Pharmacogenetic differences in response to albuterol between Puerto Ricans and Mexicans with asthma

Disparities in prevalence and outcomes of respiratory disease in low- and middle-income countries

OBJECTIVES

To provide a comprehensive overview of disparities in prevalence and outcomes of respiratory diseases and notable challenges for providing optimal treatment to pediatric patients with respiratory diseases living in low- and middle-income countries (LMICs), as an input to help better understand the roots of respiratory health disparities.

METHODS

We conducted a narrative review of relevant literature published in electronic databases from inception to February 2023 that present data on disparities in prevalence and outcomes of respiratory disease in LMICs. Additionally, we included studies that describe and discuss challenges for providing optimal treatment to pediatric patients with respiratory diseases living in LMICs.

RESULTS

A number of early life exposures have been associated with adverse respiratory outcomes in later life. Several studies have shown marked geographical variations in the prevalence and burden of pediatric asthma, with consistently lower prevalence rates but significantly higher burdens and worse outcomes in LMICs. There is a wide range of challenges that adversely affect the efficient care of children with respiratory diseases that can be classified into three categories: patient-related factors, social/environmental factors, and factors related to healthcare providers or the healthcare system.

CONCLUSIONS

Respiratory health disparities in children living in LMICs represent a global public health issue mainly explained by an unequal distribution of preventable and modifiable risk factors for respiratory diseases across different demographic groups.

Multi-omic approach associates blood methylome with bronchodilator drug response in pediatric asthma

BACKGROUND

Albuterol is the drug most widely used as asthma treatment among African Americans despite having a lower bronchodilator drug response (BDR) than other populations. Although BDR is affected by gene and environmental factors, the influence of DNA methylation is unknown.

OBJECTIVE

This study aimed to identify epigenetic markers in whole blood associated with BDR, study their functional consequences by multi-omic integration, and assess their clinical applicability in admixed populations with a high asthma burden.

METHODS

We studied 414 children and young adults (8-21 years old) with asthma in a discovery and replication design. We performed an epigenome-wide association study on 221 African Americans and replicated the results on 193 Latinos. Functional consequences were assessed by integrating epigenomics with genomics, transcriptomics, and environmental exposure data. Machine learning was used to develop a panel of epigenetic markers to classify treatment response.

RESULTS

We identified 5 differentially methylated regions and 2 CpGs genome-wide significantly associated with BDR in African Americans located in FGL2 (cg08241295, P = 6.8 × 10-9) and DNASE2 (cg15341340, P = 7.8 × 10-8), which were regulated by genetic variation and/or associated with gene expression of nearby genes (false discovery rate < 0.05). The CpG cg15341340 was replicated in Latinos (P = 3.5 × 10-3). Moreover, a panel of 70 CpGs showed good classification for those with response and nonresponse to albuterol therapy in African American and Latino children (area under the receiver operating characteristic curve for training, 0.99; for validation, 0.70-0.71). The DNA methylation model showed similar discrimination as clinical predictors (P > .05).

CONCLUSIONS

We report novel associations of epigenetic markers with BDR in pediatric asthma and demonstrate for the first time the applicability of pharmacoepigenetics in precision medicine of respiratory diseases.

Immunogenetics and pharmacogenetics of allergic asthma in Africa

Asthma is a common chronic condition in children and in an African setting is often highly prevalent in urban areas as compared to rural areas. Asthma is a heritable disease and the genetic risk is often exacerbated by unique localised environmental factors. The Global Initiative for Asthma (GINA) recommendation for the control of asthma includes inhaled corticosteroids (ICS) alone or together with short-acting β₂-agonists (SABA) or long-acting β₂-agonists (LABA). While these drugs can relieve asthma symptoms, there is evidence of reduced efficacy in people of African ancestry. Whether this is due to immunogenetics, genomic variability in drug metabolising genes (pharmacogenetics) or genetics of asthma-related traits is not well defined. Pharmacogenetic evidence of first-line asthma drugs in people of African ancestry is lacking and is further compounded by the lack of representative genetic association studies in the continent. In this review, we will discuss the paucity of data related to the pharmacogenetics of asthma drugs in people of African ancestry, mainly drawing from African American data. We will further discuss how this gap can be bridged to improve asthma health outcomes in Africa.

Adverse Drug Events Related to Common Asthma Medications in US Hospitalized Children, 2000-2016

BACKGROUND

The reduction in adverse drug events is a priority in healthcare. Medications are frequently prescribed for asthmatic children, but epidemiological trends of adverse drug events related to anti-asthmatic medications have not been described in hospitalized children.

OBJECTIVE

The objective of this study was to report incidence trends, risk factors, and healthcare utilization of adverse drug events related to anti-asthmatic medications by major drug classes in hospitalized children in the USA from 2000 to 2016.

METHODS

A population-based temporal analysis included those aged 0-20 years who were hospitalized with asthma from the 2000 to 2016 Kids Inpatient Database. Age-stratified weighted temporal trends of the inpatient incidence of adverse drug events related to anti-asthmatic medications (i.e., corticosteroids and bronchodilators) were estimated. Stepwise multivariate logistic regression models generated risk factors for adverse drug events.

RESULTS

From 2000 to 2016, 12,640 out of 698,501 pediatric asthma discharges (1.7%) were associated with adverse drug events from anti-asthmatic medications. 0.83% were adverse drug events from corticosteroids, resulting in a 1.14-fold increase in the length of stay (days) and a 1.42-fold increase in hospitalization charges (dollars). The overall incidence (per 1000 discharges) of anti-asthmatic medication adverse drug events increased from 5.3 (95% confidence interval [CI] 4.6-6.1) in 2000 to 21.6 (95% CI 18.7-24.6) in 2016 (p-trend = 0.024). Children aged 0-4 years had the most dramatic increase in the incidence of bronchodilator adverse drug events from 0.2 (95% CI 0.1-0.4) to 19.3 (95% CI 15.2-23.4) [p-trend ≤ 0.001]. In general, discharges among asthmatic children with some comorbidities were associated with an approximately two to five times higher odds of adverse drug events.

CONCLUSIONS

The incidence of adverse drug events from common anti-asthmatic medications quadrupled over the past decade, particularly among preschool-age children who used bronchodilators, resulting in substantial increased healthcare costs. Those asthmatic children with complex medical conditions may benefit the most from adverse drug event monitoring.

Pharmacogenomics and Pediatric Asthmatic Medications

Asthma is a respiratory condition often stemming from childhood, characterized by difficulty breathing and/or chest tightness. Current treatment options for both adults and children include beta-2 agonists, inhaled corticosteroids (ICS), and leukotriene modifiers (LTM). Despite recommendations by the Global Initiative for Asthma, a substantial number of patients are unresponsive to treatment and unable to control symptoms. Pharmacogenomics have increasingly become the front line of precision medicine, especially with the recent use of candidate gene and genome- wide association studies (GWAS). Screening patients preemptively could likely decrease adverse events and therapeutic failure. However, research in asthma, specifically in pediatrics, has been low. Although numerous adult trials have evaluated the impact of pharmacogenomics and treatment response, the lack of evidence in children has hindered progress towards clinical application. This review aims to discuss the impact of genetic variability and response to asthmatic medications in the pediatric population.

Ethnic Differences in Severe Asthma Clinical Care and Outcomes: An Analysis of United Kingdom Primary and Specialist Care

BACKGROUND

Understanding the effects of ethnicity in severe asthma is important for optimal personalized patient care.

OBJECTIVE

To assess ethnic differences in disease control, exacerbations, biological phenotype, and treatment in severe asthma in the United Kingdom.

METHODS

We compared demographics, type 2 biomarkers, lung function, asthma control, medications, and health care use between White and underrepresented ethnic group patients in the UK Severe Asthma Registry (UKSAR) and Optimum Patient Care Research Database (OPCRD).

RESULTS

A total of 3637 patients (665 from the underrepresented ethnic group) were included from UKSAR and 10,549 (577 from the underrepresented ethnic group) from OPCRD. Patients in the underrepresented ethnic group had higher levels of uncontrolled disease when measurements were made using the asthma control questionnaire in UKSAR (odds ratio [OR] = 1.47; 95% confidence interval [CI], 1.12-1.93) and the Royal College of Physicians 3 Questions in OPCRD (OR = 1.82; 95% CI, 1.27-2.60). Although exacerbation rates were similar, patients in the underrepresented ethnic group were more likely to have recently attended the emergency department (OR = 1.55; 95% CI, 1.26-1.92) or to have been hospitalized (OR = 1.31; 95% CI, 1.07-1.59) owing to asthma. Inflammatory biomarkers were consistently higher in the underrepresented ethnic group, including blood eosinophils in OPCRD (ratio = 1.12; 95% CI, 1.05-1.20) and in UKSAR blood eosinophils (ratio = 1.16; 95% CI, 1.06-1.27), FeNO (ratio = 1.14; 95% CI, 1.04-1.26), and IgE (ratio = 1.70; 95% CI, 1.47-1.97). Patients in the underrepresented ethnic group were more likely to be atopic in the UKSAR (OR = 1.32; 95% CI, 1.07-1.63) and OPCRD (OR = 1.67; 95% CI, 1.26-2.21), and less likely to be using maintenance oral corticosteroids at referral (OR = 0.75; 95% CI, 0.61-0.92).

CONCLUSIONS

Severe asthma patients from underrepresented ethnic groups presented with a higher disease burden and were more likely to attend the emergency department. They had a distinct phenotypic presentation and differences in medicine use, with higher levels of type 2 biomarkers.

Seeing the Window, Finding the Spider: Applying Critical Race Theory to Medical Education to Make Up Where Biomedical Models and Social Determinants of Health Curricula Fall Short

A professional and moral medical education should equip trainees with the knowledge and skills necessary to effectively advance health equity. In this Perspective, we argue that critical theoretical frameworks should be taught to physicians so they can interrogate structural sources of racial inequities and achieve this goal. We begin by elucidating the shortcomings in the pedagogic approaches contemporary Biomedical and Social Determinants of Health (SDOH) curricula use in their discussion of health disparities. In particular, current medical pedagogy lacks self-reflexivity; encodes social identities like race and gender as essential risk factors; neglects to examine root causes of health inequity; and fails to teach learners how to challenge injustice. In contrast, we argue that Critical Race Theory (CRT) is a theoretical framework uniquely adept at addressing these concerns. It offers needed interdisciplinary perspectives that teach learners how to abolish biological racism; leverage historical contexts of oppression to inform interventions; center the scholarship of the marginalized; and understand the institutional mechanisms and ubiquity of racism. In sum, CRT does what biomedical and SDOH curricula cannot: rigorously teach physician trainees how to combat health inequity. In this essay, we demonstrate how the theoretical paradigms operationalized in discussions of health injustice affect the ability of learners to confront health inequity. We expound on CRT tenets, discuss their application to medical pedagogy, and provide an in-depth case study to ground our major argument that theory matters. We introduce MedCRT: a CRT-based framework for medical education, and advocate for its implementation into physician training.

A meta-analysis of the influence of ADRB2 genetic polymorphisms on albuterol (salbutamol) therapy in patients with asthma

AIMS

The associations of 2 nonsynonymous single nucleotide polymorphisms (Arg16Gly and Gln27Glu) in the adrenoceptor β2 (ADRB2) gene with response after albuterol use are conflicting. We conducted a meta-analysis to examine the cumulative evidence of the effects of these 2 variants on percent forced expiratory volume in 1 second (FEV1.0%) after albuterol use in asthma patients.

METHODS

We conducted a comprehensive literature search using MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials to identify studies examining the association between ADRB2 Arg16Gly and Gln27Glu and FEV1.0% shortly after albuterol administration. The individual study results were combined with weights based on the inverse variance method. This systematic review was registered in the PROSPERO (registration number: CRD42019074554).

RESULTS

Among 273 initial studies identified, 7 studies met the inclusion criteria for quantitative evaluation. Results of the overall meta-analysis indicated no statistically significant mean difference of FEV1.0% between genotypes of Arg16Gly and Gln27Glu. In subgroup analyses, significant associations were found for Arg16Gly GG (vs AA) among studies where no methacholine bronchoconstriction was conducted (mean difference, -3.92; 95% confidence interval, -7.29 to -0.54; I2 = 0%), and for Arg16Gly GG (vs GA) among studies that included patients with no comorbidities (mean difference, -1.93; 95% confidence interval, -3.77 to -0.10; I2 = 0%).

CONCLUSION

Synthesis of the studies to date shows weak evidence for an association between ADRB2 Arg16Gly and Gln27Glu and FEV1.0% after albuterol use, results of which underscore significant heterogeneity across studies and the need for careful design and sample size considerations.

An epistatic interaction between pre-natal smoke exposure and socioeconomic status has a significant impact on bronchodilator drug response in African American youth with asthma

BACKGROUND

Asthma is one of the leading chronic illnesses among children in the United States. Asthma prevalence is higher among African Americans (11.2%) compared to European Americans (7.7%). Bronchodilator medications are part of the first-line therapy, and the rescue medication, for acute asthma symptoms. Bronchodilator drug response (BDR) varies substantially among different racial/ethnic groups. Asthma prevalence in African Americans is only 3.5% higher than that of European Americans, however, asthma mortality among African Americans is four times that of European Americans; variation in BDR may play an important role in explaining this health disparity. To improve our understanding of disparate health outcomes in complex phenotypes such as BDR, it is important to consider interactions between environmental and biological variables.

RESULTS

We evaluated the impact of pairwise and three-variable interactions between environmental, social, and biological variables on BDR in 233 African American youth with asthma using Visualization of Statistical Epistasis Networks (ViSEN). ViSEN is a non-parametric entropy-based approach able to quantify interaction effects using an information-theory metric known as Information Gain (IG). We performed analyses in the full dataset and in sex-stratified subsets. Our analyses identified several interaction models significantly, and suggestively, associated with BDR. The strongest interaction significantly associated with BDR was a pairwise interaction between pre-natal smoke exposure and socioeconomic status (full dataset IG: 2.78%, p = 0.001; female IG: 7.27%, p = 0.004)). Sex-stratified analyses yielded divergent results for females and males, indicating the presence of sex-specific effects.

CONCLUSIONS

Our study identified novel interaction effects significantly, and suggestively, associated with BDR in African American children with asthma. Notably, we found that all of the interactions identified by ViSEN were "pure" interaction effects, in that they were not the result of strong main effects on BDR, highlighting the complexity of the network of biological and environmental factors impacting this phenotype. Several associations uncovered by ViSEN would not have been detected using regression-based methods, thus emphasizing the importance of employing statistical methods optimized to detect both additive and non-additive interaction effects when studying complex phenotypes such as BDR. The information gained in this study increases our understanding and appreciation of the complex nature of the interactions between environmental and health-related factors that influence BDR and will be invaluable to biomedical researchers designing future studies.

Pharmacologic Management of Severe Bronchopulmonary Dysplasia

Few medications are available and well tested to treat infants who already have developed or inevitably will develop severe bronchopulmonary dysplasia (sBPD). Infants who develop sBPD clearly have not benefited from decades of research efforts to identify clinically meaningful preventive therapies for very preterm infants in the first days and weeks of their postnatal lives. This review addresses challenges to individualized approaches to medication use for sBPD. Specific challenges include understanding the combination of an individual infant's postmenstrual and postnatal age and the developmental status of drug-metabolizing enzymes and receptor expression. This review will also explore the reasons for the variable responsiveness of infants to specific therapies, based on current understanding of developmental pharmacology and pharmacogenetics. Data demonstrating the remarkable variability in the use of commonly prescribed drugs for sBPD are presented, and a discussion about the current use of some of these medications is provided. Finally, the potential use of antifibrotic medications in late-stage sBPD, which is characterized by a profibrotic state, is addressed.

A genome-wide association study of prostate cancer in Latinos

Latinos represent <1% of samples analyzed to date in genome-wide association studies of cancer. The clinical value of genetic information in guiding personalized medicine in populations of non-European ancestry will require additional discovery and risk locus characterization efforts across populations. In the present study, we performed a GWAS of prostate cancer (PrCa) in 2,820 Latino PrCa cases and 5,293 controls to search for novel PrCa risk loci and to examine the generalizability of known PrCa risk loci in Latino men. We also conducted a genetic admixture-mapping scan to identify PrCa risk alleles associated with local ancestry. Genome-wide significant associations were observed with 84 variants all located at the known PrCa risk regions at 8q24 (128.484-128.548) and 10q11.22 (MSMB gene). In admixture mapping, we observed genome-wide significant associations with local African ancestry at 8q24. Of the 162 established PrCa risk variants that are common in Latino men, 135 (83.3%) had effects that were directionally consistent as previously reported, among which 55 (34.0%) were statistically significant with p < 0.05. A polygenic risk model of the known PrCa risk variants showed that, compared to men with average risk (25th-75th percentile of the polygenic risk score distribution), men in the top 10% had a 3.19-fold (95% CI: 2.65, 3.84) increased PrCa risk. In conclusion, we found that the known PrCa risk variants can effectively stratify PrCa risk in Latino men. Larger studies in Latino populations will be required to discover and characterize genetic risk variants for PrCa and improve risk stratification for this population.

How does race and ethnicity effect the precision treatment of asthma?

Introduction

Asthma is a common condition that affects large numbers of children and adults, yet the burden of disease is not equally distributed amongst groups. In the United States, African Americans and Puerto Ricans have higher rates of asthma and its complications when compared with European Americans. However, clinical trials and genetic studies have largely focused on the latter group.

Areas covered

Here we examine what is known regarding differences in asthma treatment response by race-ethnicity. We also review existing genetic studies related to the use of asthma medications, paying special attention to studies that included substantial numbers of non-white population groups. Publicly accessible search engines of the medical literature were queried using combinations of the terms asthma, race, ethnicity, pharmacogenomics, and pharmacogenetics, as well as the names of individual asthma medication classes. The list of articles reviewed was supplemented by bibliographies and expert knowledge.

Expert opinion

A substantial and coordinated effort is still needed to both identify and validate genetic biomarkers of asthma medication response, as currently there are no clinically actionable genetic markers available for this purpose. The path to identifying such markers in non-white populations is even more formidable, since these groups are underrepresented in existing data.

Association of β2-adrenergic receptor gene polymorphisms (rs1042713, rs1042714, rs1042711) with asthma risk: a systematic review and updated meta-analysis

Background

The published data on the association between β2-adrenergic receptor gene polymorphisms and asthma susceptibility are inconclusive. To derive a more precise estimation of this association, a meta-analysis was performed.

Methods

A literature search was conducted in PubMed, Web of Science, EMBASE, Wanfang, and the China National Knowledge Infrastructure (CNKI) databases to identify eligible studies. The pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to calculate the strength of the association. A sensitivity analysis was performed to evaluate the influence of individual studies on the overall effect estimates, and funnel plots and Egger’s tests were used for indications of publication bias.

Results

Seventy three studies with three single nucleotide polymorphisms (SNP) (rs1042713, c.G46A, p.Gly16Arg; rs1042714, c.G79C, p.Gln27Glu; rs1042711, c.T-47C, p.Cys19Arg) were finally identified. For the rs1042713 polymorphism, no significant association with asthma risk was found in the overall population. However, a significant protective association was found in the Indian population in the dominant model comparison (OR = 0.72, 95% CI = 0.59–0.87, I² = 25%, studies = 5, cases = 1190, controls = 1241). A significant risk association was found in the Arab population in the dominant model comparison (OR = 1.75, 95% CI = 1.14–2.70, I² = 0%, studies = 2, cases = 307, controls = 361) and the homozygote model comparison (OR = 1.88, 95% CI = 1.17–3.02, I² = 0%, studies = 2, cases = 307, controls = 361), and in the Hispanic-Latino population in the dominant model comparison (OR = 1.68, 95% CI = 1.10–2.55, I² = 77%, studies = 5, cases = 1026, controls = 1412). For the rs1042714 polymorphism, we found a significant association in the recessive model comparison (OR = 0.83, 95% CI = 0.70–0.98, I² = 44%, studies = 52, cases = 8242, controls = 16,832), the homozygote genotype comparison (OR = 0.84, 95% CI = 0.72–0.98, I² = 25%, studies = 52, cases = 8242, controls = 16,832) and the allelic genetic model (OR = 0.91, 95% CI = 0.83–0.99, I² = 59%, studies = 52, cases = 8242, controls = 16,832) in the overall population. When stratified by age, a significant association was also found in children in the recessive model comparison (OR = 0.59, 95% CI = 0.39–0.88, I² = 58%, studies = 18, cases = 2498, controls = 2510) and the homozygote genotype comparison (OR = 0.63, 95% CI = 0.43–0.92, I² = 46%, studies = 18, cases = 2498, controls = 2510), but not in adult. For the rs1042711 polymorphism, no significant associations were found in the any genetic model.

Conclusion

The meta-analysis suggests that the ADRB2 rs1042714 polymorphism has a protective association with asthma in the overall population and the pediatric subgroup.

Racial/Ethnic-Specific Differences in the Effects of Inhaled Corticosteroid Use on Bronchodilator Response in Patients With Asthma

American Thoracic Society guidelines recommend inhaled corticosteroid (ICS) therapy, plus a short-acting bronchodilator, in patients with persistent asthma. However, few prior studies have examined the efficacy of this combination in children of all racial/ethnic groups. We evaluated the association between ICS use and bronchodilator response (BDR) in three pediatric populations with persistent asthma (656 African American, 916 Puerto Rican, and 398 Mexican American children). The association was assessed using multivariable quantile regression. After adjusting for baseline forced expiratory volume in one second and use of controller medications, ICS use was significantly associated with increased BDR only among Mexican Americans (1.56%, P = 0.028) but not African Americans (0.49%, P = 0.426) or Puerto Ricans (0.16%, P = 0.813). Our results demonstrate that ICS augmentation is disproportionate across racial/ethnic groups, where improved BDR is observed in Mexican Americans only. This study highlights the complexities of treating asthma in children, and reinforces the importance of investigating the influence of race/ethnicity on pharmacological response.

The Influence of Beta-2 Adrenergic Receptor Gene Polymorphisms on Albuterol Therapy for Patients With Asthma: Protocol for a Systematic Review and Meta-Analysis

Background

Albuterol is one of the most frequently used medications in clinical practice and seeing varying responses to albuterol between individuals is not uncommon. Multiple studies have been conducted to investigate the associations of differing responses due to albuterol, particularly with regards to the two nonsynonymous single nucleotide polymorphisms (SNPs) at positions 16 (Arg16Gly: substitution of arginine to glycine at position 16; rs1042713) and 27 (Glu27Gln: substitution of glutamic acid to glutamine at position 27; rs1042714) on the β-2 adrenergic receptor (ADRB2) gene. However, the directions of the correlations are conflicting.

Objective

The objective of this systematic review and meta-analysis is to assess the effect of the two SNPs on the ADRB2 gene, in terms of the responses that present in asthmatic patients shortly after albuterol inhalation.

Methods

The primary outcome of this work is a detailed study of the associations of the two SNPs in the ADRB2 gene with treatment response and lung function testing shortly after administration of albuterol to asthmatic patients. A comprehensive literature search, using the OVID platform, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, will be conducted by a specialized librarian without language restrictions. We will include both prospective and retrospective original observational studies, and we will exclude nonhuman or in vitro studies. All abstracts will be reviewed by two authors who will also individually perform data extraction from each eligible study. Any arising disagreements will be resolved through discussion with a third party. Risk of bias for all included studies will be independently assessed using the quality of genetic association studies tool. We will report the systematic review and meta-analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A narrative synthesis of study results or meta-analyses will be undertaken when appropriate.

Results

At the moment of writing, we have already started the preliminary literature search and piloting of the study selection process. The anticipated completion date is September 30, 2019.

Conclusions

Our systematic review and meta-analysis aims to clarify the current evidence of associations between the two nonsynonymous SNPs in the ADRB2 gene and the responses that present in asthmatic patients shortly after albuterol inhalation. If positive correlations are found, this knowledge may be used to improve personalized pharmacotherapy of albuterol use.

Trial Registration

PROSPERO CRD42019074554; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=74554

International Registered Report Identifier (IRRID)

PRR1-10.2196/14759

Longitudinal Patterns of Mexican and Puerto Rican Children's Asthma Controller Medication Adherence and Acute Healthcare Use

Rationale: Researchers tend to study Latinos as a single group, but recent asthma research confirmed differences among Latino subgroups. Variations in controller medication adherence may be a factor in the observed health disparities between Mexican and Puerto Rican children. Adherence is not a stable phenomenon; however, there is a paucity of data on patterns of adherence, sociodemographic predictors of patterns, and variations in asthma-related acute healthcare use by adherence pattern among Latino subgroups. Objectives: To identify patterns of inhaled corticosteroid medication adherence over 12 months among Mexican and Puerto Rican children with persistent asthma, to examine sociodemographic predictors of adherence patterns by ethnicity, and to investigate asthma-related acute healthcare use based on these patterns. Methods: We analyzed controller medication Doser data from Mexican and Puerto Rican children (n = 123; ages 5-12 yr) with persistent asthma who participated with their caregivers in a longitudinal nonintervention study (Phoenix, AZ, and Bronx, NY). Interview and medical record data were collected at enrollment and at 3, 6, 9, and 12 months after enrollment. Results: Forty-seven to fifty-three percent of children had poor adherence (<50%) over each of the follow-up periods (cross-sectional). Children with lowest adherence were Puerto Rican, from nonpoor families, or female. Longitudinal latent class analysis yielded four adherence classes: poor, moderate, decreasing adherence, and increasing adherence. Puerto Rican children had significantly higher odds of "decreasing" (odds ratio [OR], 2.86; 95% confidence interval [CI], 0.40 to 20.50) and "poor" (OR, 5.62; 95% CI, 1.44 to 21.90) adherence than Mexican children. Females had significantly greater odds of "decreasing" (OR, 4.80; 95% CI, 0.73 to 31.74) and "poor" (OR, 5.20; 95% CI, 1.77 to 15.30) adherence group membership than males. The "decreasing" adherence group was comprised of only poor children. Children in the "poor" adherence class had the highest mean number of acute visits and emergency department visits/hospitalizations across all assessment periods. Conclusions: This study demonstrated that unique ethnicity within Latino populations may be associated with different risk levels for suboptimal controller medication adherence, which may be a factor in the observed asthma health disparities between Mexican and Puerto Rican children. Increased understanding of and attention to children's controller medication adherence patterns will provide evidence needed to identify children at highest risk for acute healthcare use and offer more-intensive intervention using less-intensive approaches for those at low risk. Clinical trial registered with www.clinicaltrials.gov (NCT01099800).

Role of THRB, ARG1, and ADRB2 Genetic Variants on Bronchodilators Response in Asthmatic Children

Background: An interindividual variability in response to short-acting bronchodilator drugs (short-acting inhaled β2-agonists, SABA) exists and this is linked in part to genetic factors. The aim of this study was to verify the influence of single nucleotide polymorphisms (SNPs) of a previously studied gene (ADRB2) and of new candidate genes (THRB and ARG1) on the acute response to SABA in children with asthma. Methods: One hundred asthmatic children (mean age 9.6 ± 3.0 years, 77 boys) underwent allergological and lung function evaluations. Spirometry was performed before and after bronchodilation test (BD test). The ADRB2 region containing the Arg16Gly (rs1042713) and Gln27Glu (rs1042714) variants were amplified by polymerase chain reaction, whereas ARG1 rs2781659 (A>G) and THRB rs892940 (G>A) SNPs were genotyped by high-resolution melting (HRM) analysis. Results: Seventy-seven percent of children developed asthma in the first 6 years of life. Allergic sensitization was observed in 92% (total immunoglobulin G: 529.8 ± 477. kU/L). All patients exhibited respiratory allergy: 43% has multiple respiratory, 22% to single respiratory, and 27% multiple respiratory and food allergies. Fifty four percent children showed positive BD response (forced expiratory volume in 1 second [FEV1] > 12%). Presence of Arg/Gly or Gly/Gly genotypes in position 16 of ADRB2 was significantly associated to a worse BD response (post-BD FEV1: 108.68% ± 15.62% in Arg/Arg vs. 101.86% ± 14.03% in Arg/Gly or Gly/Gly patients, p = 0.02). No significant association was found between spirometric parameters before and after BD for the other three examined SNPs. Conclusion: The influence of genetic variability on responsiveness to drugs could become a key parameter to optimize a tailored therapy for young patients with asthma, especially if drug-resistance occurs.

Differentiating non-responders from responders in children with moderate and severe asthma exacerbations

Objective: Our goal was to assess factors associated with non-response to treatment in children presenting to the Emergency Department (ED) with moderate and severe asthma exacerbations. Methods: A retrospective chart review was completed from 9/2014 to 2/2017 for patients with a discharge diagnosis of asthma exacerbation. The Modified Pulmonary Index Score (MPIS) was used to quantify illness acuity. The rate of change of MPIS per hour was calculated, and differentiated responders from non-responders. After examining a histogram of ΔMPIS/h, a threshold of ΔMPIS/h > 0 was used to define response for duration of ED stay. Children included were >2 years and had initial MPIS > 10. Results: Eight hundred and fifty-two children were included. There were 178 (21%) non-responders and 674 (79%) responders. Non-responders were significantly older (7.0 ± 4.0 versus 5.6 ± 3.2 years; p < 0.001), but there were no differences in gender, race, ethnicity or insurance status. There was also no statistical difference in time to first albuterol treatment (50 ± 41 versus 43 ± 40 min; p = 0.05), or in time to corticosteroid (95 ± 75 versus 79 ± 64 min; p = 0.06). Non-responders were significantly more likely to arrive by ambulance (OR 2.2; 95% CI 1.6-3.2), to be admitted to the hospital (OR 2.7; 95% CI 1.8-4.0), and to be admitted to the ICU (OR 5.0; 95% CI 3.1-8.1). Conclusions: One in five children with exacerbations did not respond to treatment. These children were older and more likely to be admitted. Non-measured factors, possibly genetic, may contribute to response to treatment.

ADRB2 Gene Polymorphisms and Salbutamol Responsiveness in Serbian Children with Asthma

Inhaled β2 adrenergic receptor (β2-AR) agonists are the mainstay of asthma therapy. The β2-AR protein is encoded by the ADRB2 gene and variants within this gene can have significant consequences for modulating the response to asthma therapy. This cross-sectional study performed at the University Children’s Hospital in Belgrade, included 54 children with asthma. The subjects were genotyped for ADRB2 +46A>G (Arg16Gly, rs1042713) and +79C>G (Gln27Glu, rs 1042714) polymorphisms and the association with asthma severity and response to inhaled salbutamol was examined. In Serbian asthmatic children, allele +46A was detected with a frequency of 41.7% and allele +79G was detected with a frequency of 23.1%. Allele +46G was found to be associated with a better response to inhaled salbutamol (p <0.05) and with mild form of asthma (p <0.05). Polymorphism ADRB2 +46A>G may be a determinant of asthma severity and response to salbutamol in children with asthma. We did not find any association of +79C>G polymorphisms with the asthma severity and bronchodilator response to inhaled salbutamol. The results of this study can be potentially useful for personalization of asthma treatment.

A genome-wide association and admixture mapping study of bronchodilator drug response in African Americans with asthma

Short-acting β₂-adrenergic receptor agonists (SABAs) are the most commonly prescribed asthma medications worldwide. Response to SABAs is measured as bronchodilator drug response (BDR), which varies among racial/ethnic groups in the U.S^{1, 2}. However, the genetic variation that contributes to BDR is largely undefined in African Americans with asthma³. To identify genetic variants that may contribute to differences in BDR in African Americans with asthma, we performed a genome-wide association study (GWAS) of BDR in 949 African American children with asthma, genotyped with the Axiom World Array 4 (Affymetrix, Santa Clara, CA) followed by imputation using 1000 Genomes phase III genotypes. We used linear regression models adjusting for age, sex, body mass index (BMI) and genetic ancestry to test for an association between BDR and genotype at single nucleotide polymorphisms (SNPs). To increase power and distinguish between shared vs. population-specific associations with BDR in children with asthma, we performed a meta-analysis across 949 African Americans and 1,830 Latinos (Total=2,779). Lastly, we performed genome-wide admixture mapping to identify regions whereby local African or European ancestry is associated with BDR in African Americans. We identified a population-specific association with an intergenic SNP on chromosome 9q21 that was significantly associated with BDR (rs73650726, p=7.69×10⁻⁹). A trans-ethnic meta-analysis across African Americans and Latinos identified three additional SNPs within the intron of PRKG1 that were significantly associated with BDR (rs7903366, rs7070958, and rs7081864, p≤5×10⁻⁸). Our results failed to replicate in three additional populations of 416 Latinos and 1,615 African Americans. Our findings indicate that both population specific and shared genetic variation contributes to differences in BDR in minority children with asthma, and that the genetic underpinnings of BDR may differ between racial/ethnic groups.

Preschool wheeze, genes and treatment

Preschool wheeze is a common but poorly understood cause of respiratory morbidity that is both distinct from and overlaps with infantile bronchiolitis and school age asthma. Attempts at classification by epidemiology, pathophysiology, therapeutic response and clinical phenotype are imperfect and yet fundamental to both treatment choice and research design. The four main therapeutic classes for preschool wheeze, namely beta₂ agonists, anticholinergics, corticosteroids and leukotriene modifiers are employed with variable and often scanty evidence base, with evidence for a genetic influence on response variations. The article will discuss the pharmacogenetics of the various options, summarise current treatment recommendations, and explore future research directions.

An American Thoracic Society/National Heart, Lung, and Blood Institute Workshop Report: Addressing Respiratory Health Equality in the United States

Health disparities related to race, ethnicity, and socioeconomic status persist and are commonly encountered by practitioners of pediatric and adult pulmonary, critical care, and sleep medicine in the United States. To address such disparities and thus progress toward equality in respiratory health, the American Thoracic Society and the National Heart, Lung, and Blood Institute convened a workshop in May of 2015. The workshop participants addressed health disparities by focusing on six topics, each of which concluded with a panel discussion that proposed recommendations for research on racial, ethnic, and socioeconomic disparities in pulmonary, critical care, and sleep medicine. Such recommendations address best practices to advance research on respiratory health disparities (e.g., characterize broad ethnic groups into subgroups known to differ with regard to a disease of interest), risk factors for respiratory health disparities (e.g., study the impact of new tobacco or nicotine products on respiratory diseases in minority populations), addressing equity in access to healthcare and quality of care (e.g., conduct longitudinal studies of the impact of the Affordable Care Act on respiratory and sleep disorders), the impact of personalized medicine on disparities research (e.g., implement large studies of pharmacogenetics in minority populations), improving design and methodology for research studies in respiratory health disparities (e.g., use study designs that reduce participants' burden and foster trust by engaging participants as decision-makers), and achieving equity in the pulmonary, critical care, and sleep medicine workforce (e.g., develop and maintain robust mentoring programs for junior faculty, including local and external mentors). Addressing these research needs should advance efforts to reduce, and potentially eliminate, respiratory, sleep, and critical care disparities in the United States.

Review on Pharmacogenetics and Pharmacogenomics Applied to the Study of Asthma

Nearly one-half of asthmatic patients do not respond to the most common therapies. Evidence suggests that genetic factors may be involved in the heterogeneity in therapeutic response and adverse events to asthma therapies. We focus on the three major classes of asthma medication: β-adrenergic receptor agonist, inhaled corticosteroids, and leukotriene modifiers. Pharmacogenetics and pharmacogenomics studies have identified several candidate genes associated with drug response.In this chapter, the main pharmacogenetic and pharmacogenomic studies in addition to the future perspectives in personalized medicine will be reviewed. The ideal treatment of asthma would be a tailored approach to health care in which adverse effects are minimized and the therapeutic benefit for an individual asthmatic is maximized leading to a more cost-effective care.

Pharmacogenetics and interstitial lung disease

PURPOSE OF REVIEW

Interstitial lung disease (ILD) is comprised of a heterogeneous group of disorders with highly variable natural histories and response to therapies. Pharmacogenetics focuses on the variability in drug response because of the presence of genetic factors that influence drug metabolism or disease activity. In this article, we review relevant drug-specific and disease-specific polymorphisms that may influence therapeutic response, and then highlight a recently identified drug-gene interaction in patients with idiopathic pulmonary fibrosis (IPF).

RECENT FINDINGS

The emergence of high-throughput genomic technology has allowed for identification of gene polymorphisms associated with susceptibility to specific disease states, including IPF and several connective tissue diseases known to cause ILD. IPF risk loci span a diverse group of genes, while most associated with connective tissue disease are critical to immune signaling. A recent pharmacogenetic analysis of patients enrolled in an IPF clinical trial identified a variant within TOLLIP to be associated with differential response to N-acetylcysteine therapy.

SUMMARY

Though few pharmacogenetic investigations have been conducted in patients with ILD to date, ample opportunities for pharmacogenetic exploration exist in this patient population. Such exploration will advance our understanding of specific ILDs and help usher in an era of personalized medicine.

Health Disparities in Patients with Pulmonary Arterial Hypertension: A Blueprint for Action. An Official American Thoracic Society Statement

BACKGROUND

Health disparities have a major impact in the quality of life and clinical care received by minorities in the United States. Pulmonary arterial hypertension (PAH) is a rare cardiopulmonary disorder that affects children and adults and that, if untreated, results in premature death. The impact of health disparities in the diagnosis, treatment, and clinical outcome of patients with PAH has not been systematically investigated.

OBJECTIVES

The specific goals of this research statement were to conduct a critical review of the literature concerning health disparities in PAH, identify major research gaps and prioritize direction for future research.

METHODS

Literature searches from multiple reference databases were performed using medical subject headings and text words for pulmonary hypertension and health disparities. Members of the committee discussed the evidence and provided recommendations for future research.

RESULTS

Few studies were found discussing the impact of health disparities in PAH. Using recent research statements focused on health disparities, the group identified six major study topics that would help address the contribution of health disparities to PAH. Representative studies in each topic were discussed and specific recommendations were made by the group concerning the most urgent questions to address in future research studies.

CONCLUSIONS

At present, there are few studies that address health disparities in PAH. Given the potential adverse impact of health disparities, we recommend that research efforts be undertaken to address the topics discussed in the document. Awareness of health disparities will likely improve advocacy efforts, public health policy and the quality of care of vulnerable populations with PAH.

ADRB2 gene polymorphism and emphysema heterogeneity can modulate bronchodilator response in patients with emphysema

BACKGROUND

Genetic variation in the β₂-adrenergic receptor (ADRB2) gene has been thought to have an important role in the differential response to β₂-agonist therapy for asthma. However, previous studies have shown little evidence for an association between these ADRB2 variants and the bronchial dilator response (BDR) in chronic obstructive pulmonary disease (COPD) patients. This discrepancy could be explained by differences in the distribution and heterogeneity of pulmonary emphysema in COPD patients, since emphysema distribution and heterogeneity are thought to have a role in pulmonary function in COPD patients. We hypothesized that differences in emphysema distribution and heterogeneity may have masked significant alterations of the bronchodilator response among ADRB2 genotypes in COPD patients in previous studies.

METHODS

The BDR (induced by 20 μg of procaterol) was measured in 211 patients who had a smoking history of more than 10 pack/years and had undergone chest high resolution computed tomography examination. A low attenuations area (<960 Hounsfield Units) was identified and the emphysema heterogeneity index (EHI%) was calculated with a range in value from -100% to 100%. ADRB2 Arg16Gly genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

The BDR was augmented in patients with homogenous emphysema compared with those with upper-dominant emphysema. In patients carrying the AA genotype of ADRB2, the BDR was significantly increased in patients with upper-dominant emphysema, but not in patients with lower-dominant emphysema.

CONCLUSION

Combination analysis of ADRB2 Arg16Gly polymorphism and EHI% may predict the effectiveness of β₂-adrenergic receptor agonist treatment in patients with COPD and emphysema.

Pharmacogenetics and the treatment of asthma

Heterogeneity defines both the natural history of asthma as well as patient's response to treatment. Pharmacogenomics contribute to understand the genetic basis of drug response and thus to define new therapeutic targets or molecular biomarkers to evaluate treatment effectiveness. This review is initially focused on different genes so far involved in the pharmacological response to asthma treatment. Specific considerations regarding allergic asthma, the pharmacogenetics aspects of polypharmacy and the application of pharmacogenomics in new drugs in asthma will also be addressed. Finally, future perspectives related to epigenetic regulatory elements and the potential impact of systems biology in pharmacogenetics of asthma will be considered.

Genetic ancestry and prostate cancer susceptibility SNPs in Puerto Rican and African American men

BACKGROUND

The Puerto Rican (PR) population is a racially admixed population that has a high prostate cancer (PCa) mortality rate. We hypothesized in this pilot study that West African Ancestry (WAA) was associated with PCa in this heterogeneous (PR) population.

METHODS

A case/case and case/control study was performed. Controls, 207 African American (AA) and 133 PR were defined as men with no PCa, a serum PSA < 2.5 ng/mL and a negative rectal examination. Cases were patients with pathological specimens from radical prostatectomies (RP) (291 PR and 200 AA). DNA was extracted from whole blood of controls and from paraffin embedded normal seminal vesicle from the RPs. We assessed the association of PCa and aggressiveness with genetic ancestry using an ancestry informative marker panel (AIMs) and Wilcoxon rank-sum test and the association of PCa and aggressiveness with 15 previously PCa associated SNPs using Chi square test. Gleason Score (GS) and tumor stage (TS) were used to define low risk (GS ≤ 7[3 + 4]), TS ≤ pT2) and high risk (GS≥ 7[4 + 3], TS > pT2) PCa. Statistical analyses were done using SAS.

RESULTS

No difference in overall percent WAA was found between PR cases and controls. Among PR or AA cases WAA was not associated with disease severity based upon risk group, Gleason score or stage. Among AA controls WAA was significantly higher than in cases. The SNP rs7824364 (chromosome 8q24) PCa risk allele was significantly increased among cases versus controls for both AA (P < 0.0001) and PR (P = 0.0001) men. PR men with ≥1 risk allele exhibited a higher percent of WAA (39% vs 29%, P = 0.034).

CONCLUSION

The SNP rs7824364, a local marker of WAA in the 8q24 region was associated with PCa among both AA and PR men and with increased WAA among PR men. This novel relationship of PCA risk loci, WAA with PCa and its phenotype among PR men deserves further study.

Warfarin Anticoagulation Therapy in Caribbean Hispanics of Puerto Rico: A Candidate Gene Association Study

Existing algorithms account for ~50% of observed variance in warfarin dose requirements after including common polymorphisms. However, they do not perform as well in populations other than Caucasians, in part because some ethno-specific genetic variants are overlooked. The objective of the present study was to identify genetic polymorphisms that can explain variability in warfarin dose requirements among Caribbean Hispanics of Puerto Rico. Next-Generation Sequencing of candidate genes CYP2C9 and VKORC1 and genotyping by DMET® Plus Assay of cardiovascular patients were performed. We also aimed at characterizing the genomic structure and admixture pattern of this study cohort. Our study used the Extreme Discordant Phenotype approach to perform a case-control association analysis. The CYP2C9 variant rs2860905, which was found in all the major haplotypes occurring in the Puerto Rican population, showed stronger association with warfarin sensitivity (<4 mg/day) than common variants CYP2C9*2 and CYP2C9*3. Although, CYP2C9*2 and CYP2C9*3 are separately contained within two of the haplotypes, 10 subjects with the sensitive phenotype were carriers of only the CYP2C9 rs2860905 variant. Other polymorphisms in CES2 and ABCB1 were found to be associated with warfarin resistance. Incorporation of rs2860905 in a regression model (R2 = 0.63, MSE = 0.37) that also includes additional genetics (i.e., VKORC1-1639 G>A; CYP2C9 rs1856908; ABCB1 c.IVS9-44A>G/ rs10276036; CES2 c.269-965A>G/ rs4783745) and non-genetic factors (i.e., hypertension, diabetes and age) showed better prediction of warfarin dose requirements than CYP2C9*2 and CYP2C9*3 combined (partial R2 = 0.132 vs. 0.023 and 0.007, respectively, p < 0.001). The genetic background of Puerto Ricans in the study cohort showed a tri-hybrid admixture pattern, with a slightly higher than expected contribution of Native American ancestry (25%). The genomic diversity of Puerto Ricans is highlighted by the presence of four different major haplotype blocks in the CYP2C9 locus. Although, our findings need further replication, this study contributes to the field by identifying novel genetic variants that increase predictability of stable warfarin dosing among Caribbean Hispanics.

ADRB2 Polymorphism and Salbutamol Responsiveness in Northern Indian Children with Mild to Moderate Exacerbation of Asthma

OBJECTIVE

The primary objective was to determine the association between beta-2 adrenergic receptor (ADRB2) gene polymorphism (rs1042713, c.46A>G, p.Arg16Gly) and the response to inhaled salbutamol in North Indian children aged 5 to 15 years, with mild to moderate exacerbation of asthma.

METHODS

This cross-sectional study was done at a tertiary-care hospital in Northern India from June 2011 to May 2013. 120 children with asthma with mild to moderate exacerbation underwent spirometry at baseline and after administration of three doses of salbutamol. An increase in FEV1 =15% was considered as positive response. Blood samples from these children were analysed for ADRB2 polymorphism (p.Arg16Gly). 94 non-asthmatic adult controls were also studied to determine the prevalence of ADRB2 polymorphism.

RESULTS

In asthmatic children, the frequency of AA, GG, AG genotypes were 24.2%, 24.2% and 51.7% compared to 20.2%, 20.2% and 59.6%, respectively in the non-asthmatic adults. Salbutamol responsiveness showed no correlation with the studied ADRB2 polymorphism (p= 0.55). A trend towards greater bronchodilator responsiveness amongst AA genotype, compared to GG genotype was observed (Median change in percent predicted FEV1 14.5% and 7.5%, respectively).

CONCLUSION

No correlation was found between salbutamol responsiveness and ADRB2 genotype in Northern Indian children with asthma with mild-to moderate exacerbation.

Asthma in childhood

Several topics on childhood asthma were addressed in the Paediatric Clinical Year in Review session at the 2015 European Respiratory Society International Congress. With regard to the relationship between lower respiratory tract infections and asthma, it emerges that is the number of respiratory episodes in the first years of life, but not the particular viral trigger, to be associated with later asthma development. Understanding which characteristics of individual patients are associated with an increased risk for asthma exacerbation is a critical step to implement strategies preventing these seasonal events. Recent data suggest the possibility that exhaled volatile organic compounds may qualify as biomarkers in detecting early signs of asthma. Adding information of exhaled volatile organic compounds and expression of inflammation genes to a clinical tool significantly improves asthma prediction in preschool wheezy children. Personal communication with children and adolescents is likely more important than the tools actually used for monitoring asthma. Systemic corticosteroids do not affect the long-term prognosis in children with first viral-induced wheezing episode and should be used cautiously during acute episodes. Finally, stress and a polymorphism upstream of a specific gene are both associated with reduced bronchodilator response in children with asthma.

Pharmacogenetic research activity in Central America and the Caribbean: a systematic review

AIM

The present review was aimed at analyzing the pharmacogenetic scientific activity in Central America and the Caribbean.

MATERIALS & METHODS

A literature search for pharmacogenetic studies in each country of the region was conducted on three databases using a list of the most relevant pharmacogenetic biomarkers including 'phenotyping probe drugs' for major drug metabolizing enzymes. The review included 132 papers involving 47 biomarkers and 35,079 subjects (11,129 healthy volunteers and 23,950 patients).

RESULTS

The country with the most intensive pharmacogenetic research was Costa Rica. The most studied medical therapeutic area was oncology, and the most investigated biomarkers were CYP2D6 and HLA-A/B. Conclusion: Research activity on pharmacogenetics in Central American and the Caribbean populations is limited or absent. Therefore, strategies to promote effective collaborations, and foster interregional initiatives and research efforts among countries from the region could help for the rational clinical implementation of pharmacogenetics and personalized medicine.

Analysis of ADRB2 (Arg16Gly) Gene Variant with Susceptibility, Pharmacogenetic Response and Disease Severity in South Indian Asthmatics

β2-Adrenergic receptor (β2-AR) plays a crucial role in asthma pathophysiology by regulating, processes of the lung function, and clinical response to bronchodilators. The +46G>A- Gly16Arg polymorphism in the gene encoding β2 adrenergic receptor (ADRB2) has been associated with receptor non-responsiveness after β2-agonist exposure. In the present study, we sought to evaluate the possible association of Gly16Arg polymorphism with asthma susceptibility, pharmacogenetic response to Salbutamol, and varying degrees of disease severity. Three hundred ninety-eight clinically diagnosed patients and 456 healthy controls were enrolled for the study. Patients were classified into severity classes according to Global Initiative for Asthma guidelines. To assess bronchodilator response, spirometry was performed before and 15 min after Salbutamol (200 μg) delivery. Responders to Salbutamol were categorized if percentage reversibility was greater than or equal to 12% in them, while those showing reversibility less than 12% were classified as non-responders. Genotyping was carried out by ARMS-PCR technique. Statistical methods were applied to test for the significance of the results. In the present study, there was lack of significant association of polymorphism with disease susceptibility as well as with bronchodilator response. The polymorphism was not associated with mild and moderate asthma subtypes; however, there was a notable association with severe asthma subtype. In addition, the polymorphism was associated with severe asthma compared to subtypes of mild and moderate asthma combined. In a South Indian population, the ADRB2 Arg/Gly may not form a susceptible variant to develop asthma nor can be a standard predictive marker to bronchodilator response; nevertheless, the patterns in asthma severity can be predicted by analyzing this variant.

Pharmacogenetics of healthy volunteers in Puerto Rico

Puerto Ricans are a unique Hispanic population with European, Native American (Taino), and higher West African ancestral contributions than other non-Caribbean Hispanics. In admixed populations, such as Puerto Ricans, genetic variants can be found at different frequencies when compared to parental populations and uniquely combined and distributed. Therefore, in this review, we aimed to collect data from studies conducted in healthy Puerto Ricans and to report the frequencies of genetic polymorphisms with major relevance in drug response. Filtering for healthy volunteers or individuals, we performed a search of pharmacogenetic studies in academic literature databases without limiting the period of the results. The search was limited to Puerto Ricans living in the island, excluding those studies performed in mainland (United States). We found that the genetic markers impacting pharmacological therapy in the areas of cardiovascular, oncology, and neurology are the most frequently investigated. Coincidently, the top causes of mortality in the island are cardiovascular diseases, cancer, diabetes, Alzheimer's disease, and stroke. In addition, polymorphisms in genes that encode for members of the CYP450 family (CYP2C9, CYP2C19, and CYP2D6) are also available due to their relevance in the metabolism of drugs. The complex genetic background of Puerto Ricans is responsible for the divergence in the reported allele frequencies when compared to parental populations (Africans, East Asians, and Europeans). The importance of reporting the findings of pharmacogenetic studies conducted in Puerto Ricans is to identify genetic variants with potential utility among this genetically complex population and eventually move forward the adoption of personalized medicine in the island.

A case-control study of innate immunity pathway gene polymorphisms in Puerto Ricans reveals association of toll-like receptor 2 +596 variant with asthma

BACKGROUND

For many years, African Dust Storms (ADE) has been thought to be associated with high prevalence of asthma in Puerto Rico (PR). Endotoxins (ENX) have been associated with ADE particulate matter (PM) and are known to promote pro-inflammatory responses in lung cells of susceptible individuals through the Toll-like receptor (TLR2/4) signaling pathways. Genetic variants are plausible contributors to such susceptibility. Therefore, we have evaluated a series of nine single nucleotide polymorphisms (SNPs) in TLR genes, which have been correlated positive and negatively to asthma prevalence and/or risk, in the Puerto Rican asthmatic population.

METHODS

The following SNPs were evaluated in 62 asthmatics and 61 controls through Taqman® Real Time PCR Assay: TLR4 (+896A/G, +1196C/T, -6687A/G); TLR2 (+596C/T, -16934 T/A, +399A/G, +1349C/T) and CD14 (-159C/T, +1188C/G). Genotypes were assessed for asthma association employing an odds ratio (OR) analysis.

RESULTS

Minor allele frequencies (n = 123) were determined for those variants as 0.07, 0.06, 0.35, 0.35, 0.37, 0.29, 0.04, 0.35 and 0.11, respectively. Two (+596C/T, +399A/G) TLR2 SNPs showed to be more represented in the asthmatic group by 89 % and 65 %, respectively. TLR4 SNP +896A/G analysis revealed only 1 G/G genotype (2 %) on the asthmatic group. The CD14 SNPs were similarly represented in the Puerto Rican population. Only the TLR2 +596 SNP was found to be significantly associated to asthma (OR = 3.24 for CT, 2.71 for TT) and particularly to females.

CONCLUSIONS

The identification of TLR SNPs will reveal potential candidates for gene-environment interactions in Puerto Ricans. As far as we know this is the first study to evaluate this type of TLR gene polymorphisms in Puerto Rican asthmatics, contributing to the current knowledge in the Hispanic population.

Efficacy and Safety of Roflumilast in Korean Patients with COPD

PURPOSE

Roflumilast is the only oral phosphodiesterase 4 inhibitor approved to treat chronic obstructive pulmonary disease (COPD) patients [post-bronchodilator forced expiratory volume in 1 second (FEV₁) <50% predicted] with chronic bronchitis and a history of frequent exacerbations. This study evaluated the efficacy and safety of roflumilast in Korean patients with COPD and compared the efficacy based on the severity of airflow limitation.

MATERIALS AND METHODS

A post-hoc subgroup analysis was performed in Korean COPD patients participating in JADE, a 12-week, double-blinded, placebo-controlled, parallel-group, phase III trial in Asia. The primary efficacy endpoint was the mean [least-squares mean adjusted for covariates (LSMean)] change in post-bronchodilator FEV₁ from baseline to each post-randomization visit. Safety endpoints included adverse events (AEs) and changes in laboratory values, vital signs, and electrocardiograms.

RESULTS

A total of 260 Korean COPD patients were recruited, of which 207 were randomized to roflumilast (n=102) or placebo (n=105) treatment. After 12 weeks, LSMean post-bronchodilator FEV₁ increased by 43 mL for patients receiving roflumilast and decreased by 60 mL for those taking placebo. Adverse events were more common in the roflumilast group than in the placebo group; however, the types and frequency of AEs were comparable to those reported in previous studies.

CONCLUSION

Roflumilast significantly improved lung function with a tolerable safety profile in Korean COPD patients irrespective of the severity of airflow limitation.

Childhood asthma exacerbations and the Arg16 β2-receptor polymorphism: A meta-analysis stratified by treatment

BACKGROUND

The Gly-to-Arg substitution at the 16 position (rs1042713) in the β2-adrenoceptor gene (ADRB2) is associated with enhanced downregulation and uncoupling of β2-receptors.

OBJECTIVES

We sought to undertake a meta-analysis to test the hypothesis that there is an interaction between the A allele of rs1042713 (Arg16 amino acid) and long-acting β-agonist (LABA) exposure for asthma exacerbations in children.

METHODS

Children with diagnosed asthma were recruited in 5 populations (BREATHE, Genes-Environments and Admixture in Latino Americans II, PACMAN, the Paediatric Asthma Gene Environment Study, and the Pharmacogenetics of Adrenal Suppression with Inhaled Steroid Study). A history of recent exacerbation and asthma treatment was determined from questionnaire data. DNA was extracted, and the Gly16Arg genotype was determined.

RESULTS

Data from 4226 children of white Northern European and Latino origin were analyzed, and the odds ratio for exacerbation increased by 1.52 (95% CI, 1.17-1.99; P = .0021) for each copy of the A allele among the 637 children treated with inhaled corticosteroids (ICSs) plus LABAs but not for treatment with ICSs alone (n = 1758) or ICSs plus leukotriene receptor antagonist (LTRAs; n = 354) or ICSs plus LABAs plus LTRAs (n = 569).

CONCLUSIONS

The use of a LABA but not an LTRA as an "add-on controller" is associated with increased risk of asthma exacerbation in children carrying 1 or 2 A alleles at rs1042713. Prospective genotype-stratified clinical trials are now required to explore the potential role of rs1042713 genotyping for personalized asthma therapy in children.

Relationship between periodontal disease and asthma among overweight/obese adults

AIM

To assess the relationship between oral health and asthma.

METHODS

Data from 1315 overweight or obese individuals, aged 40-65 years were used. Asthma was self-reported, whereas periodontitis, bleeding on probing (BOP) and plaque index were determined by clinical examinations.

RESULTS

Using logistic regression adjusting for gender, smoking status, age, body mass index, family history of asthma and income level, revealed that the odds ratio (OR) of asthma for a participant with severe periodontitis was 0.44 (95% confidence interval: 0.27, 0.70) that of a participant with none/mild periodontitis. On the other hand, proportion of BOP sites and plaque index were not statistically significant. For a participant with severe periodontitis, the OR of taking asthma medication was 0.20 (95% confidence interval: 0.09, 0.43) that of a participant with none/mild periodontitis. Moreover, proportion of BOP sites was statistically associated with use of asthma medication, whereas plaque index still remained non-significant.

CONCLUSION

Participants with severe periodontitis were less likely to have asthma. Stronger evidence of an inverse association was found when using asthma medication as outcome.

Magnesium nebulization utilization in management of pediatric asthma (MagNUM PA) trial: study protocol for a randomized controlled trial

BACKGROUND

Up to 30 % of children with acute asthma are refractory to initial therapy, and 84 % of this subpopulation needs hospitalization. Finding safe, noninvasive, and effective strategies to treat this high-risk group would substantially decrease hospitalizations, healthcare costs, and the psycho-social burden of the disease. Whereas intravenous magnesium (Mg) is effective in severe refractory asthma, its use is sporadic due to safety concerns, with the main treatment goal being to prevent intensive care unit admission. In contrast, nebulized Mg is noninvasive, allows higher pulmonary drug concentrations, and has a much higher safety potential due to the lower rate of systemic delivery. Previous studies of inhaled Mg show disparate results due to the use of unknown/inefficient delivery methods and other methodological flaws.

METHODS/DESIGN

The study is a randomized double-blind controlled trial in seven Canadian pediatric Emergency Departments (two-center pilot 2011 to 2014, Canada-wide November 2014 to December 2017). The trial will include 816 otherwise healthy children who are 2 to 17 years old, having had at least one previous wheezing episode, have received systemic corticosteroids, and have a Pediatric Respiratory Assessment Measure (PRAM) ≥ 5 points after three salbutamol and ipratropium treatments for a current acute asthma exacerbation. Eligible consenting children will receive three experimental treatments of nebulized salbutamol with either 600 mg of Mg sulfate or placebo 20 min apart, using an Aeroneb Go nebulizer, which has been shown to maximize pulmonary delivery while maintaining safety. The primary outcome is hospitalization within 24 h of the start of the experimental therapy for persistent respiratory distress or supplemental oxygen. Secondary outcomes include all-cause hospitalization within 24 h, PRAM, vital signs, number of bronchodilator treatments by 240 min, and the association between the difference in the primary outcome between the groups, age, gender, baseline PRAM, atopy, and "viral induced wheeze" phenotype (Fig. 1).

DISCUSSION

If effective, inhaled Mg may represent an effective strategy to minimize morbidity in pediatric refractory acute asthma. Unlike previous works, this trial targets nonresponders to optimized initial therapy who are the most likely to benefit from inhaled Mg. Future dissemination of results will include knowledge translation, incorporation into a Cochrane Review, presentation at scientific meetings, and a peer-reviewed publication.

TRIAL REGISTRATION

NCTO1429415 , registered 2 September 2011.

Ethnic differences in adverse drug reactions to asthma medications: a systematic review

BACKGROUND

Information on ethnic diversity of adverse drug reactions (ADRs) to asthma medications is rare despite evidence suggesting higher risk for African Americans when using β2-adrenergic receptor agonists. The objectives are to investigate how ethnic background was involved in ADR assessment and to examine the relationship between ethnic background and ADRs to asthma medications.

METHODS

MEDLINE was searched until March 2014. All types of studies reporting ADRs to asthma medications involving more than one ethnic group were included. Extracted information includes study designs, ethnic backgrounds, intervention, and types and severities of ADRs.

RESULTS

Among the selected 15 randomised clinical trials, six pooled analyses of randomized clinical trials, and five prospective observational studies, only six studies compared ADRs across different ethnic groups. The majority of the comparisons were either statistically insignificant or inconclusive.

CONCLUSIONS

Ethnicity was largely overlooked. Most studies neglected to report ADRs by ethnicity. Lack of consistency in defining ethnicities complicated further pooled analyses. Despite the higher prevalence of asthma among specific ethnic minority groups, few studies disaggregated information by ethnic background, and reports of ADRs to asthma medications in different ethnic groups were rare. We suggest that the inclusion of ADR analysis by different ethnic backgrounds is desirable.

Stress and Bronchodilator Response in Children with Asthma

RATIONALE

Stress is associated with asthma morbidity in Puerto Ricans (PRs), who have reduced bronchodilator response (BDR).

OBJECTIVES

To examine whether stress and/or a gene regulating anxiety (ADCYAP1R1) is associated with BDR in PR and non-PR children with asthma.

METHODS

This was a cross-sectional study of stress and BDR (percent change in FEV1 after BD) in 234 PRs ages 9-14 years with asthma. We assessed child stress using the Checklist of Children's Distress Symptoms, and maternal stress using the Perceived Stress Scale. Replication analyses were conducted in two cohorts. Polymorphisms in ADCYAP1R1 were genotyped in our study and six replication studies. Multivariable models of stress and BDR were adjusted for age, sex, income, environmental tobacco smoke, and use of inhaled corticosteroids.

MEASUREMENTS AND MAIN RESULTS

High child stress was associated with reduced BDR in three cohorts. PR children who were highly stressed (upper quartile, Checklist of Children's Distress Symptoms) and whose mothers had high stress (upper quartile, Perceived Stress Scale) had a BDR that was 10.2% (95% confidence interval, 6.1-14.2%) lower than children who had neither high stress nor a highly stressed mother. A polymorphism in ADCYAP1R1 (rs34548976) was associated with reduced BDR. This single-nucleotide polymorphism is associated with reduced expression of the gene for the β2-adrenergic receptor (ADRB2) in CD4(+) lymphocytes of subjects with asthma, and it affects brain connectivity of the amygdala and the insula (a biomarker of anxiety).

CONCLUSIONS

High child stress and an ADCYAP1R1 single-nucleotide polymorphism are associated with reduced BDR in children with asthma. This is likely caused by down-regulation of ADRB2 in highly stressed children.

Influence of ethnicity on response to asthma drugs

INTRODUCTION

Understanding variability in the response to asthma medications is essential to ensure appropriate prescribing. Given that there are increased asthma treatment failures observed in ethnic minorities receiving asthma therapeutics, it is fundamental to understand the factors related to ethnicity that can modify the response to asthma therapy.

AREAS COVERED

Race/ethnicity is an important determinant of drug response and therefore contributes to interindividual variability. It is generally recognized that its effects on drug response are determined by both genetic and environmental factors to a varying extent, depending on the ethnic groups and probe drugs studied. Also, adherence to therapy can influence pharmacological response to asthma therapeutics.

EXPERT OPINION

Health-care professionals might never use the treatment in their patients irrespective of their ethnicity and thus inadvertently increase ethnic health inequality. However, our understanding of whether and/or how ethnicity influences pharmacological response to asthma therapeutics is still very scarce. A holistic, integrative systems biology approach that combines large-scale molecular profiling traits (e.g., transcriptomic, proteomic, metabolomic traits) and genetic variants could help to personalize the treatment of asthmatic patients regardless of race/ethnicity.

Effect of ADRB2 (adrenergic receptor β2) gene polymorphisms on the occurrence of asthma and on the response to nebulized salbutamol in South Indian patients with bronchial asthma

INTRODUCTION

Genetic mutations in the β2 receptor could alter its functioning and the response to β2 agonists. The study was done to find out the effect of two commonly occurring polymorphisms-Arg16Gly and Gln27Glu, on cause of asthma and on response to nebulized salbutamol in South Indian subjects of asthma.

METHODS

After baseline measurements of Forced Expiratory Volume in 1st second (FEV1), Forced Vital Capacity (FVC) and Peak Expiratory Flow Rate (PEFR), five mg of nebulized salbutamol was administered and spirometry was repeated. The increase in these parameters was calculated and patients were included for genotyping if the percentage increase in FEV1 was ≥12%. The frequencies of these polymorphisms in patients were compared with those of healthy volunteers.

RESULTS

112 patients and 127 healthy volunteers were genotyped. The frequencies of the polymorphisms were found to be similar to previously published Dravidian population frequencies. The frequencies of genotypes in asthmatics were similar to healthy volunteers. The increase in FEV1, FVC and PEFR was similar across various genotypes and haplotypes in both the polymorphisms. The GG-CG haplotype was associated with 3.1 times increased occurrence of asthma (p value = 0.02). The G allele of the Arg16Gly polymorphism was associated with lower baseline FEV1, FVC and PEFR values, but these were not statistically significant.

CONCLUSION

The Arg16Gly and Gln27Glu polymorphisms do not determine the occurrence of asthma individually, but the GG-CG haplotype is associated with an increased risk of asthma. There is no effect of the genotypes on the response to nebulized salbutamol.

Genome-wide association study of short-acting β2-agonists. A novel genome-wide significant locus on chromosome 2 near ASB3

RATIONALE

β2-Agonists are the most common form of treatment of asthma, but there is significant variability in response to these medications. A significant proportion of this responsiveness may be heritable.

OBJECTIVES

To investigate whether a genome-wide association study (GWAS) could identify novel pharmacogenetic loci in asthma.

METHODS

We performed a GWAS of acute bronchodilator response (BDR) to inhaled β2-agonists. A total of 444,088 single-nucleotide polymorphisms (SNPs) were examined in 724 individuals from the SNP Health Association Resource (SHARe) Asthma Resource Project (SHARP). The top 50 SNPs were carried forward to replication in a population of 444 individuals.

MEASUREMENTS AND MAIN RESULTS

The combined P value for four SNPs reached statistical genome-wide significance aftercorrecting for multiple comparisons. Combined P values for rs350729, rs1840321, rs1384918, and rs1319797 were 2.21 × 10(-10), 5.75 × 10(-8), 9.3 × 10(-8), and 3.95 × 10(-8), respectively. The significant variants all map to a novel genetic region on chromosome 2 near the ASB3 gene, a region associated with smooth muscle proliferation. As compared with the wild type, the presence of the minor alleles reduced the degree of BDR by 20% in the original population and by a similar percentage in the confirmatory population.

CONCLUSIONS

These GWAS findings for BDR in subjects with asthma suggest that a gene associated with smooth muscle proliferation may influence a proportion of the smooth muscle relaxation that occurs in asthma.