Distinct Phenotypes of Cigarette Smokers Identified by Cluster Analysis of Patients with Severe Asthma

Living in environmental justice areas worsens asthma severity and control: Differential interactions with disease duration, age at onset, and pollution

BACKGROUND

Impoverished and historically marginalized communities often reside in areas with increased air pollution.

OBJECTIVE

We evaluated the association between environmental justice (EJ) track and asthma severity and control as modified by traffic-related air pollution (TRAP).

METHODS

We performed a retrospective study of 1526 adult asthma patients in Allegheny County, Pa, enrolled in an asthma registry during 2007-20. Asthma severity and control were determined using global guidelines. EJ tract designation was based on residency in census tracts with ≥30% non-White and/or ≥20% impoverished populations. TRAP exposures (NO2 and black carbon) for each census tract were normalized into pollution quartiles. Generalized linear model analyses determined the effect of EJ tract and TRAP on asthma.

RESULTS

TRAP exposure in the highest quartile range was more frequent among patients living in an EJ tract (66.4% vs 20.8%, P < .05). Living in an EJ tract increased the odds of severe asthma in later onset asthma. The odds of uncontrolled asthma increased with disease duration in all patients living in EJ tracts (P < .05). Living in the highest quartile of NO2 also increased the odds of uncontrolled asthma in patients with severe disease (P < .05), while there was no effect of TRAP on uncontrolled asthma in patients with less severe disease (P > .05).

CONCLUSIONS

Living in an EJ tract increased the odds of severe and uncontrolled asthma and was influenced by age at onset, disease duration, and potentially by TRAP exposure. This study underscores the need to better understand the complex environmental interactions that affect lung health in groups that have been economically and/or socially marginalized.

Advanced Biomarkers of Hepatotoxicity in Psychiatry: A Narrative Review and Recommendations for New Psychoactive Substances

One of the factors that increase the effectiveness of the pharmacotherapy used in patients abusing various types of new psychoactive substances (NPSs) is the proper functioning of the liver. However, the articles published to date on NPS hepatotoxicity only address non-specific hepatic parameters. The aim of this manuscript was to review three advanced markers of hepatotoxicity in psychiatry, namely, osteopontin (OPN), high-mobility group box 1 protein (HMGB1) and glutathione dehydrogenase (GDH, GLDH), and, on this basis, to identify recommendations that should be included in future studies in patients abusing NPSs. This will make it possible to determine whether NPSs do indeed have a hepatotoxic effect or whether other factors, such as additional substances taken or hepatitis C virus (HCV) infection, are responsible. NPS abusers are at particular risk of HCV infection, and for this reason, it is all the more important to determine what factors actually show a hepatotoxic effect in them.

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.

Eosinophils from Physiology to Disease: A Comprehensive Review

Despite being the second least represented granulocyte subpopulation in the circulating blood, eosinophils are receiving a growing interest from the scientific community, due to their complex pathophysiological role in a broad range of local and systemic inflammatory diseases as well as in cancer and thrombosis. Eosinophils are crucial for the control of parasitic infections, but increasing evidence suggests that they are also involved in vital defensive tasks against bacterial and viral pathogens including HIV. On the other side of the coin, eosinophil potential to provide a strong defensive response against invading microbes through the release of a large array of compounds can prove toxic to the host tissues and dysregulate haemostasis. Increasing knowledge of eosinophil biological behaviour is leading to major changes in established paradigms for the classification and diagnosis of several allergic and autoimmune diseases and has paved the way to a "golden age" of eosinophil-targeted agents. In this review, we provide a comprehensive update on the pathophysiological role of eosinophils in host defence, inflammation, and cancer and discuss potential clinical implications in light of recent therapeutic advances.

Allergic bronchopulmonary aspergillosis in Japan: A nationwide survey

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic pulmonary disease characterized by a hypersensitivity reaction to Aspergillus species colonizing the airways. The clinical characteristics of ABPA may differ depending on genetic and environmental background. We performed a nationwide survey to determine the clinical characteristics of ABPA in Japan.

METHODS

In 2013, a questionnaire on physician-diagnosed ABPA/allergic bronchopulmonary mycosis was sent to 903 medical centers specializing in respiratory or allergic diseases. Cases fulfilling the following criteria were categorized as possible ABPA-central bronchiectasis (ABPA-CB): 1) presence of specific serum immunoglobulin E (IgE) antibodies or a positive skin reaction to Aspergillus, and 2) bronchiectasis or mucoid impaction in the central bronchi.

RESULTS

Of 499 physician-diagnosed cases reported by 132 clinical centers, 358 cases met the criteria for possible ABPA-CB. Median age of ABPA-CB onset was 57 (interquartile range, 44-68) years; later-onset disease, developing ≥50 years of age, accounted for 66% of the cases and was associated with female sex, delayed onset of asthma, and lower levels of serum IgE. A third of the patients (120 patients, 34%) exhibited low levels of serum total IgE (<1000 IU/mL). Aspergillus species were isolated from sputum in 126/213 cases (59%), and Schizophyllum commune was identified in 12 (6%) patients. During the course of the treatment, ABPA recurred in 169 (48%) cases.

CONCLUSIONS

This nationwide survey identified several unique clinical characteristics of ABPA in Japan, such as late-onset, relatively lower serum IgE levels, and frequent recurrences/flares.

Biomarkers in Severe Asthma

Biomarkers have been critical for studies of disease pathogenesis and the development of new therapies in severe asthma. In particular, biomarkers of type 2 inflammation have proven valuable for endotyping and targeting new biological agents. Because of these successes in understanding and marking type 2 inflammation, lack of knowledge regarding non-type 2 inflammatory mechanisms in asthma will soon be the major obstacle to the development of new treatments and management strategies in severe asthma. Biomarkers can play a role in these investigations as well by providing insight into the underlying biology in human studies of patients with severe asthma.

Identifying Distinct Subgroups of ICU Patients: A Machine Learning Approach

OBJECTIVES

Identifying subgroups of ICU patients with similar clinical needs and trajectories may provide a framework for more efficient ICU care through the design of care platforms tailored around patients' shared needs. However, objective methods for identifying these ICU patient subgroups are lacking. We used a machine learning approach to empirically identify ICU patient subgroups through clustering analysis and evaluate whether these groups might represent appropriate targets for care redesign efforts.

DESIGN

We performed clustering analysis using data from patients' hospital stays to retrospectively identify patient subgroups from a large, heterogeneous ICU population.

SETTING

Kaiser Permanente Northern California, a healthcare delivery system serving 3.9 million members.

PATIENTS

ICU patients 18 years old or older with an ICU admission between January 1, 2012, and December 31, 2012, at one of 21 Kaiser Permanente Northern California hospitals.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We used clustering analysis to identify putative clusters among 5,000 patients randomly selected from 24,884 ICU patients. To assess cluster validity, we evaluated the distribution and frequency of patient characteristics and the need for invasive therapies. We then applied a classifier built from the sample cohort to the remaining 19,884 patients to compare the derivation and validation clusters. Clustering analysis successfully identified six clinically recognizable subgroups that differed significantly in all baseline characteristics and clinical trajectories, despite sharing common diagnoses. In the validation cohort, the proportion of patients assigned to each cluster was similar and demonstrated significant differences across clusters for all variables.

CONCLUSIONS

A machine learning approach revealed important differences between empirically derived subgroups of ICU patients that are not typically revealed by admitting diagnosis or severity of illness alone. Similar data-driven approaches may provide a framework for future organizational innovations in ICU care tailored around patients' shared needs.

Targeting patients with asthma for omalizumab therapy: choosing the right patient to get the best value for money

The asthma syndrome has many manifestations, termed phenotypes, that arise by specific cellular and molecular mechanisms, termed endotypes. Understanding an individual's asthma phenotype helps clinicians make rational therapeutic decisions while the understanding of endotypes has led to the development of specific precision medications. Allergic asthma is an example of an asthma phenotype and omalizumab, a monoclonal antibody that neutralizes serum immunoglobulin (Ig)E, is a specific targeted treatment which was developed as a result of an understanding of the endotype of allergic asthma. Omalizumab has been widely used in clinical practice in Europe for over a decade as an add-on therapy to treat patients who have severe refractory allergic asthma. Over this period, many centres have reported their experience with omalizumab as an add-on therapy in patients with severe asthma. These 'real world' clinical effectiveness studies have confirmed the benefits, cost-effectiveness and clinical utility of this medication. Combining the outcomes of both sources of research has yielded important insights that may benefit patients with severe asthma, clinicians who treat them, as well as the funding agencies that reimburse the cost of this medication. The purpose of this review is to describe how to identify and evaluate a patient with asthma for whom treatment with omalizumab may be of clinical and cost-effective benefit. The assessment and investigations used to confirm allergic asthma, the objective assessment of adherence to asthma therapy and the expected benefits of add-on omalizumab treatment are described.

Blood Eosinophil Count and Outcomes in Severe Uncontrolled Asthma: A Prospective Study

BACKGROUND

Severe uncontrolled asthma (SUA) is associated with increased asthma exacerbations. Whether high blood eosinophil counts are related to this burden is uncertain.

OBJECTIVES

To determine the relationship of blood eosinophil counts to asthma exacerbations, utilization, and cost in patients with SUA.

METHODS

Patients with persistent asthma (age ≥ 12 years) were identified administratively with SUA in phase I by evidencing (1) 2 or more asthma exacerbations; (2) 6 or more medium- or high-dose dispensed canisters of inhaled corticosteroid (ICS) as monotherapy or with long-acting β₂-agonist; and (3) 3 or more dispensed non-ICS controllers. Of the 541 patients with SUA invited to participate in the prospective phase II follow-up study, 261 (48.2%) had blood tests (index date) to determine eosinophil count and other atopic biomarkers. The relationship of blood eosinophil cutoff points to asthma exacerbations and direct costs 1 year after the index date were determined by multivariable regression.

RESULTS

A blood eosinophil cutoff point of greater than or equal to 400 cells/mm³ compared with less than 400 cells/mm³, but not 150 cells/mm³ or 300 cells/mm³, was a risk factor in the outcome year in adjusted analyses for 2 or more asthma exacerbations (risk ratio, 1.55; 95% CI, 1.02-2.35; P =.04) and any asthma emergency department visit or hospitalization (risk ratio, 2.29; 95% CI, 1.16-4.55; P =.02), but not for rate of asthma exacerbations or incremental total direct asthma costs per patient ($202; 95% CI, -286 to 691).

CONCLUSIONS

A high blood eosinophil count was an independent risk factor for 2 or more asthma exacerbations or any asthma emergency department visit or hospitalization, but not direct costs in patients with SUA, possibly constrained by limited power.

Severe or life-threatening asthma exacerbation: patient heterogeneity identified by cluster analysis

BACKGROUND

Severe or life-threatening asthma exacerbation is one of the worst outcomes of asthma because of the risk of death. To date, few studies have explored the potential heterogeneity of this condition.

OBJECTIVES

To examine the clinical characteristics and heterogeneity of patients with severe or life-threatening asthma exacerbation.

METHODS

This was a multicentre, prospective study of patients with severe or life-threatening asthma exacerbation and pulse oxygen saturation < 90% who were admitted to 17 institutions across Japan. Cluster analysis was performed using variables from patient- and physician-orientated structured questionnaires.

RESULTS

Analysis of data from 175 patients with severe or life-threatening asthma exacerbation revealed five distinct clusters. Cluster 1 (n = 27) was younger-onset asthma with severe symptoms at baseline, including limitation of activities, a higher frequency of treatment with oral corticosteroids and short-acting beta-agonists, and a higher frequency of asthma hospitalizations in the past year. Cluster 2 (n = 35) was predominantly composed of elderly females, with the highest frequency of comorbid, chronic hyperplastic rhinosinusitis/nasal polyposis, and a long disease duration. Cluster 3 (n = 40) was allergic asthma without inhaled corticosteroid use at baseline. Patients in this cluster had a higher frequency of atopy, including allergic rhinitis and furred pet hypersensitivity, and a better prognosis during hospitalization compared with the other clusters. Cluster 4 (n = 34) was characterized by elderly males with concomitant chronic obstructive pulmonary disease (COPD). Although cluster 5 (n = 39) had very mild symptoms at baseline according to the patient questionnaires, 41% had previously been hospitalized for asthma.

CONCLUSIONS & CLINICAL RELEVANCE

This study demonstrated that significant heterogeneity exists among patients with severe or life-threatening asthma exacerbation. Differences were observed in the severity of asthma symptoms and use of inhaled corticosteroids at baseline, and the presence of comorbid COPD. These findings may contribute to a deeper understanding and better management of this patient population.