated with logistic regression.

Results

In total, 266 045 women gave birth to 284 214 singletons during the study period. Maternal asthma was noted in 26 586 (9.4%) pregnancies. There was an association between maternal asthma and increased risks of pregnancy complications including preeclampsia or eclampsia (adjusted OR 1.15; 95% CI 1.06–1.24) and premature contractions (adj OR 1.52; 95% CI 1.29–1.80). There was also a significant association between maternal asthma and emergency caesarean section (adj OR 1.29; 95% CI 1.23–1.34), low birth weight, and small for gestational age (adj OR 1.23; 95% CI 1.13–1.33). The risk of adverse outcomes such as low birth weight increased with increasing asthma severity. For women with uncontrolled compared to those with controlled asthma the results for adverse outcomes were inconsistent displaying both increased and decreased OR for some outcomes.

Conclusion

Maternal asthma is associated with a number of serious pregnancy complications and adverse perinatal outcomes. Some complications are even more likely with increased asthma severity. With greater awareness and proper management, outcomes would most likely improve.

A polymorphism in the histone deacetylase 1 gene is associated with the response to corticosteroids in asthmatics

BACKGROUND/AIMS

Recent investigations suggest that histone deacetylase 1 (HDAC1) and HDAC2 may be target molecules to predict therapeutic responses to corticosteroids. We evaluated the effects of variation in HDAC1 and HDAC2 on the response to corticosteroids in asthmatics.

METHODS

Two single nucleotide polymorphisms (SNPs) were selected after resequencing HDAC1 and HDAC2. For the first analysis, we evaluated the association between those SNPs and asthma severity in 477 asthmatics. For the second analysis, we evaluated the effects of these SNPs on lung function improvements in response to corticosteroid treatment in 35 independent adult asthmatics and 70 childhood asthmatics.

RESULTS

We found that one SNP in HDAC1 (rs1741981) was significantly related to asthma severity in a recessive model (corrected p = 0.036). Adult asthmatics who were homozygous for the minor allele of rs1741981 showed significantly lower % forced expiratory volume in 1 second (%FEV1) increases in response to systemic corticosteroids treatment compared with the heterozygotes or those homozygous for the major allele (12.7% ± 7.2% vs. 37.4% ± 33.7%, p = 0.018). Similarly, childhood asthmatics who were homozygous for the minor allele of rs1741981 showed significantly lower %FEV1 increases in response to inhaled corticosteroid treatment compared with the heterozygotes or those homozygous for the major allele (14.1% ± 5.9% vs. 19.4% ± 8.9%, p = 0.035).

CONCLUSIONS

The present study demonstrated that rs1741981 in HDAC1 was significantly associated with the response to corticosteroid treatment in asthmatics.

Expression of semaphorin 3A and neuropilin 1 in asthma

Neuropilin 1 (NP1) is a part of essential receptor complexes mediating both semaphorin3A (SEMA3A) and vascular endothelial growth factor (VEGF) which is one of important mediators involved in the pathogenesis of asthma. Therefore, it is possible that SEMA3A plays a role in the pathogenesis of asthma through attenuation of VEGF-mediated effects. In the present study, we aimed to evaluate expression levels of SEMA3A and NP1 using induced sputum of asthmatics and a murine model of asthma. Firstly, SEMA3A and NP1 expressions in induced sputum of asthmatics and SEMA3A and NP1 expression on bronchoalveolar lavage (BAL) cells and lung homogenates of asthmatic mice were determined. Then we evaluated the immunolocalization of VEGF receptor 1 (VEGFR1), VEGF receptor 2 (VEGFR2), and NP1 expressions on asthmatic mice lung tissue and their subcellular distributions using fibroblast and BEAS2B cell lines. Sputum SEMA3A and NP1 expressions were significantly higher in asthmatics than controls. Similarly, SEMA3A and NP1 expressions on BAL cells and lung homogenates were significantly elevated in asthmatic mice compared to control mice. Immunohistochemical analysis showed that VEGFR1, VEGFR2, and NP1 expressions were also uniformly increased in asthmatic mice. Our observations suggest that SEMA3A and NP1 may play important roles in the pathogenesis of asthma.

A study of asthma severity in adult twins

INTRODUCTION

The tendency to develop asthma runs in families, but whether the severity of asthma symptoms is inherited is not known.

OBJECTIVES

The aim of this study was to examine whether genetic factors influence the variation in the severity of asthma.

METHODS

Of a sample of 21 133 adult twins from the Danish Twin Registry, a total of 575 subjects (256 intact pairs and 63 single twins) who themselves and/or their co-twins reported a history of asthma at a questionnaire survey were clinically examined. The severity of asthma symptoms was graded according to a clinical interview, and markers of airway impairment and allergy were measured.

RESULTS

After adjusting for confounders, genetic factors explained 24% (10%-37%), P = 0.0004, of the variation in overall asthma symptom severity, whereas non-shared environment accounted for the remaining 76% of the variation. A significant genetic component was also found for the severity of specific asthma symptoms; wheezing 12% (3%-22%), P = 0.007 and shortness of breath 17% (7%-27%), P = 0.0006, but not for chest tightness and cough. Asthma symptom severity correlated weakly with rhinitis severity as well as with objective markers of lung function, airway inflammation, airway responsiveness and allergic sensitization.

CONCLUSION

The individual variation in asthma symptom severity is to some degree influenced by genetic factors, but environmental factors explain the main part of the variation. The genetic architectures underlying the severity of asthma symptoms and objectively measured asthma-related traits, respectively, seem to differ.

Serum Adiponectin is Associated with Adverse Outcomes of Asthma in Men but Not in Women

Background: Murine studies suggest a beneficial effect of systemic adiponectin on asthma. Our objective was to determine the association between serum adiponectin concentrations and asthma control/severity outcomes in men and women separately. Methods: Cross-sectional and longitudinal analyses of data from years 10, 15, and 20 examinations of the prospective coronary artery risk development in young adults study in the United States were performed. Asthma was defined by self-reported provider diagnosis at or prior to year 15 examination. Outcomes included presence of active disease, number of respiratory symptoms, and number of asthma medications; as well as longitudinal decline in absolute FEV₁. Year 15 serum adiponectin concentration was the predictor variable. Results: In a multivariable analysis of 411 eligible subjects, after adjusting for body mass index and covariates, higher serum adiponectin concentrations were associated with more frequent active disease (including more frequent use of any asthma medication), and greater number of respiratory symptoms and asthma medications among men but not among women with asthma (p for interactions between sex and adiponectin for all analyses < 0.05). Conclusions: Higher serum adiponectin concentrations may be independently associated with adverse clinical outcomes of asthma in men but not in women. If biological effect is confirmed in future studies, modification of systemic adiponectin concentrations may open up newer ways to treat asthma in men.

Comparing lung regions of interest in gamma scintigraphy for assessing inhaled therapeutic aerosol deposition

BACKGROUND

Two-dimensional gamma scintigraphy is an important technique used to evaluate the lung deposition from inhaled therapeutic aerosols. Images are divided into regions of interest and deposition indices are derived to quantify aerosol distribution within the intrapulmonary airways. In this article, we compared the different approaches that have been historically used between different laboratories for geometrically defining lung regions of interest. We evaluated the effect of these different approaches on the derived indices classically used to assess inhaled aerosol deposition in the lungs. Our primary intention was to assess the ability of different regional lung templates to discriminate between central and peripheral airway deposition patterns generated by inhaling aerosols of different particle sizes.

METHODS

We investigated six methods most commonly reported in the scientific literature to define lung regions of interest and assessed how different each of the derived regional lung indices were between the methods to quantify regional lung deposition. We used monodisperse albuterol aerosols of differing particle size (1.5, 3, and 6 μm) in five mild asthmatic subjects [forced expiratory volume in 1 sec (FEV(1)) 90% predicted] to test the different approaches of each laboratory.

RESULTS

We observed the areas of geometry used to delineate central (C) and peripheral (P) lung regions of interest varied markedly between different laboratories. There was greater similarity between methods in values of penetration index (PI), defined as P/C aerosol counts normalized by P/C krypton ventilation counts, compared to nonnormalized C/P or P/C aerosol count-ratios. Normalizing the aerosol deposition P/C count-ratios by the ventilation P/C count-ratios, reduced the variability of the data. There was dependence of the regional lung deposition indices on the size of the P region of interest in that, as P increased, C/P count-ratios decreased and P/C count-ratios increased, whereas PI was less affected by variations in the P area. We found particle size, itself, strongly influenced the indices of regional aerosol deposition such that C/P count-ratios increased with increasing particle size for each method and conversely, P/C count-ratios and PI decreased.

CONCLUSIONS

Different approaches used to determine pulmonary regions of interest and quantify aerosol deposition produce different results. Our research highlights a genuine need for a consensus to standardize the methodology to facilitate data comparison between laboratories on aerosol deposition.

Deposition, imaging, and clearance: what remains to be done?

Deposition and clearance studies are used during product development and in fundamental research. These studies mostly involve radionuclide imaging, but pharmacokinetic methods are also used to assess the amount of drug absorbed through the lungs, which is closely related to lung deposition. Radionuclide imaging may be two-dimensional (gamma scintigraphy or planar imaging), or three-dimensional (single photon emission computed tomography and positron emission tomography). In October 2009, a group of scientists met at the "Thousand Years of Pharmaceutical Aerosols" conference in Reykjavik, Iceland, to discuss future research in key areas of pulmonary drug delivery. This article reports the session on "Deposition, imaging and clearance." The objective was partly to review our current understanding, but more importantly to assess "what remains to be done?" A need to standardize methodology and provide a regulatory framework by which data from radionuclide imaging methods could be compared between centers and used in the drug approval process was recognized. There is also a requirement for novel radiolabeling methods that are more representative of production processes for dry powder inhalers and pressurized metered dose inhalers. A need was identified for studies to aid our understanding of the relationship between clinical effects and regional deposition patterns of inhaled drugs. A robust methodology to assess clearance from small conducting airways should be developed, as a potential biomarker for therapies in cystic fibrosis and other diseases. The mechanisms by which inhaled nanoparticles are removed from the lungs, and the factors on which their removal depends, require further investigation. Last, and by no means least, we need a better understanding of patient-related factors, including how to reduce the variability in pulmonary drug delivery, in order to improve the precision of deposition and clearance measurements.

Dexamethasone-induced FKBP51 expression in peripheral blood mononuclear cells could play a role in predicting the response of asthmatics to treatment with corticosteroids

BACKGROUND

Corticosteroids (CSs) are the preferred anti-inflammatory therapy for the treatment of asthma, but the responses of asthmatics to CSs are known to vary. It has thus become important to discover reliable markers in predicting responses to CSs.

METHODS

We performed time-series microarrays using a murine model of asthma after a single dose of dexamethasone, based on the assumption that the gene showing a greater change in response to CSs can also be a potential marker for that finding. We then evaluated the clinical meaning of the gene discovered in the microarray experiments.

RESULTS

We found that the expression of FK506 binding protein 51 gene (FKBP51) in lung tissue markedly increased after dexamethasone treatment in a murine model of asthma. We then measured dexamethasone-induced FKBP51 expression in peripheral blood mononuclear cells (PBMCs) in asthmatics. Dexamethasone-induced FKBP51 expression in PBMCs was significantly higher in severe asthmatics compared with mild-to-moderate asthmatics treated with inhaled CSs. In addition, we found that dexamethasone-induced FKBP51 expression in PBMCs was inversely correlated with improvement in lung function after treatment with orally administered prednisolone in six steroid-naive asthmatics.

CONCLUSION

Dexamethasone-induced FKBP51 expression in PBMCs may be a reliable and practical biomarker in predicting the response to CSs in asthmatics.

Toll-like receptor expression on peripheral blood mononuclear cells in asthmatics; implications for asthma management

BACKGROUND

Accumulating evidence indicates that cells expressing Toll-like receptors (TLRs) play an important role in allergic diseases. The authors undertook this study to explore the hypothesis that TLR-mediated inflammatory signals are important from the perspective of asthma management.

METHODS

The expressions of TLR1, TLR2, TLR3, TLR4, TLR6, and TLR9 and levels of pro-inflammatory cytokines (TNF-alpha, IL-1beta, IL-6, IL-8, and IFN-gamma) on the peripheral blood mononuclear cells (PBMCs) of 36 stable asthmatics on treatment (the on-treatment group), 15 asthmatics (the treatment-naïve group) before and after a 7-day course of oral prednisolone (30 mg/day), and on the PBMCs of 15 healthy controls were measured after in vitro stimulation using TLR-specific ligands.

RESULTS

In the on-treatment group, TLR1, TLR2, TLR6, and TLR9 expressions on PBMCs were significantly different between asthmatics and controls. And the expression of TLR4 on PBMCs and TNF-alpha production stimulated by lipopolysaccharide (LPS), were significantly higher in mild to moderate than in severe asthmatics. Interestingly, in the treatment-naïve group, short-term prednisolone significantly increased LPS-induced TNF-alpha and IFN-gamma productions by PBMCs.

CONCLUSION

TLR-mediated inflammatory signals contribute to the development and severity of asthma and are not reduced by glucocorticoid treatment, which suggests that a TLR-specific antagonist and glucocorticoid are required for the effective control of airway inflammation in asthmatics.

Additive role of tiotropium in severe asthmatics and Arg16Gly in ADRB2 as a potential marker to predict response

BACKGROUND

Recent findings have raised new interests about the use of anticholinergics, especially tiotropium, for the treatment of asthma. This study was performed to determine whether an additional improvement in lung function is obtained when tiotropium is administrated in addition to conventional therapies in severe asthmatics, and to identify factors capable of predicting the response to tiotropium, using a pharmacogenetic approach.

METHODS

A total of 138 severe asthmatics on conventional medications and with decreased lung function were randomly recruited. Tiotropium 18 microg was added once a day and lung functions were measured every 4 weeks. Responders were defined as those with an improvement of > or = 15% (or 200 ml) in the forced expiratory volume in 1 s (FEV1) that was maintained for at least 8 successive weeks. Eleven single nucleotide polymorphisms (SNPs) in CHRM1-3 (coding muscarinic receptors one to three) which were identified by re-sequencing, and Arg16Gly and Gln27Glu in ADRB2 (coding beta(2) adrenoreceptor) were scored in 80 of the 138 asthmatics.

RESULTS

Forty-six of the 138 asthmatics (33.3%) responded to tiotropium treatment. Logistic regression analyses (controlled for age, gender, and smoking status) showed that Arg16Gly in ADRB2 [P = 0.003, OR (95% CI) = 0.21 (0.07-0.59) in a minor allele-dominant model] was significantly associated with response to tiotropium.

CONCLUSIONS

As many as 30% of severe asthmatics on conventional medications with reduced lung function were found to respond to adjuvant tiotropium. The presence of Arg16Gly in ADRB2 may predict response to tiotropium.

Asthma control score based on filled medication prescriptions: a validation study

BACKGROUND

Periodic measurement of disease control is recommended to characterize asthma and monitor treatment.

OBJECTIVE

To elaborate and validate an asthma control score (ACS) for use in studies based on administrative health databases.

METHODS

Adult patients with asthma were recruited from a clinic. The ACS is based on the average number of doses of short-acting inhaled beta(2)-agonists taken per week and short courses of oral corticosteroids dispensed over a three-month period. Data were obtained from the Régie de l'assurance maladie du Québec database in Canada. The ACS was compared with the asthma control questionnaire and the use of health care services for asthma over a 12-month period.

RESULTS

A total of 60 patients were enrolled. They had a mean (+/- SD) age of 50.4+/-13.9 years, and 43.3% were male. Patients had had asthma for 20.8+/-15.1 years on average and had a mean prebronchodilator forced expiratory volume in 1 s of 77.0% of the predicted value. The mean ACS was 8.3+/-11.6, with a range of 0 to 60. The ACS was not found to be correlated with the asthma control questionnaire, but it was significantly associated with health care services used. For each additional point in the ACS, patients were 2% more likely to need acute care for asthma (rate ratio 1.02; P=0.02).

CONCLUSIONS

Further studies including patients followed by general practitioners are required before the general use of this score. This innovative score is useful to rapidly assess the control of asthma over long periods of time and at a low cost in studies using administrative drug databases.

Use of health information in air pollution health research: past successes and emerging needs

In September 2006, the US Environmental Protection Agency and the US Centers for Disease Control (CDC) co-organized a symposium on "Air Pollution Exposure and Health." The main objective of this symposium was to identify opportunities for improving the use of exposure and health information in future studies of air pollution health effects. This paper deals with the health information needs of such studies. We begin with a selected review of different types of health data and how they were used in previous epidemiologic studies of health effects of ambient particulate matter (PM). We then examine the current and emerging information needs of the environmental health community, dealing with PM and other air pollutants of health concern. We conclude that the past use of routinely collected health data proved to be essential for activities to protect public health, including the identification and evaluation of health hazards by air pollution research, setting standards for criteria pollutants, surveillance of health outcomes to identify incidence trends, and the more recent CDC environmental public health tracking program. Unfortunately, access to vital statistics records that have informed such pivotal research has recently been curtailed sharply, threatening the continuation of the type of research necessary to support future standard setting and research on emerging exposure and health problems (e.g. asthma, multiple sclerosis, diabetes, and others), as well as our ability to evaluate the efficacy of regulatory and other prevention activities. A comprehensive devoted effort, perhaps new legislation, will be needed to address the standardization, centralization, and sharing of data sets, as well as to harmonize the interpretation of confidentiality and privacy protections across jurisdictions. These actions, combined with assuring researchers and public health practitioners appropriate access to data for evaluation of environmental risks, will be essential for the achievement of our environmental health protection goals.

Association between genetic variations in prostaglandin E2 receptor subtype EP3 gene (Ptger3) and asthma in the Korean population

BACKGROUND

Recent investigations suggest that prostaglandin E2 (PGE2) is important in the pathogenesis of not only aspirin-intolerant asthma but also asthma unrelated to aspirin intolerance.

OBJECTIVES

This study was conducted to evaluate the effects of variations in the gene coding PGE2 receptor subtype EP1-4 (Ptger1-4) on the risk of asthma in the Korean population.

METHODS

Nineteen single nucleotide polymorphisms (SNPs) were selected after re-sequencing Ptger1-4 and were genotyped in 480 asthmatics and 140 healthy controls, who were randomly recruited.

RESULTS

By logistic regression analyses controlling for age and sex, 1388T>C in Ptger3 was found to be significantly associated with asthma [P=0.002, odds ratio (95% confidence interval)=0.63 (0.46-0.85) in the allele model], and this remained significant after applying the Bonferroni correction. In terms of haplotype, the frequency of the C-C-A-A haplotype in Ptger3 was significantly lower in asthmatics than in healthy controls (P=0.004). Moreover, the prevalence of this haplotype was significantly lower in moderate-to-severe asthmatics than in mild asthmatics (P=0.045; mild vs. moderate and P=0.034; mild vs. severe). However, no association was found between any genetic variation in Ptger1, Ptger2, or Ptger4 and asthma.

CONCLUSION

The present study demonstrated that genetic variations in Ptger3 are significantly associated with the risk and severity of asthma in the Korean population.

Exposure to environmental tobacco smoke among children presenting to the emergency department with acute asthma: a multicenter study

Environmental tobacco smoke (ETS) exposure has been associated with increased use of the emergency department (ED) for acute asthma care. The purpose of this study was to determine the prevalence of ETS exposure among children presenting to the ED for acute asthma care and whether ETS exposure affects acute asthma severity or response to therapy. We conducted a multi-center study of children 2-11 years with physician-diagnosed acute asthma presenting to 44 EDs in 18 states. Chi-square test, Student's t-test, Wilcoxon rank sum test, and logistic regression were used for the analyses. The study population included 954 children. Thirty-six percent (95% CI, 33-39%) of caregivers reported that their child was exposed to ETS. Among exposed children, 35% were exposed 1-6 days/week, and 65% were exposed daily. Compared to unexposed children, ETS-exposed children were older at asthma diagnosis, older at ED presentation, and were less likely to be Hispanic. Indicators of chronic asthma severity were higher among unexposed children (i.e., total number of medications, use of controller medications, use of beta(2) agonists, number of urgent clinic visits, and lifetime hospitalizations). There was a weak association between ETS and acute asthma severity. Response to therapy (including ED disposition) did not differ between groups. On multivariate analysis, ETS-exposed children were more likely to be older, female, non-Hispanic, have lower household income, not use controller medications, and have a pet at home (all P < 0.05). Our study showed that the prevalence of ETS exposure among children presenting to the ED with acute asthma differs across demographic factors. There were no significant differences in acute asthma symptoms or response to ED therapy between ETS-exposed and unexposed children. Lower use of controller medications and less frequent urgent clinic visits among ETS-exposed children suggest inadequate asthma care or milder disease. The weak association between ETS exposure and acute asthma severity might reflect confounding by psychological factors and/or chronic asthma severity. The frequency of ETS exposure suggests that the ED may be an appropriate venue to engage caregivers of children with asthma in asthma education and smoking cessation efforts.

Development and validation of database indexes of asthma severity and control

BACKGROUND

The use of administrative databases to perform epidemiological studies in asthma has increased in recent years. The absence of clinical parameters to measure the level of asthma severity and control is a major limitation of database studies. A study was undertaken to develop and validate two database indexes to measure the control and severity of asthma.

METHODS

Database indexes of asthma severity and control were derived from definitions in the Canadian Asthma Consensus Guidelines based on dispensed prescriptions and on medical services recorded in two large administrative databases from the Canadian province of Québec (Régie de l'Assurance Maladie du Québec (RAMQ) and MED-ECHO) over 12 months. The database indexes of asthma severity and control were validated against the pulmonary function test results of 71 patients with asthma randomly selected from two asthma clinics, and they were also applied to a cohort of patients with asthma followed up for 139 283 person-years selected from the RAMQ and MED-ECHO databases between 1 January 1997 and 31 December 2004.

RESULTS

According to the database indexes, 49.3%, 29.6% and 21.1% of patients recruited at the asthma clinics were found to have mild, moderate and severe asthma, respectively, while 53.5% were found to have controlled asthma. The mean predicted value of the forced expiratory volume in 1 s (FEV(1)) ranged from 89.8% for mild asthma to 61.5% for severe asthma (p<0.001), whereas the range from controlled to uncontrolled asthma was 89.5% to 67.3% (p<0.001). The ratio of the FEV(1) to the forced vital capacity (FEV(1)/FVC ratio) measured in 56 patients ranged from 75.8% for mild asthma to 61.8% for severe asthma (p = 0.030), whereas the range from controlled to uncontrolled asthma was 75.3% to 65.7% (p<0.001).

CONCLUSION

In the absence of clinical data, these database indexes could be used in epidemiological studies to assess the severity and control of asthma.

Poor asthma control in children: evidence from epidemiological surveys and implications for clinical practice

The objectives of this study is to compile current knowledge about asthma control in children in relation to goals proposed in international guidelines, to elucidate the factors associated with insufficient asthma control and to address the implications for clinical practice. Review of recent worldwide large population epidemiological surveys and clinical asthma studies of more than 20,000 children are the methods used in this study. The studies report high frequencies of sleep disturbances, emergency visits, school absence and limitations of physical activity due to asthma. Only a small percentage of children with asthma reach the goals of good asthma control set out by Global Initiative for Asthma (GINA). There is evidence of underuse of inhaled corticosteroids even in children with moderate or severe persistent asthma and over-reliance on short-acting beta(2)-agonist rescue medication. Both parents and physicians generally overestimate asthma control and have low expectations about the level of achievable control. Many children with asthma are not being managed in accordance with guideline recommendations, and asthma management practices vary widely between countries. Asthma control falls short of guideline recommendations in large proportions of children with asthma worldwide. Simple methods for assessing asthma control in clinical practice are needed. Treatment goals based on raised expectations should be established in partnership with the asthmatic child and the parents. Effective anti-inflammatory treatment should be used more frequently, and patients should be reviewed regularly.

STAT4 expression in human T cells is regulated by DNA methylation but not by promoter polymorphism

STAT4, which plays a pivotal role in Th1 immune responses, enhances IFN-gamma transcription in response to the interaction of IL-12 with the IL-12R. Mice deficient in STAT4 lack IL-12-induced IFN-gamma production and Th1 differentiation and display a predominantly Th2 phenotype. Although these findings indicate that STAT4 expression levels are important for the development of cytokine-producing Th1 cells, the transcriptional and posttranscriptional mechanisms regulating STAT4 expression are unknown. We sought to identify and characterize the transcriptional regulatory elements in the promoter region of the human STAT4 gene. We found that disruption of multiple transcriptional regions covering the CREB, OCT1, and SP1 motifs significantly reduced STAT4 promoter activity. However, genomic DNA isolated from 91 patients with asthma or rheumatoid arthritis showed no evidence of mutations in the defined STAT4 essential promoter region. The 5' flanking region of the promoter was found to contain a -149A/G change in approximately 20-35% of patients, but this polymorphism had no effect on promoter activity. Interestingly, STAT4 expression was drastically increased in human T cells following treatment with a DNA methyltransferase inhibitor, and truncation of methylation sites in the proximal regulatory elements of the STAT4 promoter markedly enhanced transcriptional activity. Thus, our findings provide molecular insight into STAT4 expression and suggest that, in human T cells, STAT4 expressional regulation is associated with DNA hypermethylation, but not promoter polymorphisms.

Closer to an ???Ideal Inhaler??? with the Easyhaler??

The characteristics of an ideal inhaler are based around the design and formulation of the device, patient use and the clinical effect, together with concordance and patient preference. To ensure consistent drug delivery to the lungs, with regular adherence to the prescribed dosage regimen, it is essential that all these characteristics simultaneously interact to provide smooth and sustained therapeutic control affected only by the clinical status of the patient. The literature highlights that dose emission from an Easyhaler is fairly consistent irrespective of the inhalation technique used by patients of all age groups. Clinical studies have shown equivalence of this device to those frequently prescribed and that it is preferred by many patients. Although further research is required into the development of inhalation devices, the literature describing the Easyhaler dry powder inhaler indicates how an inhaler can closely meet the criteria for an ideal inhaler.

Simultaneous treatment of asthma and allergic rhinitis

Asthma and allergic rhinitis (AR) form a well-recognized comorbidity. This study aims at assessing the efficacy of nasally inhaled beclomethasone dipropionate (BDP) in their simultaneous treatment. A randomized controlled trial was conducted with 78 allergic rhinitis and asthma patients aged 5-17 years. Seventy-five individuals completed the study. During 8 weeks, 38 subjects received BDP-CFC aerosol (>or= 500 mcg/day) exclusively via nasal inhalation through a facemask attached to a plastic valved spacer. The control group (37 patients) received 200 mcg/day of aqueous intranasal beclomethasone plus oral inhalation of BDP-CFC (>or= 500 mcg/day) through a mouthpiece connected to the same spacer. Primary outcomes analyzed in order to assess the response to treatment were clinical scoring for allergic rhinitis and measurements of nasal inspiratory peak flow (NIPF). AR clinical scoring and NIPF did not differ in the two groups at admission or at nearly all follow-up visits. Nasal inhalation of beclomethasone dipropionate provides AR symptom relief while maintaining control of asthma by delivering it to the lungs. Therefore, this therapeutic strategy might be considered for patients suffering from this comorbidity, especially in low-resource countries, since it is less expensive than the conventional treatment.

In-vitro intra- and inter-inhaler flow rate-dependent dosage emission from a combination of budesonide and eformoterol in a dry powder inhaler

Some dry powder inhalers have profound inhalation flow rate-dependent dosage emission, and it has been suggested that there are links between the in vitro emitted dose, total lung deposition, and subsequent clinical response. We have measured the in vitro dosage delivery for a combination of budesonide and eformoterol in a new version of the Turbuhaler. At inhalation flow rates of 30, 60, and 90 Lmin(-1), the total dose emission for 10 separate inhalations from each of six inhalers was determined. The aerodynamic characteristics of the emitted dose using inhalation flow rates of 28.3 and 60 Lmin(-1) were measured using the Andersen Cascade Impactor. The mean (SD) emitted dose for budesonide, at 30, 60, and 90 Lmin(-1), was 37.5%(18.2%), 64.4%(16.6%), and 107.4%(36.0%) (of the nominal emitted dose), respectively, and for eformoterol were 38.0%(20.3%), 65.0%(16.8%), and 104.9%(36.2%) (of the nominal emitted dose), respectively. Variability of dose emission characteristics from each inhaler and between inhalers at each flow rate was found. The aerodynamic particle size characterization of the emitted dose at flow rates of 28.3 and 60 Lmin(-1) revealed a mean fine particle dose for budesonide of 11.9% and 28.6% of the nominal emitted dose, respectively, and similarly 10.0% and 26.3% for eformoterol. At 28.3 Lmin(-1), the majority of the emitted dose (54.8% for budesonide and 64.5% for eformoterol) was deposited in the throat and preseparator of the Andersen Cascade Impactor. The mass median aerodynamic diameters for budesonide and eformoterol at 28.3 Lmin(-1) were 3.2 and 3.6 microm, respectively, and similarly at 60 Lmin(-1) were 2.4 and 2.5 microm. The modified Turbuhaler containing a budesonide and eformoterol combined formulation shows intra- and inter-inhaler flow-dependent dosage emission. The clinical significance of the in vitro dose-dependent properties should be investigated.