Body mass index and mortality in chronic obstructive pulmonary disease: a meta-analysis

Evolving perspectives on evaluating obesity: from traditional methods to cutting-edge techniques

Objective: This review examines the evolution of obesity evaluation methods, from traditional anthropometric indices to advanced imaging techniques, focusing on their clinical utility, limitations, and potential for personalized assessment of visceral adiposity and associated metabolic risks.

Methods: A comprehensive analysis of existing literature was conducted, encompassing anthropometric indices (BMI, WC, WHR, WHtR, NC), lipid-related metrics (LAP, VAI, CVAI, mBMI), and imaging technologies (3D scanning, BIA, ultrasound, DXA, CT, MRI). The study highlights the biological roles of white, brown, and beige adipocytes, emphasizing visceral adipose tissue (VAT) as a critical mediator of metabolic diseases.

Conclusion: Although BMI and other anthropometric measurements are still included in the guidelines, indicators that incorporate lipid metabolism information can more accurately reflect the relationship between metabolic diseases and visceral obesity. At the same time, the use of more modern medical equipment, such as ultrasound, X-rays, and CT scans, allows for a more intuitive assessment of the extent of visceral obesity.

Relationship between advanced lung cancer inflammation index and all-cause and cause-specific mortality among chronic inflammatory airway diseases patients: a population-based study

Background

Chronic inflammatory airway diseases (CIAD), such as asthma, chronic bronchitis, and chronic obstructive pulmonary disease, pose a significant threat to public health, with its prognosis closely tied to the body's inflammation level and nutritional status. As a composite indicator, the advanced lung cancer inflammation index (ALI) integrates inflammation and nutritional status. Despite its potential utility, the link between ALI and the prognosis of patients with CIAD remains unexplored. This study aimed to investigate this relationship.

Methods

We gathered data from the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2018. The National Death Index was used to calculate mortality until December 31, 2019. Kaplan-Meier analysis was employed to investigate the relationships between ALI and all-cause and cause-specific mortality in patients with CIAD. Furthermore, weighted univariable and multivariable Cox proportional hazards models were employed to further examine their relationship. Multiple factors that could impact the results were adjusted in the analysis. We also utilized a restricted cubic spline analysis to estimate the non-linear relationships between ALI and all-cause and cause-specific mortality rates in patients with CIAD. Finally, subgroup and sensitivity analyses were conducted to ensure the reliability of the findings.

Results

The study involved 2,884 CIAD patients. An elevated ALI was significantly related to a decreased risk of all-cause mortality, as well as mortality from cardiovascular and respiratory diseases among CIAD patients. Results from RCS analysis revealed a reverse J-shaped non-linear association between ALI and all-cause mortality in CIAD patients, with an inflection point at 99 (p for nonlinearity <0.0001). The inflection point in the J-shaped relationship represents the ALI value with the lowest risk of mortality. For ALI values below 99, a 10-unit rise in ALI was linked to a 14% reduction in the risk of all-cause mortality (HR: 0.86, 95% CI:0.81-0.92, Ptrend=0.01). Conversely, if ALI exceeded 99, a 10-unit increase in ALI resulted in a 3% rise in the risk of all-cause mortality (HR: 1.03, 95% CI:1.01-1.06, Ptrend=0.02). A similar J-shaped association was observed in mortality due to cardiovascular and respiratory diseases, with inflection points at 94 and 96, respectively. These findings were consistent across sociodemographic and prior disease-related subgroups, and remained stable in sensitivity analyses.

Conclusion

This study revealed a novel association between elevated ALI level and reduced all-cause and cause-specific mortality risk in patients with CIAD. Furthermore, the relationship between ALI and mortality rates from all cause, as well as cardiovascular and respiratory diseases, exhibited an non-linear, J-shaped curve. These findings underscore the importance of maintaining optimal ALI levels within a specific range to promote long-term survival in CIAD patients. The dynamic variation in ALI over time also can help clinicians establish personalized ALI standards to maximize the long-term outcomes for CIAD patients.

Predictive value of six anthropometric indicators for prevalence and mortality of obstructive sleep apnoea asthma and COPD using NHANES data

Obesity is linked to a greater risk of respiratory diseases. Due to limitations in body mass index (BMI), alternative anthropometric indicators have been developed to reflect body fat distribution. This study compares six anthropometric measures-BMI, waist circumference (WC), the waist-to-height ratio (WHtR), the body roundness index (BRI), the body shape index (ABSI), and the weight-adjusted waist index (WWI)-and their relationships with the prevalence and mortality of obstructive sleep apnoea (OSA), asthma, and chronic obstructive pulmonary disease (COPD) in the US population. Data from four NHANES cycles were analyzed. Multivariable logistic regression assessed the cross-sectional associations between the six anthropometric measures and disease prevalence. Mortality associations were analysed via Cox proportional hazards models, and time‒dependent ROC curve was utilised to evaluate the predictive performance of the significant marker for mortality. BMI, WC, WWI, BRI, ABSI, and WHtR were positively correlated with the prevalence of OSA, and COPD. For asthma, BMI, WC, BRI, and WHtR were positively associated with prevalence, while ABSI and WWI were negatively associated. Concerning mortality, higher WC and BMI were associated with better survival in the OSA and COPD groups, whereas elevated WWI and ABSI were linked to greater mortality risk in the participants with OSA symptoms. An increase of one standard deviation (SD) in the ABSI resulted in an 18% increase in mortality (95% CI 1.09-1.27) for the OSA population. The area under the curve (AUC) for ABSI was 0.752 for 3-year, 0.755 for 5-year, and 0.744 for 10-year mortality. Novel anthropometric indicators, including WWI, BRI, ABSI, and WHtR, show positive associations with the prevalence of OSA, and COPD, alongside traditional measures like BMI and WC. However, WWI and ABSI were more limited in their association with asthma prevalence. Longitudinal analyses revealed that traditional anthropometric indicators such as BMI and WC were negatively associated with mortality risks in the OSA and COPD, supporting the "obesity paradox." ABSI, however, emerged as a significant mortality predictor for OSA, providing a more nuanced view of central obesity's impact on mortality. However, in COPD patients, routine anthropometric measurements may not fully capture the effects of obesity.

Body Mass Index and Lung Function in Hospitalized Severe AECOPD Patients: Investigating Nonlinear Associations and the Role of Hemoglobin

Background

Chronic obstructive pulmonary disease (COPD) is a leading cause of global morbidity and mortality. Patients hospitalized with severe acute exacerbations of COPD (AECOPD) represent a high-risk group with poor outcomes and accelerated lung function decline. Body mass index (BMI) shows inconsistent associations with lung function across populations, and its role in AECOPD remains unclear. Understanding this relationship may improve clinical management. Hemoglobin (Hb), essential for oxygen transport, may further influence this association through physiological mechanisms. This study aimed to explore the relationship between BMI and lung function in hospitalized patients with severe AECOPD and to assess whether BMI influences length of hospital stay (LOHS), while evaluating the potential modifying role of Hb.

Methods

A retrospective, single-center cross-sectional study was conducted among 579 patients hospitalized for severe AECOPD from 2021 to 2023. Data on BMI, lung function, Hb levels, and LOHS were collected. Nonlinear and threshold effect analyses were used to explore associations between BMI and lung function or LOHS. Subgroup analyses assessed the modifying effect of Hb.

Results

BMI exhibited a nonlinear positive association with FEV1, FVC, FEV1% predicted, and FVC% predicted. Thresholds were identified at 25.39 kg/m² for FEV1, 26.23 kg/m² for FEV1% predicted, 21.67 kg/m² for FVC, and 22.19 kg/m² for FVC% predicted. The association was more pronounced in patients with higher Hb levels. No significant association was found between BMI and LOHS, suggesting that other factors such as infection severity, comorbidities, or treatment strategies may may exert greater influence.

Conclusion

A nonlinear, inverse L-shaped association was observed between BMI and lung function, further modified by Hb levels. These findings highlight the importance of individualized treatment and stratification strategies in severe AECOPD. Future longitudinal studies are needed to validate these observations.

Decoding the complexity: mechanistic insights into comorbidities in idiopathic pulmonary fibrosis

The complex pathogenic relationships between idiopathic pulmonary fibrosis (IPF) and its usually associated comorbidities remain poorly understood. While evidence suggests that some comorbidities may directly influence the development or progression of IPF, or vice versa, whether these associations are causal or arise independently due to shared risk factors, such as ageing, smoking, lifestyle and genetic susceptibility, is still uncertain. Some comorbidities, such as metabolic syndromes, gastro-oesophageal reflux disease and obstructive sleep apnoea, precede the development of IPF. In contrast, others, such as pulmonary hypertension and lung cancer, often become apparent after IPF onset or during its progression. These timing patterns suggest a directional relationship in their associations. The issue is further complicated by the fact that patients often have multiple comorbidities, which may interact and exacerbate one another, creating a vicious cycle. To clarify these correlations, some studies have used causal inference methods (e.g. Mendelian randomisation) and exploration of underlying mechanisms; however, these efforts have not yet generated conclusive insights. In this review, we provide a general overview of the relationship between IPF and its comorbidities, emphasising the pathogenic mechanisms underlying each comorbidity, potential shared pathobiology with IPF and, when available, causal insights from Mendelian randomisation studies.

Comparison of the Changes in Visceral Adipose Tissue After Lobectomy and Segmentectomy for Patients With Early-Stage Lung Cancer

BACKGROUND

The impact of lobectomy versus segmentectomy on body composition changes, particularly adipose tissue, in patients with early-stage lung cancer remains unclear. This study aimed to determine the association between these surgical approaches and postoperative changes in adipose tissue.

METHODS

We retrospectively analysed visceral fat area (VFA) and waist circumference (WC) at the L3 level using cross-sectional computed tomography images from 346 recurrence-free patients who underwent lobectomy (n = 240) or segmentectomy (n = 106) for clinical stage 0-I primary lung cancer between January 2016 and December 2018. Long-term postoperative changes in VFA and WC by the third postoperative year (POY3) were compared between the lobectomy and segmentectomy groups using two-way repeated measures analysis of variance (ANOVA). Risk factors for VFA reduction were identified through multivariable analysis using logistic regression model. Propensity score matching (PSM, 1:1 matching) was also performed to compare VFA and WC changes between the lobectomy and segmentectomy groups.

RESULTS

At 6 months postoperatively, VFA and WC decreased by 16.4% and 1.0% in the lobectomy groups, respectively, and increased by 0.1% and 0.2% in the segmentectomy groups (p < 0.001 and p = 0.029, respectively). The two-way repeated measure ANOVA showed that the VFA and WC significantly decreased in the lobectomy group compared with the segmentectomy group within the POY3 (p < 0.001 and p = 0.038, respectively). Patients with a VFA change of ≥ -13% at POY3 (n = 238) had significantly better OS than those with a change of < -13% (n = 108) (5-year OS rate, 97.7% vs. 93.4%, p = 0.017), and VFA change < -13% at POY3 was an independent poor prognostic factor for OS (hazard ratio, 4.14; p = 0.013). Lobectomy was identified as an independent risk factor for a VFA change of < -13% at POY3 (odds ratio, 2.86; p < 0.001). After PSM (n = 93 for each group), VFA and WC significantly decreased in the lobectomy group compared with the lobectomy group within the POY3 (p = 0.009 and p = 0.020, respectively).

CONCLUSIONS

In patients with early-stage lung cancer without recurrence, long-term postoperative changes in VFA and WC differed between lobectomy and segmentectomy. Lobectomy resulted in a greater decrease in VFA from 6 months to 3 years postoperatively. In contrast, segmentectomy was associated with neither long-term postoperative VFA nor WC reduction.

Postoperative Changes in Body Composition Predict Long-Term Prognosis in Patients with Gastric Cancer

BACKGROUND

Postoperative changes in body composition (BC) have not been clearly defined. The aim of this study was to clarify the impact of postoperative comprehensive changes in BC on long-term prognosis in gastric cancer (GC) patients.

METHODS

A total of 366 GC patients who underwent radical gastrectomy were included. Postoperative changes in skeletal muscle volume, body fat volume, and skeletal muscle density were investigated at six months postoperatively using computed tomography and evaluated their association with long-term survival.

RESULTS

Patients with decreased muscle volume, decreased fat volume, and increased muscle density had a poor prognosis, respectively. When the risk scores based on these three BC parameters were applied, patients were classified from score 0 to 4, with survival rate declining as the scores improved: score 0, interim 5-year overall survival 94%; score 1, 82%; score 2, 73%; score 3, 56%; and score 4, 20%. BC change (score > 2) was an independent poor prognosticator (HR, 3.086; p < 0.001). Preoperative myosteatosis, high Charlson comorbidity, and total gastrectomy were identified as significant independent risk factors for BC change.

CONCLUSIONS

Each of postoperative skeletal muscle loss, body fat loss, and muscle hyperdensity negatively affected prognosis of GC patients after surgery, and the BC risk scoring assessment well predicted the prognosis of postoperative patients with GC.

Therapeutic Management in Patients with Chronic Obstructive Pulmonary Disease Who Are Overweight or Obese: A Systematic Review and Meta-Analysis

Introduction/Objective: The relationship between chronic obstructive pulmonary disease (COPD) and overweight is complex and multifaceted, as these conditions can interact in terms of symptoms, severity and clinical management. To analyse the clinical and therapeutic management of patients suffering from COPD and overweight. Methods: This systematic review was carried out, in accordance with the PRISMA statement, during November 2024, following a search of the Medline/PubMed databases. The search equation used, with MESH descriptors, was: "(Pulmonary Disease, Chronic Obstructive OR COPD) AND (obesity OR overweight)". Both inclusion and exclusion criteria were applied, focusing on the selection of clinical trials. The studies were classified into two main groups: by their focus on the relationship between overweight/obesity and COPD; and by the benefits provided by physical exercise to patients with these conditions. A random-effects meta-analysis was performed on the data obtained. The protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (CRD42024576389). Results: The search produced nine relevant clinical trials with a total of 1345 COPD patients. Four of the trials incorporated obesity (BMI ≥ 30) as an inclusion criterion, while the other five had mixed samples, with patients presenting either overweight or obesity (four patients with BMI ≥ 25 and one with BMI ≥ 27). The risk of bias tool for randomised trials showed that all nine studies had a low risk of bias. Overall, these studies highlight the importance of overweight management and reject the use of extreme measures. Furthermore, they confirm the association between overweight/obesity and COPD, for which this condition is a risk factor, to a degree depending on the BMI. Four studies reported significant improvements in the clinical management of COPD patients following appropriate physical exercise. Specifically, one study observed that supervised exercise improved cardio-vascular performance; another, that observed that aquatic exercise increased maximal capacity, endurance and quality of life; another, that found cycling improved ventilatory performance; and the fourth, that observed exercise complementary to standard therapy in hospitalised obese COPD patients improved strength, exercise capacity and other perceived variables such as anxiety, mobility and dyspnoea. Conclusions: The therapeutic management of overweight COPD patients should include weight control, physical exercise and appropriate pharmacological treatment. Physical exercise is associated with improvements in endurance, exercise capacity, cardio-vascular performance, ventilatory performance and strength. In addition, the participants in these studies self-perceived clinical improvement. These findings justify the performance of further RCTs examining the role of physical exercise in patients with COPD and overweight/obesity, in order to improve their clinical outcomes and quality of life.

COPD and cardiovascular risk

Chronic Obstructive Pulmonary Disease (COPD) usually presents joined to other pathologies we call comorbidities. The more frequent of them are those related to cardiovascular risk, either its risk factors or its clinical manifestations. Cardiovascular risk of these patients grows up with the severity of the airflow obstruction, specially during and after an exacerbation of COPD. Patients with COPD have between 2 and 5 times more risk of ischaemic heart disease than people without COPD, even after adjusting for cofounding factors. Cardiovascular diseases are up to the second cause of mortality in these patients, close to those due to the lung disease. Although COPD is associated to several cardiovascular risk factors such as tobacco, arterial hypertension or Diabetes Mellitus, they don't explain all the excess in cardiovascular risk these patients have. Despite that excess of cardiovascular risk in COPD patients, most widely used cardiovascular risk scores don't include COPD as a risk factor itself, so global risk is understimated in these patients. In this review, we make a bibliography revision of the avaliable evidence about COPD and cardiovascular risk factors as well as the excess of cardiovascular risk COPD itself involves.

Longitudinal analysis of adiponectin to leptin and apolipoprotein B to A1 ratios as markers of future airflow obstruction and lung function decline

Previous studies suggest associations between the risk of developing chronic obstructive pulmonary disease (COPD) and adiponectin/leptin (ALR) and apolipoprotein B/A1 (APOR) ratios. This longitudinal observational study, using data from the Korean Genome and Epidemiology Study (KoGES), examined the rate of lung function decline, risk factors for the airflow obstruction (AFO), and the time to first AFO based on ALR and APOR groups. Among 5578 participants, high ALR and low APOR were associated with rapid decline in lung function and a shorter time to the first AFO. The high ALR group and the combined high ALR and low APOR group showed higher risk of experiencing AFO both at least once (RR 1.46, 95% CI 1.12-1.90; RR 1.74, 95% CI 1.23-2.46, respectively) and at the final follow up (RR 1.44, 95% CI 1.05-1.96; RR 1.72, 95% CI 1.14-2.60, respectively). High ALR and the combined high ALR and low APOR were identified as risk factors for earlier time to first AFO. This study highlights the potential of ALR and APOR as makers for predicting the risk of future airflow obstruction.

Effects of Low-Carbohydrate and Low-Fat Diets on Morbidity and Mortality of COPD

Purpose

Although low-carbohydrate and low-fat diets improve weight loss, cardiovascular disease, and diabetes, the relationship between these dietary patterns, highlighting macronutrient sources, and chronic obstructive pulmonary disease (COPD) remains unclear. This study aimed to assess the association between low-carbohydrate diets (LCDs) and low-fat diets (LFDs) and the odds of COPD and mortality among people with COPD in the National Health and Nutrition Examination Survey.

Patients and Methods

Clinical data were extracted from the 2007-2008, 2009-2010, and 2011-2012 National Health and Nutrition Examination Survey (NHANES) cycles that met the inclusion criteria. Multivariable logistic regression was used to evaluate the associations between LCD and LFD scores and COPD, and multivariable Cox proportional hazards regression and restricted cubic spline (RCS) regression were used to assess the relationship between all-cause mortality and LCD and LFD scores.

Results

Comparing extreme tertiles, multivariable-adjusted odds ratio (OR) were 1 (reference), 1.09 (95% CI, 0.77-1.55), 1.84 (95% CI, 1.09-3.09) (P = 0.045 for trend) for unhealthy LFD scores. After multivariate adjustment, a per 5-point increase in unhealthy LCD score was associated with a 21% higher risk of total mortality (hazard ratio, 1.21; 95% CI, 1.03-1.43); while a per 5-point increase in healthy LFD scores was associated with a 21% lower risk of total mortality (HR, 0.79; 95% CI, 0.67-0.94).

Conclusion

Higher unhealthy LFD score was associated with an increased odds of COPD. Unhealthy LCD scores were significantly associated with higher total mortality, whereas healthy LFD scores were associated with lower total mortality in patients with COPD.

The Obesity Paradox in Pulmonary Rehabilitation: Relevance and Implications to Clinical Practice

Pulmonary rehabilitation (PR) increases exercise capacity, reduces dyspnea, and improves quality of life (QoL) in patients with chronic obstructive pulmonary disease (COPD). Patients requiring PR can present with multiple comorbidities. One of the most common comorbidities is obesity. The prevalence of obesity in patients with COPD is increasing at an alarming rate. To date the efficacy of PR to ameliorate obesity in patients with COPD is unclear. Obesity in patients with COPD is associated with increased morbidity and mortality compared to patients without obesity. However, the benefits of obesity paradox in lower mortality rate health-related QoL and health care utilization remain unclear. This review discusses the challenges of prescribing PR to patients with obesity and COPD. In addition, the definition of and the potential challenges and benefits of the obesity paradox in patients with COPD will be discussed. Treatment strategies that include combining PR with lifestyle management, individually tailored nutritional advice, pharmacotherapy, and surgery need to be tested in prospective, randomized controlled trials. The challenges of providing complex care, prioritizing patient needs, and future directions will also be discussed for patients with obesity and COPD.

Assessment of Metabolic Syndrome in Patients with Chronic Obstructive Pulmonary Disease: A 6-Month Follow-Up Study

BACKGROUND/OBJECTIVES

The association between chronic obstructive pulmonary disease (COPD) and metabolic syndrome (MetS) is a common one, with long-term therapeutic and prognostic impact. In view of the high pulmonary and cardiovascular morbidity and mortality, self-management contributes to decreasing the risk of an acute cardiac event or pulmonary decompensation.

METHODS

We conducted a prospective cohort study on 100 patients admitted to Iasi Clinical Rehabilitation Hospital who were divided into two groups according to the presence (67 patients) or absence (33 patients) of MetS. All patients benefited from multidisciplinary counseling sessions on their active role in improving modifiable cardiovascular risk factors and thus increasing quality of life. The aim of this study was to examine the impact of metabolic syndrome on lung function and the role of self-management in a 6-month follow-up period. The demographic, anthropometric, cardiovascular risk factors, and respiratory function were analyzed at baseline and at 6 months.

RESULTS

The presence of MetS was associated with higher fasting blood glucose (p = 0.004) and triglycerides (p = 0.003) but not with higher levels of interleukins or TNF-alpha. At the 6-month follow-up, abdominal circumference, forced expiratory volume in one second (FEV1), dyspnea severity, and blood pressure values improved in male patients with COPD. Systolic and diastolic blood pressure decreased in the COPD group as a whole, but especially in male patients with and without associated MetS. BMI was positively correlated with FEV1 (r = 0.389, p = 0.001) and the FEV1/forced vital capacity (FVC) ratio (r = 0.508, p < 0.001) in all COPD patients and in the MetS subgroup. In the COPD group as a whole. the six-minute walk test (6MWT) results (m) were positively correlated with FEV1 and FVC. The correlation remained significant for FVC in COPD patients with and without MetS. An increase in BMI by one unit led to an increase in TG values by 3.358 mg/dL, and the presence of metabolic syndrome led to an increase in TG values by 17.433 mg/dL.

CONCLUSIONS

In our study, MetS is a common comorbidity in patients with COPD and is associated with higher BMI, fasting glucose, and triglycerides but not with the inflammatory parameters. A mixed pulmonary-cardiovascular rehabilitation intervention leads to improvement in various parameters in both female and male COPD patients.

Impact of Body Mass Index on Risk of Exacerbation in Patients With COPD: A Systematic Review and Meta-Analysis

Objective

The objective of this review is to synthesize current evidence of the association between body mass index (BMI) categories and the risk of exacerbation in patients with chronic obstructive pulmonary disease (COPD).

Methods

A systematic search was conducted across 3 electronic databases: PubMed, Embase, and Scopus. Eligible studies must have reported on the association between BMI (either as continuous or categorical) and risk of COPD exacerbation, as defined according to recognized clinical criteria. Observational studies (cohort, case-control, cross-sectional) were eligible for inclusion. The Newcastle Ottawa Scale (NOS) was used to evaluate the methodological quality. Combined effect sizes were reported as relative risk (RR) and corresponding 95% confidence intervals (CI).

Results

A total of 11 studies were included. Of them, 4 studies were prospective, 4 were retrospective cohorts in design, 2 were cross-sectional studies, and one study was a secondary data analysis from a randomized trial. Compared to patients with a normal BMI, underweight patients had an increased risk of COPD exacerbation (RR 1.90, 95% CI: 1.03, 3.48; N=7, I2=94.2%). Overweight and obese BMI status was associated with a similar risk of exacerbation.

Conclusion

Our findings report that underweight, but not overweight or obese patients, have an increased risk of COPD exacerbation, compared to individuals with a normal BMI. This differential association emphasizes the need for nuanced investigations into the underlying mechanisms of the impact of BMI on the course of COPD. Further research is needed to inform personalized interventions and improve COPD management strategies.

Prognostic significance of body mass index and weight loss in patients with idiopathic pleuroparenchymal fibroelastosis

BACKGROUND AND AIM

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare form of idiopathic interstitial pneumonias; its physical characteristics include a slender build with platythorax and progressive weight loss. However, the clinical significance of body mass index (BMI) and weight loss remains unclear in patients with IPPFE. Therefore, we aimed to clarify the association between baseline BMI, weight loss after diagnosis, and the prognosis of patients with IPPFE.

METHODS

This retrospective study included 71 patients diagnosed with IPPFE at our institution between 2005-2021. BMI at diagnosis was classified into three: underweight (<18.5 kg/m2), normal weight (≥18.5 to <25.0 kg/m2), or overweight (≥25.0 kg/m2). An annual rate of weight change after the diagnosis was evaluated, and ≥5% per year decrease was defined as a significant weight loss. We investigated clinical features and prognosis based on baseline BMI and weight loss.

RESULTS

Of the 71 patients, 48 (67.6%) and 23 (32.4%) were classified as underweight and normal weight, respectively, and none were overweight. Significant weight loss occurred in 24 (33.8%) patients, and they tended to have more cases of dyspnea and had significantly older age, lower BMI, higher rates of co-existence of lower-lobe interstitial lung disease, lower pulmonary function test results and higher incidence of pneumothorax after the diagnosis than those without weight loss. Patients with BMI <18.5 kg/m2 and those with weight loss had a significantly worse prognosis than those with BMI ≥18.5 kg/m2 or those without weight loss, respectively (p=0.005, p<0.001). Multivariate analysis revealed that low BMI and weight loss were independent poor prognostic factors.

CONCLUSIONS

Low BMI and weight loss are associated with poor prognosis in patients with IPPFE.

Associations of obesity with chronic inflammatory airway diseases and mortality in adults: a population-based investigation

BACKGROUND

The association between obesity and respiratory diseases has been confirmed. However, few studies have reported the relationship between obesity and the risk and mortality of chronic inflammatory airway disease (CIAD). The aim of this study was to reveal the association between obesity and the risk of CIAD, and mortality in patients with CIAD.

METHODS

The study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) 2013 to 2018 among adults aged 20 years and above. All participants were grouped according to body mass index (BMI) and waist circumference (WC) levels to study the relationship between obesity and CIAD. Multivariate logistic regression analysis was utilized to examine the connection between CIAD and obesity in a cross-sectional study. The association between obesity and all-cause mortality in individuals with CIAD was examined using multiple cox regression models and smooth curve fitting in a prospective cohort study.

RESULTS

When stratified based on BMI in comparison to the normal weight group, the ORs with 95%CIs of CIAD for underweight and obesity were 1.39 (1.01-1.93) and 1.42 (1.27-1.58), respectively. The OR with 95%CI of CIAD for obesity was 1.20 (1.09-1.31) when stratified according to WC. Additionally, underweight was associated with a higher mortality (HR = 2.44, 95% CI = 1.31-4.55), whereas overweight (HR = 0.58,95% CI = 0.39-0.87) and obesity (HR = 0.59,95% CI = 0.4-0.87) were associated with a lower mortality (P for trend < 0.05). There was a non-linear association between BMI and all-cause mortality (P for non-linear = 0.001). An analysis of a segmentation regression model between BMI and all-cause mortality revealed a BMI turning point value of 32.4 kg/m2. The mortality of CIAD patients was lowest when BMI was 32.4 kg/m2. When BMI ≤ 32.4 kg/m2, BMI was inversely associated with all-cause mortality in patients with CIAD (HR: 0.92, 95%CI:0.88-0.97). However, when BMI > 32.4 kg/m2, there was no association between BMI and all-cause mortality (HR:1.02, 95%CI:0.97-1.06).

CONCLUSION

Compared to normal weight, underweight and obesity were associated with the increased risk of CIAD. Underweight was associated with increased all-cause mortality, while overweight was associated with reduced all-cause mortality. There was a non-linear association between BMI and all-cause mortality in patients with CIAD. The all-cause mortality was lowest when BMI was 32.4 kg/m2.

Comorbidity of patients with noncommunicable diseases in general practice. Eurasian guidelines

Создание руководства поддержано Советом по терапевтическим наукам отделения клинической медицины Российской академии наук.

Effect of abnormal body weight on mortality and functional recovery in adults after stroke: An umbrella review

BACKGROUND

Several published systematic reviews have drawn conflicting conclusions on the effect of abnormal body weight (i.e. being underweight, overweight or obese) on outcomes following stroke. The 'obesity paradox' seen in several diseases (wherein obesity, often associated with mortality and morbidity, appears to be protective and improve outcomes) may be evident after stroke, but inconsistent results of existing reviews, and the issue of being underweight, are worth investigating further.

AIMS

To better understand the impact of body weight on prognosis after stroke, we aimed to answer the following research question: What is the effect of abnormal body weight (underweight, overweight, or obesity) on mortality and functional recovery in adults after stroke?

SUMMARY OF REVIEW

We conducted an umbrella review to synthesize existing evidence on the effects of abnormal body weight on stroke outcomes. We searched Cumulated Index to Nursing and Allied Health Literature (CINAHL) Complete, COCHRANE Database of Systematic Reviews, PubMed, Medline, PEDro, and EMBASE Classic + EMBASE, from inception until 28 February 2023. Seven systematic reviews (1,136,929 participants) from 184 primary studies (counting duplicates) were included. While the risk of mortality increases with being underweight (body mass index (BMI) < 18.5 kg/m2), excess body weight (being overweight (BMI = 25-29.9 kg/m2) or obese (BMI > 30 kg/m2)) is associated with reduced mortality. The impact of abnormal body weight on functional recovery is less clear; data from studies of being underweight are associated with poor functional outcomes while those from studies of excess body weight are inconclusive.

CONCLUSION

Abnormal body weight effects post-stroke outcomes and should be considered in clinical decision-making, prognostic research, and clinical trials of rehabilitation interventions. The "obesity paradox" is evident after stroke, and excess body weight is associated with reduced mortality compared to normal body weight. It is recommended that body weight is routinely recorded for stroke patients, and further research, including well-designed cohort studies with reliable weight data, is needed to further investigate the impact of body weight and distribution on post-stroke outcomes.

Longitudinal BMI change and outcomes in Chronic Obstructive Pulmonary Disease: a nationwide population-based cohort study

BACKGROUND

The association between longitudinal body mass index (BMI) change and clinical outcomes in patients with chronic obstructive pulmonary disease (COPD) has not fully investigated.

METHODS

This retrospective cohort study included 116,463 COPD patients aged ≥ 40, with at least two health examinations, one within 2 years before and another within 3 years after COPD diagnosis (January 1, 2014, to December 31, 2019). Associations between BMI percentage change with all-cause mortality, primary endpoint, and initial severe exacerbation were assessed.

RESULTS

BMI decreased > 5% in 14,728 (12.6%), while maintained in 80,689 (69.2%), and increased > 5% in 21,046 (18.1%) after COPD diagnosis. Compared to maintenance group, adjusted hazard ratio (aHR) for all-cause mortality was 1.70 in BMI decrease group (95% CI:1.61, 1.79) and 1.13 in BMI increase group (95% CI:1.07, 1.20). In subgroup analysis, decrease in BMI showed a stronger effect on mortality as baseline BMI was lower, while an increase in BMI was related to an increase in mortality only in obese COPD patients with aHRs of 1.18 (95% CI: 1.03, 1.36). The aHRs for the risk of severe exacerbation (BMI decrease group and increase group vs. maintenance group) were 1.30 (95% CI:1.24, 1.35) and 1.12 (95% CI:1.07, 1.16), respectively.

CONCLUSIONS

A decrease in BMI was associated with an increased risk of all-cause mortality in a dose-dependent manner in patients with COPD. This was most significant in underweight patients. Regular monitoring for weight loss might be an important component for COPD management.

Prediction model and assessment of malnutrition in patients with stable chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) combined with malnutrition results in decreased exercise capacity and a worse quality of life. We aimed to develop an observational case-control study to explore the effective and convenient method to identify potential individuals is lacking. This study included data from 251 patients with COPD and 85 participants in the control group. Parameters and body composition were compared between groups, and among patients with varied severity. The LASSO approach was employed to select the features for fitting a logistic model to predict the risk of malnutrition in patients with stable COPD. Patients with COPD exhibited significantly lower 6-min walk distance (6MWD), handgrip strength, fat-free mass index (FFMI), skeletal muscle mass (SMM) and protein. The significant predictors identified following LASSO selection included 6MWD, waist-to-hip ratio (WHR), GOLD grades, the COPD Assessment Test (CAT) score, and the prevalence of acute exacerbations. The risk score model yielded good accuracy (C-index, 0.866 [95% CI 0.824-0.909]) and calibration (Brier score = 0.150). After internal validation, the adjusted C-index and Brier score were 0.849, and 0.165, respectively. This model may provide primary physicians with a simple scoring system to identify malnourished patients with COPD and develop appropriate rehabilitation interventions.

Impact of the COVID-19 pandemic on COPD exacerbations in Japanese patients: a retrospective study

Various infection control measures implemented during the coronavirus disease (COVID-19) pandemic have reduced the number of respiratory infections, which are the most common cause of chronic obstructive pulmonary disease (COPD) exacerbations. Here, we investigated whether infectious disease prevention during the COVID-19 pandemic reduced COPD exacerbations and the characteristics of patients exhibiting exacerbations before and during the COVID-19 pandemic. We included outpatients and inpatients with moderate or severe COPD exacerbations who required systemic steroids between April 1, 2018 and March 31, 2022. Their medical records were retrospectively compared and analyzed in 2-year intervals (before and during the COVID-19 pandemic). During the 4-year observation period, 70,847 outpatients and 2,772 inpatients were enrolled; 55 COPD exacerbations were recorded. The number of COPD exacerbations decreased from 36 before to 19 during the COVID-19 pandemic. Regarding the characteristics of patients with exacerbations, the % forced expiratory volume in one second (52.3% vs. 38.6%, P = 0.0224) and body mass index (BMI) (22.5 vs. 19.3, P = 0.0127) were significantly lower during the COVID-19 pandemic than before the pandemic. The number of COPD exacerbations during the pandemic decreased. Additionally, the tendency for a reduction in COPD exacerbation was greatest in patients with preserved lung function or above-standard BMI patients.

Estimating the prevalence and clinical significance of chronic obstructive pulmonary disease-obstructive sleep apnea overlap in South Korea

INTRODUCTION

Concurrent obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) are referred to as COPD-OSA overlap. We investigated the prevalence and clinical significance of COPD-OSA overlap in the general population of South Korea.

METHODS

Data were obtained from the 2019 Korea National Health and Nutrition Examination Survey. Participants ≥40 years of age with complete STOP-Bang questionnaire and spirometry data were included. OSA was presumed in individuals with a STOP-Bang score of ≥3. COPD was determined using forced expiratory volume at 1 s/forced vital capacity <0.7. Participants were classified on the basis of the STOP-Bang score and spirometry findings. Clinical characteristics, comorbidities, and quality of life (using the EuroQoL 5-dimension instrument) were compared between the overlap group and COPD-alone or OSA-alone groups.

RESULTS

Among the 3157 participants, 6.9 % demonstrated COPD-OSA overlap. Individuals with OSA alone and COPD alone were 31.8 % and 5.2 %, respectively. The overlap group included more males, ever smokers, and frequent alcohol drinkers than the COPD- or OSA-alone groups. The overlap group had more diagnoses of hypertension, diabetes, and stroke than the COPD-alone group. The risk of anxiety/depression was approximately 2.5 times higher in the overlap group than in the COPD-alone group. COPD-OSA overlap was a significant risk factor for anxiety/depression after adjusting for age, sex, household income, and education levels.

CONCLUSION

COPD-OSA overlap is not rare within the general population of South Korea. Patients with overlap showed more comorbidities and higher levels of anxiety/depression than those in the COPD-alone group.

Adipose Tissue Hypoxia in Obesity: Clinical Reappraisal of Hypoxia Hypothesis

Obese subjects exhibit lower adipose tissue oxygen consumption in accordance with the lower adipose tissue blood flow. Thereby, compared to lean subjects, obese individuals have almost half lower capillary density and more than half lower vascular endothelial growth factor (VEGF). The VEGF expression together with hypoxia-inducible transcription factor-1 alpha (HIF-1α) activity also requires phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR)-mediated signaling. Especially HIF-1α is an important signaling molecule for hypoxia to induce the inflammatory responses. Hypoxia contributes to several biological functions, such as angiogenesis, cell proliferation, apoptosis, inflammation, and insulin resistance (IR). Pathogenesis of obesity-related comorbidities is attributed to intermittent hypoxia (IH), which is mostly observed in visceral obesity. Proinflammatory phenotype of the adipose tissue is a crucial link between IH and the development of IR. Inhibition of adaptive unfolded protein response (UPR) in hypoxia increases β cell death. Moreover, deletion of HIF-1α worsens β cell function. Oxidative stress, as well as the release of proinflammatory cytokines/adipokines in obesity, is proportional to the severity of IH. Reactive oxygen species (ROS) generation at mitochondria is responsible for propagation of the hypoxic signal; however, mitochondrial ROS production is required for hypoxic HIF-1α protein stabilization. Alterations in oxygen availability of adipose tissue directly affect the macrophage polarization and are responsible for the dysregulated adipocytokines production in obesity. Hypoxia both inhibits adipocyte differentiation from preadipocytes and macrophage migration from the hypoxic adipose tissue. Upon reaching a hypertrophic threshold beyond the adipocyte fat loading capacity, excess extracellular matrix (ECM) components are deposited, causing fibrosis. HIF-1α initiates the whole pathological process of fibrosis and inflammation in the obese adipose tissue. In addition to stressed adipocytes, hypoxia contributes to immune cell migration and activation which further aggravates adipose tissue fibrosis. Therefore, targeting HIF-1α might be an efficient way to suppress hypoxia-induced pathological changes in the ECM. The fibrosis score of adipose tissue correlates negatively with the body mass index and metabolic parameters. Inducers of browning/beiging adipocytes and adipokines, as well as modulations of matrix remodeling enzyme inhibitors, and associated gene regulators, are potential pharmacological targets for treating obesity.

BMI trajectory in adulthood in relation to all-cause and cause-specific mortality: A retrospective cohort study in Taiwan

A dynamic change of weight over time has been known as an important factor that impacts mortality risk. The aims of this study were to identify the heterogeneity of BMI trajectory groups and to examine the association of the trajectories of BMI and all-cause and cause-specific mortality. The data for this study were obtained from a large prospective cohort study in Taiwan between 1998 and 2019 that was linked to the National Death Registry for death information. The participants were stratified into four groups by age and gender; self-reported demographics and measured BMI data were used. We used group-based trajectory analysis to identify the distinct trajectories of changes in BMI. A Cox proportional hazards model was used to assess the hazard ratio (HR) of all-cause and cause-specific mortality risk. Data were analyzed in April 2020 and included 89,886 participants. Four trajectory groups were identified by the pattern of BMI change over time. Our study shows that different trajectories were associated with mortality. Our findings suggest that the mortality risk differs in each trajectory group and in each age and gender stratification. It appears that obesity is a protective factor in cancer-related mortality in females but not in males in group of old age participants; low-normal weight is a risk factor in respiratory-related mortality in all participants. Our findings can be used to suggest the appropriate BMI in each age and gender groups and thereby earlier health interventions can be taken to avoid mortality.

Mortality in individuals with COPD on long-term home non-invasive ventilation

BACKGROUND

Real-world evidence regarding survival of patients with chronic obstructive pulmonary disease (COPD) using chronic non-invasive ventilation (NIV) is scarce.

RESEARCH QUESTION

How do obesity and other factors relate to mortality in patients with COPD on chronic NIV?

STUDY DESIGN

and Methods: We retrospectively analyzed data from COPD patients enrolled in a home ventilation program between 2014 and 2018. Survival was compared between obese and non-obese groups using the Kaplan-Meier method. Factors associated with mortality were identified using multivariable Cox proportional regression analyses with Least Absolute Selection and Shrinkage Operator (LASSO) regularization. Univariable analyses were also done stratified by obesity.

RESULTS

Median survival was 80.0 (95% CI: 71.0-NA) months among obese (n = 205) and 30.0 (95%CI: 19.0-42.0) months in non-obese (n = 61) patients. NIV adherence was high in both groups. Mortality was associated with male gender [HR 1.44], chronic opioids or benzodiazepines use [HR 1.07], home oxygen use [HR 1.82], fixed pressure mode of ventilation [HR 1.55], NIV inspiratory pressure [HR 1.05], and thoracic cancer [HR 1.27]; obesity [HR: 0.43], age [HR 0.99] and NIV expiratory pressure [HR 0.94] were associated with decreased mortality. In the obese, univariable analyses revealed that chest wall disease, thoracic cancer, home oxygen use, FEV1% predicted, and ventilation parameters were associated with mortality. In the non-obese, male gender and respiratory comorbidities were related to mortality.

INTERPRETATION

Obesity is associated with improved survival in COPD patients highly adherent to NIV. Other factors associated with mortality reflect disease severity and ventilator parameters, with differences between obese and non-obese patients.

Unintentional weight loss is reflected in worse one-year clinical outcomes among COPD outpatients

RATIONALE

Unintentional weight loss (UWL) is prevalent among patients with chronic obstructive pulmonary disease (COPD). However, little research has been done on UWL as an independent variable in terms of clinical outcome. The aim of this study was to investigate the association between BMI, UWL, and clinical outcome in terms of hospitalization, length of stay, exacerbations, mortality, and quality of life (QoL) within six months and one year in a hospital outpatient setting.

METHODS

A prospective single-center cohort study enrolled 200 patients from the COPD outpatient clinic between October 2020 and May 2021 at a Danish Hospital. At baseline, data was collected using patients' electronic journals and a quantitative questionnaire was gathered with a patient-reported UWL of 5% of body weight within three months. At six months and one-year follow-ups, data was collected using the patients' medical journals and a telephonic interview with the EQ-5D-5L and SARC-F questionnaire and the number of non-hospitalization exacerbations since inclusion. Data were analyzed using logistic and Cox hazard regression analysis.

RESULTS

A total of 187 patients were eligible for follow-up (mean age 69.2 years, 43.9% males, median BMI 26.8 kg/m2), and the prevalence of UWL was 13.4%. UWL was associated with an almost trifold risk of >five days stay (OR = 2.94, p = 0.021). Additionally, UWL was associated with a worse QoL. A higher risk of exacerbation was found in the underweight patients (OR = 4.94, p = 0.014). No significant difference in mortality was found.

CONCLUSION

UWL as a solitary factor is associated with increased hospital length of stay and a worse QoL. The results provide further evidence that implementation of regular screening for UWL in addition to BMI might be beneficial to include in international COPD guidelines for outpatient settings.

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.

Impaired Skeletal Muscle in Patients with Stable Chronic Obstructive Pulmonary Disease (COPD) Compared with Non-COPD Patients

Purpose

This study was designed to investigate the differences in skeletal-muscle atrophy between patients with stable chronic obstructive pulmonary disease (COPD) and healthy controls; associated factors were also considered. The study comprised selected residents of communities near the First Affiliated Hospital of Soochow University in Suzhou City, East China.

Patients and Methods

Included in this study were 123 COPD patients and 60 controls. All patients completed spirometry as well as examinations to determine their functional exercise capacity, body composition, and handgrip strength (HGS).

Results

COPD patients had less fat-free mass (FFM), a lower FFM index (FFMI), and a lower 6-min walking distance (6MWD) compared with controls (P = 0.007, P = 0.020, and P < 0.001, respectively) (FFMI: 17.59 ± 1.83 vs 18.34 ± 1.64). The HGS of these patients was also lower compared with that of controls (32.88 ± 7.84 vs 35.48 ± 7.42), and HGS tended toward statistical significance (P = 0.064, respectively). In multivariate analysis, age (β = -0.107, P < 0.001), gender (β = 0.212, P < 0.001), body mass index (BMI) (β = 0.462, P < 0.001), FEV1% (β = 0.108, P = 0.009), and calf circumference (CC) (β = 0.457, P < 0.001) were significantly associated with FFMI.

Conclusion

Impaired skeletal muscle mass was more common in COPD patients than in controls. Multiple regression analysis showed that CC may be used to detect the degree of impairment, particularly by health-care providers working outside of the hospital.

Obesity Paradox in Lung Diseases: What Explains It?

BACKGROUND

Obesity is a globally increasing health problem that impacts multiple organ systems and a potentially modifiable risk factor for many diseases. Obesity has a significant impact on lung function and is strongly linked to the pathophysiology that contributes to lung diseases. On the other hand, reports have emerged that obesity is associated with a better prognosis than for normal weight individuals in some lung diseases, including pneumonia, acute lung injury/acute respiratory distress syndrome, chronic obstructive pulmonary disease, and lung cancer. The lesser mortality and better prognosis in patients with obesity is known as obesity paradox. While obesity paradox is both recognized and disputed in epidemiological studies, recent research has suggested possible mechanisms.

SUMMARY

In this review, we attempted to explain and summarize these factors and mechanisms, including immune response, pulmonary fibrosis, lung function, microbiota, fat and muscle reserves, which are significantly altered by obesity and may contribute to the obesity paradox in lung diseases. We also discuss contrary literature that attributes the "obesity paradox" to confounding.

KEY MESSAGES

The review will illustrate the possible role of obesity in the prognosis or course of lung diseases, leading to a better understanding of the obesity paradox and provide hints for further basic and clinical research in lung diseases.

The Role of Smoking in the Mechanisms of Development of Chronic Obstructive Pulmonary Disease and Atherosclerosis

Tobacco smoking is a major cause of chronic obstructive pulmonary disease (COPD) and atherosclerotic cardiovascular disease (ASCVD). These diseases share common pathogenesis and significantly influence each other's clinical presentation and prognosis. There is increasing evidence that the mechanisms underlying the comorbidity of COPD and ASCVD are complex and multifactorial. Smoking-induced systemic inflammation, impaired endothelial function and oxidative stress may contribute to the development and progression of both diseases. The components present in tobacco smoke can have adverse effects on various cellular functions, including macrophages and endothelial cells. Smoking may also affect the innate immune system, impair apoptosis, and promote oxidative stress in the respiratory and vascular systems. The purpose of this review is to discuss the importance of smoking in the mechanisms underlying the comorbid course of COPD and ASCVD.

Recent Prevalence of and Factors Associated With Chronic Obstructive Pulmonary Disease in a Rapidly Aging Society: Korea National Health and Nutrition Examination Survey 2015-2019

BACKGROUND

The prevalence of chronic obstructive pulmonary disease (COPD) increases with age, and aging is an important risk factor for COPD development. In the era of global aging, demographic information about the prevalence of and factors associated with COPD are important to establish COPD care plans. However, limited information is available in rapidly aging societies, including Korea.

METHODS

We conducted a cross-sectional observational study using Korea National Health and Nutrition Examination Survey data from 2015-2019. We included 15,613 participants and analyzed trends of and factors associated with COPD.

RESULTS

During the study period, the overall prevalence of COPD was 12.9%. Over five years, the yearly prevalence of COPD was fairly constant, ranging from 11.5% to 13.6%. Among individuals aged ≥ 70 years, nearly one-third met COPD diagnostic criteria. In the multivariable analysis, age 70 years or older was the most strong factor associated with COPD (adjusted odds ratio [aOR], 17.86; 95% confidence interval [CI], 14.16-22.52; compared with age 40-49), followed by asthma (aOR, 3.39; 95% CI, 2.44-4.71), male sex (aOR, 2.64; 95% CI, 2.18-3.19), and current smokers (aOR, 2.60; 95% CI, 2.08-3.25). Additionally, ex-smokers, low income, decreased forced expiratory volume in 1 second %pred, and a history of pulmonary tuberculosis were associated with COPD. On the other hand, body mass index (BMI) ≥ 25 kg/m² (aOR, 0.62; 95% CI, 0.54-0.71; compared with BMI 18.5-24.9 kg/m²) had an inverse association with COPD.

CONCLUSION

Recent trends in the prevalence of COPD in South Korea are relatively stable. Approximately one-third of participants aged 70 years and older had COPD. Aging was the most important factor associated with COPD.

Interrelationships between tuberculosis and chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Our objective was to review the current literature regarding socioeconomic, environmental, clinical, and immunologic factors common to chronic obstructive pulmonary disease (COPD) and tuberculosis (TB).

RECENT FINDINGS

Recent studies suggest that TB patients might be at increased risk for developing COPD. Conversely, additional prospective cohort studies have determined that COPD patients are at increased risk for active TB: a risk that appears to be partially mediated through inhaled corticosteroid use. Tobacco smoking, poverty, air pollution, and malnutrition are associated with COPD and TB. Vitamin D has been shown to prevent COPD exacerbations, but its use for preventing TB infection remains unclear. Surfactant deficiency, elevated matrix metalloproteinases, and toll-like receptor 4 polymorphisms play key roles in the pathogenesis of both diseases.

SUMMARY

Recent studies have elucidated interrelationships between COPD and TB. Future research is needed to optimize clinical and public health approaches that could mitigate risk factors contributing to both diseases.

Obesity Paradox: Fact or Fiction?

PURPOSE OF REVIEW

Obesity is related to several comorbidities such as type 2 diabetes mellitus, cardiovascular disease, heart failure, and various types of cancers. While the detrimental effect of obesity in both mortality and morbidity has been well established, the concept of the obesity paradox in specific chronic diseases remains a topic of continuous interest. In the present review, we examine the controversial issues around the obesity paradox in certain conditions such as cardiovascular disease, several types of cancer and chronic obstructive pulmonary disease, and the factors that may confound the relation between obesity and mortality.

RECENT FINDINGS

We refer to the obesity paradox when particular chronic diseases exhibit an interesting "paradoxical" protective association between the body mass index (BMI) and clinical outcomes. This association, however, may be driven by multiple factors among which the limitations of the BMI itself; the unintended weight loss precipitated by chronic illness; the various phenotypes of obesity, i.e., sarcopenic obesity or the athlete's obesity phenotype; and the cardiorespiratory fitness levels of the included patients. Recent evidence highlighted that previous cardioprotective medications, obesity duration, and smoking status seem to play a role in the obesity paradox. The obesity paradox has been described in a plethora of chronic diseases. It cannot be emphasized enough that the incomplete information received from a single BMI measurement may interfere with outcomes of studies arguing in favor of the obesity paradox. Thus, the development of carefully designed studies, unhampered by confounding factors, is of great importance.

A Systematic Review of the Prognostic Significance of the Body Mass Index in Idiopathic Pulmonary Fibrosis

The identification of novel prognostic biomarkers might enhance individualized management strategies in patients with idiopathic pulmonary fibrosis (IPF). Although several patient characteristics are currently used to predict outcomes, the prognostic significance of the body mass index (BMI), a surrogate measure of excess fat mass, has not been specifically investigated until recently. We systematically searched PubMed, Web of Science, and Scopus, from inception to July 2022, for studies investigating associations between the BMI and clinical endpoints in IPF. The Joanna Briggs Institute Critical Appraisal Checklist was used to assess the risk of bias. The PRISMA 2020 statement on the reporting of systematic reviews was followed. Thirty-six studies were identified (9958 IPF patients, low risk of bias in 20), of which 26 were published over the last five years. Significant associations between lower BMI values and adverse outcomes were reported in 10 out of 21 studies on mortality, four out of six studies on disease progression or hospitalization, and two out of three studies on nintedanib tolerability. In contrast, 10 out of 11 studies did not report any significant association between the BMI and disease exacerbation. Our systematic review suggests that the BMI might be useful to predict mortality, disease progression, hospitalization, and treatment-related toxicity in IPF (PROSPERO registration number: CRD42022353363).

Association of reduced BMI, length of hospital stay, mortality, and malnutrition diagnosis in patients with acute exacerbation COPD: A secondary analysis of a cohort study

BACKGROUND

Body mass index (BMI) presents prognostic value in chronic obstructive pulmonary disease (COPD), and despite its limitations in capturing malnutrition, its use is common to assess nutritional status. We aimed to confirm the association between BMI and in-hospital outcomes in acute exacerbation of COPD (AECOPD) and its inaccuracy in diagnosing malnutrition.

METHODS

We diagnosed malnutrition using the Subjective global assessment (SGA), Academy of Nutrition and Dietetics-American Society for Parenteral and Enteral Nutrition (AND-ASPEN), and two cutoff values for reduced BMI (age-related and ≤ 21.0). BMI accuracy was assessed using the area under the receiver operating characteristic (AUC-ROC) curve and SGA and AND-ASPEN as references. We evaluated in-hospital mortality and hospital stay outcomes and constructed logistic regression models.

RESULTS

The median hospital stay was 11 (7-18) days, and 7.5% of patients died. Malnutrition prevalence according to BMI, SGA, and AND-ASPEN was 21.4% (mean of both cutoff values), 50%, and 54%, respectively. Reduced BMI presented low agreement (κ = 0.315-0.383) and unsatisfactory accuracy (AUC-ROC curve = 0.333-0.679) with reference methods for malnutrition diagnosis. Age-related reduced BMI (odds ratio [OR] = 2.11; 95% CI, 1.10-4.04) and BMI ≤ 21.0 (OR = 2.25; 95% CI, 1.13-4.48) were associated with hospital stays longer than the median in adjusted models, but not in-hospital mortality.

CONCLUSION

BMI was inaccurate in identifying malnutrition in hospitalized patients with AECOPD and was associated with hospital stays longer than ten days.

Real-World Clinical Outcomes Based on Body Mass Index and Annualized Weight Change in Patients with Idiopathic Pulmonary Fibrosis

INTRODUCTION

Identification of clinical characteristics associated with prognosis for idiopathic pulmonary fibrosis (IPF) may help to guide management decisions. This analysis utilized data from the Pulmonary Fibrosis Foundation Patient Registry to examine the relationships between clinical outcomes and both body mass index (BMI) at study enrollment (hereafter referred to as baseline BMI) and annualized percent change in body weight in patients with IPF in a real-world setting.

METHODS

The following outcomes over 24 months were stratified by baseline BMI and annualized percent change in body weight: all-cause mortality; annualized change in percent predicted forced vital capacity (%FVC), percent predicted diffusing capacity for carbon monoxide, and 6-min walk distance; all-cause and respiratory-related hospitalizations; and acute exacerbations.

RESULTS

Overall, 600 patients with IPF were included (baseline BMI: < 25 kg/m², n = 120; 25 to < 30 kg/m², n = 242; ≥ 30 kg/m², n = 238; annualized percent change in body weight: no loss, n = 95; > 0% to < 5% loss, n = 425; ≥ 5% loss, n = 80). Enrollment demographics and characteristics were generally similar across subgroups. There was no association between mortality and BMI. All-cause mortality was lower among patients who experienced no annualized weight loss versus those with ≥ 5% (OR [95% CI] 3.28 [1.15, 10.95]) or > 0 to < 5% weight loss (OR [95% CI] 2.83 [1.14, 8.62]) over 24 months. Patients with baseline BMI < 25 kg/m² had a significantly greater estimated annualized decline in %FVC versus patients with baseline BMI ≥ 30 kg/m² (difference [95% CI] 1.47 [0.01, 2.93]). No relationship was observed between %FVC and weight loss. Other clinical outcomes were generally similar across subgroups.

CONCLUSIONS

Some clinical outcomes may be worse in patients with IPF who have a low BMI (< 25 kg/m²) or who experience weight loss over 24 months, but the causation for these relationships is unknown. These results may help to inform management decisions for patients with IPF.

CLINICALTRIALS

GOV IDENTIFIER

NCT02758808.

Normal weight and waist obesity indicated by increased total body fat associated with all-cause mortality in stage 3–5 chronic kidney disease

Patients with chronic kidney disease (CKD) demonstrate a survival benefit with a high body mass index (BMI); this is the obesity paradox. Central obesity has a higher prognostic value than BMI, even in those with normal weight. Whether total body fat percentage (TBF%) provides more information than BMI and waist circumference (WC) remains unknown. We included 3,262 Asian patients with stage 3–5 CKD and divided these patients by TBF% and waist-to-height ratio (WHtR) quartiles (Q1–Q4). TBF% was associated with BMI, WC, nutritional markers, and C-reactive protein. In all patients, BMI but not TBF% or WHtR demonstrated a survival paradox. In patients with BMI &lt;25 kg/m2, but not in those with BMI ≥ 25 kg/m2, TBF% Q4 and WHtR Q4 were associated with all-cause mortality, with hazard ratios [HRs; 95% confidence intervals (CIs)] of 2.35 (1.31–4.22) and 1.38 (1.06–1.80), respectively. The HRs of TBF% Q4 for all-cause mortality were 2.90 (1.50–5.58) in patients with a normal WC and 3.81 (1.93–7.50) in patients with normal weight and normal WC (All P for interaction &lt; 0.05). In conclusion, TBF% can predict all-cause mortality in patients with advanced CKD and a normal weight, normal WC, or both.

Obesity may increase survival, regardless of nutritional status: a Swedish cohort study in nursing homes

Background

To investigate the associations between the body mass index (BMI), Mini Nutritional Assessment–Short Form (MNA-SF) scores, and 2-year mortality.

Methods

A nationwide cohort study using data from a national quality register of older (age ≥ 65 years) nursing home residents (N = 47,686). Individuals were categorized according to BMI as underweight (< 18.5 kg/m²), normal-weight (18.5–24.9 kg/m²), overweight (25.0–29.9 kg/m²), and obese (class I, 30.0–34.9 kg/m²; class II, 35.0–39.9 kg/m²; class III, ≥ 40.0 kg/m²). Participants’ nutritional status were categorized as good (MNA-SF score 12–14), at risk of malnutrition (MNA-SF score 8–11), or malnutrition (MNA-SF score 0–7). Associations with mortality were analysed using Cox proportional-hazards models.

Results

At baseline, 16.0% had obesity, and 14.6% were malnourished. During 2 years of follow-up, 23,335 (48.9%) individuals died. Compared with normal-weight individuals, mortality was greater among underweight individuals [hazard ratio (HR) 1.62, 95% confidence interval (CI) 1.55–1.69] and lesser among individuals with class I (HR 0.63, 95% CI 0.60–0.66), class II (HR 0.62, 95% CI 0.56–0.68), and class III (HR 0.80, 95% CI 0.69–0.94) obesity. Compared with individuals with good nutritional status, mortality was increased for those with malnutrition (HR 2.98,95% CI 2.87–3.10). Lower mortality among obese individuals was also seen in subgroups defined according to MNA-SF scores.

Conclusions

Among older nursing home residents, obesity, including severe obesity, was associated with lower 2-year mortality. Higher BMIs were associated with better survival, regardless of nutritional status according to MNA-SF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03356-1.

The Relationship of Energy Malnutrition, Skeletal Muscle and Physical Functional Performance in Patients with Stable Chronic Obstructive Pulmonary Disease

Weight loss is a factor that affects prognosis in patients with chronic obstructive pulmonary disease (COPD) independent of lung function. One of the major factors for weight loss is energy malnutrition. There have been no reports on the factors related to energy malnutrition in COPD patients. This retrospective observational study aimed to investigate these factors. We included 163 male subjects with COPD. Respiratory quotient (RQ), an index of energy malnutrition, was calculated by expiratory gas analysis using an indirect calorimeter. RQ < 0.85 was defined as the energy-malnutrition group and RQ ≥ 0.85 as the no energy-malnutrition group. Factors related to energy malnutrition were examined by multivariate and decision-tree analysis. We finally analyzed data from 56 selected subjects (median age: 74 years, BMI: 22.5 kg/m2). Energy malnutrition was observed in 43%. The independent factors associated with energy malnutrition were tidal volume (VT) (OR 0.99; 95% CI 0.985−0.998; p = 0.015) and Th12 erector spinae muscle cross-sectional area SMI (Th12ESMSMI) (OR 0.71; 95% CI 0.535−0.946; p = 0.019). In decision-tree profiling of energy malnutrition, VT was extracted as the first distinguishable factor, and Th12ESMSMI as the second. In ROC analysis, VT < 647 mL (AUC, 0.72) or Th12ESMSMI < 10.1 (AUC, 0.70) was the cutoff value for energy malnutrition. Energy malnutrition may be an early warning sign of nutritional disorders.

The Obesity Paradox in Chronic Heart Disease and Chronic Obstructive Pulmonary Disease

Obesity in recent years has become an epidemic. A high body mass index (BMI) is one of today's most crucial population health indicators. BMI does not directly quantify body fat but correlates well with easier body fat measurements. Like smoking, obesity impacts multiple organ systems and is a major modifiable risk factor for countless diseases. Despite this, reports have emerged that obesity positively impacts the prognosis of patients with chronic illnesses such as chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD), a phenomenon known as the Obesity Paradox. This article attempts to explain and summarize this phenomenon.

As it stands, two theories explain this paradox. The muscle mass hypothesis states that obese patients are better adapted to tide through acute exacerbations due to increased reserve because of greater muscle mass. The other theory focuses on brown adipose tissue and its anti-inflammatory effects on the body.

We performed a literature review on research articles published in English from 1983 to the present in the following databases - PubMed, Elsevier, and Google Scholar. The following search strings and Medical Subject Headings (MeSH) terms were used: "Obesity," "Heart Failure," "COPD," and "Cardio-Respiratory Fitness." In this review, we looked at the obesity paradox in Heart Failure and COPD. We summarized the current literature on the Obesity Paradox and reviewed its relationship with Cardio-Respiratory Fitness.

The Association of Body Mass Index With Mortality Among Pulmonary Hypertension Patients: A Systematic Review and Meta-Analysis of Cohort Studies

Objective

To run a systematic review and meta-analysis of related studies on body mass index (BMI) and the risk of death among pulmonary hypertension (PH) patients, as well as, to shed light on the shape and strength of the dose-response association.

Methods

Studies published up to Jun 2021 in scientific databases such as Scopus, and PubMed as well as Google Scholar were searched. Cohort studies that reported risk estimates for at least two categories of BMI or per certain increase in BMI in relation to mortality in PH patients were included. Summary relative risks were determined with random effects models. Non-linear relationship was discovered with dose-response analysis.

Results

All in all, 15 cohort studies were selected. The number of participants was 127,215 out of which 73,999 were reported dead. The summary RR for mortality per a 5-unit increment in BMI was 0.83 (95% confidence interval 0.77–0.89; I² = 75.6%, n = 9) among PH patients. There was a non-linear dose-response relation between BMI and mortality in PH patients (P_{non−linearity} < 0.001), with the lowest risk being at BMI 32–38 kg/m².

Conclusion

Higher BMI is related to decreased risk of mortality among PH patients and the lowest point of the curve was seen at BMI 32–38.

Evaluation of Apixaban safety and effectiveness in morbidly obese patients with atrial fibrillation: a retrospective cohort study

Background

The benefit of apixaban to reduce stroke risk in morbidly obese patients with nonvalvular atrial fibrillation (AF) is still undetermined. The International Society of Thrombosis and Hemostasis recommends avoiding the use of direct oral anticoagulants (DOAC)s in morbidly obese patients (body mass index > 40 or weight > 120 kg) because of limited clinical data. This exploratory study aims to evaluate the effectiveness and safety of using apixaban in morbidly obese (body mass index (BMI) ≥ 40) patients with AF.

Methods

An exploratory retrospective cohort study was conducted at a single-center, including adult patients with non-valvular AF using apixaban between 01/01/2016 and 31/12/2019. Patients were excluded if they were known to have liver cirrhosis Child-Pugh C, mechanical valve, serum creatinine > 1.5 mg/dL, follow up < 3 months, or using apixaban with a dose of ≤5 or > 10 mg/day. Included patients were categorized into two groups based on their BMI (BMI<40 Vs. BMI ≥ 40). The primary outcome was all thrombotic events, while the secondary outcomes were major and minor bleeding after apixaban initiation. Propensity score (PS) matching was used (1:1 ratio) based on the patient’s age, gender, and HAS-BLED score.

Results

A total of 722 patients were eligible; 254 patients were included after propensity score matching based on the selected criteria. The prevalence of all thrombotic events was similar between the two groups in the first year of apixaban initiation (OR (95%CI): 0.58 (0.13, 2.5), p-value = 0.46). In addition, the odds of developing major and minor bleeding were not statistically significant between the two groups (OR (95%CI): 0.39 (0.07, 2.03), p-value = 0.26 and OR (95%CI): 1.27 (0.56, 2.84), p-value = 0.40), respectively).

Conclusion

This exploratory study showed similar effectiveness and safety of apixaban use in both morbid and non-morbid obese patients with non-valvular AF. However, a larger randomized controlled trial with a longer follow-up period needs to confirm our findings.

Obesity survival paradox in patients hospitalized with community-acquired pneumonia. Assessing sex-differences in a population-based cohort study

AIM

To assess the effect of obesity status (no obesity/obesity/ morbid obesity) on hospital outcomes (length of hospital stay [LOHS] and in-hospital mortality [IHM]), among patients hospitalized with community-acquired pneumonia (CAP) and according to sex.

METHODS

We conducted a retrospective cohort study based on national hospital discharge data of all subjects aged≥ 18 years hospitalized with CAP in Spain from 2016 to 2019.

RESULTS

We identified 519,750 hospital discharges with CAP. The prevalence of obesity was 6.38% and 1.78%. for morbid obesity. The mean age was higher for patients without obesity followed by those with obesity and morbid obesity (74.61, 72.5 and 70.2 years respectively; p<0.001). The mean number of comorbidities was similar for patients with obesity and morbid obesity (2.30 and 2.29) and significantly higher than for non-obese individuals (2.10). The crude IHM was higher among the non-obese patients (12.71%) followed by those with morbid obesity (8.56%) and obesity (7.72%), without finding differences between men and women. Among men, after multivariable logistic regression analysis, the probability of dying in the hospital was significantly lower for those with obesity (Adjusted-OR 0.59;95%CI 0.55-0.63) and morbid obesity (Adjusted-OR 0.62;95%CI 0.54-0.71) compared with non-obese. The protective effect of obesity (Adjusted-OR 0.71;95%CI 0.67-0.75) and morbid obesity (Adjusted OR 0.73;95%CI 0.66-0.8) was also observed among women.

CONCLUSIONS

Obese and obesity morbid patients with CAP have a lower risk of IHM than non-obese patients, without sex differences in this association. These data confirm the existence of the obesity paradox in this patient population.

Impact of obesity and diabetes on postoperative outcomes following surgical treatment of nontraumatic subarachnoid hemorrhage: Analysis of the ACS-NSQIP Database

BACKGROUND

Nontraumatic subarachnoid hemorrhage (SAH) refers to high pressure extravasation of blood into the subarachnoid space that typically occurs spontaneously from rupture of cerebral aneurysm. The purpose of this study was to identify postoperative complications requiring increased surveillance in obese, diabetic, and hypertensive patients.

METHODS

Patients who underwent surgical treatment for nontraumatic SAH were queried in the American College of Surgeons National Quality Improvement Program (ACS-NSQIP) database from the years 2012-2018. Cases were identified using ICD codes and then classified independently by three dichotomous diagnoses: obesity, diabetes, and hypertension.

RESULTS

Among 1,002 patients meeting inclusion criteria, 311 (31%) were obese (BMI >30), 86 (9%) had diabetes treated with insulin or non-insulin agents and 409 (41%) required medication for hypertension. There was a statistically significant association between diabetes and post-operative pneumonia (OR = 1.694; 95% CI 0.995 - 2.883; p = 0.050), prolonged ventilator dependence (OR = 1.700; 95% CI 1.087 - 2.661; p = 0.019), and death (OR = 1.846; 95% CI 1.071 - 3.179; p = 0.025). Medicationdependent hypertension was statistically associated with incidence of stroke/CVA (OR = 1.763; 95% CI 1.056 - 2.943; p = 0.023). Obesity was not associated with adverse outcomes in this population.

CONCLUSIONS

In patients undergoing surgical management of SAH, hypertensive and diabetic patients had poorer outcomes, including prolonged ventilator dependence, pneumonia, stroke/CVA, and death. Surprisingly, preexisting obesity was not associated with poor outcomes. In fact, overweight BMI, Class I, and Class II obesity had decreased need for transfusion in the 30-day postoperative period.

Effects of Obstructive Sleep Apnea and Obesity on 30-Day Readmissions in Patients with Chronic Obstructive Pulmonary Disease: A Cross-Sectional Mediation Analysis

Rationale: Comorbidity is a significant driver of health status and healthcare utilization in chronic obstructive pulmonary disease (COPD). Obstructive sleep apnea (OSA) portends poorer outcomes, whereas obesity is protective. Objectives: We describe the prevalence and influence of these comorbidities on COPD readmissions. Methods: We collated discharge records for COPD exacerbations spanning 2010-2016 from the Nationwide Readmissions Database using Medicare's Hospital Readmissions Reduction Program criteria, with OSA-COPD overlap identified by concomitant diagnosis code for OSA. We used mixed-effects logistic regression to predict readmission odds. A cross-sectional mediation analysis was performed to evaluate the extent that OSA attenuated obesity's impact on readmission. Results: Of 1,662,983 qualifying COPD discharges, 19.1% carried a diagnosis of obesity and 12.9% had OSA, with both diagnoses present in 7.8%. In unadjusted analyses, obesity (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.03-1.05; P < 0.001) and OSA (OR, 1.11; 95% CI, 1.10-1.13; P < 0.001) had increased readmission odds. In models adjusted for patient and hospital characteristics, 71% of readmission risk from obesity was attributable to OSA. When additionally adjusted for Charlson Comorbidity Index, we found that OSA remained a significant risk factor (OR, 1.05; 95% CI, 1.03-1.06; P < 0.001), whereas obesity remained protective (OR, 0.96; 95% CI, 0.94-0.97; P < 0.001) even after accounting for OSA. Conclusions: A significant proportion of patients with COPD suffer comorbid OSA and obesity with resultant readmission risk. Interestingly, obesity's protective effect attenuates readmission odds from OSA. Taken together, OSA and aggregate comorbidity influence readmissions in patients with COPD. Testing for and treating OSA-COPD overlap may provide a mechanism to reduce avoidable readmissions.

The HUNT study: Association of comorbidity clusters with long-term survival and incidence of exacerbation in a population-based Norwegian COPD cohort

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease often viewed as part of a multimorbidity complex. There is a need for better phenotyping of the disease, characterization of its interplay with other comorbidities and its association with long-term outcomes. This study aims to examine how clusters of comorbidities are associated with severe exacerbations and mortality in COPD.

METHODS

Participants with potential COPD were recruited from the second (1995-1997) and third (2006-2008) survey of the HUNT Study and followed up until April 2020. Ten objectively identified comorbidities were clustered using self-organizing maps. Severe COPD exacerbations requiring hospitalization were assessed using hospital data. All-cause mortality was collected from national registries. Multivariable Cox regression was used to calculate hazard ratios (HRs) with 95% CIs for the association between comorbidity clusters and all-cause mortality. Poisson regression was used to calculate incidence rate ratios (IRRs) with 95% CI for the cumulative number of severe exacerbations for each cluster.

RESULTS

Five distinct clusters were identified, including 'less comorbidity', 'psychological', 'cardiovascular', 'metabolic' and 'cachectic' clusters. Using the less comorbidity cluster as reference, the psychological and cachectic clusters were associated with all-cause mortality (HR 1.23 [1.04-1.45] and HR 1.83 [1.52-2.20], adjusted for age and sex). The same clusters also had increased risk of exacerbations (unadjusted IRR of 1.24 [95% CI 1.04-1.48] and 1.50 [95% CI 1.23-1.83], respectively).

CONCLUSION

During 25 years of follow-up, individuals in the psychological and cachectic clusters had increased mortality. Furthermore, these clusters were associated with increased risk of severe COPD exacerbations.