Pharmacogenetics of inhaled corticosteroids and exacerbation risk in adults with asthma

The Rotterdam Study. Design update and major findings between 2020 and 2024

The Rotterdam Study is a population-based cohort study, started in 1990 in the district of Ommoord in the city of Rotterdam, the Netherlands, with the aim to describe the prevalence and incidence, unravel the etiology, and identify targets for prediction, prevention or intervention of multifactorial diseases in mid-life and elderly. The study currently includes 17,931 participants (overall response rate 65%), aged 40 years and over, who are examined in-person every 3 to 5 years in a dedicated research facility, and who are followed-up continuously through automated linkage with health care providers, both regionally and nationally. Research within the Rotterdam Study is carried out along two axes. First, research lines are oriented around diseases and clinical conditions, which are reflective of medical specializations. Second, cross-cutting research lines transverse these clinical demarcations allowing for inter- and multidisciplinary research. These research lines generally reflect subdomains within epidemiology. This paper describes recent methodological updates and main findings from each of these research lines. Also, future perspective for coming years highlighted.

Asthma exacerbations and eosinophilia in the UK Biobank: a genome-wide association study

Background

Asthma exacerbations reflect disease severity, affect morbidity and mortality, and may lead to declining lung function. Inflammatory endotypes (e.g. T2-high (eosinophilic)) may play a key role in asthma exacerbations. We aimed to assess whether genetic susceptibility underlies asthma exacerbation risk and additionally tested for an interaction between genetic variants and eosinophilia on exacerbation risk.

Methods

UK Biobank data were used to perform a genome-wide association study of individuals with asthma and at least one exacerbation compared to individuals with asthma and no history of exacerbations. Individuals with asthma were identified using self-reported data, hospitalisation data and general practitioner records. Exacerbations were identified as either asthma-related hospitalisation, general practitioner record of asthma exacerbation or an oral corticosteroid burst prescription. A logistic regression model adjusted for age, sex, smoking status and genetic ancestry via principal components was used to assess the association between genetic variants and asthma exacerbations. We sought replication for suggestive associations (p<5×10-6) in the GERA cohort.

Results

In the UK Biobank, we identified 11 604 cases and 37 890 controls. While no variants reached genome-wide significance (p<5×10-8) in the primary analysis, 116 signals were suggestively significant (p<5×10-6). In GERA, two single nucleotide polymorphisms (rs34643691 and rs149721630) replicated (p<0.05), representing signals near the NTRK3 and ABCA13 genes.

Conclusions

Our study has identified reproducible associations with asthma exacerbations in the UK Biobank and GERA cohorts. Confirmation of these findings in different asthma subphenotypes in diverse ancestries and functional investigation will be required to understand their mechanisms of action and potentially inform therapeutic development.

CRHR1 polymorphism at rs242941, rs242940, and rs72834580: association of symptoms improvement with intranasal corticosteroids in allergic rhinitis Jordanian patients

OBJECTIVES

Rhinitis is classified into several types with allergic rhinitis (AR) being the most common. AR is among the inflammatory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), in which corticosteroids are administered to overcome the decrease in cortisol production. The treatment options available for AR vary with 1st line treatment being intranasal corticosteroids (INCS). The responsiveness to corticosteroids is due to their binding to corticotropin-releasing hormone receptor-1 (CRHR1). Various studies have studied the responsiveness to corticosteroids treatment in patients with asthma and COPD in association with CRHR1 gene single nucleotide polymorphisms (SNPs).

METHODS

In our study, we investigated the association of three SNPs of CRHR1 gene (rs242941, rs242940, and rs72834580) with symptoms improvement post-treatment in AR patients. Blood samples were collected from 103 patients for DNA extraction and gene sequencing. Those patients started to receive INCS for 8 weeks and their symptoms were assessed, through a questionnaire, before treatment and post-treatment to check for symptoms improvement.

RESULTS

Our data showed that improvement of eye redness is significantly less following INCS treatment in patients with allele (C) (AOR=0.289, p-value-0.028, 95 % CI=0.096-0.873) and genotype (CC) (AOR=0.048, p-value-0.037, 95 % CI=0.003-0.832) of rs242941 SNP. There was no correlation with other genotypes, alleles, or haplotypes of the investigated SNPs.

CONCLUSIONS

Our findings show that there is no correlation between CRHR1 gene polymorphism and symptoms improvement following INCS treatment. Further studies are required to evaluate the association of INCS and symptoms improvement post-treatment with larger sample size.

Cost-effectiveness of Arg16Gly in ADRB2 pharmacogenomic-guided treatment for pediatric asthma

OBJECTIVES

To assess the cost-effectiveness of Arg16Gly ADRB2 pharmacogenomic testing compared with no Arg16Gly ADRB2 testing to guide the use of long-acting β2 receptor agonist (LABA) in asthma patients aged 1 to 5 years in China.

METHODS

This economic evaluation developed a Markov model with four health states (no exacerbation, mild exacerbation, moderate-to-severe exacerbation, and death). Transition probabilities were estimated from the rate of exacerbations, the case-fatality rate of patients hospitalized for exacerbations, and natural mortality. Costs included drug costs and exacerbation management costs. Cost inputs and utilities for each health state were gained from public databases and the literatures. Costs and quality-adjusted life years (QALYs) were estimated for ten years. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

In the base case analysis, in contrast to the group without the genotype test, the incremental total cost was -¥334.7, and the incremental QALY was 0.001 in the Arg16Gly ADRB2 genotyping group. Therefore, the Arg16Gly ADRB2 test group was the dominant strategy for children with asthma in China. The sensitivity analyses showed that the model was relatively stable.

CONCLUSION

Arg16Gly ADRB2 testing before using LABA is a cost-effective approach compared with no gene testing for pediatric asthma.

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.

The GLCCI1 rs37973 variant and the efficacy of inhaled corticosteroids in the treatment of asthma: A meta-analysis

OBJECTIVE

This study investigated the relationship between the glucocorticoid-induced transcript 1 (GLCCI1) gene variant and the degree of improvement in lung function with inhaled corticosteroids (ICS).

METHODS

We searched the PubMed, Embase, Cochrane Library, CBM, CNKI and Wanfang databases to obtain studies on the GLCCI1 rs37973 variant and the efficacy of ICS in asthma.

RESULTS

The overall meta-analysis showed that patients with the GG phenotype (mutant homozygotes) exhibited significantly smaller forced expiratory volume in 1 sec (FEV1) change than patients with the AG phenotype (mutant heterozygous) (MD = -0.08, 95% CI [-0.12, -0.03], P = 0.001). Compared with the AA phenotype (wild homozygotes), the GG phenotype (MD = -4.23, 95% CI [-6.09, -2.38], P < 0.00001) and AG phenotype (MD = -1.92, 95% CI [-2.35, -1.49], P < 0.00001) had significantly smaller FEV1%pred changes. The FEV1 change subgroup analysis showed that the GG phenotype group was smaller than the AA phenotype group at 8 (MD = -0.53, 95% CI [-0.91, -0.14], P = 0.007), 12 (MD = -0.16, 95% CI [-0.30, -0.02], P = 0.02) and 24 (MD = -0.09, 95% CI [-0.17, -0.01], P = 0.02) weeks of treatment; the GG phenotype group was smaller than the AG phenotype group at 12 weeks (MD = -0.08, 95% CI [-0.15, -0.01], P = 0.02).

CONCLUSION

This meta-analysis suggests that the GLCCI1 rs37973 variant affects the efficacy of ICS and that the presence of the G allele attenuates the improvement in lung function with ICS.

Genetic Variants Associated with Bronchial Asthma Specific to the Population of the Russian Federation

Bronchial asthma (BA) is a disease that still lacks an exhaustive treatment protocol. In this regard, the global medical community pays special attention to the genetic prerequisites for the occurrence of this disease. Therefore, the search for the genetic polymorphisms underlying bronchial asthma has expanded considerably. As the present study progressed, a significant amount of scientific medical literature was analyzed and 167 genes reported to be associated with the development of bronchial asthma were identified. A group of participants (n = 7,303) who had voluntarily provided their biomaterial (venous blood) to be used in the research conducted by the Federal Medical Biological Agency of Russia was formed to subsequently perform a bioinformatic verification of known associations and search for new ones. This group of participants was divided into four cohorts, including two sex-distinct cohorts of individuals with a history of asthma and two sex-distinct cohorts of apparently healthy individuals. A search for polymorphisms was made in each cohort among the selected genes, and genetic variants were identified whose difference in occurrence in the different cohorts was statistically significant (significance level less than 0.0001). The study revealed 11 polymorphisms that affect the development of asthma: four genetic variants (rs869106717, rs1461555098, rs189649077, and rs1199362453), which are more common in men with bronchial asthma compared to apparently healthy men; five genetic variants (rs1923038536, rs181066119, rs143247175, rs140597386, and rs762042586), which are more common in women with bronchial asthma compared to apparently healthy women; and two genetic variants (rs1219244986 and rs2291651) that are rare in women with a history of asthma.

Genetic Determinants of Poor Response to Treatment in Severe Asthma

Severe asthma is a multifactorial disorder with marked phenotypic heterogeneity and complex interactions between genetics and environmental risk factors, which could, at least in part, explain why during standard pharmacologic treatment, many patients remain poorly controlled and at an increased risk of airway remodeling and disease progression. The concept of “precision medicine” to better suit individual unique needs is an emerging trend in the management of chronic respiratory diseases. Over the past few years, Genome-Wide Association Studies (GWAS) have revealed novel pharmacogenetic variants related to responses to inhaled corticosteroids and the clinical efficacy of bronchodilators. Optimal clinical response to treatment may vary between racial/ethnic groups or individuals due to genetic differences. It is also plausible to assume that epigenetic factors play a key role in the modulation of gene expression patterns and inflammatory cytokines. Remarkably, specific genetic variants related to treatment effectiveness may indicate promising pathways for novel therapies in severe asthma. In this review, we provide a concise update of genetic determinants of poor response to treatment in severe asthma and future directions in the field.