The obese-asthma phenotype in children: An exacerbating situation?

Prevalence and associations between metabolically unhealthy obesity and asthma exacerbations and emergency department usage

BACKGROUND

Th1 cell polarization and monocyte cell activation influence FEV1/FVC and are affected by body mass index (BMI), insulin resistance, and serum lipoproteins. No study has assessed the impact of metabolic syndrome components on asthma symptom control.

OBJECTIVE

We aimed to determine the prevalence of patients with metabolically unhealthy obesity (MUO) and asthma. Our secondary objective was to compare the strength of associations between asthma outcomes in obese patients measured by BMI, waist circumference, and MUO.

METHODS

A cross-sectional analysis of the combined 2011-2016 cycles of NHANES was performed among persons with asthma. MUO was defined as a BMI ≥ 30kg/m 2 and one of the following: increased waist circumference, insulin resistance, low physical activity, hyperlipidemia, or hypertension. Multiple logistic regression models were computed to assess asthma exacerbations and emergency department usage for asthma in patients with metabolically healthy compared to unhealthy obesity.

RESULTS

Among respondents with MUO, 50.09% (n=543; N=17011880) had asthma compared to 7.91% in those with metabolically healthy obesity (n=77; N=2685858). Persons with MUO were significantly more likely to report the use of an emergency department for their asthma symptoms within the past 12 months (OR 3.53; 95%CI 1.54-8.09). Persons with elevated waist circumference were more likely to report asthma exacerbations (OR 1.58; 95%CI 1.09-2.26). No significant difference existed in reported asthma exacerbations or emergency department usage in patients measured by BMI.

CONCLUSION

Metabolically unhealthy obesity is associated with increased emergency department usage for asthma and is better at predicting exacerbations and emergency department usage than BMI alone.

Obesity Is Associated with Sustained Symptomatology and Unique Inflammatory Features in Children with Asthma

BACKGROUND

Obesity complicates the clinical manifestations of asthma in children. However, few studies have examined longitudinal outcomes or markers of systemic inflammation in obese asthmatic children.

OBJECTIVE

We hypothesized that obese children with asthma would have: (1) poorer clinical outcomes over 12 months, (2) decreased responsiveness to systemic corticosteroid administration, (3) greater markers of systemic inflammation, and (4) unique amino acid metabolites associated with oxidative stress.

METHODS

Children 6 to 17 years of age (lean, N = 257; overweight, N = 99; obese, N = 138) completed a baseline visit and follow-up visit at 12 months. Outcome measures included asthma control, quality of life, lung function, and exacerbations. A subset received intramuscular triamcinolone and were re-evaluated at 7(+7) days. Leptin, adiponectin, C-reactive protein, total cholesterol, interleukin (IL)-1β, IL-6, IL-17, interferon gamma, tumor necrosis factor alpha, monocyte-chemoattractant protein-1, and amino acid metabolites were also quantified in plasma as potential biomarkers of outcomes in obese children.

RESULTS

Obesity was associated with more symptoms, poorer quality life, and more exacerbations that persisted over 1 year despite greater medication requirements. Obese children also had minimal clinical improvement in asthma control and lung function after intramuscular triamcinolone. Leptin, C-reactive protein, and amino acid metabolites associated with glutathione synthesis and oxidative stress differed in obese children. Within the obese group, lower concentrations of arginine-related metabolites also distinguished uncontrolled from controlled asthma at 12 months.

CONCLUSION

Obesity is associated with poorer asthma outcomes and unique systemic inflammatory features that may not be adequately modified with conventional asthma therapies. Novel approaches may be needed given increased symptoms and unique inflammation and oxidative stress in obese children with asthma.

Caregivers' perceptions of the relationship among weight, health status, and asthma in their children

Asthma and obesity are the two most common childhood illnesses and are physiologically interrelated. Few studies have assessed parental perceptions and beliefs about this relationship to better target education and therapy. This study aimed to determine caregiver beliefs and perceptions regarding weight, health status, and asthma diagnoses. Data from a survey of caregivers to children aged 4-11 years are merged with corresponding anthropometric and medical data from the electronic medical record. Caregivers of children with asthma completed a supplemental questionnaire. Univariable and multivariable logistic regressions were used to evaluate associations between perception of health problem, asthma, and weight status. Increased weight status was ≥ 85th body mass index percentile per Centers for Disease Control classifications. Compared to caregivers of healthy children and those of children with healthy weight and asthma, caregivers of dual diagnosis children were more likely to identify weight as a health problem (OR = 3.89, 95% confidence interval [1.48, 10.21]). Nevertheless, only 31% of caregivers of children with dual diagnosis believed weight contributed to the severity of their child's asthma. Less than one third of caregivers of dual diagnosis children believed that these diagnoses are interrelated. Addressing this gap in understanding is a critical next step to developing family-centered interventions.

Nonadherence to inhaled corticosteroids: A characteristic of the pediatric obese-asthma phenotype?

BACKGROUND

Children with excess weight and asthma tend to respond less well to inhaled corticosteroids (ICS) than children with normal weight, potentially resulting in nonadherence to ICS.

OBJECTIVES

To assess whether excess weight (body mass index ≥85th percentile) was associated with general, unintentional, and intentional nonadherence to ICS in children with asthma.

METHODS

We analyzed data from 566 children aged 4-13 years with asthma, who used ICS as maintenance therapy, from the cross-sectional Pharmacogenetics of Asthma medication in Children: Medication with Anti-inflammatory effects study. General nonadherence was measured objectively with the proportion of days covered (<50%) and subjectively with the parent-reported Medication Adherence Rating Scale (MARS <21) reflecting parent-reported nonadherent behavior. Unintentional and intentional nonadherence were defined as forgetting to take medication and deliberately changing or skipping doses, respectively, from specific items of the MARS. We performed logistic regression analyses, stratifying estimates by asthma severity and age group.

RESULTS

Excess weight was associated with a trend towards increased odds of parent-reported nonadherent behavior (odds ratio [OR]: 1.54; 95% confidence interval [CI]: 0.84-2.81) and objectively measured general nonadherence, but only in moderate-to-severe asthma (OR: 1.71; 95% CI: 0.84-3.48). The odds of intentional, but not unintentional, nonadherence seemed to be greater in children with excess weight than normal weight (OR: 1.94; 95% CI: 0.94-4.01), and the association appeared to be stronger in younger (OR: 2.17; 95% CI 1.00-4.73) versus older children (OR: 1.18; 95% CI: 0.36-3.94).

CONCLUSIONS

Excess weight was associated with general nonadherence to ICS, but only in children with moderate-to-severe asthma, and nonadherent behavior, which seemed to be intentional.

Contribution of comorbidities to obesity-related asthma in children

Children with obesity are at increased risk for developing asthma that is difficult to control. A complicating factor to asthma management among these children is likely the commonplace co-morbidities that also result from obesity. We discuss three common obesity-related comorbidities which appear to complicate the effective management of asthma, including hypovitaminosis D, obstructive sleep apnea and gastro-esophageal reflux. Each conditions requires more research to understand their effects on asthma management.

Incidence, risk factors and re-exacerbation rate of severe asthma exacerbations in a multinational, multidatabase pediatric cohort study

BACKGROUND

There are sparse real-world data on severe asthma exacerbations (SAE) in children. This multinational cohort study assessed the incidence of and risk factors for SAE and the incidence of asthma-related rehospitalization in children with asthma.

METHODS

Asthma patients 5-17 years old with ≥1 year of follow-up were identified in six European electronic databases from the Netherlands, Italy, the UK, Denmark and Spain in 2008-2013. Asthma was defined as ≥1 asthma-specific disease code within 3 months of prescriptions/dispensing of asthma medication. Severe asthma was defined as high-dosed inhaled corticosteroids plus a second controller. SAE was defined by systemic corticosteroids, emergency department visit and/or hospitalization all for reason of asthma. Risk factors for SAE were estimated by Poisson regression analyses.

RESULTS

The cohort consisted of 212 060 paediatric asthma patients contributing to 678 625 patient-years (PY). SAE rates ranged between 17 and 198/1000 PY and were higher in severe asthma and highest in severe asthma patients with a history of exacerbations. Prior SAE (incidence rate ratio 3-45) and younger age increased the SAE risk in all countries, whereas obesity, atopy and GERD were a risk factor in some but not all countries. Rehospitalization rates were up to 79% within 1 year.

CONCLUSIONS

In a real-world setting, SAE rates were highest in children with severe asthma with a history of exacerbations. Many severe asthma patients were rehospitalized within 1 year. Asthma management focusing on prevention of SAE is important to reduce the burden of asthma.

Overweight Proxies Are Associated with Atopic Asthma: A Matched Case-Control Study

BACKGROUND

Many studies have documented a link between overweight and asthma in children with contradictory results regarding the best way to measure overweight. Moreover, often, the dynamic development of atopy, overweight, and asthma is controlled for age dependency insufficiently.

OBJECTIVE

This study assesses and compares the associations of overweight measured as waist circumference, waist to height ratio (WHtR), neck circumference, and body mass index with the occurrence of asthma - best possibly controlling for age-dependencies of these parameters.

METHODS

From a sample of 2,511 children aged 6-17 years, we matched 157 children with asthma with 2 controls (n = 471) according to age and atopy status and performed conditional logistic regression analyses. We further investigated the role of known influencing factors of asthma occurrence.

RESULTS

In children with atopy, all overweight proxies were consistently positively associated with asthma. Statistical significance was reached for WHtR-SD score (OR 1.26, 95% CI 1.03-1.54, p = 0.025) and persisted when further covariates, such as birth weight or social status, were added to the model. Groups of atopic versus nonatopic participants do not differ in levels of interleukin-6 or high-sensitivity C-reactive protein.

CONCLUSION

In our cohort, overweight seems to carry a risk for asthma only if accompanied with atopy. We call for more strict age matching in pediatric cohort studies and longitudinal studies for a better understanding for causal links of overweight, atopy, and asthma.

[Asthma and obesity in adults]

Asthma is a chronic inflammatory airway disorder characterized by a multitude of phenotypes. Epidemiological studies show an increase in asthma prevalence in obese patients regardless of age. The association of asthma and obesity is now considered as a phenotype with its own clinical, biological and functional characteristics. Regarding the pathophysiology of asthma and obesity, numerous factors such as nutrition, genetic predisposition, microbiome, ventilatory mechanics and the role of adipose tissue have been identified to explain the heterogeneous characteristics of patients with asthma and obesity. In adult patients with asthma and obesity, respiratory symptoms are particularly prominent and atopy and eosinophilic inflammation is uncommon compared to normal weight asthma patients. Obese asthma patients experience more hospitalizations and use more rescue medications than normal weight asthmatics. Management of asthma in obese patients is complex because these patients have less response to the usual anti-asthmatic treatments. Weight loss through caloric restriction combined with exercise is the main intervention to obtain improvement of asthma outcomes. Bariatric surgery is an invasive procedure with interesting results.

Inhibiting the Notch signaling pathway suppresses Th17-associated airway hyperresponsiveness in obese asthmatic mice

Notch signaling is crucial for the regulation of asthma and obesity. The interleukin (IL)-17-expressing CD4⁺ T cell (Th17 cell) response and airway hyperresponsiveness (AHR) are critical features of both asthma and obesity. We previously demonstrated that inhibiting the Notch signaling pathway alleviates the Th17 response in a mouse model of asthma. However, obese asthmatic individuals show increased Th17 responses and AHR, with the underlying mechanism not currently understood. We aimed to assess the function of Notch signaling in obese mice with asthma and to determine the impact of a γ-secretase inhibitor (GSI), which inhibits the Notch signaling pathway, on the regulation of the Th17 response and AHR. C57BL/6 mice were administered ovalbumin (OVA) to induce asthma, while a high-fat diet (HFD) was used to induce mouse diet-induced obesity (DIO). GSI was then administered intranasally for 7 days in DIO-OVA-induced mice. The results showed increased Notch1 and hes family bHLH transcription factor 1 (Hes1) mRNA levels and Notch receptor intracellular domain (NICD) protein levels in obese asthmatic mice. Furthermore, these mice showed an increased proportion of Th17 cells, serum IL-17A, IL-6, and IL-1β levels, mucin 5AC (MUC5AC) mRNA level, retinoic acid-related orphan receptor-γt (RORγt) mRNA and protein levels, and increased AHR severity. Interestingly, GSI treatment resulted in reduced Notch1 and Hes1 mRNA and NICD protein levels in DIO-OVA-induced mice, with a decreased Th17 cell proportion and IL-17A quantity and alleviated AHR. These data strongly indicate that the Notch pathway is critical in obese asthmatic mice. In addition, inhibiting the Notch pathway ameliorates AHR and the Th17 response in obese mice with asthma.

ERS/EAACI statement on severe exacerbations in asthma in adults: facts, priorities and key research questions

Despite the use of effective medications to control asthma, severe exacerbations in asthma are still a major health risk and require urgent action on the part of the patient and physician to prevent serious outcomes such as hospitalisation or death. Moreover, severe exacerbations are associated with substantial healthcare costs and psychological burden, including anxiety and fear for patients and their families. The European Academy of Allergy and Clinical Immunology (EAACI) and the European Respiratory Society (ERS) set up a task force to search for a clear definition of severe exacerbations, and to also define research questions and priorities. The statement includes comments from patients who were members of the task force.

[Obesity in childhood: What are the respiratory risks?]

In childhood and adolescence overweight is defined as a body mass index (BMI) above the 97th percentile for age and sex, according to the curves established by the International Obesity Task Force (IOTF). In France, it is estimated that 25 % of children under 18 years old are overweight. Overweight and obesity in this population are multifactorial, with an important influence of genetic factors, modulated by pre and post-natal (maternal smoking), societal and psychological determinants. The impact of obesity on respiratory function in children is mostly characterized by a decreased FEV1/FCV. Moreover, several studies have shown an association between asthma and overweight/obesity, with a pejorative impact of BMI on asthma control. However, asthma is still poorly characterized in this population, and the determinants of bronchial obstruction seem to differ from non-obese children, with less eosinophilic inflammation. Obstructive sleep apnea syndrome (OSAS) is a frequent complication of obesity, affecting up to 80% of obese children and adolescents. It has a specific polysomnographic definition in children. Symptoms are similar to adult OSAS, but with cognitive and neurobehavioral alterations often more important in adolescents. The treatment consists in ENT surgery when indicated (with systematic post-operative polysomnography), and nocturnal continuous positive airway pressure (CPAP). The obesity-hypoventilation syndrome (OHS) has the same definition in children as in adults and affects up to 20% of obese patients. Treatment consists in nocturnal ventilation using bilevel positive airway pressure (BiPAP). Finally, in some extreme cases, bariatric surgery can be performed. The indication should be discussed in a specialised paediatric reference centre.

Influence of weight status in the response to Step-2 maintenance therapies in children with asthma

Introduction

Overweight children with asthma may display impaired response to inhaled corticosteroids (ICS), possibly due to non-eosinophilic inflammation or weight-related lung compression; these mechanisms may differentially affect response to ICS and leukotriene receptor antagonists (LTRAs). We assessed whether weight status modified the response to low-dose ICS and LTRA Step-2 monotherapy.

Methods

A historical cohort study from clinical data linked to administrative databases was conducted among children aged 2–18 years with specialist-diagnosed asthma who were initiating or continuing a Step-2 monotherapy from 2000 to 2007 at the Montreal Children’s Hospital Asthma Centre. The outcome was time-to-management failure defined as any step-up in therapy, acute care visit, hospitalisation or oral corticosteroids for asthma, whichever occurred first. The independent and joint effects of weight status (body mass index [BMI] percentile) and time-varying treatment on time-to-management failure were estimated with marginal structural Cox models. The likelihood ratio test (LRT) and relative excess risk due to interaction (RERI) were computed to assess treatment effect modification by weight status on the multiplicative and additive scales.

Results

Of the 433 and 85 visits with a low-dose ICS and LTRA prescription, respectively, 388 management failures occurred over 14 529 visit-weeks of follow-up. Children using LTRA compared with low-dose ICS tended to have an overall higher risk of early management failure (HR 1.52; 95% CI 0.72 to 3.22). Irrespective of treatment, the hazard of management failure increased by 5% (HR 1.05; 95% CI 1.01 to 1.10) for every 10-unit increase in BMI percentile. An additional hazard reduction of 17% (HR 0.83; 95% CI 0.70 to 0.99) was observed for every 10-unit increase in BMI percentile among LTRA users, but not for ICS (HR 0.95; 95% CI 0.86 to 1.04). The LRT indicated a departure from exact multiplicativity (p<0.0001), and the RERIs for ICS and LTRA were −0.05 (95% CI −0.14 to 0.05) and −0.52 (95% CI −1.76 to 0.71).

Conclusions

Weight status was associated with earlier time-to-management failure in children prescribed Step-2 therapy. This hypothesis-generating study suggests that LTRA response increases in children with higher BMI percentiles, although further research is warranted to confirm findings.

Weight status and nonadherence to asthma maintenance therapy among children enrolled in a public drug insurance plan

Objective: The pediatric obese-asthma phenotype is associated with poor control, perhaps because of medication nonadherence. This study aimed to assess whether weight status is associated with nonadherence in children prescribed new asthma maintenance therapies.Methods: A historical cohort was constructed from a clinical database linking individual patient and prescription data to Quebec's prescription claims registry. Children aged 2-18 years with specialist-diagnosed asthma who were newly prescribed one of the following maintenance controllers: leukotriene receptor antagonists (LTRA); low-dose inhaled corticosteroids (ICS); medium/high-dose ICS; or combination therapy (ICS with long-acting beta-2 agonists and/or LTRA), at the Asthma Center of the Montreal Children's Hospital from 2000-2007 were included. Primary nonadherence was defined as not claiming any prescriptions, whereas secondary nonadherence was measured with the proportion of prescribed days covered (PPDC ≤ 50%) among primary adherers over a 6-month follow-up period. A modified Poisson regression model served to estimate the effect of excess weight (BMI > 85^th percentile) on primary and secondary nonadherence.Results: Approximately one third of patients were primary nonadherers and 60% took less than 50% of prescribed therapy. Excess weight was associated with a trend toward increased risk of primary nonadherence in children newly prescribed low-dose ICS (RR 1.53, 95%CI 0.94-2.49), and of secondary nonadherence in children initiating medium/high-dose ICS (RR 1.24; 95%CI 0.98-1.59).Conclusions: Excess weight status is a possible determinant of primary nonadherence in children initiating low-dose ICS and secondary nonadherence to higher-dose ICS regimens. This hypothesis-generating study suggests that nonadherence may be a potential contributor to higher morbidity in children with obese-asthma.

Can asthma be well controlled with NAEPP guideline care in morbidly obese children? The Breathmobile

BACKGROUND

Obesity is thought to be associated with poor asthma control, increased health resource utilization, and reduced responsiveness to inhaled corticosteroids.

OBJECTIVE

Based on previous experience, our hypothesis was that by improved access to comprehensive guideline care, outcomes in normal weight would be comparable in obese children with asthma.

METHODS

This was a retrospective cohort study of predominately Hispanic children (3-18 years of age) in underserved areas of Orange County, California, who enrolled in the Breathmobile Program from 2003 to 2012. Outcomes were examined by using Cox regression and generalized estimating equations analyses, adjusted for potential confounding factors.

RESULTS

Clinical outcomes in more than 1,200 children followed up for a mean of 6 visits (standard deviation [SD] = 2.2) across 403 days (SD = 112) were improved, on average, regardless of body mass index (BMI). Morbidly obese (MOB) patients were able to achieve significant reductions of approximately 60% or more in report of emergency department (ED) visits, hospitalizations, school absenteeism, usual exercise limitations, and exacerbations to levels that were comparable those of normal weight (NW) patients. The importance of close follow-up, particularly for the MOB patient, was evidenced by achieving 80% cumulative probability of well controlled asthma by visit 3, similar to patients in lower BMI risk groups with good adherence, when the visit interval did not exceed 90 days. These outcomes were achieved across all BMI groups with similar mean step of therapy, adjusted for severity (P < .001).

CONCLUSION

Access to effective community-based care where trust, education, and continuity of care consistent with National Asthma Education and Prevention Program (NAEPP) guidelines is possible, as demonstrated by the Breathmobile Program, can provide an opportunity for children with asthma in all BMI categories to achieve well-controlled disease.