Respiratory function and the obesity paradox

Associations between different body mass index and lung function impairment in Chinese people aged over 40 years: a multicenter cross-sectional study

OBJECTIVE

The aim of this study was to explore the associations between different body mass index (BMI) levels and different lung function impairment (LFI) in Chinese people aged over 40 years.

METHODS

We used a multi-stage stratified cluster random sampling method to investigate 3000 residents aged over 40 years from 5 areas in Hubei province of China in 2019-20. The data on questionnaire, physical measurements, and spirometry of the participants were collected. The associations of different BMI levels with different LFI were analyzed using multivariate logistic regressions after complex weighting. The spirometry data were analyzed using one-factor analysis of variance (ANOVA), and post-hoc was performed using the least significance difference (LSD)-t test.

RESULTS

A total of 2860 subjects were included. The prevalence (95%CI) of obstructive lung disease (OLD), restrictive lung disease (RLD), mixed lung disease (MLD), chronic obstructive pulmonary disease (COPD), COPD mild, and COPD moderate/severe/very severe were 24.1% (95% CI: 22.2-26.2), 11.6% (95% CI: 10.3-12.9), 4.0% (95% CI: 3.3-4.8), 12.6% (95% CI: 11.0-14.1), 7.2% (95% CI: 6.0-8.4), and 5.3% (95% CI: 4.3-6.4) respectively. After multivariate adjustment, the risk of OLD, COPD, and COPD mild decreased with the increment of BMI levels (both P for trend < 0.05). When compared to the normal weight group, the overweight group and obese group were at lower risk of experiencing OLD than normal group, the ORs were 0.77 (95% CI: 0.59-0.99) and 0.59 (95% CI: 0.40-0.86) respectively. The obese group was at lower risk for people with COPD mild (OR: 0.42, 95%CI: 0.21-0.85). Participants in underweight group were more likely to experience COPD and COPD moderate/severe/very severe, the ORs were 2.82 (95% CI: 1.07-7.39) and 3.89 (95% CI: 1.28-11.87) respectively.

CONCLUSION

Higher BMI levels were associated with an decreased risk of OLD and COPD. Obesity had a protective effect on lung function in OLD patients and COPD patients. However, there was no significant difference in RLD and MLD prevalence between different BMI groups.

Adipocyte dysfunction promotes lung inflammation and aberrant repair: a potential target of COPD

Background

Obesity and chronic obstructive pulmonary disease (COPD) are prevailing worldwide, bringing a heavy medical burden. Clinical and pathophysiological relationship between obesity and COPD is paradoxical and elusive. We aim to explore their inherent associations from clinical, genetic, and animal levels.

Methods

We performed literature review and cohort analysis of patients with COPD to compare lung function, symptom, and prognosis among different weight groups. After retrieving datasets of obesity and COPD in Gene Expression Omnibus (GEO) database, we carried out differentially expressed gene analysis, functional enrichment, protein-protein interactions network, and weighted gene co-expression network analysis. Then, we acquired paraffin-embedded lung tissues of fatty acid-binding protein 4-Cre-BMPR2fl/fl conditional knockout (CKO) mice that were characterized by adipocyte-specific knockout of bone morphogenetic protein receptor 2 (BMPR2) for staining and analysis.

Results

Our cohort study reports the effect of obesity on COPD is inconsistent with previous clinical studies. Lung function of overweight group was statistically superior to that of other groups. We also found that the inflammatory factors were significantly increased hub genes, and cytokine-associated pathways were enriched in white adipose tissue of patients with obesity. Similarly, injury repair-associated genes and pathways were further enhanced in the small airways of patients with COPD. CKO mice spontaneously developed lung injury, emphysema, and pulmonary vascular remodeling, along with increased infiltration of macrophages. BMPR2-defiecient adipocytes had dysregulated expression of adipocytokines.

Conclusion

Inflammation and abnormal repair might be potential mechanisms of the pathological association between obesity and COPD. BMPR2-associated adipocyte dysfunction promoted lung inflammation and aberrant repair, in which adipocytokines might play a role and thus could be a promising therapeutic target.

A risk-predictive model for obstructive sleep apnea in patients with chronic obstructive pulmonary disease

Background

Obstructive sleep apnea syndrome (OSA) is increasingly reported in patients with chronic obstructive pulmonary disease (COPD). Our research aimed to analyze the clinical characteristics of patients with overlap syndrome (OS) and develop a nomogram for predicting OSA in patients with COPD.

Methods

We retroactively collected data on 330 patients with COPD treated at Wuhan Union Hospital (Wuhan, China) from March 2017 to March 2022. Multivariate logistic regression was used to select predictors applied to develop a simple nomogram. The area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis (DCA) were used to assess the value of the model.

Results

A total of 330 consecutive patients with COPD were enrolled in this study, with 96 patients (29.1%) confirmed with OSA. Patients were randomly divided into the training group (70%, n = 230) and the validation group (30%, n = 100). Age [odds ratio (OR): 1.062, 1.003–1.124], type 2 diabetes (OR: 3.166, 1.263–7.939), neck circumference (NC) (OR: 1.370, 1.098–1,709), modified Medical Research Council (mMRC) dyspnea scale (OR: 0.503, 0.325–0.777), Sleep Apnea Clinical Score (SACS) (OR: 1.083, 1.004–1.168), and C-reactive protein (CRP) (OR: 0.977, 0.962–0.993) were identified as valuable predictors used for developing a nomogram. The prediction model performed good discrimination [AUC: 0.928, 95% confidence interval (CI): 0.873–0.984] and calibration in the validation group. The DCA showed excellent clinical practicability.

Conclusion

We established a concise and practical nomogram that will benefit the advanced diagnosis of OSA in patients with COPD.

Characterising hospitalisation risk for chronic obstructive pulmonary disease exacerbations: Bedside and outpatient clinic assessments of easily measured variables

OBJECTIVE

To identify the characteristics of people with chronic obstructive pulmonary disease (COPD) who require hospitalisation for exacerbations.

METHODS

People with COPD were recruited either during hospitalisation or from out-patient respiratory medicine clinics. Hospital admissions were tracked throughout the 5-months recruitment period. For participants who were admitted, hospital readmissions were tracked for at least 30 days following discharge. Participants were grouped as either needing; (i) no hospital admission during the study period (no admission; ø-A), (ii) one or more hospital admissions during the study period but no readmission within 30 days of discharge (no rapid readmission; ø-RR) or (iii) one or more hospital admissions with a readmission within 30 days of discharge (rapid readmission; RR).

RESULTS

Compared with the ø-A group (n=211), factors that independently increased the risk of ø-RR (n=146) and/or RR (n=57) group membership were being aged >60 years, identifying as an Indigenous person (relative risk ratio, 95% confidence interval 7.8 [1.8 to 34.0]) and the use of a support person or community service for activities of daily living (1.5 [1.0 to 2.4]. A body mass index ≥25 kg/m2 was protective.

CONCLUSIONS

Variables recorded at the bedside or in clinic provided information on hospitalisation risk.

Factors Associated with Emergency Department Visits and Consequent Hospitalization and Death in Korea Using a Population-Based National Health Database

We aim to investigate common diagnoses and risk factors for emergency department (ED) visits as well as those for hospitalization and death after ED visits. This study describes the clinical course of ED visits by using the 2014–2015 population data retrieved from the National Health Insurance Service. Sociodemographic, medical, and behavioral factors were analyzed through multiple logistic regression. Older people were more likely to be hospitalized or to die after an ED visit, but younger people showed a higher risk for ED visits. Females were at a higher risk for ED visits, but males were at a higher risk for ED-associated hospitalization and death. Individuals in the highest quartile of income had a lower risk of ED death relative to lowest income level individuals. Disabilities, comorbidities, and medical issues, including previous ED visits or prior hospitalizations, were risk factors for all ED-related outcomes. Unhealthy behaviors, including current smoking, heavy alcohol consumption, and not engaging in regular exercise, were also significantly associated with ED visits, hospitalization, and death. Common diagnoses and risk factors for ED visits and post-visit hospitalization and death found in this study provide a perspective from which to establish health polices for the emergency medical care system.

Association of Body Mass Index and Abdominal Obesity with the Risk of Airflow Obstruction: National Health and Nutrition Examination Survey (NHANES) 2007-2012

This study aimed to explore the relationship between body mass index (BMI) and abdominal obesity and the risk of airflow obstruction, based on the data from the 2007-2012 National Health and Nutrition Survey (NHANES). Logistic regression was applied to assess the relationships between BMI or abdominal obesity and the risk of airflow obstruction by the fixed ratio method and the lower limit of normal (LLN) method. We further used the restricted cubic splines with 3 knots located at the 5th, 50th, and 95th percentiles of the distribution to evaluate the dose-response relationship. A total of 12,865 individuals aged 20-80 years old were included. In the fixed ratio method, underweight was positively correlated with the risk of airflow obstruction, and overweight and obesity were negatively correlated with the risk of airflow obstruction. In the LLN method, the results were consistent with the fixed ratio method. Abdominal obesity was positively associated with the risk of airflow obstruction only in the fixed ratio method (OR: 1.41, 95% CI: 1.04-1.90). There was an additive interaction between underweight and smoking on airflow obstruction in both methods. Abdominal obesity and smoking had additive interactions in the LLN method. Dose-response analysis indicated that there was a non-linear trend between BMI and the risk of airflow obstruction (P_{for nonlinearity} < 0.01). Our study suggested that underweight and abdominal obesity were associated with the increased risk of airflow obstruction, and overweight and general obesity were associated with the decreased risk of airflow obstruction.

Association of body mass index and COPD exacerbation among patients with chronic bronchitis

Background and objective

Chronic obstructive pulmonary disease (COPD) patients with a body mass index (BMI) < 25 kg/m² are prone to develop adverse event of pharmacological treatment for frequent exacerbation. As chronic bronchitis (CB) is one of the strong risk factors of exacerbation, we investigated the associations between BMI and COPD exacerbations in patients with CB.

Methods

Patients with COPD were included from the Korean COPD Subgroup Study (KOCOSS), a multicenter observational cohort study. CB was defined using the St. George’s Respiratory Questionnaire and the participants were categorized according to BMI cut-off of 25 kg/m². Exacerbations during a 1-year follow-up were compared among four groups: non-CB with BMI ≥ 25 kg/m², non-CB with BMI < 25 kg/m², CB with BMI ≥ 25 kg/m², and CB with BMI < 25 kg/m².

Results

Among the 1264 patients with COPD, 451 (35.7%) had CB and 353 (27.9%) had both CB and BMI < 25 kg/m². The COPD exacerbation risk increased across the non-CB with BMI < 25 kg/m², CB with BMI ≥ 25 kg/m², and CB with BMI < 25 kg/m² groups (adjusted incidence rate ratio [95% confidence interval] 1.21 [0.89–1.62], 1.20 [0.77–1.88], and 1.41 [1.02–1.91], respectively, compared to the non-CB with BMI ≥ 25 kg/m² group).

Conclusions

COPD patients having both CB and a BMI < 25 kg/m² are at higher risk of exacerbations. Considering that a BMI < 25 kg/m² often limits treatment options preventing exacerbations, modified guidelines might be needed for non-obese CB patients in Asia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01957-3.

Long-Term Prognosis of Asthma-Bronchiectasis Overlapped Patients: A Nationwide Population-Based Cohort Study

Purpose

Asthma and bronchiectasis are common chronic respiratory diseases, and their coexistence is frequently observed but not well investigated. Our aim was to study the effect of comorbid bronchiectasis on asthma.

Methods

A propensity score-matched cohort study was conducted using the National Health Insurance Service-Health Screening Cohort database. From 2005 to 2008, 8,034 participants with asthma were weighted based on propensity scores in a 1:3 ratio with 24,099 participants without asthma. From the asthma group, 141 participants with overlapped bronchiectasis were identified, and 7,892 participants had only asthma. Clinical outcomes of acute asthma exacerbation(s) and mortality rates were compared among the study groups.

Results

The prevalence of bronchiectasis (1.7%) was 3 times higher in asthmatics than in the general population of Korea. Patients who had asthma comorbid with bronchiectasis experienced acute exacerbation(s) more frequently than non-comorbid patients (11.3% vs. 5.8%, P = 0.007). Time to the first acute exacerbation was also shorter in the asthmatics with bronchiectasis group (1,970.9 days vs. 2,479.7 days, P = 0.005). Although bronchiectasis was identified as a risk factor for acute exacerbation (adjusted odds ratio, 1.73; 95% confidence interval [CI], 1.05–2.86), there was no significant relationship between bronchiectasis and all-cause or respiratory mortality (adjusted hazard ratio [aHR], 1.17; 95% CI, 0.67–2.04 and aHR, 0.81; 95% CI, 0.11–6.08).

Conclusions

Comorbid bronchiectasis increases asthma-related acute exacerbation, but it does not-raise the risk of all-cause or respiratory mortality. Close monitoring and accurate diagnosis of bronchiectasis are required for patients with frequent exacerbations of asthma.

Impaired pulmonary function is associated with dynapenia, but not with abdominal obesity and dynapenic abdominal obesity in older adults

PURPOSE

No studies have previously analyzed the association between dynapenic abdominal obesity (DAO) and pulmonary function in older adults. The aim of this study was to analyze whether there is an association between pulmonary function and abdominal obesity, dynapenia, and DAO in community-dwelling older adults.

METHODS

A cross-sectional study was conducted with community-dwelling older adults (n = 383) of Macapá, Amapá, Brazil. Pulmonary function variables were evaluated with spirometry; and DAO was evaluated with the combination of dynapenia and abdominal obesity. Cutoff points for handgrip strength, 26 kg force for men and 16 kg force for women, were used to detect dynapenia; and cutoff points of abdominal circumference of > 102 cm for men and > 88 cm for women were used to identify abdominal obesity.

RESULTS

Most of the studied pulmonary function variables (obtained values and obtained versus predicted values) were associated with abdominal obesity, dynapenia, and DAO. However, in the adjusted model, there was an association of FVC (β = - 0.163; p < 0.001), FEV₁ (β = - 0.119; p = 0.006), and PEF (β = - 0.110; p = 0.017) only with dynapenia.

CONCLUSIONS

Older adults with abdominal obesity, dynapenia, and DAO presented impaired pulmonary function when compared to those without these conditions. Most of the pulmonary function variables were associated with abdominal obesity, dynapenia, and DAO conditions. However, in the adjusted model, there was an association of reduced FVC, FEV₁, and PEF values only with dynapenia.

An organ systems-based review of outcomes associated with sleep apnea in hospitalized patients

The current global health crisis due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has prompted the medical community to investigate the effects of underlying medical conditions, including sleep-disordered breathing, on inpatient care. Obstructive sleep apnea (OSA) is a common form of sleep-disordered breathing that may complicate numerous acquired conditions, particularly in inpatient and critical care settings. Viral pneumonia is a major contributor to intensive care unit (ICU) admissions and often presents more severely in patients with underlying pulmonary disease, especially those with obesity and OSA. This review summarizes the most recent data regarding complications of both OSA and obesity and highlights their impact on clinical outcomes in hospitalized patients. Additionally, it will highlight pertinent evidence for the complications of OSA in an organ-systems approach. Finally, this review will also discuss impatient treatment approaches for OSA, particularly in relation to the SARS-CoV-2 pandemic.

Association of Body Mass Index with Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

The association between body mass index (BMI) and chronic obstructive pulmonary disease (COPD) remains controversial. Therefore, a meta-analysis was conducted to further evaluate the relationship. A comprehensive literature search was performed in PubMed, Web of Science, EMBASE, China National Knowledge Infrastructure (CNKI), and Wanfang databases to identify eligible articles until July 15, 2020. Random effect model (REM) was used to compute the pooled results with 95% confidence intervals (CIs). We conducted meta-regression and subgroup analysis to explore potential sources of heterogeneity. Publication bias was evaluated by funnel plots and Egger's test. Thirty articles with 1,578,449 participants were included in the meta-analysis. The pooled OR of COPD was 1.96 (95% CI: 1.78-2.17) for the underweight group, 0.80 (95% CI: 0.73-0.87) for overweight group, and 0.86 (95% CI: 0.73-1.02) for obesity group. After further excluding 5 studies of high between-study heterogeneity in sensitivity analysis, the pooled OR of COPD was 0.77 (95% CI: 0.68-0.86) for the obesity group. This meta-analysis indicated that BMI was associated with COPD. Specifically, underweight might increase the risk of COPD; overweight and obesity might reduce the risk of COPD.

Should patients with obesity be more afraid of COVID-19?

COVID-19 crisis has lasted since the late 2019 to the present day. The severity of the disease is positively correlated with several factors, such as age and coexisting diseases. Furthermore, obesity is increasingly considered as a yet another risk factor, particularly, because it has been observed that people suffering from excessive body weight may experience a more severe course of COVID-19 infection. On the basis of current research, in our nonsystematic review, we have investigated the extent to which obesity can affect the SARS-CoV-2 course and identify the potential mechanisms of the disease. We have also described the role of proper nutrition, physical activity and other aspects relevant to the management of obesity.

Differences in the Outcome of Patients with COPD according to Body Mass Index

BACKGROUND

In chronic obstructive pulmonary disease (COPD), the "obesity paradox" is a phenomenon without a clear cause. The objective is to analyze the complications of COPD patients according to their body mass index (BMI).

METHODS

An observational study with a six-year prospective follow-up of 273 COPD patients who attended a spirometry test in 2011. Survival and acute events were analyzed according to the BMI quartiles.

RESULTS

A total of 273 patients were included. BMI quartiles were ≤24.23; 24.24-27.69; 27.70-31.25; ≥31.26. During the follow-up, 93 patients died. No differences were found in exacerbations, pneumonia, emergency visits, hospital admissions or income in a critical unit . Survival was lower in the quartile 1 of BMI with respect to each of the 2-4 quartiles (p-value 0.019, 0.013, and 0.004, respectively). Advanced age (hazard ratio, HR 1.06; 95% confidence interval, CI 1.03-1.09), low pulmonary function (HR 0.93; 95% CI 0.86-0.99), exacerbator with chronic bronchitis phenotype (HR 1.76; 95% CI 1.01-3.06), high Charlson (HR 1.32, 95% CI 1.18-1.49), and the quartile 1 of BMI (HR 1.99, 95% CI 1.08-3.69) were identified as risk factors independently associated with mortality.

CONCLUSIONS

In COPD, low BMI conditions a lower survival, although not for having more acute events.

[Dyspnea : A challenging symptom in the primary care setting]

Dyspnea is a very common symptom leading to visits to a general physician (GP). Correct differential diagnosis is the major challenge for the GP. There are no guidelines on dyspnea. This review provides an overview of the main causal diseases for dyspnea, presents methods for history taking and differential diagnosis, and specifies the role of GPs in the primary care setting in the case of dyspnea.

Diabetes Mellitus and Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is a common disease with an increasing prevalence, characterised by persistent respiratory symptoms and airflow limitation. Apart from cigarette smoking, certain occupational and environmental exposures, low socioeconomic status and genetic factors may contribute to the pathogenesis of COPD. Comorbidities, e. g. diabetes mellitus (DM), can negatively affect quality of life, COPD outcomes and cardiovascular risk. The present narrative review considers the potential links between COPD and DM, such as systemic inflammation, oxidative stress, hypoxaemia and hyperglycaemia. The effects of antidiabetic drugs on lung function and COPD outcomes, as well as the possibility of common therapeutic modalities are also briefly considered. Further research is needed in this field to elucidate these relationships as well as their potential clinical implications in daily practice.

Investigation of the Obesity Paradox in Chronic Obstructive Pulmonary Disease, According to Smoking Status, in the United States

An obesity paradox in chronic obstructive pulmonary disease (COPD), whereby overweight/obese individuals have improved survival, has been well-described. These studies have generally included smokers. It is unknown whether the paradox exists in individuals with COPD arising from factors other than smoking. Nonsmoking COPD is understudied yet represents some 25%-45% of the disease worldwide. To determine whether the obesity paradox differs between ever- and never-smokers with COPD, 1,723 adult participants with this condition were examined from 2 iterations of the National Health and Nutrition Examination Survey (1988-1994, 2007-2010), with mortality outcomes followed through December 2011. Using Cox proportional hazards models, adjusted for sociodemographic factors, lung function, and survey cycle, ever/never-smoking was found to modify the association between body mass index and hazard of death. Compared with normal-weight participants, overweight/obese participants had lower hazard of death among ever-smokers (for overweight, adjusted hazard ratio (aHR) = 0.56, 95% confidence interval (CI): 0.43, 0.74; for obesity, aHR = 0.66, 95% CI: 0.48, 0.92), but never-smokers did not (overweight, aHR = 1.41, 95% CI: 0.66, 3.03; obesity, aHR = 1.29, 95% CI: 0.48, 3.48). An obesity paradox appeared to be absent among never-smokers with COPD. This, to our knowledge, novel finding might be explained by pathophysiological differences between smoking-related and nonsmoking COPD or by smoking-associated methodological biases.

Body weight and mortality in COPD: focus on the obesity paradox

The positive association between overweight, obesity, and cardiovascular and all-cause mortality is well established, even though this relation is typically U shaped with an increased risk also in low-weight subjects. However, being overweight or obese has been associated with a better prognosis in subjects suffering from chronic diseases, id est the "obesity paradox". In both community-dwelling and hospitalized patients with COPD, several studies have reported a significant protective effect of obesity on all-cause mortality, indicating that also in obstructive pulmonary diseases, an obesity paradox may be present. Interestingly, the "paradox" is more evident for subjects with severe bronchial obstruction (i.e., a lower FEV1), while in mild-moderate conditions, the weight-related mortality shows a behavior similar to that observed in the general population. Several factors may confound the relation between COPD, obesity and mortality. The lower FEV1 found in obese people may be linked to a restrictive defect rather than to an obstructive one. Due to the modified chest wall mechanical properties-related to increased fat mass-obese COPD patients may present, respect to their lean counterpart, a lower lung hyperinflation which is associated with higher mortality. The traditional classification of COPD attributes to obese "blue bloaters" a low-grade emphysema in opposition to lean "pink puffers"; the fact that emphysema extent is related to mortality may bias the relationship between weight and survival. It is also to underline that the majority of the studies, consider BMI rather than body composition (a better predictor of mortality) when studying the intriguing relation between weight, COPD, and mortality. Reverse bias has also to be taken into account, hypothesizing that an unintentional weight loss may be the deleterious factor related to mortality, rather than considering obesity a protective one. Further prospective studies are needed to shed light on the complexity of this emerging issue.

LEVEL OF EVIDENCE

Level V: Narrative Review.

Obesity modulates diaphragm curvature in subjects with and without COPD

Obesity is a common comorbidity of chronic obstructive pulmonary disease (COPD) and has been associated with worse outcomes. However, it is unknown whether the interaction between obesity and COPD modulates diaphragm shape and consequently its function. The body mass index (BMI) has been used as a correlate of obesity. We tested the hypothesis that the shape of the diaphragm muscle and size of the ring of its insertion in non-COPD and COPD subjects are modulated by BMI. We recruited 48 COPD patients with postbronchiodilator forced expiratory volume in 1 s (FEV1)-to-forced vital capacity (FVC) < 0.7 and 29 age-matched smoker/exsmoker control (non-COPD) subjects, who underwent chest computed tomography (CT) at lung volumes ranging from functional residual capacity (FRC) to total lung capacity (TLC). We then computed maximum principal diaphragm curvature in the midcostal region of the left hemidiaphragm at the end of inspiration during quiet breathing (EI) and at TLC. The radius of maximum curvature of diaphragm muscle increased with BMI in both COPD and non-COPD subjects. The size of diaphragm ring of insertion on the chest wall also increased significantly with increasing BMI. Surprisingly, COPD severity did not appear to cause significant alteration in diaphragm shape except in normal-weight subjects at TLC. Our data uncovered important factors such as BMI, the size of the diaphragm ring of insertion, and disease severity that modulate the structure of the ventilatory pump in non-COPD and COPD subjects.

Cachexia in chronic obstructive pulmonary disease: new insights and therapeutic perspective

Cachexia and muscle wasting are well recognized as common and partly reversible features of chronic obstructive pulmonary disease (COPD), adversely affecting disease progression and prognosis. This argues for integration of weight and muscle maintenance in patient care. In this review, recent insights are presented in the diagnosis of muscle wasting in COPD, the pathophysiology of muscle wasting, and putative mechanisms involved in a disturbed energy balance as cachexia driver. We discuss the therapeutic implications of these new insights for optimizing and personalizing management of COPD-induced cachexia.

Patient characteristics associated with risk of first hospital admission and readmission for acute exacerbation of chronic obstructive pulmonary disease (COPD) following primary care COPD diagnosis: a cohort study using linked electronic patient records

OBJECTIVES

To investigate patient characteristics of an unselected primary care population associated with risk of first hospital admission and readmission for acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

DESIGN

Retrospective open cohort using pseudonymised electronic primary care data linked to secondary care data.

SETTING

Primary care; Lothian (population approximately 800,000), Scotland.

PARTICIPANTS

Data from 7002 patients from 72 general practices with a COPD diagnosis date between 2000 and 2008 recorded in their primary care record. Patients were followed up until 2010, death or they left a participating practice.

MAIN OUTCOME MEASURES

First and subsequent admissions for AECOPD (International Classification of Diseases (ICD) 10 codes J44.0, J44.1 in any diagnostic position) after COPD diagnosis in primary care.

RESULTS

1756 (25%) patients had at least 1 AECOPD admission; 794 (11%) had at least 1 readmission and the risk of readmission increased with each admission. Older age at diagnosis, more severe COPD, low body mass index (BMI), current smoking, increasing deprivation, COPD admissions and interventions for COPD prior to diagnosis in primary care, and comorbidities were associated with higher risk of first AECOPD admission in an adjusted Cox proportional hazards regression model. More severe COPD and COPD admission prior to primary care diagnosis were associated with increased risk of AECOPD readmission in an adjusted Prentice-Williams-Peterson model. High BMI was associated with a lower risk of first AECOPD admission and readmission.

CONCLUSIONS

Several patient characteristics were associated with first AECOPD admission in a primary care cohort of people with COPD but fewer were associated with readmission. Prompt diagnosis in primary care may reduce the risk of AECOPD admission and readmission. The study highlights the important role of primary care in preventing or delaying a first AECOPD admission.

Survival impact of postoperative body mass index in gastric cancer patients undergoing gastrectomy

BACKGROUND

The relationship between preoperative body mass index (BMI) and the survival of postoperative gastric cancer patients is not clear. Furthermore, the survival impact with postoperative BMI is not known, even though weight loss is inevitable after gastrectomy.

METHODS

Patients who underwent gastrectomy for gastric cancer between 2000 and 2008 were included in the study (n = 1909). Patients were divided into three groups based on their BMIs: low (<18.5 kg/m(2)), normal (18.5-24.9 kg/m(2)), and high BMI (≥ 25.0 kg/m(2)). Patient survival was compared according to BMI at two time points: baseline and 1 year after surgery.

RESULTS

Regarding BMI 1 year after surgery, overall survival, disease-specific survival, and recurrence-free survival were longer in the high BMI group than the low and normal BMI groups. In a Cox proportional hazards model, adjusting for the patient's age, sex, type of surgery, tumour stage, histology, curative resection, and BMI at baseline, a high BMI 1 year after surgery was associated with lower overall mortality compared to normal BMI (hazard ratio 0.51; 95% confidence interval, 0.26-0.98). However, BMI at baseline was not an independent prognostic factor.

CONCLUSION

BMI 1 year after surgery significantly predicted the long-term survival of patients with gastric cancer compared with the preoperative BMI.

Obesity and Pulmonary Function in African Americans

Background

Obesity prevalence in United States (US) adults exceeds 30% with highest prevalence being among blacks. Obesity is known to have significant effects on respiratory function and obese patients commonly report respiratory complaints requiring pulmonary function tests (PFTs). However, there is no large study showing the relationship between body mass index (BMI) and PFTs in healthy African Americans (AA).

Objective

To determine the effect of BMI on PFTs in AA patients who did not have evidence of underlying diseases of the respiratory system.

Methods

We reviewed PFTs of 339 individuals sent for lung function testing who had normal spirometry and lung diffusion capacity for carbon monoxide (DLCO) with wide range of BMI.

Results

Functional residual capacity (FRC) and expiratory reserve volume (ERV) decreased exponentially with increasing BMI, such that morbid obesity resulted in patients breathing near their residual volume (RV). However, the effects on the extremes of lung volumes, at total lung capacity (TLC) and residual volume (RV) were modest. There was a significant linear inverse relationship between BMI and DLCO, but the group means values remained within the normal ranges even for morbidly obese patients.

Conclusions

We showed that BMI has significant effects on lung function in AA adults and the greatest effects were on FRC and ERV, which occurred at BMI values < 30 kg/m2. These physiological effects of weight gain should be considered when interpreting PFTs and their effects on respiratory symptoms even in the absence of disease and may also exaggerate existing lung diseases.

The 2014 ESPEN Arvid Wretlind Lecture: Metabolism & nutrition: Shifting paradigms in COPD management

COPD is a chronic disease of the lungs, but heterogeneous with respect to clinical manifestations and disease progression. This has consequences for health risk assessment, stratification and management. Heterogeneity can be driven by pulmonary events but also by systemic consequences (e.g. cachexia and muscle weakness) and co-morbidity (e.g. osteoporosis, diabetes and cardiovascular disease). This paper shows how a metabolic perspective on COPD has contributed significantly to understanding clinical heterogeneity and the need for a paradigm shift from reactive medicine towards predictive, preventive, personalized and participatory medicine. These insights have also lead to a paradigm shift in nutritional therapy for COPD from initial ignorance or focusing on putative adverse effects of carbohydrate overload on the ventilatory system to beneficial effects of nutritional intervention on body composition and physical functioning as integral part of disease management. The wider implications beyond COPD as disease have been as clinical model for translational cachexia research.

Chest wall strapping. An old physiology experiment with new relevance to small airways diseases

Chest wall strapping (CWS) induces breathing at low lung volumes. Mild to moderate obesity can lead to similar changes in lung volumes, due to chest wall and abdominal restriction. Chest wall strapping is also conceptually similar to a mismatch between significantly oversized donor lungs transplanted into a recipient with a smaller chest cavity. Chest wall strapping increases lung elastic recoil, reduces pulmonary compliance, and substantially increases maximal expiratory flows. The interactions between elastic properties of the lung parenchyma and small airways are critical for pulmonary function. Chest wall strapping lowers residual volume and closing volume, likely from the interdependence between increased elastic recoil and airways, leading to greater radial distending forces on small airways and small airway dilation. Chronic obstructive pulmonary disease (COPD) and chronic rejection of the transplanted lung, bronchiolitis obliterans syndrome (BOS), are primarily diseases of the small airways, and are characterized by progressive obstruction and subsequent loss of small airways. In COPD, higher body mass index (BMI) (conceptually like being more tightly strapped) is associated with lower lung volumes, increased airway conductance, and lower risk of progression to emphysema or death. Likewise, in lung transplantation, oversized donor lungs have been linked to higher expiratory airflows, lower risk of bronchiolitis obliterans syndrome, and improved survival. This article reviews the physiology of chest wall strapping and explores how it could enhance the understanding or even the treatment of small airway diseases, such as COPD and bronchiolitis obliterans syndrome.

When obesity and chronic obstructive pulmonary disease collide. Physiological and clinical consequences

In many parts of the world, the prevalence of both chronic obstructive pulmonary disease (COPD) and obesity is increasing at an alarming rate. Such patients tend to have greater respiratory symptoms, more severe restriction of daily activities, poorer health-related quality of life, and greater health care use than their nonobese counterparts. Physiologically, increasing weight gain is associated with lung volume reduction effects in both health and disease, and this should be considered when interpreting common pulmonary function tests where lung volume is the denominator, such as FEV1/FVC and the ratio of diffusing capacity of carbon monoxide to alveolar volume, or indeed when evaluating the physiological consequences of emphysema in obese individuals. Contrary to expectation, the presence of mild to moderate obesity in COPD appears to have little deleterious effect on respiratory mechanics and muscle function, exertional dyspnea, and peak symptom-limited oxygen uptake during cardiopulmonary exercise testing. Thus, in evaluating obese patients with COPD reporting activity restriction, additional nonpulmonary factors, such as increased metabolic loading, cardiocirculatory impairment, and musculoskeletal abnormalities, should be considered. Care should be taken to recognize the presence of obstructive sleep apnea in obese patients with COPD, as effective treatment of the former condition likely conveys an important survival advantage. Finally, morbid obesity in COPD presents significant challenges to effective management, given the combined effects of erosion of the ventilatory reserve and serious metabolic and cardiovascular comorbidities that collectively predispose to an increased risk of death from respiratory failure.

Paradoxical association between body mass index and in-hospital mortality in elderly patients with chronic obstructive pulmonary disease in Japan

Background and objective

The prevalence and mortality of chronic obstructive pulmonary disease (COPD) in elderly patients are increasing worldwide. Low body mass index (BMI) is a well-known prognostic factor for COPD. However, the obesity paradox in elderly patients with COPD has not been well elucidated. We investigated the association between BMI and in-hospital mortality in elderly COPD patients.

Methods

Using the Diagnosis Procedure Combination database in Japan, we retrospectively collected data for elderly patients (>65 years) with COPD who were hospitalized between July 2010 and March 2013. We performed multivariable logistic regression analysis to compare all-cause in-hospital mortality between patients with BMI of <18.5 kg/m² (underweight), 18.5–22.9 kg/m² (low–normal weight), 23.0–24.9 kg/m² (high–normal weight), 25.0–29.9 kg/m² (overweight), and ≥30.0 kg/m² (obesity) with adjustment for patient backgrounds.

Results

In all, 263,940 eligible patients were identified. In-hospital mortality was 14.3%, 7.3%, 4.9%, 4.3%, and 4.4%, respectively, in underweight, low–normal weight, high–normal weight, overweight, and obese patients. Underweight patients had a significantly higher mortality than low–normal weight patients (odds ratio [OR]: 1.55, 95% confidence interval [CI]: 1.48–1.63), whereas lower mortality was associated with high–normal weight (OR: 0.76, CI: 0.70–0.82), overweight (OR: 0.73, CI: 0.66–0.80), and obesity (OR: 0.67, CI: 0.52–0.86). Higher mortality was significantly associated with older age, male sex, more severe dyspnea, lower level of consciousness, and lower activities of daily living.

Conclusion

Overweight and obese patients had a lower mortality than low–normal weight patients, which supports the obesity paradox.

Influence of diet and obesity on COPD development and outcomes

The global increase in the prevalence and incidence of obesity has called serious attention to this issue as a major public health concern. Obesity is associated with many chronic diseases, including cardiovascular disease and diabetes, and recently the role of overweight and obesity in lung disease has received new interest. Independently of obesity, diet also plays a role as a risk factor for many chronic diseases, and evidence is accumulating to support a role for diet in the prevention and management of several lung diseases. Chronic obstructive lung disease is the third-leading cause of death globally, and both obesity and diet appear to play roles in its pathophysiology. Obesity has been associated with decreased lung-function measures in population-based studies, with increased prevalence of several lung diseases and with compromised pulmonary function. In contrast, obesity has a protective effect against mortality in severe chronic obstructive pulmonary disease (COPD). Nutrient intake and dietary patterns have also been associated with lung-function measures and the development and progression of COPD. Taken together, this suggests that a focus on obesity and diet should be part of public health campaigns to reduce the burden of lung disease, and could have important implications for clinicians in the management of their patients. Future research should also focus on elucidating these relationships in diverse populations and age-groups, and on understanding the complex interaction between behavior, environment, and genetics in the development and progression of COPD. The goal of this article is to review current evidence regarding the role that obesity and diet play in the development of COPD, and in COPD-related outcomes.

Review on the impact of pregnancy and obesity on influenza virus infection

A myriad of risk factors have been linked to an increase in the severity of the pandemic H1N1 2009 influenza A virus [A(H1N1)pdm09] including pregnancy and obesity where death rates can be elevated as compared to the general population. The goal of this review is to provide an overview of the influence of pregnancy and obesity on the reported cases of A(H1N1)pdm09 virus infection and of how the concurrent presence of these factors may have an exacerbating effect on infection outcome. Also, the hypothesized immunologic mechanisms that contribute to A(H1N1)pdm09 virus severity during pregnant or obese states are outlined. Identifying the mechanisms underlying the increased disease severity in these populations may result in improved therapeutic approaches and future pandemic preparedness.

Respiratory Consequences of Mild-to-Moderate Obesity: Impact on Exercise Performance in Health and in Chronic Obstructive Pulmonary Disease

In many parts of the world, the prevalence of obesity is increasing at an alarming rate. The association between obesity, multiple comorbidities, and increased mortality is now firmly established in many epidemiological studies. However, the link between obesity and exercise intolerance is less well studied and is the focus of this paper. Although exercise limitation is likely to be multifactorial in obesity, it is widely believed that the respiratory mechanical constraints and the attendant dyspnea are important contributors. In this paper, we examined the evidence that critical ventilatory constraint is a proximate source of exercise limitation in individuals with mild-to-moderate obesity. We first reviewed existing information on exercise performance, including ventilatory and perceptual response patterns, in obese individuals who are otherwise healthy. We then considered the impact of obesity in patients with preexisting respiratory mechanical abnormalities due to chronic obstructive pulmonary disease (COPD), with particular reference to the effect on dyspnea and exercise performance. Our main conclusion, based on the existing and rather sparse literature on the subject, is that abnormalities of dynamic respiratory mechanics are not likely to be the dominant source of dyspnea and exercise intolerance in otherwise healthy individuals or in patients with COPD with mild-to-moderate obesity.

Effects of body mass index on task-related oxygen uptake and dyspnea during activities of daily life in COPD

BACKGROUND

Patients with COPD use a higher proportion of their peak aerobic capacity during the performance of domestic activities of daily life (ADLs) compared to healthy peers, accompanied by a higher degree of task-related symptoms. To date, the influence of body mass index (BMI) on the task-related metabolic demands remains unknown in patients with COPD. Therefore, the aim of our study was to determine the effects of BMI on metabolic load during the performance of 5 consecutive domestic ADLs in patients with COPD.

METHODOLOGY

Ninety-four COPD patients and 20 healhty peers performed 5 consecutive, self-paced domestic ADLs putting on socks, shoes and vest; folding 8 towels; putting away groceries; washing up 4 dishes, cups and saucers; and sweeping the floor for 4 min. Task-related oxygen uptake and ventilation were assessed using a mobile oxycon, while Borg scores were used to assess task-related dyspnea and fatigue.

PRINCIPAL FINDINGS

1. Relative task-related oxygen uptake after the performance of domestic ADLs was increased in patients with COPD compared to healthy elderly, whereas absolute oxygen uptake is similar between groups; 2. Relative oxygen uptake and oxygen uptake per kilogram fat-free mass were comparable between BMI groups; and 3. Borg symptom scores for dyspnea en fatigue were comparable between BMI groups.

CONCLUSION

Patients with COPD in different BMI groups perform self-paced domestic ADLs at the same relative metabolic load, accompanied by comparable Borg symptom scores for dyspnea and fatigue.