Novel Trajectories for Identifying Asthma Phenotypes: A Longitudinal Study in Korean Asthma Cohort, COREA

Current Challenges in Pediatric Asthma

Asthma is a chronic lung disease characterized by reversible bronchoconstriction and inflammation of the bronchi. Its increasing prevalence in childhood as well as different triggers make asthma a challenging disease in several ways: defining its phenotype/endotype, the diagnostic approach (especially in younger children), therapeutic options, and systematic follow-up. Considering these problems, this review approaches the current status and limitations of guidelines used for asthma management in children. It also emphasizes the key points which could lead to a better understanding and the direction to take in future studies.

Soluble ACE2 and TMPRSS2 Levels in the Serum of Asthmatic Patients

BACKGROUND

Angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2) are key proteins mediating viral entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although gene expressions of ACE2 and TMPRSS2 have been analyzed in various organs and diseases, their soluble forms have been less studied, particularly in asthma. Therefore, we aimed to measure circulating ACE2 and TMPRSS2 in the serum of asthmatics and examine their relationship with clinical characteristics.

METHODS

Clinical data and serum samples of 400 participants were obtained from an asthma cohort. The soluble ACE2 (sACE2) and soluble TMPRSS2 (sTMPRSS2) level was measured by enzyme-linked immunosorbent assay, and the values underwent a natural log transformation. Associations between sACE2 and TMPRSS2 levels and various clinical variables were analyzed.

RESULTS

The patients younger than 70 years old, those with eosinophilic asthma (eosinophils ≥ 200 cells/µL), and inhaled corticosteroids (ICS) non-users were associated with higher levels of sACE2. Blood eosinophils and fractionated exhaled nitric oxide levels were positively correlated with serum ACE2. In contrast, lower levels of sTMPRSS2 were noted in patients below 70 years and those with eosinophilic asthma, while no association was noted between ICS use and sTMPRSS2. The level of sTMPRSS2 also differed according to sex, smoking history, coexisting hypertension, and forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio. The proportion of sputum neutrophils was positively correlated with sTMPRSS2, while the FEV1/FVC ratio reported a negative correlation with sTMPRSS2.

CONCLUSION

The levels of ACE2 and TMPRSS2 were differently expressed according to age, ICS use, and several inflammatory markers. These findings suggest variable susceptibility and prognosis of SARS-CoV-2 infection among asthmatic patients.

Association Between Clinical Burden and Blood Eosinophil Counts in Asthma: Findings From a Korean Adult Asthma Cohort

BACKGROUND

Some reports have suggested that the clinical and economic burdens of asthma are associated with blood eosinophil levels. The association between clinical burden and blood eosinophil counts were evaluated in a Korean adult asthma cohort.

METHODS

Clinical information including blood eosinophil counts that were not affected by systemic corticosteroids were extracted from the Cohort for Reality and Evolution of Adult Asthma in Korea database. Clinical burden was defined as 1) asthma control status, 2) medication demand and 3) acute exacerbation (AE) events during 1 consecutive year after enrollment. All patients were divided into atopic and non-atopic asthmatics. The associations between asthma outcomes and the blood eosinophil count were evaluated.

RESULTS

In total, 302 patients (124 atopic and 178 non-atopic asthmatics) were enrolled. In all asthmatics, the risk of severe AE was higher in patients with blood eosinophil levels < 100 cells/µL than in patients with levels ≥ 100 cells/µL (odds ratio [OR], 5.406; 95% confidence interval [CI], 1.266-23.078; adjusted P = 0.023). Among atopic asthmatics, the risk of moderate AE was higher in patients with blood eosinophil levels ≥ 300 cells/µL than in patients with levels < 300 cells/µL (OR, 3.558; 95% CI, 1.083-11.686; adjusted P = 0.036). Among non-atopic asthmatics, the risk of medication of Global Initiative for Asthma (GINA) steps 4 or 5 was higher in patients with high blood eosinophil levels than in patients with low blood eosinophil levels at cutoffs of 100, 200, 300, 400, and 500 cells/µL.

CONCLUSION

The baseline blood eosinophil count may predict the future clinical burden of asthma.

Association of genetic variants of oxidative stress responsive kinase 1 (OXSR1) with asthma exacerbations in non-smoking asthmatics

BACKGROUND

Asthma exacerbation threatens patient's life. Several genetic studies have been conducted to determine the risk factors for asthma exacerbation, but this information is still lacking. We aimed to determine whether genetic variants of Oxidative Stress Responsive Kinase 1 (OXSR1), a gene with functions of salt transport, immune response, and oxidative stress, are associated with exacerbation of asthma.

METHODS

Clinical data were obtained from 1454 asthmatics and single nucleotide polymorphisms (SNPs) of OXSR1 were genotyped. Genetic associations with annual exacerbation rate were analyzed depending on smoking status.

RESULTS

Eleven SNPs were selected using Asian data in the International HapMap database. The common allele of rs1384006 C > T of OXSR1 showed a significantly higher annual exacerbation rate than the rare allele in non-smoking asthmatics (CC vs. CT vs. TT: 0.43 ± 0.04 vs. 0.28 ± 0.03 vs. 0.31 ± 0.09, P = 0.004, Pcorr = 0.039). The frequent exacerbators had a significantly higher frequency of the common allele of rs1384006 C > T than did the infrequent exacerbators (74.4% vs. 55.2%, P = 0.004, Pcorr = 0.038).

CONCLUSION

The common allele of rs1384006 C > T of OXSR1 was associated with the asthma exacerbation rate and a higher risk of being a frequent exacerbator, indicating that non-smoking asthmatics who carry common alleles may be vulnerable to asthma exacerbations.

Pragmatic Randomized Controlled Trial for Stepping Down Asthma Controller Treatment in Patients Controlled with Low-Dose Inhaled Corticosteroid and Long-Acting β2-Agonist: Step-Down of Intervention and Grade in Moderate Asthma Study

BACKGROUND

Current asthma guidelines recommend stepping down controller treatment when the condition is well-controlled for a certain time. However, the optimal step-down strategy for well-controlled patients receiving a low-dose inhaled corticosteroid (ICS) with a long-acting β₂-agonist (LABA) remains unclear.

OBJECTIVE

This study was a randomized, open-label, three-arm, parallel pragmatic trial comparing two kinds of step-down approaches for maintaining treatment.

METHODS

Adults with asthma who were aged 18 years or older, and who had been stable with low-dose ICS/LABA for at least 3 months, were enrolled. Subjects (n = 225) were randomly allocated into one of three groups (maintaining low-dose ICS/LABA [G1], discontinuing LABA [G2], and reducing ICS/LABA to once daily [G3]), and were observed for 6 months. The primary end point was a change in Asthma Control Test (ACT) scores between randomization and the final 6-month follow-up.

RESULTS

The change in ACT was analyzed in the per-protocol population; noninferiority was not demonstrated in either step-down group compared with the maintenance group (95% confidence interval of the difference, G2 vs G1 = -1.40-0.55; G3 vs G1 = -1.19-0.77). Although over 90% of patients were fine, higher rates of treatment failure were observed in step-down groups (G1: 0%; G2: 9.46%; and G3: 9.09%; P = .027). There were no significant differences between step-down approaches in terms of ACT change or treatment failure.

CONCLUSIONS

Both step-down methods were not noninferior to maintenance of treatment. Step-down therapy can be attempted when patients are stable, but appropriate monitoring and supervision are necessary with precautions regarding loss of disease control.

Unraveling the Heterogeneity of Hidradenitis Suppurativa with Phenotype Schema

One of the major challenges faced with hidradenitis suppurativa (HS) is the variability in manifestations and treatment responses. Cazzaniga et al. (2020) conducted a cross-sectional study and latent class analysis to explain disease heterogeneity and formulate HS phenotypes. HS phenotypes might be useful for disease or treatment outcomes. Future studies should assess rater reliability and predictive validity for outcomes such as treatment response or disease progression.

A Systematic Review of Asthma Phenotypes Derived by Data-Driven Methods

Classification of asthma phenotypes has a potentially relevant impact on the clinical management of the disease. Methods for statistical classification without a priori assumptions (data-driven approaches) may contribute to developing a better comprehension of trait heterogeneity in disease phenotyping. This study aimed to summarize and characterize asthma phenotypes derived by data-driven methods. We performed a systematic review using three scientific databases, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. We included studies reporting adult asthma phenotypes derived by data-driven methods using easily accessible variables in clinical practice. Two independent reviewers assessed studies. The methodological quality of included primary studies was assessed using the ROBINS-I tool. We retrieved 7446 results and included 68 studies of which 65% (n = 44) used data from specialized centers and 53% (n = 36) evaluated the consistency of phenotypes. The most frequent data-driven method was hierarchical cluster analysis (n = 19). Three major asthma-related domains of easily measurable clinical variables used for phenotyping were identified: personal (n = 49), functional (n = 48) and clinical (n = 47). The identified asthma phenotypes varied according to the sample’s characteristics, variables included in the model, and data availability. Overall, the most frequent phenotypes were related to atopy, gender, and severe disease. This review shows a large variability of asthma phenotypes derived from data-driven methods. Further research should include more population-based samples and assess longitudinal consistency of data-driven phenotypes.

A Randomized, Noninferiority Trial Comparing ICS + LABA with ICS + LABA + LAMA in Asthma-COPD Overlap (ACO) Treatment: The ACO Treatment with Optimal Medications (ATOMIC) Study

BACKGROUND

Current guidelines for the treatment of asthma and chronic obstructive pulmonary disease overlap (ACO) recommend initial treatment using inhaled corticosteroids (ICSs) plus 1 or more bronchodilators.

OBJECTIVE

To clarify which therapeutic effect is better between the ICS + long-acting β₂ agonist (LABA) and ICS + LABA + long-acting muscarinic antagonist (LAMA) treatment in patients with ACO.

METHODS

We conducted a multicenter, 48-week, randomized, noninferiority trial. Patients with ACO were enrolled if they were treated with a moderate to high dose of ICS + LABA. In total, 303 patients were involved in the present trial, with 149 receiving ICS + LABA + LAMA. The primary end point was the time to first exacerbation. Secondary outcomes included changes in FEV₁, forced vital capacity, FEV₁/forced vital capacity ratio, asthma control, blood eosinophil count, and fractional exhaled nitric oxide.

RESULTS

In the ICS + LABA treatment group, 29 of 154 patients (18.83%) experienced exacerbation, whereas 28 of 149 patients (18.79%) experienced exacerbation in the ICS + LABA + LAMA treatment group. The results of this noninferiority study were ultimately inconclusive (hazard ratio, 1.1; 95% CI, 0.66-1.84). However, the patients treated with the addition of LAMA showed significant improvements in FEV₁ and forced vital capacity (P < .001). Asthma control did not improve in either group.

CONCLUSIONS

Although this study was unable to conclude that ICS + LABA treatment is not inferior to ICS + LABA + LAMA in terms of exacerbation, it is obvious that the ICS + LABA + LAMA treatment group had improved lung function in ACO.

Relationship between age and bronchodilator response at diagnosis in adult-onset asthma

BACKGROUND

Possible variation in bronchodilator response (BDR) according to age at the diagnosis of adult-onset asthma is unknown. Our aim was to assess if BDR in FEV1 is related to age at diagnosis of adult-onset asthma and how many subjects fulfill the 400 mL criterion of BDR, the suggested cut-off for asthma-like reversibility in asthma-COPD overlap (ACO).

METHODS

A total of 1030 patients with adult-onset asthma were included; 245 from SAAS (Seinäjoki Adult Asthma Study, Finland) and 785 from COREA (Cohort for Reality and Evolution of Adult Asthma in Korea) cohorts. BDR in FEV1 at the diagnosis of asthma was assessed. Patients were divided into groups based on age at asthma diagnosis: < 40, 40-59.9, and ≥ 60 years. The cohorts were analyzed separately.

RESULTS

BDR % in FEV1 did not differ between the groups of different age at asthma diagnosis and no correlation between BDR and age was found. Of patients aged ≥40 years, only 18% (SAAS-cohort) and 5% (COREA-cohort) reached the 400 mL BDR in FEV1. After exclusion of possible ACO patients, the results remained similar.

CONCLUSION

By using two large cohorts of steroid-naive patients with asthma, we have shown that BDR at diagnosis of asthma is constant over large age span range, and the limit of 400 mL in BDR in FEV1 is rarely reached.

TRIAL REGISTRATION

Seinäjoki Adult Asthma Study is registered at ClinicalTrials.gov with identifier number NCT02733016 .

Clinical phenotypes and prediction of chronicity in sarcoidosis using cluster analysis in a prospective cohort of 694 patients

BACKGROUND

Sarcoidosis is a heterogeneous disease with high variability in natural history and clinical spectrum. The study aimed to reveal different clinical phenotypes of patients with similar characteristics and prognosis.

METHODS

Cluster analysis including 26 phenotypic variables was performed in a large cohort of 694 sarcoidosis patients, collected and followed-up from 1976 to 2018 at Bellvitge University Hospital, Barcelona, Spain.

RESULTS

Six homogeneous groups were identified after cluster analysis: C1 (n=47; 6.8%), C2 (n=85; 12.2%), C3 (n=153; 22%), C4 (n=29; 4.2%), C5 (n=168; 24.2%), and C6 (n=212; 30.5%). Presence of bilateral hilar lymphadenopathy (BHL) ranged from 65.5% (C4) to 97.9% (C1). Patients with Löfgren syndrome (LS) were distributed across 3 phenotypes (C1, C2, and C3). In contrast, phenotypes with pulmonary (PS) and/or extrapulmonary sarcoidosis (EPS) were represented by groups C4 (PS 100% with no EPS), C5 (PS 88.7% plus EPS), and C6 (EPS). EPS was concentrated in groups C5 (skin lesions, peripheral and abdominal lymph nodes, and hepatosplenic involvement) and C6 (skin lesions, peripheral lymph nodes, and neurological and ocular involvement). Unlike patients from LS groups, most patients with PS and/or EPS were treated with immunosuppressive therapy, and evolved to chronicity in higher proportion. Finally, the cluster model worked moderately well as a predictive model of chronicity (AUC=0.705).

CONCLUSION

Cluster analysis identified 6 different clinical patterns with similar phenotypic variables and predicted chronicity in our large cohort of patients with sarcoidosis. Classification of sarcoidosis into phenotypes with prognostic value may help physicians to improve the efficacy of clinical decisions.