Association between insulin resistance and lung function trajectory over 4 years in South Korea: community-based prospective cohort

Association of triglyceride glucose and obesity indices with chronic obstructive pulmonary disease in US adults: data from 2013 to 2018 NHANES

BACKGROUND

The impact of insulin resistance (IR) on chronic obstructive pulmonary disease (COPD) has caught increasing attention, and the triglyceride-glucose (TyG) index and related indices are deemed reliable indicators for evaluating IR. Nevertheless, the potential associations of TyG and obesity-related indexes with COPD are currently understudied. Hence, this paper was to inspect the links of TyG and obesity-related indices with COPD.

METHODS

This was a cross-sectional study based on data from the NHANES 2013-2018. Weighted logistic regression (WLR), restricted cubic sample (RCS), and receiver operating characteristic (ROC) curves were leveraged to examine the links of the TyG index and obesity indices with COPD. The stability of the correlations was also assessed via subgroup analyses.

RESULTS

Data from 6383 participants were finally included, including 583 patients with COPD. WLR discovered positive associations of TyG, TyG-body mass index (TyG-BMI), TyG-waist circumference (TyG-WC), and TyG-waist height ratio (TyG-WHtR) with COPD regardless of covariate adjustment (p-value < 0.05, p for trend test < 0.05). After adjusting for all confounders, RCS analysis signaled notable linear links of TyG and obesity-related indices with COPD (p-value < 0.05, p for nonlinear > 0.05). TyG-WHtR showed the highest association with COPD among the indices tested, albeit with limited discriminative ability (AUC = 0.643, 95% CI: 0.619 ~ 0.665). Subgroup analyses further validated the stability and reliability of the results.

CONCLUSION

TyG and its combination with obesity-related indicators are associated with COPD. Among these, TyG-WHtR showed the strongest association with COPD, although causal relationships cannot be inferred and its discriminative ability remained modest. Further prospective studies are warranted to validate these findings.

CLINICAL TRIAL NUMBER

Not applicable.

Triglyceride-glucose index as an independent predictor of mortality in patients with chronic respiratory diseases

Objective

The consequences of chronic pulmonary illness are known to exacerbate in individuals with metabolic syndrome and insulin resistance. However, the relationship between triglyceride-glucose (TyG) index, a reliable alternative biomarker of metabolic dysfunction, and chronic respiratory diseases (CRDs) are inconclusive.

Research design and methods

Our research involved a total of 7,819 adult individuals diagnosed with CRDs who participated in the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018. To assess the correlation between the TyG index and survival rates, we employed multivariable weighted Cox regression analysis, smoothing curve fitting, survival curve analysis and subgroup analysis to investigate the relationship.

Results

Higher TyG index among CRDs shown a substantial positive correlation with all-cause mortality after controlling for relevant confounders. The restricted cubic spline analysis showed a nonlinear relationship between the TyG score and all-cause mortality in CRDs. Patients with higher TyG indexes had a greater risk of all-cause mortality according to Kaplan-Meier survival curves.

Conclusion

The clinical relevance of the TyG index in predicting the life expectancy of individuals with CRDs is highlighted by our research. The TyG index can serve as a substitute biomarker for monitoring the wellbeing of the individuals with CRDs.

The association between triglyceride glucose-body mass index and mortality in critically ill patients with respiratory failure: insights from ICU data

Respiratory failure (RF) lead to high mortality rates and extended hospital stays in intensive care unit (ICU). The Triglyceride-Glucose (TyG) index, a reliable surrogate marker for insulin resistance (IR), predicted adverse outcomes in various diseases. Combining weight-related indices like body mass index (BMI) with TyG to form the TyG-BMI enhanced the assessment of IR and its impact on patient outcomes. However, the association between TyG-BMI and outcomes in patients with RF remained underexplored. This study retrospectively analyzed data from the MIMIC-IV database, focusing on critically ill patients with RF. From an initial cohort of 19,429 patients, 2177 met the inclusion criteria and were divided into quartiles based on TyG-BMI values. Key clinical information was collected within the first 24 h of ICU admission, including demographics, lab results, vital signs, and scoring systems such as SAPS II and SOFA. Primary outcome was 28-day, secondary outcomes were 180-day and 1-year mortality. Data were analyzed using multivariable Cox regression models, Kaplan-Meier survival curves, and restricted cubic splines to assess the nonlinear relationship between TyG-BMI and mortality. The study found significant differences in baseline characteristics across TyG-BMI quartiles. Kaplan-Meier survival curves indicated a higher survival probability for patients in the lowest TyG-BMI quartile (Q1) compared to higher quartiles (Q2-Q4). Adjusted hazard ratios demonstrated a nonlinear association between higher TyG-BMI values and increased mortality risk at all three time points. The RCS-derived cut-off value of 269 for TyG-BMI was identified as a significant threshold, with higher TyG-BMI values correlating with lower mortality risks. Subgroup analyses reinforced these findings across different patient demographics and clinical profiles. Higher TyG-BMI was associated to lower short-term and long-term mortality, suggesting a potential protective effect. These findings highlighted the importance of the TyG-BMI as a robust prognostic marker, providing valuable insights for improving treatment strategies for patients with RF.

The role of type 2 diabetes in the severity of adult asthma

PURPOSE OF REVIEW

This review summarizes recent basic, translational, and clinical research on type 2 diabetes (T2D) and its relationship with asthma severity in the context of T2D mechanisms and asthma outcomes.

RECENT FINDINGS

Several clinical asthma outcomes, such as lung function and exacerbations, demonstrate a strong association between T2D and asthma and support that T2D contributes to worse asthma outcomes. Multiple mechanisms underlying those observed associations, and their representative biomarkers, have been proposed. However, prospective, controlled human studies in the context of both T2D and asthma are limited.

SUMMARY

T2D is associated with worse asthma outcomes and more severe asthma. Yet patients with more severe or uncontrolled asthma are also at a higher risk for systemic steroid exposure, which worsens glycemic control and metabolic dysregulation. Preclinical and translational studies point to metabolic dysregulation as a driver of airway inflammation. Addressing these metabolic pathways through T2D treatment may, in turn, directly or indirectly improve clinical asthma outcomes. While additional research is needed to identify biomarkers of risk and treatment response in metabolic asthma, this review highlights the importance of considering T2D as a clinically relevant asthma comorbidity.

Diabetes-inducing effects of bronchial asthma

BACKGROUND

The relationship between diabetes mellitus (DM) and asthma is complex and can impact disease trajectories.

AIM

To explore the bidirectional influences between the two conditions on clinical outcomes and disease control.

METHODS

We systematically reviewed the literature on the relationship between DM and asthma, focusing on their impacts, mechanisms, and therapeutic implications. Various studies were assessed, which investigated the effect of glycemic control on asthma outcomes, lung function, and exacerbations. The study highlighted the role of specific diabetes medications in managing asthma.

RESULTS

The results showed that poor glycemic control in diabetes can exacerbate asthma, increase hospitalizations, and reduce lung function. Conversely, severe asthma, especially in obese individuals, can complicate diabetes management and make glycemic control more difficult. The diabetes-associated mechanisms, such as inflammation, microangiopathy, and oxidative stress, can exacerbate asthma and decrease lung function. Some diabetes medications exhibit anti-inflammatory effects that show promise in mitigating asthma exacerbations.

CONCLUSION

The complex interrelationship between diabetes and asthma suggests bidirectional influences that affect disease course and outcomes. Inflammation and microvascular complications associated with diabetes may worsen asthma outcomes, while asthma severity, especially in obese individuals, complicates diabetes control. However, the current research has limitations, and more diverse longitudinal studies are required to establish causal relationships and identify effective treatment strategies for individuals with both conditions.

Genome-Wide Association Analysis of Rapid Decline in Lung Function: Analysis From the Korean Genome and Epidemiology Study

BACKGROUND

A rapid decline in forced expiratory volume in 1 second (FEV1) is considered an important phenotype of the development of chronic obstructive pulmonary disease (COPD). However, the associations between specific genetic variants (single-nucleotide polymorphisms; SNPs) and this phenotype remain uncertain.

METHODS

We enrolled 6,516 individuals from the Korean Genome and Epidemiology Study (KoGES). A rapid decline in FEV1 was defined as an annual decrease of FEV1 ≥ 60 mL/year. A multivariable logistic regression model was used to assess the associations between SNP variants and the rapid decline in FEV1. Considering the significant impact of smoking on lung function, a subgroup analysis based on smoking history was also conducted.

RESULTS

A genome-wide association analysis of the rapid decline in FEV1 identified 15 association signals (P < 5.0 × 10-8). Among the 15 nucleotide variants, rs9833533 and rs1496255 have been previously reported to be associated with lung function development. In the subgroup analysis, rs16951883 (adjusted odds ratio [aOR], 3.24; P = 5.87 × 10-8) was the most significant SNP associated with rapid decline in FEV1 among never smokers, followed by rs41476549, rs16840064, and rs1350110. Conversely, among ever smokers, rs10959478 (aOR, 4.74; P = 8.27 × 10-7) showed the highest significance, followed by rs6805861, rs9833533, and rs16906215.

CONCLUSION

We identified 15 nucleotide variants linked to a rapid decline in FEV1, including two SNPs previously reported to be associated with lung function development. Additional SNPs, which were associated with COPD, may be found using novel phenotypes.

Association Between Triglyceride-Glucose Index and Lung Function Parameters in the General Population Undergoing Health Examinations

Purpose

To investigate the relationship between the triglyceride-glucose (TyG) index and pulmonary function metrics among the general population undergoing health examinations.

Materials and Methods

The enrollment totaled 696 participants. Fasting triglycerides and glucose levels were used to calculate the TyG index. Participants were divided into two categories according to their median TyG: one with high TyG and the other with low TyG. A portable spirometer was used to assess lung function. Fundamental clinical features and lung function indicators were compared between the two groups, and the relationship between the TyG index and lung function parameters was explored.

Results

Compared with the low TyG group, the high TyG group exhibited significantly reduced levels of FEV1/FVC, FVC% pred, FEV1% pred, FEV3% pred, FEV3/FVC, FEF75, FEF75% pred, FEF25-75% pred, and MVV% pred, suggesting poor pulmonary function. The TyG index was significantly inversely correlated with multiple pulmonary function metrics, including FVC% pred, FEV1% pred, FEV3% pred, FEV1/FVC, FEV3/FVC, FEF75, FEF75% pred and FEF25-75% pred, which persisted even after accounting for confounding variables.

Conclusion

In summary, the present study establishes a correlation between the TyG index and some lung function indicators, offering a new indicator of metabolic abnormalities related to lung functionality.

Homeostatic Measure of Insulin Resistance Is Associated With Future Asthma Exacerbations: A 1-Year Prospective Cohort Study

BACKGROUND

Recent evidence suggests that insulin resistance affects asthma outcomes. However, the effect of the homeostatic measure of insulin resistance (HOMA-IR) on airway inflammation and asthma exacerbations (AEs) is poorly understood.

OBJECTIVE

To analyze the relationship between HOMA-IR and clinical and inflammatory characteristics in patients with asthma, and the association between HOMA-IR and AEs in the following year.

METHODS

A prospective cohort study recruited participants with asthma, who were classified into the HOMA-IRhigh group and HOMA-IRlow group based on the cutoff value of 3.80 for HOMA-IR and were observed within 12 months. We evaluated the clinical and inflammatory features and conducted a 1-year follow-up to study the exacerbations. We used negative binomial regression models to analyze the association between HOMA-IR and AEs.

RESULTS

Compared with patients in the HOMA-IRlow group (n = 564), those in the HOMA-IRhigh group (n = 61) had higher levels of body mass index, a higher waist circumference and waist-hip ratio, higher triglycerides, lower cholesterol high-density lipoproteins, more neutrophils in the peripheral blood, and elevated IL-5 levels in the induced sputum. Furthermore, patients in the HOMA-IRhigh group had a significantly increased risk for moderate to severe AEs (adjusted incidence rate ratio [aIRR] = 2.26; 95% CI, 1.38-3.70), severe AEs (aIRR = 2.42; 95% CI, 1.26-4.67), hospitalization (aIRR = 2.54; 95% CI, 1.20-5.38), and emergency visits (aIRR = 3.04; 95% CI, 1.80-8.53).

CONCLUSIONS

The homeostatic measure of insulin resistance was associated with asthma-related clinical features and airway inflammation, and was an independent risk factor for future AEs. Therefore, insulin resistance may have important implications for managing asthma as a potential treatable trait.

A clinician's guide to effects of obesity on childhood asthma and into adulthood

INTRODUCTION

Obesity, one of the most common chronic conditions affecting the human race globally, affects several organ systems, including the respiratory system, where it contributes to onset and high burden of asthma. Childhood onset of obesity-related asthma is associated with high persistent morbidity into adulthood.

AREAS COVERED

In this review, we discuss the disease burden in children and adults to highlight the overlap between symptoms and pulmonary function deficits associated with obesity-related asthma in both age ranges, and then discuss the potential role of three distinct mechanisms, that of mechanical fat load, immune perturbations, and of metabolic perturbations on the disease burden. We also discuss interventions, including medical interventions for weight loss such as diet modification, that of antibiotics and anti-inflammatory therapies, as well as that of surgical intervention on amelioration of burden of obesity-related asthma.

EXPERT OPINION

With increase in obesity-related asthma due to increasing burden of obesity, it is evident that it is a disease entity distinct from asthma among lean individuals. The time is ripe to investigate the underlying mechanisms, focusing on identifying novel therapeutic targets as well as consideration to repurpose medications effective for other obesity-mediated complications, such as insulin resistance, dyslipidemia and systemic inflammation.

Obesity and Insulin Resistance in Asthma Pathogenesis and Clinical Outcomes

Common inflammatory ground links obesity, insulin resistance, and asthma. As recognition of their interplay, one worsening the natural course of the other, is recognised, questions remain about how to adequately address them altogether to improve clinical outcomes. The present manuscript sheds light on the problem, describing possible pathophysiological links, clinical views, and therapeutic challenges, raising questions about what remains to be done, and calling for multidisciplinary treatment of these patients to detect diseases early and adequately address them before they become full-blown and deteriorate their health and quality of life.

Independent effect of the triglyceride-glucose index on all-cause mortality in critically ill patients with chronic obstructive pulmonary disease and asthma: A retrospective cohort study

BACKGROUND

The triglyceride-glucose (TyG) index serves as a reliable proxy for insulin resistance (IR). IR has been linked to heightened incidence, prevalence, or severity of chronic obstructive pulmonary disease (COPD) and asthma. Prior research indicates that critically ill patients are prone to developing IR. Nevertheless, few studies have delved into the correlation between IR and all-cause mortality in critically ill patients with COPD and asthma. Therefore, the aim of this study is to explore the association between the TyG index and all-cause mortality in patients with COPD and asthma, with the goal of assessing the impact of IR on the prognosis of this patient population.

METHODS

This is a retrospective study, and all data are from the Medical Information Mart for Intensive Care IV (MIMIC-IV) critical care database. This study included 684 ICU patients with COPD and asthma and divided them into quartiles based on TyG index levels. The primary outcomes of this study were all-cause mortality during follow-up, encompassing mortality at 30 days, 90 days, and 180 days. The Kaplan-Meier analysis was used to compare all-cause mortality among the above four groups. Cox proportional hazards analyses were performed to examine the association between TyG index and all-cause mortality in critically ill patients with COPD and asthma. Restricted cubic spline analysis was used to assess potential nonlinear association between the TyG index and the primary outcome.

RESULTS

A total of 684 patients (53.9% female) were included. The 90-days all-cause mortality rate and 180-days all-cause mortality were 11.7% and 12.3%, respectively. Kaplan-Meier analysis revealed a significant association between the TyG index and both 90-days all-cause mortality (log-rank p = .039) and 180-days all-cause mortality (log-rank p = .017). Cox proportional hazards analysis revealed a significant association between the TyG index and 90-days all-cause mortality in both the unadjusted model (HR, 1.30 [95% CI 1.08-1.57] p = .005) and the model adjusted for age, gender, and diabetes (HR, 1.38 [95% CI 1.15-1.67] p < .001). Similarly, the TyG index was associated with 180-days all-cause mortality in the unadjusted model (HR, 1.30 [95% CI 1.09-1.56] p = .004) and the model adjusted for age, sex, and diabetes (HR, 1.38 [95% CI 1.15-1.66] p < .001). The restricted cubic splines (RCS) regression model indicated a significant nonlinear association between the TyG index and both 90-days and 180-days all-cause mortality. Specifically, TyG index >4.8 was associated with an increased risk of mortality at both 90 days and 180 days.

CONCLUSIONS

In summary, our results extend the utility of the TyG index to critically ill patients with COPD and asthma. Our study shows that the TyG index is a potential predictor of all-cause mortality in critically ill patients with COPD and asthma. In addition, in patients with a TyG index exceeding 4.8, there was a heightened risk of mortality. Measuring the TyG index may help with risk stratification and prognosis prediction in critically ill patients with COPD and asthma. Further prospective studies are needed to confirm our findings.

Pulmonary function testing in patients with liver cirrhosis (Review)

Liver cirrhosis is a common long-term outcome of chronic hepatic inflammation. Patients with liver cirrhosis may also have pulmonary complications. There are several reasons for pulmonary dysfunction in liver cirrhosis, including intrinsic cardiopulmonary dysfunction unrelated to liver disease and specific disorders related to the presence of liver cirrhosis and/or portal hypertension. The most prevalent and clinically significant pulmonary complications are hepatic hydrothorax, hepatopulmonary syndrome, spontaneous pulmonary empyema and portopulmonary hypertension. Pulmonary function tests (PFTs) have traditionally been used to assess the lung function of patients with liver cirrhosis. To the best of our knowledge, the present review is the first to detail all types of PFTs performed in patients with liver cirrhosis and discuss their clinical significance. Patients with liver cirrhosis have reduced values of spirometric parameters, diffusion capacity for carbon monoxide (DLCO), lung volumes, maximal inspiratory pressure and maximal expiratory pressure. Furthermore, they have a higher closing volume, a greater airway occlusion pressure 0.1 sec after the onset of inspiratory flow and greater exhaled nitric oxide values. In order to improve pulmonary function, patients with ascites may require therapeutic paracentesis. Such findings should be considered when evaluating individuals with liver disease, particularly those who may require surgery. Poor lung function, particularly restrictive lung disease, can have an impact on post-transplant outcomes, such as ventilator time, length of hospital duration and post-operative pulmonary complications; thus, the transplant care team needs to be aware of its prevalence and relevance.

Mechanistic Links Between Obesity and Airway Pathobiology Inform Therapies for Obesity-Related Asthma

Obesity-related asthma is associated with a high disease burden and a poor response to existent asthma therapies, suggesting that it is a distinct asthma phenotype. The proposed mechanisms that contribute to obesity-related asthma include the effects of the mechanical load of obesity, adipokine perturbations, and immune dysregulation. Each of these influences airway smooth muscle function. Mechanical fat load alters airway smooth muscle stretch affecting airway wall geometry, airway smooth muscle contractility, and agonist delivery; weight loss strategies, including medically induced weight loss, counter these effects. Among the metabolic disturbances, insulin resistance and free fatty acid receptor activation influence distinct signaling pathways in the airway smooth muscle downstream of both the M2 muscarinic receptor and the β2 adrenergic receptor, such as phospholipase C and the extracellular signal-regulated kinase signaling cascade. Medications that decrease insulin resistance and dyslipidemia are associated with a lower asthma disease burden. Leptin resistance is best understood to modulate muscarinic receptors via the neural pathways but there are no specific therapies for leptin resistance. From the immune perspective, monocytes and T helper cells are involved in systemic pro-inflammatory profiles driven by obesity, notably associated with elevated levels of interleukin-6. Clinical trials on tocilizumab, an anti-interleukin antibody, are ongoing for obesity-related asthma. This armamentarium of therapies is distinct from standard asthma medications, and once investigated for its efficacy and safety among children, will serve as a novel therapeutic intervention for pediatric obesity-related asthma. Irrespective of the directionality of the association between asthma and obesity, airway-specific mechanistic studies are needed to identify additional novel therapeutic targets for obesity-related asthma.

De novo discovery of traits co-occurring with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous group of chronic lung conditions. Genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) associated with COPD and the co-occurring conditions, suggesting common biological mechanisms underlying COPD and these co-occurring conditions. To identify them, we have integrated information across different biological levels (i.e., genetic variants, lung-specific 3D genome structure, gene expression and protein-protein interactions) to build lung-specific gene regulatory and protein-protein interaction networks. We have queried these networks using disease-associated SNPs for COPD, unipolar depression and coronary artery disease. COPD-associated SNPs can control genes involved in the regulation of lung or pulmonary function, asthma, brain region volumes, cortical surface area, depressed affect, neuroticism, Parkinson's disease, white matter microstructure and smoking behaviour. We describe the regulatory connections, genes and biochemical pathways that underlay these co-occurring trait-SNP-gene associations. Collectively, our findings provide new avenues for the investigation of the underlying biology and diverse clinical presentations of COPD. In so doing, we identify a collection of genetic variants and genes that may aid COPD patient stratification and treatment.

Metabolic Contributions to Pathobiology of Asthma

Asthma is a heterogenous disorder driven by inflammatory mechanisms that result in multiple phenotypes. Given the complex nature of this condition, metabolomics is being used to delineate the pathobiology of asthma. Metabolomics is the study of metabolites in biology, which includes biofluids, cells, and tissues. These metabolites have a vital role in a disease as they contribute to the pathogenesis of said condition. This review describes how macrometabolic and micrometabolic studies pertaining to these metabolites have contributed to our current understanding of asthma, as well as its many phenotypes. One of the main phenotypes this review will discuss in further detail is obesity as well as diabetes. Distinct roles of metabolites in endotyping asthma and their translation to potential therapy development for asthma is also discussed in this review.

The Impact of Insulin Resistance on Loss of Lung Function and Response to Treatment in Asthma

Rationale: The role of obesity-associated insulin resistance (IR) in airflow limitation in asthma is uncertain. Objectives: Using data in the Severe Asthma Research Program 3 (SARP-3), we evaluated relationships between homeostatic measure of IR (HOMA-IR), lung function (cross-sectional and longitudinal analyses), and treatment responses to bronchodilators and corticosteroids. Methods: HOMA-IR values were categorized as without (<3.0), moderate (3.0-5.0), or severe (>5.0). Lung function included FEV1 and FVC measured before and after treatment with inhaled albuterol and intramuscular triamcinolone acetonide and yearly for 5 years. Measurements and Main Results: Among 307 participants in SARP-3, 170 (55%) were obese and 140 (46%) had IR. Compared with patients without IR, those with IR had significantly lower values for FEV1 and FVC, and these lower values were not attributable to obesity effects. Compared with patients without IR, those with IR had lower FEV1 responses to β-adrenergic agonists and systemic corticosteroids. The annualized decline in FEV1 was significantly greater in patients with moderate IR (-41 ml/year) and severe IR (-32 ml/year,) than in patients without IR (-13 ml/year, P < 0.001 for both comparisons). Conclusions: IR is common in asthma and is associated with lower lung function, accelerated loss of lung function, and suboptimal lung function responses to bronchodilator and corticosteroid treatments. Clinical trials in patients with asthma and IR are needed to determine if improving IR might also improve lung function.