Underdiagnosis and overdiagnosis of asthma in the morbidly obese

Effects of Weight Change and Weight Cycling on Lung Function in Overweight and Obese Adults

Rationale: Epidemiological studies have reported on the detrimental effects on lung function after natural, and thus limited, weight gain in unselected populations. Studies on bariatric surgery, on the contrary, have indicated large improvements in lung function after substantial weight loss. Objectives: To study the associations between profound weight loss or gain and pulmonary function within the same population. A second objective was to investigate the effect of weight cycling on pulmonary function. Methods: From our lung function database, we selected the records of subjects in follow-up for continuous positive airway pressure therapy for sleep apnea with a weight change of ⩾20 kg within 5 years. Lung function (N = 255) at baseline was normal except for a tendency toward mild restriction in morbid obesity. Within this sample, 73 subjects were identified with significant "weight cycling", defined as a ⩾10-kg opposite change in body weight before or after the ⩾20-kg weight change. Results: Weight change affected pulmonary function more in men than in women (P < 0.001). In men, forced vital capacity (FVC) increased an average of 1.4% predicted per unit of body mass index after weight loss and the reverse after weight gain, whereas women exhibited a smaller change of 0.9% predicted per unit of body mass index. Weight loss slightly increased the ratio of forced expiratory volume in 1 second to FVC and decreased the specific airway resistance, whereas the opposite occurred with weight gain. Greater effects of weight change on lung function were observed in leaner subjects (P = 0.02) and in older subjects (P < 0.002). Changes in total lung capacity followed the changes in FVC, with no change in residual volume, and the greatest change was observed in functional residual capacity. In subjects with weight cycling, the improvement in lung function due to weight loss was reversed by subsequent weight gain and vice versa. Conclusions: This study provides evidence that the detrimental effect of obesity on lung function is a passive and reversible process.

Clinical inertia in asthma

Despite advances in pharmaceutical treatment in recent years, a relatively high proportion of patients with asthma do not have adequate asthma control, causing chronic disability, poor quality of life, and multiple emergency department visits and hospitalizations. A multifaceted approach is needed to overcome the problems with managing asthma, and clinical inertia (CI) is a crucial concept to assist with this approach. It divides clinical inertia into three main categories, which include healthcare provider-related, patient-related, and healthcare system-related CI. The strategies to overcome these CI are complex, and the M-GAP approach, which combines a multidisciplinary approach, dissemination of guidelines, utilization of applications, and development and promotion of low-cost prescriptions, will help clinicians.

Association of Asthma With Patients Diagnosed With Metabolic Syndrome: A Cohort Study in a Tertiary Care Hospital

Introduction Asthma is defined as a chronic inflammatory airway disease. The prevalence of both asthma and obesity has been rising simultaneously, demonstrating a parallel trend. Obesity is a significant factor in metabolic syndrome, and numerous studies have indicated a connection between metabolic syndrome and bronchial asthma. Aims and objectives The aim of this paper is to evaluate the association of asthma with patients diagnosed with metabolic syndrome. The main objectives were to analyze the clinical profile and spirometric indices in patients with metabolic syndrome and to assess asthmatic patients among them with spirometry and clinical parameters at a tertiary care hospital in Chennai. Materials and methods This hospital-based cohort study was conducted on 73 patients attending the outpatient department who had a known case of metabolic syndrome and were evaluated for asthma through history, physical examination, and a pulmonary function test. A history of cough, expectoration, shortness of breath, wheezing, chest tightness, allergy, seasonal variation, and smoking habits was asked, and a thorough physical examination was performed. Bronchial asthma was confirmed with airflow reversibility by spirometry as per the Global Initiative for Asthma Guidelines. Metabolic and spirometry parameters were examined, such as body mass index (BMI), waist circumference, waist-hip ratio, fasting blood sugar (FBS), postprandial blood sugar, hemoglobin A1C (HbA1C), serum insulin, lipid profile, C-reactive protein (CRP), forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), and FEV1/FVC pre- and post-reversibility (baseline vs. six months). Results and discussion The average BMI of all participants was 29.6511 ±2.64564. The waist-hip ratio was 0.5512 ±0.43855, which decreased during the follow-ups, demonstrating a decline in the risk of obesity in study participants. The level of HbA1C showed a drop from 6.1% to 5.9% at the first follow-up. This exhibited a further reduction at the six-month follow-up in addition to a positive reflection in insulin sensitivity, indicating successful control of diabetes among study participants. It was discovered that this was statistically significant (p<0.001). At the third and sixth months of follow-up, the FEV1/FVC ratio increased by 38% and 37%, respectively, when metabolic syndrome was under control. The results show that controlling diabetes, hypertension, obesity, and triglyceride values improved asthmatic symptoms, and this was determined to be statistically significant (p<0.001). Conclusion The results of the current study demonstrated that the regulation and maintenance of metabolic parameters such as BMI, diabetes, hyperlipidemia, and hypertension aid in improving asthma control.

[A Study of the Prevalence of Asthma in the General Population in Spain]

Introduction

Asthma is a disease with high prevalence, which affects all age groups and generates high health and social care costs. Studies carried out in a number of populations show great variability in its prevalence, even in geographically close populations, with data suggesting a relevant influence of socio-economic factors. At present, we do not have reliable data on the prevalence of this disease in the adult population of Spain. The objectives of this study are to estimate the prevalence of asthma in the Spanish population for those aged 18-79, to describe the variability between autonomous communities, to estimate the prevalence of under and overdiagnosis, to analyse the prevalence of uncontrolled asthma and steroid-dependent asthma, to evaluate the health care cost, to identify the most frequent phenotypes and to establish a starting point to evaluate the temporal trend with subsequent studies.

Methods

A cross-sectional, two-stage study will be carried out, including patients from 50 catchment areas. The study will be carried out in 3 phases: 1) screening and confirmation in the clinical history, in which patients with a previously correctly established diagnosis of asthma will be identified; 2) diagnosis of asthma to evaluate patients without a confirmed or excluded diagnosis; 3) characterization of asthma, where the characteristics of the asthmatic patients will be analysed, identifying the most frequent phenotypes.

Discussion

It seems necessary and feasible to carry out an epidemiological study of asthma in Spain to identify the prevalence of asthma, to optimize healthcare planning, to characterize the most frequent phenotypes of the disease, and to evaluate inaccurate diagnoses.

Challenges in uncontrolled asthma in pediatrics: important considerations for the clinician

INTRODUCTION

Despite symptoms control being the primary focus of asthma management according to guidelines, uncontrolled asthma is still an issue worldwide, leading to huge costs and asthma deaths at all ages. In childhood, poor asthma control can be even more harmful, as it can irreversibly compromise the children's lung function and the whole family's well-being.

AREAS COVERED

Given the problem extent, this review aims to discuss the leading modifiable causes of uncontrolled asthma in Pediatrics, giving some practical insights regarding the critical role of families and the main tools for monitoring control and drug adherence, even at a distance. The most recent GINA documents were used as the primary reference, along with the latest evidence regarding the management of asthma control and the impact of the COVID-19 pandemic on asthma.

EXPERT OPINION

In managing pediatric asthma, a multidisciplinary, multi-determinant, personalized approach is needed, actively involving families, schools, and other specialists. In addition to current strategies for implementing control, electronic health strategies, new validated asthma control tools, and the identification of novel inflammatory biomarkers could lead to increasingly tailored therapies with greater effectiveness in reaching asthma control.

Obesity and Asthma

Obesity is a major risk factor for the development of asthma, and the prevalence of obesity is higher in people with asthma than in the general population. Obese people often have severe asthma-recent studies in the United States suggest that 60% of adults with severe asthma are obese. Multiple mechanisms link obesity and asthma, which are discussed in this article, and these pathways contribute to different phenotypes of asthma among people with obesity. From a practical aspect, changes in physiology and immune markers affect diagnosis and monitoring of disease activity in people with asthma and obesity. Obesity also affects response to asthma medications and is associated with an increased risk of co-morbidities such as gastroesophageal reflux disease, depression, and obstructive sleep apnea, all of which may affect asthma control. Obese people may be at elevated risk of exacerbations related to increased risk of severe disease in response to viral infections. Interventions that target improved dietary quality, exercise, and weight loss are likely to be particularly helpful for this patient population.

European Respiratory Society Guidelines for the Diagnosis of Asthma in Adults

Although asthma is very common affecting 5-10% of the population, the diagnosis of asthma in adults remains a challenge in the real world that results in both over- and under-diagnosis. A task force (TF) was set up by the European Respiratory Society to systematically review the literature on the diagnostic accuracy of tests used to diagnose asthma in adult patients and provide recommendation for clinical practice.The TF defined eight PICO (Population, Index, Comparator, and Outcome) questions that were assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach, The TF utilised the outcomes to develop an evidenced-based diagnostic algorithm, with recommendations for a pragmatic guideline for everyday practice that was directed by real-life patient experiences.The TF support the initial use of spirometry followed, and if airway obstruction is present, by bronchodilator reversibility testing. If initial spirometry fails to show obstruction, further tests should be performed in the following order: FeNO, PEF variability or in secondary care, bronchial challenge. We present the thresholds for each test that are compatible with a diagnosis of asthma in the presence of current symptoms.The TF reinforce the priority to undertake spirometry and recognise the value of measuring blood eosinophils and serum IgE to phenotype the patient. Measuring gas trapping by body plethysmography in patients with preserved FEV1/FVC ratio deserves further attention. The TF draw attention on the difficulty of making a correct diagnosis in patients already receiving inhaled corticosteroids, the comorbidities that may obscure the diagnosis, the importance of phenotyping, and the necessity to consider the patient experience in the diagnostic process.

The use of a mobile spirometry with a feedback quality assessment in primary care setting - A nationwide cross-sectional feasibility study

OBJECTIVES

Mobile phone-linked portable spirometers are light-weight, easy to use and low cost, with new software to facilitate data collection. In this study we investigated the feasibility of the AioCare® mobile spirometry in primary care.

METHODS

In this nationwide, cross-sectional study, AioCare® spirometers (HealthUp, Poland) were distributed among primary healthcare centres across Poland. Operators (primary care professionals) received a 2-h training session, after which spirometry was performed in patients attending routine visits with respiratory symptoms or risk factors for obstructive airway diseases. Spirometry was considered technically correct when at least three manoeuvres met ERS/ATS acceptability and repeatability criteria. The most common spirometry errors were assessed and stepwise logistic regression was applied to identify factors associated with technically correct spirometry. Airway obstruction was defined as FEV₁/FVC below the lower limit of normal. A restrictive pattern was defined as FVC below the lower limit of normal.

RESULTS

Between 1 September 2018 and 1 September 2019, 10,936 spirometry examinations were performed in 9855 patients by 673 operators. 5347 (49%) spirometry examinations met both acceptability and repeatability criteria. The most common error was plateau error (17.7%). Operator age >40 years (OR 1.49, 95% CI 1.35-1.64) and repetition of the examination at the same visit (OR 1.90, 95% CI 1.66-2.16) increased the likelihood of a technically correct examination. Airway obstruction was found in 17% of correctly performed spirometry examinations.

CONCLUSIONS

Our nationwide study suggests that use of the AioCare® mobile spirometer in primary care could be feasible. More intensive and continual training should be implemented to improve the quality of spirometry examinations.

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.

[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.

Asthma, body mass and aerobic fitness, the relationship in adolescents: The exercise for asthma with commando Joe's® (X4ACJ) trial

Although an association has been suggested between asthma, obesity, fitness and physical activity, the relationship between these parameters remains to be elucidated in adolescents. Six-hundred and sixteen adolescents were recruited (334 boys; 13.0 ± 1.1years; 1.57 ± 0.10m; 52.6 ± 12.9kg), of which 155 suffered from mild-to-moderate asthma (78 boys). Participants completed a 20-metre shuttle run test, lung function and 7-day objective physical activity measurements and completed asthma control and quality of life questionnaires. Furthermore, 69 adolescents (36 asthma; 21 boys) completed an incremental ramp cycle ergometer test. Although participants with asthma completed significantly fewer shuttle runs than their peers, peak V̇O₂ did not differ between the groups. However, adolescents with asthma engaged in less physical activity (53.9 ± 23.5 vs 60.5 ± 23.6minutes) and had higher BMI (22.2 ± 4.8 vs 20.4 ± 3.7kg·m-2), than their peers. Whilst a significant relationship was found between quality of life and cardiorespiratory fitness according to peak V̇O₂, only BMI was revealed as a significant predictor of asthma status. The current findings highlight the need to use accurate measures of cardiorespiratory fitness rather than indirect estimates to assess the influence of asthma during adolescence. Furthermore, the present study suggests that BMI and fitness may be key targets for future interventions seeking to improve asthma quality of life.

Asthma medication in children who are overweight/obese: justified treatment?

BACKGROUND

The prevalence of asthma and obesity have increased over the last decades. A possible association between these two chronic illnesses has been suggested, since the prevalence of asthmatic symptoms rises with increasing Body Mass Index (BMI). However, asthma is only one of several possible causes of shortness of breath in obese children. The aim of this study is to evaluate the prevalence of overtreatment with asthma medication in a cohort overweight/obese children with respiratory symptoms visiting a pediatric outpatient clinic.

METHODS

Children referred to a pediatric outpatient clinic aged ≥4- ≤ 18 years with overweight/obesity (defined as BMI-sds > 1.1) and asthmatic symptoms were included. The diagnosis asthma was evaluated and classified in no, unlikely, probable and confirmed asthma, based on clinical parameters and/or spirometry results. Overtreatment was defined as asthma medication prescribed in participants classified as no or unlikely asthma. And undertreatment as probable or confirmed asthma without asthma medication prescribed .

RESULTS

Three hundred thirty-eight participants were included, of which 92.6% (313/338) had a prescription for asthma medication. Overtreatment was observed in 27.2% (92/338) participants. Nine participants were undertreated.

CONCLUSION

More than 25% overtreatment with asthma medication was observed in a cohort overweight/obese children with asthmatic symptoms. This finding emphasizes that the diagnosis of asthma must be confirmed before commencement of medication. The diagnosis of asthma should be based on standard questionnaires evaluating asthmatic symptoms, lung functions test and regular reassessments. Further studies concerning overtreatment with asthma medication in normal weight pediatric populations are warranted, to evaluate whether overtreatment is specific for overweight/obese children.

Over- and under-diagnosis in asthma

Asthma is extremely common with a prevalence of approximately 10% in Europe. It presents with symptoms which have a broad differential diagnosis and examination can be entirely normal. There is no agreed gold standard to diagnose asthma, and the objective tests that can aid diagnosis are often poorly available to primary care physicians. There is evidence that asthma is widely misdiagnosed. Overdiagnosis leads to unnecessary treatment and a delay in making an alternative diagnosis. Underdiagnosis risks daily symptoms, (potentially serious) exacerbations and long-term airway remodelling. An agreed standardised approach to diagnosis, with inclusion of objective measurements prior to treatment, is required to reduce misdiagnosis of asthma.

Asthma is frequently misdiagnosed. Both over- and under-diagnosis are associated with inappropriate treatment and potential patient harm. Although no gold standard diagnostic test is available, objective testing can improve diagnostic accuracy.http://ow.ly/Ej3830ohfxJ

Metabolic aspects of the relationship of asthma and obesity

Asthma and obesity are serious medical and social world problems, and their combined course is characterized by a decrease in the quality of life, an increase in the frequency and duration of hospitalization. The present review summarizes the current views on the mechanisms of formation of asthma phenotype combined with obesity, role of leptin and adiponectin imbalance in the development of systemic inflammation in obesity in the pathophysiology of asthma, its interrelations with metabolic syndrome. We present data that shows that syndrome is closely related not only to the debut of asthma, but also to a decrease in its control. Along with obesity, the role of other components of metabolic syndrome, in particular insulin resistance, as a predictor of asthma development is considered. Insulin resistance may be the most likely factor in the relationship between asthma and obesity, independent of other components of the metabolic syndrome. Insulin resistance associated with obesity can lead to disruption of nitric oxide synthesis. We reveal common mechanism of metabolic disorders of nitric oxide and arginine in metabolic syndrome and asthma and show that insulin resistance treatment can be therapeutically useful in patients with asthma in combination with obesity.

Systematic Approach to Asthma of Varying Severity

Asthma is a serious global health issue and asthma guidelines recommend a stepwise approach to management with goals to achieve control and minimize future risk. Prior to escalation of pharmacotherapy, steps to confirm accurate diagnosis as well as address comorbidities and triggers are critical to effective asthma management. This article provides readers with a structured approach to evaluation and management of asthma of varying severity.

Being Overweight or Obese and the Development of Asthma

OBJECTIVES

Adult obesity is linked to asthma cases and is estimated to lead to 250 000 new cases yearly. Similar incidence and attributable risk (AR) estimates have not been developed for children. We sought to describe the relationship between overweight and obesity and incident asthma in childhood and quantify AR statistics in the United States for overweight and obesity on pediatric asthma.

METHODS

The PEDSnet clinical data research network was used to conduct a retrospective cohort study (January 2009-December 2015) to compare asthma incidence among overweight and/or obese versus healthy weight 2- to 17-year-old children. Asthma incidence was defined as ≥2 encounters with a diagnosis of asthma and ≥1 asthma controller prescription. Stricter diagnostic criteria involved confirmation by spirometry. We used multivariable Poisson regression analyses to estimate incident asthma rates and risk ratios and accepted formulas for ARs.

RESULTS

Data from 507 496 children and 19 581 972 encounters were included. The mean participant observation period was 4 years. The adjusted risk for incident asthma was increased among children who were overweight (relative risk [RR]: 1.17; 95% confidence interval [CI]: 1.10-1.25) and obese (RR: 1.26; 95% CI: 1.18-1.34). The adjusted risk for spirometry-confirmed asthma was increased among children with obesity (RR: 1.29; 95% CI: 1.16-1.42). An estimated 23% to 27% of new asthma cases in children with obesity is directly attributable to obesity. In the absence of overweight and obesity, 10% of all cases of asthma would be avoided.

CONCLUSIONS

Obesity is a major preventable risk factor for pediatric asthma.

How the Smartphone Is Changing Allergy Diagnostics

PURPOSE OF REVIEW

Evidence-based clinical diagnosis of allergic disorders is increasingly challenging. Clinical decision support systems implemented in mobile applications (apps) are being developed to assist clinicians in diagnostic decisions at the point of care. We reviewed apps for allergic diseases general diagnosis, diagnostic refinement and diagnostic personalisation. Apps designed for specific medical devices are not addressed.

RECENT FINDINGS

Apps with potential usefulness in the initial diagnosis and diagnostic refinement of respiratory, food, skin and drug allergies are described. Apps to support diagnostic personalisation are not yet available. There is an urgent need to increase the scientific evidence on the real usefulness of these apps, as well as to develop new scientifically grounded apps designed and validated to support all allergic diseases and diagnostic levels. Apps have the potential to change the diagnosis of allergic diseases becoming part of the routine diagnostics toolset, but its usefulness needs to be established.

The asthma-obesity relationship: underlying mechanisms and treatment implications

PURPOSE OF REVIEW

Obesity is a worldwide epidemic with a prevalence that has tripled in the last two decades. Worldwide, more than 1.5 billion adults are overweight and more than 500 million obese. Obesity has been suggested to be a risk factor for the development of more difficult-to-control asthma. Although the mechanisms underlying the asthma-obesity relationship are not fully understood, several possible explanations have been put forward. These will be reviewed in this manuscript as well as the implications for the treatment of overweight and obese asthma patients.

RECENT FINDINGS

Insulin resistance is a possible factor contributing to the asthma-obesity relationship and the effect is independent of other components of the metabolic syndrome such as hypertriglyceridemia, hypertension, hyperglycemia, and systemic inflammation. Obesity has important effects on airway geometry, by especially reducing expiratory reserve volume causing obese asthmatics to breathe at low lung volumes. Furthermore, obesity affects the type of inflammation in asthma and is associated with reduced inhaled corticosteroids treatment responsiveness.

SUMMARY

Obesity induces the development of asthma with a difficult-to-control phenotype. Treatment targeting insulin resistance may be beneficial in obese asthma patients, especially when they have concomitant diabetes. Systemic corticosteroids should be avoided as much as possible as they are not very effective in obese asthma and associated with side-effects like diabetes, weight gain, and osteoporosis.

Patterns of bronchial challenge testing in Canada

BACKGROUND

Bronchial challenge testing (BCT) measures airway hyperresponsiveness; asthma guidelines recommend using BCT when symptoms manifest despite normal spirometry. Improper application of these guidelines commonly results in the misdiagnosis of asthma. Yet, statistics concerning BCT remain largely obscure. The current paper addresses this gap and explores how various health variables may elucidate adherence to asthma guidelines and patterns of BCT across Canadian provinces.

METHODS

Using the Access to Information Act, medical financial claims for BCT (or equivalent procedures) were requested from each of the Canadian provinces and territories. Based on the available information (from provinces only), correlations between frequency of BCT claims and medical demographics (e.g., prevalence of respirologists, health expenditures) are reported.

RESULTS

Controlling for population or for people with asthma, physicians from Québec claim four times more BCT per year than those in other provinces; physicians from Alberta close to eight-fold fewer. The number of respirologists per capita and BCT per capita correlated moderately, r(132) = 0.582, p < 0.001, [95% CI 0.421, 0.716]. Excluding "outliers" (i.e., British Columbia, Alberta, and Saskatchewan) greatly strengthened this correlation, r(87) = 0.930, p < 0.001, [95% CI 0.883, 0.958].

DISCUSSION

These findings demonstrate that provinces vary in their use of BCT. This result seems to stem, at least in part, from differences in the prevalence of respirologists. Interestingly, geographic region appears to wield a strong influence; in the correlation between number of tests and number of respirologists, physicians from Western provinces (i.e., Alberta, Saskatchewan, and British Columbia) administered fewer tests than their Eastern colleagues. Given the association between inadequate application of BCT and misdiagnosis of asthma, physicians should pay special attention to the Canadian guidelines when considering an asthma diagnosis.

Clinical presentation of patients with suspected obstructive sleep apnea and self-reported physician-diagnosed asthma in the ESADA cohort

Obstructive sleep apnea (OSA) and asthma are often associated and several studies suggest a bidirectional relationship between asthma and OSA. This study analyzed the characteristics of patients with suspected OSA from the European Sleep Apnea Database according to presence/absence of physician-diagnosed asthma. Cross-sectional data in 16,236 patients (29.1% female) referred for suspected OSA were analyzed according to occurrence of physician-diagnosed asthma for anthropometrics, OSA severity and sleepiness. Sleep structure was assessed in patients studied by polysomnography (i.e. 48% of the sample). The prevalence of physician-diagnosed asthma in the entire cohort was 4.8% (7.9% in women, 3.7% in men, p < 0.0001), and decreased from subjects without OSA to patients with mild-moderate and severe OSA (p = 0.02). Obesity was highly prevalent in asthmatic women, whereas BMI distribution was similar in men with and without physician-diagnosed asthma. Distribution of OSA severity was similar in patients with and without physician-diagnosed asthma, and unaffected by treatment for asthma or gastroesophageal reflux. Asthma was associated with poor sleep quality and sleepiness. Physician-diagnosed asthma was less common in a sleep clinic population than expected from the results of studies in the general population. Obesity appears as the major factor raising suspicion of OSA in asthmatic women, whereas complaints of poor sleep quality were the likely reason for referral in asthmatic men.

Pulmonary function, exhaled nitric oxide and symptoms in asthma patients with obesity: a cross-sectional study

Background

Obesity is a risk factor for the development of asthma. In patients with obesity the diagnosis of asthma is often based on symptoms, but without objective measurements. Nevertheless, obesity-associated asthma is recognized as a distinct asthma phenotype. Therefore, this study explores lung function and symptoms in asthma patients with and without obesity.

Methods

The Netherlands Epidemiology of Obesity (NEO) study is a population-based cohort study with 6671 participants (aged 45–65 years) of whom 472 had asthma. Of this latter group, linear regression analysis was used to examine differences in lung function and symptoms between asthma patients with (n = 248) and without obesity (n = 224), and between asthma patients with and without increased Fe_NO. Analyses were adjusted for confounders.

Results

Asthma patients with obesity had lower predicted FEV₁ and FVC values than patients without obesity [adjusted mean difference (MD) -3.3% predicted, 95% CI -6.5, −0.2; adjusted MD −5.0% predicted, 95% CI -7.8, −2.1]. The prevalence of symptoms was higher in patients with obesity. Asthma patients with obesity and with increased Fe_NO had lower FEV₁ and FEV₁/FVC values compared with those with low Fe_NO (adjusted MD −6.9% predicted, 95% CI -11.7, −2.0; −2.4%, 95% CI -4.6, −0.2).

Conclusion

Asthma patients with obesity had lower FEV₁ and FVC values than patients without obesity. This suggests that patients with obesity have restrictive lung function changes, rather than obstructive changes. Asthma patients with obesity and increased Fe_NO showed more obstructive changes. Fe_NO might help to identify patients with eosinophilic inflammation-driven asthma, whereas patients with low Fe_NO might have an obesity-associated asthma phenotype in which symptoms are partly caused by the obesity.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0684-9) contains supplementary material, which is available to authorized users.

Is it severe asthma or asthma with severe comorbidities?

Severe asthma is defined as asthma that requires treatment with high-dose inhaled corticosteroids (ICSs) plus a second controller and/or systemic corticosteroids to prevent it from becoming uncontrolled or that remains uncontrolled despite this therapy. This definition has limitations: 1) it does not define any biological characteristic that distinguishes severe asthma from asthma in general and 2) it relies on the clinical interpretation of asthma symptoms that are not specific. Actually, wheezing, dyspnea, cough and chest tightness may be caused by the comorbidities (such as rhinosinusitis, obesity and vocal cord dysfunction [VCD]) which are associated with asthma. In clinical practice, clinicians are often prone to diagnose uncontrolled asthma and increase doses of ICSs without considering the comorbidities, resulting in poor control of symptoms. This commentary wishes the clinicians to focus on the comorbidities of asthma, particularly in patients with severe asthma, because the correct diagnosis of these comorbidities implies specific treatments that lead to a better asthma control.

Sex-specific association between asthma and hypertension in nationally representative young Korean adults

It has been reported that people with asthma have an increased risk of hypertension. However, little is known about the specific relationship between asthma and hypertension in young adults. Among subjects who participated in the Korea National Health and Nutrition Examination Survey conducted in 2008-2013, a total of 10,138 young adults (4,226 men and 5,912 women) aged 19-39 years were analyzed. Multiple logistic regression analysis was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). The prevalence of ever asthma was 11.1% in men and 8.4% in women. The mean diastolic blood pressure (DBP) was lower in men with asthma than in men without asthma (p = 0.03), whereas the mean DBP was higher in women with asthma than in women without asthma (p = 0.04). Having asthma was inversely associated with hypertension in men (OR: 0.62, 95% CI: 0.41-0.91). In contrast, having asthma was positively associated with hypertension in women (OR: 2.19, 95% CI: 1.19-4.02). Our results suggest that asthma pathophysiology might be differentially associated with hypertension in young adults depending on sex.

Lung volumes and airway resistance in patients with a possible restrictive pattern on spirometry

Objective:

Many patients with proportional reductions in FVC and FEV1 on spirometry show no reduction in TLC. The aim of this study was to evaluate the role that measuring lung volumes and airway resistance plays in the correct classification of patients with a possible restrictive pattern on spirometry.

Methods:

This was a prospective study involving adults with reduced FVC and FEV1, as well as an FEV1/FV(C) ratio within the predicted range. Restrictive lung disease (RLD) was characterized by TLC below the 5th percentile, as determined by plethysmography. Obstructive lung disease (OLD) was characterized by high specific airway resistance, significant changes in post-bronchodilator FEV1, or an FEF25-75% < 50% of predicted, together with a high RV/TLC ratio. Nonspecific lung disease (NLD) was characterized by TLC within the predicted range and no obstruction. Combined lung disease (CLD) was characterized by reduced TLC and findings indicative of airflow obstruction. Clinical diagnoses were based on clinical suspicion, a respiratory questionnaire, and the review of tests of interest.

Results:

We included 300 patients in the study, of whom 108 (36%) were diagnosed with RLD. In addition, 120 (40%) and 72 (24%) were diagnosed with OLD/CLD and NLD, respectively. Among the latter, 24 (33%) were clinically diagnosed with OLD. In this sample, 151 patients (50.3%) were obese, and obesity was associated with all patterns of lung disease.

Conclusions:

Measuring lung volumes and airway resistance is often necessary in order to provide an appropriate characterization of the pattern of lung disease in patients presenting with a spirometry pattern suggestive of restriction. Airflow obstruction is common in such cases.

Objetivo:

Muitos pacientes com redução proporcional de CVF e VEF1 na espirometria não têm CPT reduzida. O objetivo deste estudo foi avaliar o papel da medida dos volumes pulmonares e da resistência das vias aéreas para a classificação correta de pacientes com possível restrição à espirometria.

Métodos:

Estudo prospectivo de adultos com CVF e VEF1 reduzidos e relação VEF1/CV(F) na faixa prevista. Distúrbio ventilatório restritivo (DVR) foi definido por CPT < 5º percentil por pletismografia. Distúrbio ventilatório obstrutivo (DVO) foi caracterizado por resistência específica de vias aéreas elevada, resposta significativa do VEF1 pós-broncodilatador e/ou um FEF25-75% < 50% do previsto associado a uma relação VR/CPT elevada. Distúrbio ventilatório inespecífico (DVI) foi caracterizado por CPT na faixa prevista e ausência de obstrução. Distúrbio ventilatório combinado (DVC) foi caracterizado por CPT reduzida e achados indicativos de obstrução ao fluxo aéreo. Os diagnósticos clínicos foram baseados em suspeita clínica, um questionário respiratório e revisão de exames de interesse.

Resultados:

Foram incluídos 300 pacientes no estudo, dos quais 108 (36%) tiveram diagnóstico de DVR, enquanto 120 (40%) foram diagnosticados com DVO ou DVC e 72 (24%) com DVI. Destes últimos, 24 (33%) tinham diagnóstico clínico de DVO. Nesta amostra, 151 pacientes (50,3%) eram obesos, e isso se associou com todos os padrões de distúrbios funcionais.

Conclusões:

Medidas dos volumes pulmonares e da resistência das vias aéreas são frequentemente necessárias para a caracterização adequada do tipo de distúrbio funcional em casos com possível restrição à espirometria. A obstrução ao fluxo aéreo é comum nesses casos.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.

Systematic Evaluation of Corticosteroid Use in Obese and Non-obese Individuals: A Multi-cohort Study

Background: Although the use of corticosteroids has been linked to high incidence of weight gain, no data are available concerning the differences in corticosteroid use between a diverse obese population and non-obese individuals. The main purpose of this study was to systematically explore the use of corticosteroids in obese subjects compared to non-obese controls. In addition, we also explored self-reported marked weight gain within obese subjects. Methods: Two hundred seventy-four obese outpatients (median [range] BMI: 40.1 kg/m² [30.5-67.0]), and 526 non-obese controls (BMI: 24.1 kg/m² [18.6-29.9]) from two different Dutch cohort studies were included. Corticosteroid use at the time of clinic or research site visit for up to the preceding three months was recorded in detail. Medical records and clinical data were evaluated with regard to age and body mass index in relation to corticosteroid use, single or multiple type use, and administration forms. Results: Recent corticosteroid use was nearly twice as high for obese subjects than for non-obese controls (27.0% vs. 11.9% and 14.8%, both P<.001). Largest differences were found for use of local corticosteroids, in particular inhaled forms, and simultaneous use of multiple types. Marked weight gain was self-reported during corticosteroid use in 10.5% of the obese users. Conclusion: Corticosteroid use, especially the inhaled agents, is higher in obese than in non-obese individuals. Considering the potential systemic effects of also local corticosteroids, caution is warranted on the increasing use in the general population and on its associations with weight gain.

Interacting effects of obesity, race, ethnicity and sex on the incidence and control of adult-onset asthma

Background

To improve care and control for patients with adult-onset asthma, a better understanding of determinants of their risk and outcomes is important. We investigated how associations between asthma, asthma control and obesity may be modified by patient demographic characteristics.

Methods

This retrospective study of adults enrolled in several health plans across the U.S. (n = 2,860,305) examined the interacting effects of obesity, age, race, and sex on adult-onset asthma and asthma control. Multivariable adjusted Cox and logistic regression models estimated hazard ratios (HR), and 95 % confidence intervals (CI) for the associations between body mass index (BMI) and study outcomes, and interactions of BMI with demographic characteristics.

Results

Compared with individuals who had a BMI <25 kg/m², the hazard of adult-onset asthma progressively increased with increasing BMI, from a 12 % increase among persons with a BMI of 25.0–29.9 kg/m² (HR 1.12, 95 % CI 1.10, 1.14) to an almost 250 % increase among persons with a BMI ≥50 kg/m² (HR 2.49, 95 % CI 2.38, 2.60). The magnitude of the association between obesity and asthma risk was greater for women (compared with men) and lower for Blacks (compared with non-Hispanic Whites). Among individuals with asthma, obesity was associated with poorly controlled and high-risk asthma.

Conclusions

The present study demonstrates that the magnitude of the associations between obesity and adult-onset asthma incidence and control are modified by race, age, and sex. Understanding the role of obesity in the development of adult-onset asthma will help to improve asthma treatment algorithms and to develop targeted interventions.

Avoiding Management Errors in Patients with Obesity Hypoventilation Syndrome

The prevalence of obesity hypoventilation syndrome and obstructive sleep apnea are increasing rapidly in the United States in parallel with the obesity epidemic. As the pathogenesis of this chronic illness is better understood, effective evidence-based therapies are being deployed to reduce morbidity and mortality. Nevertheless, patients with obesity hypoventilation still fall prey to at least four avoidable types of therapeutic errors, especially at the time of hospitalization for respiratory or cardiovascular decompensation: (1) patients with obesity hypoventilation syndrome may develop acute hypercapnia in response to administration of excessive supplemental oxygen; (2) excessive diuresis for peripheral edema using a loop diuretic such as furosemide exacerbates metabolic alkalosis, thereby worsening daytime hypoventilation and hypoxemia; (3) excessive or premature pharmacological treatment of psychiatric illnesses can exacerbate sleep-disordered breathing and worsen hypercapnia, thereby exacerbating psychiatric symptoms; and (4) clinicians often erroneously diagnose obstructive lung disease in patients with obesity hypoventilation, thereby exposing them to unnecessary and potentially harmful medications, including β-agonists and corticosteroids. Just as literary descriptions of pickwickian syndrome have given way to greater understanding of the pathophysiology of obesity hypoventilation, clinicians might exercise caution to consider these potential pitfalls and thus avoid inflicting unintended and avoidable complications.

Addressing the misdiagnosis of asthma in adults: where does it go wrong?

INTRODUCTION

Asthma is diagnosed based on patients' respiratory symptoms of wheeze, cough, chest tightness and/or dyspnea together with physiologic evidence of variable and reversible expiratory airflow limitation. A high prevalence of overdiagnosis, underdiagnosis and misdiagnosis of adult asthma has been reported in the literature. Areas covered: Misdiagnosis of asthma in adults can occur in the community due to physicians' failure to confirm airflow limitation using spirometry, the relatively poor sensitivity of spirometry to absolutely rule in asthma, the complexity of multiple asthma phenotypes and endotypes, and the inherent day to day variability of asthma symptoms and airflow limitation. Consequences of asthma misdiagnosis to the patient and to the healthcare system include increased medication costs, increased potential side effects related to unnecessary use of medications and lost opportunities to diagnose the true cause of patients' respiratory symptoms. Expert commentary: Here we provide a review of the problem of misdiagnosis of adult asthma and suggestions for how to decrease the risk of misdiagnosis.

Association between obesity and asthma - epidemiology, pathophysiology and clinical profile

Obesity is a risk factor for asthma, and obese asthmatics have lower disease control and increased symptom severity. Several putative links have been proposed, including genetics, mechanical restriction of the chest and the intake of corticosteroids. The most consistent evidence, however, comes from studies of cytokines produced by the adipose tissue called adipokines. Adipokine imbalance is associated with both proinflammatory status and asthma. Although reverse causation has been proposed, it is now acknowledged that obesity precedes asthma symptoms. Nevertheless, prenatal origins of both conditions complicate the search for causality. There is a confirmed role of neuro-immune cross-talk mediating obesity-induced asthma, with leptin playing a key role in these processes. Obesity-induced asthma is now considered a distinct asthma phenotype. In fact, it is one of the most important determinants of asthma phenotypes. Two main subphenotypes have been distinguished. The first phenotype, which affects adult women, is characterised by later onset and is more likely to be non-atopic. The childhood obesity-induced asthma phenotype is characterised by primary and predominantly atopic asthma. In obesity-induced asthma, the immune responses are shifted towards T helper (Th) 1 polarisation rather than the typical atopic Th2 immunological profile. Moreover, obese asthmatics might respond differently to environmental triggers. The high cost of treatment of obesity-related asthma, and the burden it causes for the patients and their families call for urgent intervention. Phenotype-specific approaches seem to be crucial for the success of prevention and treatment.

Asthma and obesity: is weight reduction the key to achieve asthma control?

PURPOSE OF REVIEW

Obesity has significant negative impact on asthma control and risk of exacerbations. The purpose of this review is to discuss recent studies evaluating the effects of weight reduction on asthma control in obese adults.

RECENT FINDINGS

Clinical studies have shown that weight reduction in obese patients is associated with improvements in symptoms, use of controller medication, and asthma-related quality of life together with a reduction in the risk for severe exacerbations. Furthermore, several studies have also revealed improvements in lung function and airway responsiveness, and more recently it has been shown that weight reduction following bariatric surgery has positive impact on small airway function, systemic inflammation and bronchial inflammation in this group of patients, which may explain the observed improvements in symptom control and lung function.

SUMMARY

Weight reduction in obese adults with asthma leads to an overall improvement in asthma control, including airway hyperresponsiveness and inflammation. Weight reduction should be a cornerstone in the management of obese patients with asthma.

Systemic inflammation and higher perception of dyspnea mimicking asthma in obese subjects

BACKGROUND

There are a variable number of obese subjects with self-reported diagnosis of asthma but without current or previous evidence of airflow limitation, bronchial reversibility, or airway hyperresponsiveness (misdiagnosed asthma). However, the mechanisms of asthma-like symptoms in obesity remain unclear.

OBJECTIVES

We sought to evaluate the perception of dyspnea during bronchial challenge and exercise testing in obese patients with asthma and misdiagnosed asthma compared with obese control subjects to identify the mechanisms of asthma-like symptoms in obesity.

METHODS

In a cross-sectional study we included obese subjects with asthma (n = 25), misdiagnosed asthma (n = 23), and no asthma or respiratory symptoms (n = 27). Spirometry, lung volumes, exhaled nitric oxide levels, and systemic biomarker levels were measured. Dyspnea scores during adenosine bronchial challenge and incremental exercise testing were obtained.

RESULTS

During bronchial challenge, patients with asthma or misdiagnosed asthma reached a higher Borg-FEV1 slope than control subjects. Moreover, maximum dyspnea and the Borg-oxygen uptake (V'O2) slope were significantly greater during exercise in subjects with asthma or misdiagnosed asthma than in control subjects. The maximum dyspnea achieved during bronchial challenge correlated with IL-1β levels, whereas peak respiratory frequency, ventilatory equivalent for CO2, and IL-6 and IL-1β levels were independent predictors of the Borg-V'O2 slope during exercise (r(2) = 0.853, P < .001).

CONCLUSIONS

A false diagnosis of asthma (misdiagnosed asthma) in obese subjects is attributable to an increased perception of dyspnea, which, during exercise, is mainly associated with systemic inflammation and excessive ventilation for metabolic demands.

Body mass index, respiratory conditions, asthma, and chronic obstructive pulmonary disease

BACKGROUND

This study aims to assess the relationship of body mass index (BMI) status with respiratory conditions, asthma, and chronic obstructive pulmonary disease (COPD) in a state population.

METHODS

Self-reported data from 11,868 adults aged ≥18 years in the 2012 South Carolina Behavioral Risk Factor Surveillance System telephone survey were analyzed using multivariable logistic regression that accounted for the complex sampling design and adjusted for sex, age, race/ethnicity, education, smoking status, physical inactivity, and cancer history.

RESULTS

The distribution of BMI (kg/m(2)) was 1.5% for underweight (<18.5), 32.3% for normal weight (18.5-24.9), 34.6% for overweight (25.0-29.9), 26.5% for obese (30.0-39.9), and 5.1% for morbidly obese (≥40.0). Among respondents, 10.0% had frequent productive cough, 4.3% had frequent shortness of breath (SOB), 7.3% strongly agreed that SOB affected physical activity, 8.4% had current asthma, and 7.4% had COPD. Adults at extremes of body weight were more likely to report having asthma or COPD, and to report respiratory conditions. Age-adjusted U-shaped relationships of BMI categories with current asthma and strongly agreeing that SOB affected physical activity, but not U-shaped relationship with COPD, persisted after controlling for the covariates (p < 0.001). Morbidly obese but not underweight or obese respondents were significantly more likely to have frequent productive cough and frequent SOB than normal weight adults after adjustment.

CONCLUSION

Our data confirm that both underweight and obesity are associated with current asthma and obesity with COPD. Increased emphasis on exercise and nutrition may improve respiratory conditions.

Misdiagnosis Among Frequent Exacerbators of Clinically Diagnosed Asthma and COPD in Absence of Confirmation of Airflow Obstruction

PURPOSE

Clinical diagnosis of severe asthma and chronic obstructive lung disease (COPD) remains a challenge and often flawed with lack of objective confirmation of airflow obstruction (AO). Misdiagnosis of asthma and COPD has been reported in stable disease, data are non-existent in frequent exacerbators. We investigated misdiagnosis and its predictors in frequent exacerbators.

METHODS

The cohort comprised of frequent severe exacerbators (requiring ≥2 emergency room (ER) visits or hospitalizations) of physician diagnosed (PD)-asthma and PD-COPD. All patients underwent a rigorous diagnostic algorithm over a follow-up period of 10 ± 6 months. Two board-certified pulmonologists ascertained final diagnosis. Patients with persistent absence of AO were identified to have misdiagnosis. Multivariate logistic regression analyses were used to identify predictors of misdiagnoses.

RESULTS

Among 333 frequent exacerbators analyzed (171 patients with PD-asthma, 162 with PD-COPD, mean annual exacerbations 3.4 ± 2.8), 24 % of patients had a baseline post-bronchodilator spirometry. Misdiagnosis was found in 26 % (87 of 333) of patients. Another 12 % (41 of 333) of patients had obstructive lung diseases other than asthma and COPD. Independent risk factors for misdiagnosis were spirometry underutilization (PD-asthma: OR = 2.8, 95 % CI 1.16-6.78, p = 0.02 and PD-COPD: OR = 10.7, 95 % CI 2.05-56.27, p = 0.005) and pack years of smoking (PD-COPD: OR = 1.05, 95 % CI 1.01-1.11, p = 0.03).

CONCLUSIONS

Objective confirmation of AO is essential in preventing misdiagnosis in frequent severe exacerbators of clinically diagnosed asthma and COPD, a third of whom have neither. Spirometry utilization is strongly associated with a reduced risk of misdiagnosis. Smoking is associated with increased risk of misdiagnosis in severe COPD, but not asthma.

Long-term improvements in pulmonary function 5 years after bariatric surgery

BACKGROUND

Obesity is associated with reduced pulmonary function. We evaluated pulmonary function and status of asthma and obstructive sleep apnoea syndrome (OSAS) before and 5 years after bariatric surgery.

METHODS

Spirometry was performed at baseline and 5 years postoperatively. Information of asthma and OSAS were recorded. Of 113 patients included, 101 had undergone gastric bypass, 10 duodenal switch and 2 sleeve gastrectomy.

RESULTS

Eighty (71%) patients were women, mean preoperative age was 40 years and preoperative weight was 133 kg in women and 158 kg in men. Five years postoperatively, weight reduction was 31% (42 kg; p < 0.001) in women and 24% (38 kg; p < 0.001) in men. Forced expiratory volume in 1 s (FEV1) increased 4.1% (116 ml; p < 0.001) in women and 6.7% (238 ml; p = 0.003) in men. Forced vital capacity (FVC) increased 5.8% (209 ml; p < 0.001) in women and 7.6% (349 ml; p < 0.001) in men. Gender and weight loss were independently associated with the improvements in FEV1 and FVC. At follow-up, FEV1 had increased 36% of the difference towards the estimated normal FEV1, and there was a corresponding 70% recovery of FVC. These improvements occurred despite an expected decline in pulmonary function by age during the study period. Of the asthmatics and OSAS patients, 48 and 80%, respectively, were without symptoms 5 years postoperatively.

CONCLUSIONS

Pulmonary function measured with spirometry was significantly improved 5 years after bariatric surgery, despite an expected age-related decline during this period. Symptoms of asthma and OSAS also improved.

Potential role of the airway wall in the asthma of obesity

The pathogenesis of late-onset TH2-low asthma in obesity is thought to be related to weight-related decreases in lung volume, but why only a subset of individuals with obesity develop this condition is unknown. We tested the hypothesis that natural variations in both airway wall stiffness and airway wall thickness could lead to a subpopulation of hyperresponsive individuals exhibiting the symptoms of asthma in the setting of obesity. Increases in airway resistance (Raw) after airway smooth muscle stimulation were simulated using a computational model of an elastic airway embedded in elastic parenchyma. Using a range of randomly chosen values for both airway wall stiffness and thickness, we determined the resulting probability distributions of Raw responsiveness for a variety of different levels of transpulmonary pressure (Ptp). As Ptp decreased from 5 to 1 cmH2O, the resulting distributions of Raw moved toward progressively higher levels of responsiveness. With appropriate choices for the mean and standard deviation of the parameter that controls either airway wall stiffness or thickness, the model predicts a relationship between airway hyperresponsiveness and body mass index that is similar to that which has been reported in populations with obesity. We conclude that natural variations in airway wall mechanics and geometry between different individuals can potentially explain why an increasing percentage of the population exhibits the symptoms of asthma as the obesity of the population increases.