Does higher body mass index contribute to worse asthma control in an urban population?

Asthma medication use in obese and healthy weight asthma: systematic review/meta-analysis

BACKGROUND

Obesity is a common comorbidity in asthma and associated with poorer asthma control, more frequent/severe exacerbations, and reduced response to asthma pharmacotherapy.

OBJECTIVE

This review aims to compare use of all classes of asthma medications in obese (body mass index (BMI) ≤30 kg·m^-2) versus healthy-weight (BMI <25 kg·m^-2) subjects with asthma.

DESIGN

Databases including CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase and MEDLINE were searched up to July 2019 for English-language studies that recorded medication use or dose in obese and healthy-weight adults with asthma. A critical appraisal checklist was utilised for scrutinising methodological quality of eligible studies. Meta-analysis was performed and heterogeneity was examined with the use of the Chi-squared test. This review was conducted based on a published protocol (www.crd.york.ac.uk/PROSPERO CRD42020148671).

RESULTS

Meta-analysis showed that obese subjects are more likely to use asthma medications, including short-acting β₂-agonists (OR 1.75, 95% CI 1.17-2.60; p=0.006, I²=41%) and maintenance oral corticosteroids (OR 1.86, 95% CI 1.49-2.31; p<0.001, I²=0%) compared to healthy-weight subjects. Inhaled corticosteroid (ICS) dose (µg·day^-1) was significantly higher in obese subjects (mean difference 208.14, 95% CI 107.01-309.27; p<0.001, I²=74%). Forced expiratory volume in 1 s (FEV₁) % predicted was significantly lower in obese subjects (mean difference -5.32%, 95% CI -6.75--3.89; p<0.001, I²=42%); however, no significant differences were observed in FEV₁/forced vital capacity (FVC) ratio between groups.

CONCLUSIONS

We found that obese subjects with asthma have higher use of all included asthma medication classes and higher ICS doses than healthy-weight asthma subjects, despite lower FEV₁ and a similar FEV₁/FVC %. A better understanding of the factors driving increased medication use is required to improve outcomes in this subgroup of asthmatics.

Association of obesity with severity outcomes in hospitalized pediatric asthma exacerbations

INTRODUCTION

While there seems to be an association between obesity and asthma, the exact nature of the relationship remains unknown. It is unclear if there is increased severity of exacerbation for those that require hospitalization. We examine the association between obesity and severity outcomes such as hospital length of stay, intensive care admissions, and need for continuous albuterol or magnesium administration.

METHODS

Patients 4 to 17 years old admitted between 1/1/2012-1/1/2016 with asthma identified by discharge codes were reviewed. Obesity was defined as BMI ≥95%. Clinical data such as age, gender, family history of asthma, use of controller medication along with outcome data such as length of stay, ICU admission, use of continuous albuterol, and use of magnesium were collected. Binary outcomes were analyzed with multivariate logistic regression while length of stay was analyzed with negative binomial regression.

RESULTS

Overall, 995 patients met inclusion criteria. The median age was 7 years old with 170 (17%) patients categorized as obese. We find no difference in length of stay (IRR 0.99 [0.91, 1.09], p = 0.9), PICU admission (OR 0.72 [0.43, 1.21], p = 0.22), or magnesium administration (OR 1.34 [0.95, 1.88], p = 0.09) between obese and non-obese patients. There were increased odds of continuous albuterol use (OR 1.47 [1.02, 2.11]) for obese patients.

CONCLUSION

We find no association between obesity and outcomes of length of stay, ICU admission, or magnesium administration. While growing evidence links obesity with asthma, our study suggests it may not be associated with the severity of exacerbation.

Evaluation of a Multidisciplinary Disease Management Program to Achieve Asthma Control in Seven Safety Net Hospitals in Louisiana

The objective was to evaluate a multidisciplinary guideline-driven disease management program focused on achievement of asthma control among sustained patients with confirmed asthma in Louisiana and to assess factors affecting achievement of asthma control. Data were extracted from the electronic health records of 1596 adults with confirmed asthma, sustained care for >1 year in the outpatient setting, and ≥2 recorded Asthma Control Test (ACT) scores. Multivariable logistic regression modeling was used to assess the association of demographic variables, comorbidities, and process measures with the best achieved asthma control as represented by the highest ACT score. Most subjects were female (81.1%) and African American (63.9%). Approximately half of them (48.9%) were able to achieve asthma control (ACT ≥20). The most prevalent comorbidities were hypertension (79.8%), rhinitis (55.3%), and obesity (50.5%). Most patients received pulmonary function testing (PFT) (88.6%), controller medication therapy (85.5%), or written asthma action plans (92.7%). Asthma control was positively associated with presence of PFT (OR = 1.63, 95% CI: 1.13, 2.37) and being a "never" smoker (OR = 1.49, 95% CI: 1.08, 2.04). Asthma control was less likely to be achieved by patients who were African American (OR = 0.68, 95% CI: 0.52, 0.87), had more comorbidities (OR = 0.89, 95% CI: 0.83, 0.96), or were on more medications (OR = 0.79, 95% CI: 0.72, 0.88). Asthma control was achieved in 48.9% of an adult, primarily African American population with the implementation of comprehensive guideline-driven care. Furthermore, this is the first study to observe that the presence of PFT may be associated with asthma control.

Obesity Does Not Increase the Risk of Asthma Readmissions

The relationship between obesity and asthma exacerbations is still under debate. The aim of our work is to analyse the relationship between obesity and hospital re-admissions in asthmatics. A review was retrospectively performed on all hospital admissions of adult patients due to asthma exacerbation occurring in our hospital for 11 years. All those cases with asthma as the first diagnosis in the discharge report were included, or those with asthma as the second diagnosis provided when the first diagnosis was respiratory infection or respiratory failure. Only the first hospital admission of each patient was included in this study. The Odds Ratios of a higher incidence of early/late readmissions due to asthma exacerbation were calculated using a binary logistic regression, using the body mass index (BMI) as independent variable, adjusted for all the variables included in the study. The study included 809 patients with a mean age of 55.6 years, and 65.2% were female. The majority (71.4%) were obese or overweight. No significant relationship was observed in the univariate or multivariate analyses between overweight or obesity and the early or late hospital readmissions due to asthma. Therefore, obesity does not seem to be a determining factor in the risk of asthma exacerbations.

Obesity and asthma: clinical and laboratory characterization of a common combination

OBJECTIVE

To evaluate the relationship between obesity and asthma.

METHODS

This was a preliminary cross-sectional analysis involving 925 subjects with mild-to-moderate or severe asthma evaluated between 2013 and 2015. Obesity was defined on the basis of body mass index (BMI) and abdominal circumference. We collected clinical, laboratory, and anthropometric parameters, as well as pulmonary function test results and data regarding comorbidities. The subjects also completed asthma control and quality of life questionnaires.

RESULTS

Obese individuals had a significantly higher number of neutrophils in peripheral blood than did nonobese individuals (p = 0.01). Among the obese individuals, 163 (61%) had positive skin-prick test results, as did 69% and 71% of the individuals classified as being overweight or normal weight, respectively. Obese individuals showed lower spirometric values than did nonobese individuals, and 32% of the obese individuals had uncontrolled asthma, a significantly higher proportion than that found in the other groups (p = 0.02).

CONCLUSIONS

Obese individuals with asthma seem to present with poorer asthma control and lower pulmonary function values than do nonobese individuals. The proportion of subjects with nonatopic asthma was higher in the obese group. Our results suggest that obese individuals with asthma show a distinct inflammatory pattern and are more likely to present with difficult-to-control asthma than are nonobese individuals.

Baseline asthma burden, comorbidities, and biomarkers in omalizumab-treated patients in PROSPERO

BACKGROUND

Patients included in clinical trials do not necessarily reflect the real-world population.

OBJECTIVE

To understand the characteristics, including disease and comorbidity burden, of patients with asthma receiving omalizumab in a real-world setting.

METHODS

The Prospective Observational Study to Evaluate Predictors of Clinical Effectiveness in Response to Omalizumab (PROSPERO) was a US-based, multicenter, single-arm, and prospective study. Patients (≥12 years of age) with allergic asthma initiating omalizumab treatment based on physician-assessed need were included and followed for 12 months. Exacerbations, health care use, adverse events, and Asthma Control Test (ACT) scores were assessed monthly. Biomarkers (blood eosinophils, fractional exhaled nitric oxide, and periostin) were evaluated and patient-reported outcomes (Asthma Quality of Life Questionnaire for 12 Years and Older [AQLQ+12] and Work Productivity and Activity Impairment: Asthma questionnaire [WPAI:Asthma]) were completed at baseline and months 6 and 12. The Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) was completed at baseline and 12 months.

RESULTS

Most of the 806 enrollees (91.4%) were adults (mean age 47.3 years, SD 17.4), white (70.3%), and female (63.5%). Allergic comorbidity was frequently reported (84.2%), as were hypertension (35.5%) and depression (22.1%). In the 12 months before study entry, 22.1% of patients reported at least 1 asthma-related hospitalization, 60.7% reported at least 2 exacerbations, and 83.3% reported ACT scores no higher than 19 (uncontrolled asthma). Most patients had low biomarker levels based on prespecified cut-points. Baseline mean patient-reported outcome scores were 4.0 (SD 1.4) for AQLQ+12, 2.7 (SD 1.4) for MiniRQLQ, and 47.7 (SD 28.9) for WPAI:Asthma percentage of activity impairment and 33.5 (SD 28.7) for percentage of overall work impairment.

CONCLUSION

The population initiating omalizumab in PROSPERO reported poorly controlled asthma and a substantial disease burden.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01922037.

Association of obesity and severity of acute asthma exacerbations in Filipino children

BACKGROUND

Increased body mass index (BMI) may be a risk factor for the development and severity of asthma. However, the effect of obesity on asthma exacerbations is unclear.

OBJECTIVE

To examine the association of obesity and the severity of acute asthma exacerbations.

METHODS

A retrospective cohort of children aged 5 to 18 years who were seen in the emergency department and admitted for acute asthma exacerbation from 2009 to 2011 was reviewed. Weight and height data to compute the BMI were taken from the medical record review. The Centers for Disease Control and Prevention BMI-for-age growth charts for boys and girls aged 2 to 20 years were used to classify underweight, normal, overweight, and obese. Severity of asthma exacerbations into mild, moderate, or severe was determined using criteria by the Global Initiative for Asthma 2010. The χ(2) test of association or the Fisher exact probability test for small samples was used to determine the association between nutritional status and severity of asthma exacerbations.

RESULTS

Of the 303 cases reviewed, most were boys with a mean (SD) age of 10 (3.8) years. The prevalence of overweight and obese children admitted for acute asthma exacerbation was 21% and 28%, respectively. No significant difference was found in the severity of asthma exacerbations, with 82.9% of the nonobese group and 86.8% of the overweight-obese group having moderate-to-severe exacerbation (likelihood ratio, 0.879; 95% CI, 0.42-0.41; P = .88).

CONCLUSION

Our findings suggest that the severity of acute asthma exacerbations was not affected by increased BMI.

Clinical characteristics of asthmatic patients with influenza-like illness and risk of severe exacerbations in Mexico

BACKGROUND

Patients with chronic inflammatory lung diseases, such as asthma, are at higher risk for influenza-like illness (ILI) complications. Viral infections are known to trigger asthma exacerbations, but a thorough description of the clinical characteristics of ILI-associated asthma exacerbations and the role of viruses as a risk factor for severe exacerbation (SE) in ILI has not been published yet.

OBJECTIVE

To investigate risk factors for SE in patients with ILI and asthma.

METHODS

Patients with ILI symptoms were recruited from 6 hospitals of Mexico (LaRed sites) during 2010 to 2014. Those with a previous asthma diagnosis and ILI symptoms and who were 5 years or older were included. Patients were assigned as cases or controls based on symptoms reported. SE was defined when participants presented with wheezing or dyspnea and required hospitalization.

RESULTS

A total of 486 patients with ILI and a diagnosis of asthma were included. There were no differences in the proportion, number, or type of viral illness among those with and without SE. Those with SE were less likely to report ILI symptoms. Muscle pain and nasal drip were predictors for patients not progressing to SE. A delay in seeking medical care was associated with SE (odds ratio, 2.93; 95% CI, 1.46-5.88).

CONCLUSION

The presence of a particular virus did not predict SE. ILI symptoms in asthma patients are not associated with severe exacerbation. Patients with asthma should be encouraged to seek early medical care when ILI symptoms are first noticed to prevent serious complications.

Obesity risk class and asthma outpatient service utilization by the middle aged and elderly in Taiwan

BACKGROUND

According to the estimates of the World Health Organization (WHO), there were about 300 million people in the world suffering from asthma in 2005. Among the risk factors of asthma is obesity, which was found to be significantly associated with asthma in recent decades.

OBJECTIVES

In this study, we analyze the relationship between obesity risk class and asthma outpatient service utilization by the middle-aged and elderly in Taiwan.

METHODS

Adopting data from the 2005 Nation Health Interview Survey (NHIS) and National Health Insurance Research Database (NHIRD), we first utilize latent class analysis (LCA) to identify obesity risk classes. Next, we utilize a logit and a negative binominal model to analyze the relationship between each obesity risk class and asthma outpatient service utilization.

RESULTS

Results indicate that compared with the "overweight/obese with low consumption of vegetable/fruit and little exercise" class, the classes "normal-weight with high consumption of vegetable/fruit and moderate exercise" and "overweight/obese with high consumption of vegetable/fruit and moderate exercise" tend to have low probabilities and less number of visits of utilizing asthma outpatient services.

CONCLUSIONS

Our results may constitute useful references for clinicians and government policy makers formulating strategies for asthma management and prevention. Better informed strategies for asthma management could, in turn, increase the efficiency of asthmatic patients' care, which could provide efficient assistance to the target group based on the obesity risk classes.

Assessment of asthma control using asthma control test in chest clinics in Cameroon: a cross-sectional study

Introduction

The goal of asthma treatment is to obtain and maintain a good control of symptoms. Investigating factors associated with inadequately control asthma could help in strategies to improve asthma control. This study aimed to determine the prevalence and factors associated with inadequately controlled asthma in asthma patients under chest specialist care.

Methods

A cross-sectional study was conducted from November 2012 to May 2013. Physician-diagnosed asthma patients aged 12 years and above were included. A questionnaire was used to collect demographic data, comorbidities, and medical history of asthma. Asthma control was assessed using the Asthma Control Test (ACT), with a score less than 20 for inadequately controlled asthma and a score greater or equal to 20 for controlled asthma. A multivariate analysis was used to identify factors associated with inadequately controlled asthma.

Results

Overall, 243 patients were included in this study. Asthma was controlled in 141 patients (58%) and inadequately controlled in 102 (42%). The mean duration of asthma was 8 years with an interquartile range of 4 and 18 years. Forty-three participants (17.7%) were not under any controller medication while the mean ACT score was 19.3 ± 4.6. Independent associations were found between inadequately controlled asthma and female gender (OR 1.91; 95% CI 1.06-3.47) and obesity (OR 1.81; 1.01-3.27).

Conclusion

Asthma remains poorly controlled in a large proportion of asthma patients under specialist care in Cameroon. Educational programs for asthma patients targeting women and based on weight loss for obese patients may help in improving the control of asthma.

Asthma and obesity: mechanisms and clinical implications

Obesity is the most common asthma co-morbidity; it has been associated with increased risk for asthma exacerbations, worse respiratory symptoms and poor control. The exact mechanisms remain elusive and are probably multifactorial, stemming from mechanical alterations of the airways and lung parenchyma, to systemic and airway inflammatory and metabolic dysregulation that adversely influences lung function and or response to therapy. However, the fact that not every obese asthmatic is equally affected by weight gain highlights the many challenges and complexities in understanding this association. The factors that determine susceptibility may not depend on being obese alone, but rather the interactions with other phenotypical characteristics, such as age of asthma onset, gender and race to name a few. Inability to account for asthma phenotypes that are differentially affected by increasing body mass index (BMI) may contribute to the lack of consistent results across studies. This review will provide a succinct summary of obesity-related mechanisms and the clinical impact on asthma including highlights on recent progress.

Prospective Study on the Relationship of Obesity to Asthma Impairment and Risk

BACKGROUND

Although studies consistently show an association between obesity and increased asthma incidence, the role of obesity in asthma control is less clear.

OBJECTIVE

The objective of this study was to evaluate the association between baseline body mass index (BMI) and measures of subsequent asthma control in a large real-world cohort of adults with persistent asthma.

METHODS

In Kaiser Permanente Southern California (KPSC), a large managed care organization, we identified adults with persistent asthma in 2006, continuous health plan enrollment in 2007 and 2008, and a BMI measurement in 2006 or 2007. Each patient's last BMI measure in 2006 or 2007 was categorized into a BMI group: normal (<25 kg/m(2)), overweight (25-29.9 kg/m(2)), or obese (≥30 kg/m(2)). Asthma control outcomes in 2008 included asthma hospitalizations or emergency department visits (EDHO), oral corticosteroid dispensings linked to an asthma encounter (OCS), and dispensing of ≥7 short-acting beta-agonist canisters (SABA7). Multivariable analyses were conducted to assess the relationships of BMI categories with the risk of the asthma control outcomes after controlling for potential confounders.

RESULTS

In the 10,233 eligible adults-after adjusting for potential demographic, comorbidity, and prior utilization confounders-we found an increased relative risk (RR) of EDHO in overweight and obese (RR 1.40, 95% CI 1.10-1.78) individuals. Only obesity was associated in adjusted analyses with a significant increased relative risk of SABA7 (RR 1.27, 95% CI 1.15-1.40).

CONCLUSIONS

Elevated BMI, particularly obesity, is associated with subsequent poor asthma control, especially in the risk domain (exacerbations). These findings further support the importance of facilitating weight loss in overweight and obese adults with asthma.

Obesity and asthma: association or epiphenomenon?

OBJECTIVE

To relate obesity and asthma by comparing gender, age, initial classification of asthma, clinical control, basal forced expiratory volume in one second (FEV1) and forced expiratory flow between 25 and 75% (FEF25-75%) with rates of body mass index (BMI) in asthmatic adolescents.

METHODS

Cross-sectional study involving 120 asthmatics patients (1.9 male: 1 female) with a mean age of 14.1 years (9 to 20.1 years of age), classified according to asthma severity and control, and evaluated by spirometry using their basal FEV1 and FEF25-75%. The data were described by frequency, mean and standard deviation or median and range and analyzed by ANOVA, unpaired t test, Fischer's exact test, Kruskal-Wallis and Pearson's correlation, considering significant p<0.05.

RESULTS

There was no difference between gender in relation to the initial classification and the level of asthma control; 91.7% (100 cases) received initial classification as persistent and 106 cases (88.3%) were partially or totally controlled. There was no statistical difference between controlled patients and the others in relation to BMI. No significant correlations were found between zBMI and FEV1 and between zBMI and FEF25-75%, analyzing all patients and only patients with overweight or obese.

CONCLUSIONS

In this study, no significant correlation was found between overweight/obesity and asthma using clinical, anthropometric and spirometric parameters.

Prevalence of obesity in asthma and its relations with asthma severity and control

OBJECTIVE: To determine the prevalence of obesity in asthmatic patients attending at an outpatient clinic, and to investigate its relationships with asthma severity and level of asthma control. METHODS: In a cross-sectional study we recruited patients aged 11 years and older with confirmed asthma diagnosis from the outpatient asthma clinic of Hospital de Clínicas de Porto Alegre, Brazil. They underwent an evaluation by a general questionnaire, an asthma control questionnaire and by pulmonary function tests. Nutritional status was classified by body mass index (BMI). RESULTS: 272 patients were included in the study. Mean age was 51.1 ± 16.5 years and there were 206 (74.9%) female patients. Mean BMI was 27.5 ± 5.3 kg/m², and 96 (35.3%) patients were classified as normal weight, 97 (35.7%) as overweight and 79 (29%) as obesity. There was a significant higher proportion of female than male patients (34.3% vs. 13.2%, p = 0.002) in the obesity group. There were no significant differences with respect to asthma control (p = 0.741) and severity classification (p = 0.506). The FEV1% predicted was significantly higher in the obese than in the non-obese group (73.7% vs. 67.2%, p = 0.037). Logistic regression analysis identified sex (OR = 3.84, p = 0.002) as an independent factor associated with obesity. CONCLUSIONS: This study showed a high prevalence of obesity in asthmatic patients. Obese and non-obese subjects were similar in regard to asthma severity and level of asthma control. Female sex was associated with obesity in this asthma population.

Prevalence of obesity in asthma and its relations with asthma severity and control

OBJECTIVE

To determine the prevalence of obesity in asthmatic patients attending at an outpatient clinic, and to investigate its relationships with asthma severity and level of asthma control.

METHODS

In a cross-sectional study we recruited patients aged 11 years and older with confirmed asthma diagnosis from the outpatient asthma clinic of Hospital de Clínicas de Porto Alegre, Brazil. They underwent an evaluation by a general questionnaire, an asthma control questionnaire and by pulmonary function tests. Nutritional status was classified by body mass index (BMI).

RESULTS

272 patients were included in the study. Mean age was 51.1 ± 16.5 years and there were 206 (74.9%) female patients. Mean BMI was 27.5 ± 5.3kg/m(2), and 96 (35.3%) patients were classified as normal weight, 97 (35.7%) as overweight and 79 (29%) as obesity. There was a significant higher proportion of female than male patients (34.3% vs. 13.2%, p = 0.002) in the obesity group. There were no significant differences with respect to asthma control (p = 0.741) and severity classification (p = 0.506). The FEV1% predicted was significantly higher in the obese than in the non-obese group (73.7% vs. 67.2%, p = 0.037). Logistic regression analysis identified sex (OR = 3.84, p = 0.002) as an independent factor associated with obesity.

CONCLUSIONS

This study showed a high prevalence of obesity in asthmatic patients. Obese and non-obese subjects were similar in regard to asthma severity and level of asthma control. Female sex was associated with obesity in this asthma population.

Obesity in children with poorly controlled asthma: Sex differences

BACKGROUND

Obesity increases asthma risk, and may alter asthma severity. In adults, sex appears to modify the effect of obesity on asthma. Among children, the effect of sex on the relationship between obesity and asthma severity remains less clear, particularly when considering race.

OBJECTIVE

To determine how obesity affects disease characteristics in a diverse cohort of children with poorly controlled asthma, and if obesity effects are altered by sex.

DESIGN

We analyzed 306 children between 6 and 17 years of age with poorly controlled asthma enrolled in a 6-month trial assessing lansoprazole for asthma control. In this secondary analysis, we determined associations between obesity and symptom severity, spirometry, exacerbation risk, airway biomarkers, bronchial reactivity, and airflow perception. We used both a multivariate linear regression and longitudinal mixed-effect model to determine if obesity interacted with sex to affect asthma severity.

RESULTS

Regardless of sex, BMI >95th percentile did not affect asthma control, exacerbation risk or airway biomarkers. Sex changed the effect of obesity on lung function (sex × obesity FEV1%, interaction P-value < 0.01, sex × obesity FEV1/FVC, interaction P-value = 0.03). Obese males had significantly worse airflow obstruction compared to non-obese males, while in females there was no obesity effect on airflow obstruction. In females, obesity was associated with significantly greater FEV1 and FVC, and a trend toward reduced airway reactivity.

CONCLUSIONS

Obesity did not affect asthma control, airway markers or disease stability; however obesity did affect lung function in a sex-dependent manner. In males, obesity associated with reduced FEV1/FVC, and in females, obesity associated with substantially improved lung function.

Role of obesity in asthma control, the obesity-asthma phenotype

Asthma is a disease with distinct phenotypes that have implications for both prognosis and therapy. Epidemiologic studies have demonstrated an association between asthma and obesity. Further studies have shown that obese asthmatics have poor asthma control and more severe asthma. This obese-asthma group may represent a unique phenotype. The mechanisms behind poor asthma control in obese subjects remain unclear, but recent research has focused on adipokines and their effects on the airways as well as the role of oxidative stress. Both surgical and nonsurgical weight loss therapy have shown promising results with improvements in asthma control and decreased asthma severity. Comorbid conditions such as gastroesophageal reflux disease and obstructive sleep apnea may also have a role in poor asthma control in obese asthmatics. Further research is needed to define the mechanisms behind this phenotype which will guide the development of targeted therapies.

Weight loss interventions in asthma: EAACI evidence-based clinical practice guideline (part I)

BACKGROUND

Asthma and obesity are chronic multifactorial conditions that are associated with gene-environment interaction and immune function. Although the data are not fully consistent, it seems that obesity increases the risk of asthma and compromises asthma control.

OBJECTIVE

To investigate the impact that weight changes have on asthma.

METHODS

We carried out a systematic review of three large biomedical databases. Studies were scrutinized and critically appraised according to agreed exclusion and inclusion criteria. Quality assessment of eligible papers was conducted using the GRADE method. Meta-analyses of comparable studies were carried out.

RESULTS

Thirty studies met the eligibility criteria of the review. Interventions were limited to dietary manipulation in three studies, one of which also used anti-obesity drugs, and bariatric surgery in four. All the other studies reported observational data. Becoming obese increased the odds for incident asthma by 1.82 (95% CI 1.47, 2.25) in adults and 1.98 (95% CI 0.71, 5.52) in children. Weight loss was associated with significant improvement in mean scores for symptoms, rescue medication score, and asthma exacerbations in the only randomized controlled trial. Similarly, evidence gathered from observational studies, with follow-up ranging between 8 weeks to 1 year, and from changes 1 year after bariatric surgery showed improvements in all asthma control-related outcomes. Changes in lung function were reported in one randomized controlled and eight observational studies of asthmatic subjects, with conflicting results. Either improvement after weight loss, decline with weight gain, or no effects at all were reported. Changes in airway inflammation and responsiveness were reported only by observational studies.

CONCLUSION

Weight increases above the obesity threshold significantly increase the risk of asthma. The available studies show weak evidence of benefits from weight reduction on asthma outcomes.

Being overweight increases susceptibility to indoor pollutants among urban children with asthma

BACKGROUND

Both being overweight and exposure to indoor pollutants, which have been associated with worse health of asthmatic patients, are common in urban minority populations. Whether being overweight is a risk factor for the effects of indoor pollutant exposure on asthma health is unknown.

OBJECTIVES

We sought to examine the effect of weight on the relationship between indoor pollutant exposure and asthma health in urban minority children.

METHODS

One hundred forty-eight children (age, 5-17 years) with persistent asthma were followed for 1 year. Asthma symptoms, health care use, lung function, pulmonary inflammation, and indoor pollutants were assessed every 3 months. Weight category was based on body mass index percentile.

RESULTS

Participants were predominantly African American (91%) and had public health insurance (85%). Four percent were underweight, 52% were normal weight, 16% were overweight, and 28% were obese. Overweight or obese participants had more symptoms associated with exposure to fine particulate matter measuring less than 2.5 μm in diameter (PM2.5) than normal-weight participants across a range of asthma symptoms. Overweight or obese participants also had more asthma symptoms associated with nitrogen dioxide (NO2) exposure than normal-weight participants, although this was not observed across all types of asthma symptoms. Weight did not affect the relationship between exposure to coarse particulate matter measuring between 2.5 and 10 μm in diameter and asthma symptoms. Relationships between indoor pollutant exposure and health care use, lung function, or pulmonary inflammation did not differ by weight.

CONCLUSION

Being overweight or obese can increase susceptibility to indoor PM2.5 and NO2 in urban children with asthma. Interventions aimed at weight loss might reduce asthma symptom responses to PM2.5 and NO2, and interventions aimed at reducing indoor pollutant levels might be particularly beneficial in overweight children.

Central obesity and asthma outcomes in adults diagnosed with asthma

OBJECTIVE

The potential role of central obesity in asthma outcomes has been examined in a few studies. The aim of this study was to examine the relationship between central obesity and asthma outcomes in a group of Iranian asthma patients.

METHODS

One hundred and forty-two outpatients with asthma were studied. Central obesity was defined according to National Institute of Health (NIH) and Asian waist circumference (WC) and waist-to-hip ratio (WHR) cut-offs. Asthma outcomes including asthma control, pulmonary function, and morbidity were evaluated. The association between central obesity and asthma outcomes was studied by linear and logistic regression analyses.

RESULTS

Linear regression analysis showed a significant association of WHR-based central obesity with forced expiratory volume in 1 s (FEV(1)) (β = -9.04; p-value = .044) and forced vital capacity (FVC) (β = -10.52; p-value = .012). Logistic regression analysis showed a significant increased risk of asthma attacks in 3 months with Asian WC-based central obesity [odds ratio (OR) = 6.31, 95% confidence interval (CI): 1.16-34.41]; emergency room (ER) visits with NIH WC-based (OR = 5.15, 95% CI: 1.36-19.55) and Asian WC-based (OR = 18.72, 95% CI: 1.92-182.63) central obesity; and hospitalization in 1 year with NIH WC-based (OR = 5.28, 95% CI: 1.28-21.84) and Asian WC-based (OR = 12.39, 95% CI: 1.29-119.53) central obesity.

CONCLUSIONS

Our study shows that the Asian WC-based central obesity is a better predictor of asthma morbidity. The results of this study emphasize, when studying the relationship between asthma control and obesity, the importance of selecting the proper definitions for asthma control or central obesity and appropriate cutpoints. Further study in this field using other asthma control and quality of life questionnaires is warranted.

[Asthma control and obesity: a solid link]

BACKGROUND AND OBJECTIVE

An epidemiological association between obesity and asthma has been confirmed, but its possible link to disease control is controversial. The aim of this study was to investigate if asthma control was related with obesity.

PATIENTS AND METHODS

Asthmatics adult outpatients with good compliance on therapy and correct inhalation technique were included. An Asthma Control Test validated for Spanish population was used to measure asthma control and it was related with: age, sex, forced expiratory volume in one second, smoking, atopy, body mass index (BMI), rhinitis, anxiety and/or depression, bronchiectasis and gastroesophageal reflux. For statistical analysis chi square distribution, Student test and a logistic regression analysis were used.

RESULTS

One hundred and ten patients were included, of whom 41 (37.3%) had BMI ≥ 30 kg/m(2). Poor asthma control was associated, in the bivariate analysis, with: BMI, rhinitis, anxiety-depressive disorders and female sex. In the multivariate analysis, it remained independently associated with: BMI (odds ratio [OR] 3.66, 95% confidence interval [95% CI] 1.49-8.92), rhinitis (OR 2.87, 95% CI 1.18-6.99 and anxiety-depressive disorder (OR 6.45, 95% CI 2.10-20).

CONCLUSIONS

We conclude that there is a link between obesity and poorly controlled asthma, hence weight loss may have major clinical implications.

The treatment of asthma in obesity

The world is facing an unprecedented epidemic of obesity. This epidemic has led to major changes in the epidemiology of common diseases such as asthma. Obesity is a major risk factor for new-onset asthma. This article will discuss the role of mechanical and metabolic factors, as well as obesity-related comorbidities, in both causing airway disease and also affecting response to therapy in obese asthmatics. Asthma in obese individuals probably includes a spectrum of disease with at least two distinct phenotypes: early-onset allergic disease complicated by obesity and late-onset disease developing in the setting of obesity. Both phenotypes are distinct from asthma in lean individuals. Treatment of asthma in obesity needs to consider altered response to controller therapy, and the fact that mechanical factors, metabolic inflammation and other comorbidities are probably contributing to airway disease. Future studies should focus on the development of therapies specifically tailored towards the treatment of asthma in obesity.

Association of obesity with asthma severity, control and quality of life

BACKGROUND

The association between asthma and obesity is becoming increasingly established but the mechanism that might explain the observed differences in asthma severity, control and quality of life between obese and non-obese adult asthmatics is not clear. THE PURPOSE OF THIS STUDY WAS: 1) to determine asthma severity, control and quality of life in obese asthmatics and 2) to explore, according to the body mass index (BMI), the systemic inflammatory state of asthmatic people.

MATERIALS AND METHODS

A cross-sectional study was conducted between 2009 and 2010. Two hundred adult asthmatic patients were included. Data analysis consisted of univariate analysis with chi-square comparison test followed by a multivariate logistic regression.

RESULTS

Obesity worsens the severity of asthma. This finding was more strongly observed among women than men. Obesity and overweight are associated with a poorer control of asthma. According to BMI, obese asthmatics had 6 times more frequent emergency visits, 5 times more frequent hospitalizations for asthma related complaints, increased missed work days and greater dose of inhaled corticosteroids (1025µg/day vs. 759µg/day of beclometasone equivalent). Mean serum level of C-reactive protein (CRP) and leptin was significantly correlated with asthma severity based on GINA classification (5.75 vs. 2.81 mg/l; 20.5 vs. 5.38 ng/ml; respectively).

CONCLUSION

In summary, it appears that obesity is significantly associated with a greater asthma severity and a poorer asthma control and quality of life. Chronic systemic inflammation state may explain the relationship between obesity and asthma.

Obesity is associated with increased asthma severity and exacerbations, and increased serum immunoglobulin E in inner-city adults

BACKGROUND

Obesity is associated with increased asthma and atopy.

OBJECTIVE

To determine whether or not obesity in inner-city adults is associated with increased asthma prevalence, severity and exacerbations and IgE responses.

METHODS

This retrospective study involved 246 adults with asthma and other atopic disorders who were seen at an asthma clinic in New York City between 1997 and 2010. Height, weight, asthma diagnosis and symptoms, peak flow (PF), spirometry, serum IgE levels and white blood cell differentials were recorded.

RESULTS

Asthmatic patients had higher body mass index than non-asthmatics (median, interquartile range: 30.5, 10.2 vs. 27.8, 8.8; Mann-Whitney U-test, P = 0.0006). Class I and II/III obesity were associated with increased asthma (I: OR: 2.35, 95% CI: 1.04-5.34, P = 0.04; II/III: OR: 3.25, 95% CI: 1.36-7.74, P = 0.008). Class I and II/III obesity were associated with worsened asthma severity (ordinal logistic regression; I: OR: 4.23, 95% CI: 1.61-11.06, P = 0.003; II/III: OR: 2.76, 95% CI: 1.08-7.09, P = 0.03). Class II/III obesity was associated with increased asthma exacerbations requiring oral corticosteroids (repeated measures logistic regression, OR: 1.13, 95% CI: 1.03-1.25; P = 0.01) and increased requirement of inhaled corticosteroid for long-term asthma management (OR: 1.45, 95% CI: 1.29-1.62; P < 0.0001). In asthmatics, class II/III obesity was associated with decreased PF (general linear model, least squares mean ± SEM: 333.8 ± 37.4 vs. 396.2 ± 32.1 L/min; P = 0.007), forced expiratory volume in 1 s (75.2 ± 4.6 vs. 88.4 ± 5.6%; P = 0.03) and forced vital capacity (83.2 ± 4.7 vs. 109.2 ± 6.0%; P = 0.0002) and increased serum IgE (480.2 ± 88.3 vs. 269.0 ± 66.6 IU/mL; P = 0.04) and neutrophils (66.6 ± 3.7 vs. 60.1 ± 3.8%; P = 0.02). Class I obesity was also associated with increased serum IgE (458.7 ± 68.9, P = 0.03).

CONCLUSION AND CLINICAL RELEVANCE

Obesity in inner-city adults may be both a risk and exacerbating factor for atopic asthma.

Effects of obstructive sleep apnea and gastroesophageal reflux disease on asthma control in obesity

BACKGROUND

Obesity is a risk factor for asthma. Obese asthmatics often have poor asthma control and respond poorly to therapy. It has been suggested that co-morbidities associated with obesity, such as reflux and obstructive sleep apnea, could be important factors contributing to poor asthma control in obese patients.

OBJECTIVES

The purpose of this study was to determine if (1) reflux and/or (2) symptoms of sleep apnea contribute to poor asthma control in obesity.

METHODS

We studied asthmatic subjects participating in a trial of reflux treatment. Participants underwent baseline evaluation of asthma symptoms and lung function. Overall 304 participants underwent esophageal pH probe testing; 246 participants were evaluated for obstructive sleep apnea symptoms.

RESULTS

Of 402 participants in this trial, 51% were obese. Role of reflux in asthma control. Those with higher body mass index (BMI) reported a higher prevalence of reflux symptoms, but the prevalence of pH probe acid reflux was similar in all groups. Reflux was not associated with measures of asthma control in obese patients. Role of obstructive sleep apnea in asthma control. Symptoms and self-report of obstructive sleep apnea were more common with increasing BMI and associated with worse asthma control as measured by the Juniper Asthma Control questionnaire and Asthma Symptom Utility Index.

CONCLUSIONS

Our data suggest that obstructive sleep apnea, but not gastroesophageal reflux disease, may contribute significantly to poor asthma control in obese patients.

Obesity is a determinant of asthma control independent of inflammation and lung mechanics

BACKGROUND

It is unclear why obesity is associated with worse asthma control. We hypothesized that (1) obesity affects asthma control independent of spirometry, airway inflammation, and airway hyperresponsiveness (AHR) and (2) residual symptoms after resolution of inflammation are due to obesity-related changes in lung mechanics.

METHODS

Forty-nine subjects with asthma underwent the following tests, before and after 3 months of high-dose inhaled corticosteroid (ICS) treatment: five-item asthma control questionnaire (ACQ-5), spirometry, fraction of exhaled nitric oxide (Feno), methacholine challenge, and the forced oscillation technique, which allows for the calculation of respiratory system resistance (Rrs) and respiratory system reactance (Xrs) as indicators of airway caliber and elastic load, respectively. The effects of treatment were assessed by BMI group (18.5-24.9, 25-29.9, and ≥ 30 kg/m²) using analysis of variance. Multiple regression analyses determined the independent predictors of ACQ-5 results.

RESULTS

At baseline, the independent predictors of ACQ-5 results were FEV(1), Feno, and BMI (model r² = 0.38, P < .001). After treatment, asthma control, spirometry, airway inflammation, and AHR improved similarly across BMI groups. The independent predictors of ACQ-5 results after treatment were Rrs and BMI (model r² = 0.42, P < .001).

CONCLUSIONS

BMI is a determinant of asthma control independent of airway inflammation, lung function, and AHR. After ICS treatment, BMI again predicts ACQ-5 results, but independent of obesity-related changes in lung mechanics.

Obesity and poor asthma control in patients with severe asthma

BACKGROUND

Asthma is a public health problem as it leads to hospitalization and eventual death, particularly in its severe forms. Many studies have demonstrated an association between obesity and asthma.

OBJECTIVE

The aim of this study was to investigate the relationship between obesity and asthma control in a group of patients at a reference center for severe asthma in Brazil.

METHODS

This cross-sectional study was conducted in the outpatient central reference clinic of the Program for Control of Asthma in the State of Bahia. It included 508 subjects with severe asthma of both genders and above 18 years of age. All the participants answered a sociodemographic and a clinical questionnaire to collect information on their asthma and comorbidities, such as rhinitis and gastro-esophageal reflux disease (GERD). Participants also completed the Asthma Control Questionnaire, performed a spirometry test, and had their weight, height, and waist and hip circumferences registered.

RESULTS

Logistic regression analysis demonstrated a positive association between body mass index (BMI) and uncontrolled asthma [odds ratio (OR) 1.5; 95% confidence interval (CI) 1.02-2.20]. Symptoms of chronic rhinitis and GERD were also significantly associated with uncontrolled asthma (OR 3.68, 95% CI 1.50-9.01; and OR 2.78, 95% CI 1.91-4.03, respectively). There was no correlation between waist-to-hip ratios and asthma control.

CONCLUSION

In our sample of patients with severe asthma, those who were obese were more likely to have uncontrolled asthma than patients with a normal BMI. Nevertheless, this is not conclusive evidence for a direct causal association between obesity and poor asthma control. Future studies are necessary to dissect the relationship between obesity and asthma outcomes.

Obesity and asthma morbidity in a community-based adult cohort in a large urban area: the Chicago Initiative to Raise Asthma Health Equity (CHIRAH)

BACKGROUND

Urban minority populations experience increased rates of obesity and increased asthma prevalence and severity. Objective. The authors sought to determine whether obesity, as measured by body mass index (BMI), was associated with asthma quality of life or asthma-related emergency department (ED)/urgent care utilization in an urban, community-based sample of adults.

METHODS

This is a cross-sectional analysis of 352 adult subjects (age 30.9 +/- 6.1, 77.8% females, forced expiratory volume in one second (FEV(1))% predicted = 87.0% +/- 18.5%) with physician-diagnosed asthma from a community-based Chicago cohort. Outcome variables included the Juniper Asthma Quality of Life Questionnaire (AQLQ) scores and health care utilization in the previous 12 months. Bivariate tests were used as appropriate to assess the relationship between BMI or obesity status and asthma outcome variables. Multivariate regression analyses were performed to predict asthma outcomes, controlling for demographics, income, depression score, and beta-agonist use.

RESULTS

One hundred ninety-one (54.3%) adults were obese (BMI > 30 kg/m(2)). Participants with a higher BMI were older (p = .008), African American (p < .001), female (p = .002), or from lower income households (p = .002). BMI was inversely related to overall AQLQ scores (r = -.174, p = .001) as well as to individual domains. In multivariate models, BMI remained an independent predictor of AQLQ. Obese participants were more likely to have received ED/urgent care for asthma than nonobese subjects (odds ratio [OR] = 1.8, p = .036).

CONCLUSIONS

In a community-based sample of urban asthmatic adults, obesity was related to worse asthma-specific quality of life and increased ED/urgent care utilization. However, compared to other variables measured such as depression, the contribution of obesity to lower AQLQ scores was relatively modest.

Asthma control, adiposity, and adipokines among inner-city adolescents

BACKGROUND

There is an association between adiposity and asthma prevalence, but the relationship to asthma control is unclear.

OBJECTIVES

We sought to understand the relationships among adiposity, sex, and asthma control in inner-city adolescents with asthma.

METHODS

We prospectively followed 368 adolescents with moderate-to-severe asthma (ages 12-20 years) living in 10 urban areas for 1 year. Asthma symptoms and exacerbations were recorded, and pulmonary function and exhaled nitric oxide levels were measured every 6 weeks. Adiposity measures (body mass index [BMI] and dual-energy X-ray absorptiometric scans) were made, and blood was collected for measurement of allergy markers, adiponectin, leptin, TNF-alpha, IL-6, and C-reactive protein levels.

RESULTS

More than 60% of female subjects and 50% of male subjects were above the 85th percentile of BMI for age. Higher BMI was associated with more symptom days (R = 0.18, P = .02) and exacerbations (R = 0.18, P = .06) among female subjects only. Adiponectin was inversely related to asthma symptoms (R = -0.18, P < .05) and exacerbations (R = -0.20, P < .05) and positively with FEV(1)/forced vital capacity ratio (R = 0.15, P < .05) in male subjects only independent of body size. There was no relationship between adiposity or adipokines and total IgE levels, blood eosinophil counts, and exhaled nitric oxide levels. Dual-energy X-ray absorptiometry provided little additional value in relating adiposity to asthma outcome in this population of adolescents.

CONCLUSION

Adiposity is associated with poorer asthma control in female subjects. Adiponectin is associated with improved asthma control in male subjects.

[Factors associated with asthma control in primary care patients: the CHAS study]

BACKGROUND

Asthma control is inadequate in all populations studied to date, leading to a major part of the cost of the disease. The aim of our study was to evaluate the prevalence of uncontrolled asthma in primary care patients and identify the associated factors.

METHODS

We carried out a cross-sectional study of the population of primary care asthmatic patients over 18 years old in Spain (n=2159). Asthma control was measured with the Asthma Control Questionnaire (ACQ). The sociodemographic variables and treatment compliance were measured using a questionnaire. We built logistic-regression models using Asthma control, a dichotomous variable generated from ACQ score.

RESULTS

The prevalence of uncontrolled asthma was 63.9%. Treatment with oral corticosteroids (OCS) (OR=6.55), greater asthma severity (OR=3.11), presence of a distressing event (OR=2.44), lower significance given to treatment compliance (OR=1.66) and living in a rural area (OR=1.29) are associated with uncontrolled asthma. On the contrary, sex, age, obesity, smoking, alcohol intake and educational level had no effect on asthma control.

CONCLUSIONS

In Spain asthma is still uncontrolled and some factors leading to this situation appear to be modifiable by the health system.

Recent insight into obesity and asthma

PURPOSE OF REVIEW

The worldwide pandemic of obesity is creating unique challenges for the diagnosis and treatment of asthma. A wealth of epidemiologic literature has established that whereas asthma can lead to obesity, obesity is a risk factor for asthma, but mechanisms are unclear. This review assesses the current understanding of the relationship between obesity and asthma.

RECENT FINDINGS

Recent studies are developing a more sophisticated understanding of the possible inflammatory, immunologic, genetic, and mechanical mechanisms underlying the association between obesity and asthma. Obese asthma may be a unique phenotype of asthma, with a more difficult clinical course and altered response to asthma controller therapy. Adipokines such as leptin and adiponectin are thought to be important, but there is new interest in other inflammatory mechanisms related to visceral obesity, insulin resistance, and the metabolic syndrome.

SUMMARY

There are still far more questions than answers as to how obesity might cause or worsen asthma. It is clear that weight gain and obesity are particularly troublesome in asthmatics, and clinicians should target these individuals for aggressive intervention. Randomized controlled trials are needed to determine the best treatment approaches for obese asthma, and prospective studies in which both obesity and asthma are well characterized are needed to better understand the underlying mechanisms.

Advances in adult asthma diagnosis and treatment in 2009

There is a growing need to standardize and validate outcomes for asthma research. In this review of asthma-related publications from the Journal in 2009, efforts to standardize methodology and reporting of translational research, the influence of the environment, therapeutics, and management of asthma are highlighted.