Quantitative Assessment of Erector Spinae Muscles in Patients with Chronic Obstructive Pulmonary Disease. Novel Chest Computed Tomography-derived Index for Prognosis

Respiratory Muscle Strength as a Predictor of Exacerbations in Patients With Chronic Obstructive Pulmonary Disease

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is closely related to skeletal muscle dysfunction, and the evaluation of respiratory muscle function has recently been recommended. We aimed to investigate the effects of respiratory muscle dysfunction on clinical outcomes.

METHODS

We retrospectively reviewed the medical records of patients with COPD whose respiratory muscle strength was measured between June 2015 and December 2021. We then analysed the effects of respiratory muscle strength on moderate-to-severe exacerbations after adjusting for confounding factors, including sex, age, forced expiratory volume in 1-s percent predicted, hand grip strength, and skeletal muscle mass index. We also compared the temporal relationship between respiratory and systemic skeletal muscle dysfunctions.

RESULTS

Respiratory muscle weakness (RMW) was observed in 48.1% (100) of the 208 patients. Low percent predicted maximal inspiratory pressure was an independent risk factor for moderate-to-severe exacerbations within 1 year in the Cox regression analysis (adjusted hazard ratio per 1 standard deviation increase, 0.521; 95% confidence interval, 0.317-0.856). Approximately half of the patients already exhibited RMW at the mild systemic skeletal muscle dysfunction, while those with sarcopenia had higher RMW rates. More patients with RMW experienced progressive systemic skeletal muscle dysfunction within 1 year compared to those without RMW.

CONCLUSION

Lower respiratory muscle strength is associated with an increased risk of exacerbation. Respiratory muscle function could serve as a marker of disease status and early prognosis in COPD.

Prognostic Benefit of Segmentectomy for Patients with Low Muscle Mass in Early-Stage Lung Cancer

BACKGROUND

Although segmentectomy is less invasive than lobectomy, little is known about the effect of these procedures on postoperative outcomes of patients with low muscle mass. This study examined the postoperative prognosis of patients with non-small cell lung cancer according to the surgical procedure type and preoperative muscle mass.

METHODS

This study retrospectively reviewed data of patients who underwent lobectomy or segmentectomy for early-stage non-small cell lung cancer with ground glass opacity-dominant tumor up to 3 cm in size or solid-dominant tumor up to 2 cm in size between 2010 and 2020. The preoperative muscle mass was evaluated based on the height-adjusted erector spinae muscle mass on preoperative chest computed tomography images. The overall survival was compared between patients with low and high muscle mass in the lobectomy and segmentectomy groups. Multivariable analyses were performed to identify prognostic factors for overall survival.

RESULTS

The study enrolled 371 patients: 162 in the lobectomy group and 209 in the segmentectomy group. The 5-year overall survival was significantly poorer for the patients with low muscle mass than for those with high muscle mass in the lobectomy group (83.9 % vs. 91.9 %; p = 0.018), whereas no significant difference was observed in the segmentectomy group (93.5 % vs. 94.9 %; p = 0.54). In the several multivariable models, low muscle mass was an independent prognostic factor in the lobectomy group (hazard ratio [HR], range, 2.3-2.4; p value range, 0.027-0.042) but not in the segmentectomy group (HR range, 1.6-2.0; p value range, 0.19-0.36).

CONCLUSIONS

Segmentectomy should be actively considered for patients with low muscle mass because of its lower invasiveness.

Antigravity muscle density on computed tomography and health-related independence in normal weight patients with chronic obstructive pulmonary disease

BACKGROUND

Low body mass index (BMI) is a prognostic factor, and skeletal muscle adiposity may affect mortality irrespective of BMI in patients with chronic obstructive pulmonary disease (COPD). However, the association between muscle adiposity and healthy life expectancy in normal-weight patients remains unestablished.

OBJECTIVE

To examine whether lower chest computed tomography (CT)-assessed erector spinae muscle density (ESMD), which represents antigravity muscle adiposity, is associated with subsequent loss of health-related independence in normal-weight patients with COPD.

METHODS

The ESMD lower limit of normal (LLN) was determined in 194 healthy subjects undergoing lung cancer screening CT. In a prospective cohort of patients with COPD undergoing baseline inspiratory/expiratory CT, the onset of loss of health-related independence, requiring long-term nursing facility or home nursing/medical care, was recorded over 5 years.

RESULTS

Smokers with COPD (n = 199) were divided into 4 groups on the basis of BMI and the ESMD-LLN: underweight (n = 22), normal-weight with (n = 40) and without (n = 81) low ESMD, and overweight (n = 56). Greater airway wall thickening was associated with BMI-independent low ESMD. A multivariable Cox proportional hazards model including only normal-weight patients with COPD (n = 121) indicated that low ESMD was independently associated with a higher loss-of-independence rate after adjusting for FEV1, COPD assessment test score, and a smaller cross-sectional area of erector spinae muscles (hazard ratio [95% confidence interval] = 3.21 [1.30-7.89]).

CONCLUSION

Low antigravity muscle density could reflect airway wall thickening and shorten healthy life expectancy in normal-weight patients with COPD.

Application of Artificial Intelligence in Thoracic Radiology: A Narrative Review

Thoracic radiology has emerged as a primary field in which artificial intelligence (AI) is extensively researched. Recent advancements highlight the potential to enhance radiologists' performance through AI. AI aids in detecting and classifying abnormalities, and in quantifying both normal and abnormal anatomical structures. Additionally, it facilitates prognostication by leveraging these quantitative values. This review article will discuss the recent achievements of AI in thoracic radiology, focusing primarily on deep learning, and explore the current limitations and future directions of this cutting-edge technique.

The Perception of Asthma, Chronic Obstructive Pulmonary Disease, Asthma and Chronic Obstructive Pulmonary Disease Overlap, and Cough Variant Asthma: A Retrospective Observational Study

Objective The prevalence rates of bronchial asthma (BA) and chronic obstructive pulmonary disease (COPD) are 3%-11% and 8%-16%, respectively, in the general Japanese adult population. Few reports on patients' perceptions of BA, cough variant asthma (CVA), COPD, and asthma and COPD overlap (ACO) are available in Japan, and we aimed to investigate the agreement between the perception and diagnosis of BA and COPD-related diseases. Methods The subjects were 229 datasets matched to the sex and age distribution of the Japanese population of 1,000 adult patients who underwent respiratory function tests and screening for each disease at Nagasaki University Hospital between July 2014 and July 2017. The patients' self-perceptions of diagnosed BA, CVA, COPD, emphysema, chronic bronchitis, and ACO were determined. Results In total, 229 datasets were included in this study. The prevalence of BA was 10.0% (23 cases, including 2 CVA and 6 ACO cases) and 11.8% (27 cases, including 6 ACO cases). The prevalence of ACO was 2.6% (28.6% of BA and 22.2% of COPD), and that of CVA was 0.9% (8.7% of BA). The perception of COPD-related diseases had a much lower sensitivity than that of asthma-related diseases (0.481 vs. 0.995, p<0.0001). Cohen's kappa for asthma-related disease was 0.976, and that for COPD-related disease was 0.621. Conclusion Self-perception of asthma-related disease was adequately high, whereas that of COPD-related disease was low. The prevalence rates of BA, COPD, ACO, and CVA in our study were 10.0%, 11.8%, 2.6%, and 0.9%, respectively. An increase in the perception of COPD may help improve community healthcare for respiratory diseases.

Computed tomography morphomics and antifibrotic therapy in idiopathic pulmonary fibrosis

AIM

Idiopathic pulmonary fibrosis (IPF) is a debilitating and fatal lung disease. Changes in body composition potentially correlate with outcomes in patients with IPF.

MATERIALS AND METHODS

Patients with IPF on antifibrotic treatment attending a single institution were identified and retrospectively evaluated (n=84). Three groups were formed based on antifibrotic treatment: pirfenidone group, nintedanib group and pirfenidone-nintedanib switch group. Morphomic analysis of muscle quantity (cross-sectional area in cm2) and quality (density in Hounsfield Units) on thoracic computed tomography (CT) was performed using a web-based morphomic segmentation tool. Bilateral erector spinae and pectoralis muscles were measured at pre-defined vertebral levels.

RESULTS

All three treatment groups showed a statistically significant decline in forced vital capacity (FVC), diffusion capacity of the lung for carbon monoxide (DLCO), pectoral muscle cross sectional area (PMA), and erector spinae muscle cross-sectional area (ESMA). Muscle density did not change significantly. Differences existed in analytic morphomics between treatment groups. Patients with a pretreatment body mass index (BMI) below 30 were found to have a significantly greater loss of PMA when treated with nintedanib instead of pirfenidone. FVC and DLCO did not differ between treatment groups.

CONCLUSION

There were no direct correlations between pulmonary function and morphomic parameters in our entire group of IPF patients. However, between different treatment groups, the rate of muscle bulk loss differed. This is an important consideration for clinicians when deciding on an antifibrotic agent of choice.

Erector Spinae Muscle to Epicardial Visceral Fat Ratio on Chest CT Predicts the Severity of Coronavirus Disease 2019

BACKGROUND

Chest computed tomography (CT) is a valuable tool for diagnosing and predicting the severity of coronavirus disease 2019 (COVID-19) and assessing extrapulmonary organs. Reduced muscle mass and visceral fat accumulation are important features of a body composition phenotype in which obesity and muscle loss coexist, but their relationship with COVID-19 outcomes remains unclear. In this study, we aimed to investigate the association between the erector spinae muscle (ESM) to epicardial adipose tissue (EAT) ratio (ESM/EAT) on chest CT and disease severity in patients with COVID-19.

METHODS

We analysed data from 1074 COVID-19 patients enrolled in the Japan COVID-19 Task Force database. The primary outcome was the rate of critical outcomes (requiring high-flow oxygen therapy, invasive ventilator support or death). The incidence of critical outcomes was compared between patients with high and low ESM/EAT ratios.

RESULTS

The low ESM/EAT group (n = 353) had a higher incidence of critical outcomes (13.3% vs. 5.13%, p < 0.001) and mortality (2.55% vs. 0.69%, p = 0.019) than the high ESM/EAT group (n = 721). In multivariable analysis, the low ESM/EAT ratio was associated with critical outcomes (adjusted odds ratio [aOR] 2.11, 95% confidence interval [CI] 1.22-3.66) independently of the known COVID-19 severity factors including age, sex, body mass index (BMI), smoking history, lifestyle-related comorbidities and pneumonia volume.

CONCLUSION

The low ESM/EAT ratio in COVID-19 patients can be obtained on chest CT and used to predict critical outcomes after disease onset, demonstrating the importance of detailed body composition assessments in COVID-19 practice.

Trajectory of the arterial-alveolar oxygen gradient in COPD for a decade

BACKGROUND

Chronic respiratory failure (CRF) is a critical complication in patients with chronic obstructive pulmonary disease (COPD) and is characterized by an increase in the arterial-alveolar oxygen gradient (A-aDO2). The long-term trajectory and prognostic significance remain unclear. This study aimed to assess the prognostic impact of A-aDO2 and elucidate its trajectory over ten years.

METHODS

We enrolled 170 outpatients with COPD from a prospective cohort study. Arterial blood gas (ABG) analyses were conducted annually for ten years while monitoring the development of CRF.

RESULTS

157 patients completed the observation period, of whom 21 developed CRF (CRF group) and 136 did not (non-CRF group). In the CRF group, there was a gradual increase in A-aDO2 along with decreases in partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2) over ten years, although there were no changes in the non-CRF group. The CRF group had higher baseline A-aDO2 and higher ΔA-aDO2 in the first year than the non-CRF group (3.76 vs. 0.42 Torr/year, p = 0.030). Kaplan-Meier analyses, and multivariate Cox proportional hazards analysis revealed that both baseline A-aDO2 and ΔA-aDO2 were significantly associated with the development of CRF. Retrospective tracking from the initiation of long-term oxygen therapy (LTOT) revealed significant increases in A-aDO2 from 5 years prior to LTOT initiation in the CRF group when compared to the non-CRF group.

CONCLUSIONS

An increasing trend in A-aDO2 may be a significant sign for the future development of CRF. A transition of the annual change of A-aDO2 from a stable state to a deterioration phase can serve as a prognostic factor for developing CRF within 5 years.

An enhanced machine learning-based prognostic prediction model for patients with AECOPD on invasive mechanical ventilation

Chronic obstructive pulmonary disease (COPD) causes irreversible airflow limitations, increasing global morbidity and mortality. Acute exacerbations (AECOPDs) worsen symptoms and may require mechanical ventilation, leading to complications. Understanding factors affecting AECOPD prognosis during mechanical ventilation is crucial. Inspired by rime ice physics, the RIME algorithm has been proposed but it had limitations in feature selection and solution space exploration. We improve RIME by adding a dispersed foraging mechanism and differential crossover operator, creating DDRIME. Our study analyzes patient data to identify factors related to invasive mechanical ventilation in AECOPD. DDRIME's performance is tested against RIME on 83 functions and 12 public datasets for feature selection. It outperformed most algorithms, with bDDRIME_KNN showing high accuracy in predicting AECOPD outcomes. Key indicators-chronic heart failure (CHF), D-dimer (D-D), fungal infection (FI), and pectoral muscle area (PMA)-predicted prognosis with >0.98 accuracy. bDDRIME is thus a valuable tool for predicting AECOPD patients' outcomes on mechanical ventilation.

Effect of osteosarcopenia on feeding status in hospitalized patients with suspected dysphagia

OBJECTIVES

Osteosarcopenia is a combination of sarcopenia and osteoporosis that increases mortality rates among older people compared with either alone. This study aimed to identify the contribution of osteosarcopenia to the development and severity of dysphagia.

METHODS

We retrospectively reviewed the medical charts of 211 patients aged ≥ 65 years who were referred to the dysphagia rehabilitation team. Based on Functional Oral Intake Scale (FOIS) scores, we classified the patients with (FOIS scores 1-5) and without (FOIS scores 6, 7) dysphagia as Type A and those with (FOIS scores 1, 2) and without (FOIS score 3-7) enteral feeding as Type B. Based on chest computed tomography (CT) findings we then defined patients with T4 (MI) and pectoralis (PMI) muscle indexes, L1 attenuation, and T4MI, PMI, and L1 attenuation below the cutoff values as having sarcopenia, osteoporosis, and osteosarcopenia, respectively.

RESULTS

The FOIS scores were significantly lower among patients with osteosarcopenia than among those without sarcopenia or osteoporosis. Moreover, PMI and FOIS scores significantly and positively correlated, and PMI was significantly lower in the group with, than without, enteral feeding. Osteoporosis and osteosarcopenia were significant in the patients who were fed enterally (p = 0.032 and 0.047, respectively).

CONCLUSIONS

Patients with sarcopenia and osteoporosis undergoing swallowing rehabilitation tended to have severe dysphagia that required much medical attention.

Low thoracic skeletal mass index, a novel marker to predict recurrence of aspiration pneumonia in the elderly stroke patients

PURPOSE

We investigated whether thoracic skeletal muscle mass index at the diagnosis of aspiration pneumonia (AP) is a predictor for AP recurrence and explored predicting factors for AP recurrence in patients with stroke.

PATIENTS AND METHODS

This study retrospectively reviewed data of patients with AP who were diagnosed with stroke and who had full medical follow-up data from January 2014 to July 2020 in the Catholic University of Korea Bucheon St. Mary's Hospital. AP was defined based on clinical signs and/or symptoms suggestive of pneumonia and radiologic findings of pneumonic infiltrations in the dependent portions of the lung. We measured thoracic muscle volume using the cross-sectional area (CSA) of the erector spinae muscle (ESMCSA, cm2) at the 12th vertebral region. Computed tomography scans at the time of AP diagnosis during the acute stroke period were used for analysis and respective CSAs were divided by height squared (m2) to yield the muscle index at T12 (T12MI, cm2/m2) to normalize for stature. Multivariate logistic regression models were used to investigate relationships between clinical parameters and AP recurrence.

RESULTS

During the study period, a total of 268 stroke patients with dysphagia who developed AP were analyzed. The mean T12MI of patients with and without recurrence of AP was 622.3±184.1 cm2/m2 and 708.1±229.9 cm2/m2, respectively (P = 0.001). Multivariate logistic regression revealed that lower T12MI (P = 0.038) and older age (P = 0.007) were independent predictors of AP recurrence in patients with stroke and dysphagia.

CONCLUSION

Low thoracic muscle index at the diagnosis of initial AP after stroke can predict subsequence AP recurrence.

The chest CT perspective on sarcopenia: Exploring reference values for muscle mass quantity/quality and its application in elderly adults

OBJECTIVE

To determine reference values for diagnosing sarcopenia through chest CT scans and evaluate their suitability for use among the Chinese elderly population.

METHODS

Chest CT scans were obtained from 500 healthy individuals aged 19-39. Skeletal muscle mass was assessed on chest CT at the level of T4 by the skeletal muscle area (T4SMA), skeletal muscle index (T4SMI), T12 erector spinae muscle area (T12ESMA), and T12 skeletal muscle index (T12SMI), as well as skeletal muscle density (SMD) at T4 and T12 levels. The diagnostic threshold for sarcopenia was defined as a gender-specific value below 2 SD of the mean value in the young group. These cutoff values were then applied to a group of older adults aged 65 and over.

RESULTS

Diagnostic thresholds for low skeletal muscle in men were 110.05 cm², 36.01 cm²/m², 29.56 cm², and 9.65 cm²/m² for T4SMA, T4SMI, T12ESMA, and T12SMI, respectively. For women, the thresholds were: 69.93 cm², 26.51 cm²/m², 17.84 cm²/m², and 6.87 cm²/m², respectively. Diagnostic thresholds for low SMD were 38.63HU in men, 34.74 HU for women at T4 level. At T12 level, the cutoff values were 40.94 HU for men and 36.63 HU for women. Sarcopenia prevalence in men, defined by T4SMA, T4SMI, T12ESMA, and T12SMI cutoffs, was 35.6%, 18.9%, 36.7%, and 23.7%, respectively. In women, sarcopenia prevalence was 5.1%, 3.2%, 3.2%, and 1.9%, respectively.

CONCLUSION

This study established reference values for sarcopenia diagnosis through chest CT scans among the Chinese population, highlighting the importance of utilizing chest CT scans for sarcopenia detection and muscle health monitoring in older adults.

Association Between Weight-Adjusted Waist Index and Emphysema in Adults in the United States: A Cross-Sectional Study Involving 44,949 Participants

Background: The relationship between obesity and respiratory diseases has been widely explored. In this context, the Weight-Adjusted Waist Index (WWI) has emerged as a novel metric for assessing visceral fat. This study aims to evaluate the association between WWI and the risk of emphysema in the U.S. population, by utilizing data from the 2001-2018 National Health and Nutrition Examination Survey (NHANES). Methods: A cross-sectional study was conducted using NHANES data from 2001 to 2018. Logistic regression models were applied to assess the relationship between WWI and emphysema risk. Interaction and subgroup analyses were performed to explore effect modifiers. Results: Our study included a total of 44,949 American adults. The results of the multivariable logistic regression analysis revealed an association between WWI and the incidence of emphysema. In the fully adjusted model, the probability of developing emphysema was 1.5 times higher in the group with WWI > 10.46 compared to those with WWI ≤ 10.46, with an odds ratio of [1.5 (1.1, 1.9), p = 0.003]. Subgroup analysis showed stronger associations among males, non-Hispanic Whites, and individuals with hypertension. Furthermore, we used a two-piece linear regression model and found a nonlinear association between WWI and emphysema, with a breakpoint at 12.5. Conclusions: Our findings indicate a significant association between WWI levels and emphysema. Larger-scale prospective studies are needed to further explore the role of WWI in emphysema.

Impact of the quantity and quality of erector spinae muscles on the short-term prognosis of elderly patients with aspiration pneumonia in Japan

BACKGROUND

Whether muscle mass and muscle quality affect the prognosis of elderly patients with aspiration pneumonia is unclear. This study aimed to evaluate the relationship between erector spinae muscle mass and muscle quality on the 30-day prognosis of elderly patients with aspiration pneumonia.

METHODS

Two hundred fifty-eight patients who were diagnosed with aspiration pneumonia and admitted to Sanuki Municipal Hospital for pulmonary rehabilitation intervention were included. The cross-sectional area (ESMCSA/BSA) and CT values (ESMCT) of the erector spinae muscles at the 12th thoracic vertebra were measured on chest CT images to represent muscle mass and quality, respectively. The primary outcome was defined as 30-day survival.

RESULTS

Twenty-six patients died within 30 days after hospitalization. The ESMCSA/BSA ratio was significantly greater in the survival group than in the nonsurvival group (p = 0.001). The cutoff values for 30-day survival were calculated as follows: the ESMCSA/BSA was 11.046 cm2/m2 in male patients and 9.600 cm2/m2 in female patients; the ESMCT was 26.85 HU in male patients and 8.00 HU in female patients. A higher ESMCSA/BSA significantly improved 30-day survival, while ESMCT did not show a significant difference. Cox proportional hazards regression analysis revealed that the ESMCSA/BSA was independently associated with 30-day short-term prognosis (hazard ratio 0.34, p = 0.034).

CONCLUSION

The short-term prognosis of elderly patients with aspiration pneumonia may be more strongly influenced by muscle mass than by the muscle quality of the erector spinae muscles.

Sarcopenia in interstitial lung disease

BACKGROUND

Interstitial lung disease (ILD) encompasses a heterogeneous group of chronic lung conditions with considerable variability in prognosis and response to treatment. People with reduced muscle mass and function, known as sarcopenia, have a higher risk of mortality and adverse clinical outcomes both in the general population and in other chronic disease states. The importance of sarcopenia across the spectrum of patients with ILD is not well established.

OBJECTIVES

In this narrative review, we explore the prevalence and clinical implications of sarcopenia in patients with ILD, evaluate the optimal methods to diagnose sarcopenia in this patient population and review treatment interventions.

FINDINGS

Almost one third of patients with chronic forms of ILD have evidence of sarcopenia. Sarcopenia is associated with adverse clinical outcomes and increased risk of mortality in select populations with ILD. Screening tests such as the SARC-F (strength, assistance walking, rise from a chair, climb stairs, falls) questionnaire and clinical assessment tools (including grip strength dynamometry) are well validated. Medical imaging modalities, including computed tomography, are hampered by lack of a gold standard and normative values, but have been used in patients with ILD in acute care and research settings. If sarcopenia is identified, multidimensional interventions such as pulmonary rehabilitation are beneficial.

CONCLUSION

Sarcopenia is common in patients with ILD and is associated with poorer outcomes. Accordingly, if identified, targeted interventions should be considered. Validated diagnostic criteria exist, but the optimal use of medical imaging techniques in this patient cohort remains an area of uncertainty.

Effect of sarcopenia on mortality in acute stroke patients receiving endovascular treatment

BACKGROUND

To investigate the effect of sarcopenia on mortality in patients with acute ischemic stroke caused by anterior circulation large artery occlusion who underwent endovascular treatment.

METHODS

Acute ischemic stroke patients (n = 194) treated with mechanical thrombectomy who underwent chest computed tomography between 2019 and 2022 (median age, 69 [interquartile range: 61-77], 95 females, 99 males) were evaluated retrospectively. The cross-sectional area and density of the pectoralis muscle [pectoralis muscle area (PMA) and pectoralis muscle density (PMD)] at the level of the aortic arch and the erector spinae muscle at the T12 level [erector spinae muscle area (ESMA) and erector spinae muscle density (ESMD)] were measured. The association between skeletal muscle parameters and mortality outcomes was investigated using the receiver operating characteristic (ROC) curve and multivariable logistic regression analyses.

RESULTS

The 90-day mortality rate was 32% in the study population (n = 62). The ROC analysis revealed that ESMD [area under the curve (AUC): 0.765] and PMD (AUC: 0.759) performed best in the prediction of 90-day mortality. In the multivariable logistic regression analysis, PMD [odds ratio (OR): 0.896; 95% confidence interval (CI): 0.846-0.948; p < 0.001], ESMA (OR: 0.929; 95% CI: 0.878-0.983; p = 0.011), and ESMD (OR: 0.947; 95% CI: 0.913-0.983; p = 0.004), but not PMA, were independent risk factors for 90-day mortality.

CONCLUSION

PMD, ESMA, and ESMD may be risk factors for 90-day mortality after mechanical thrombectomy for acute ischemic stroke.

The impact of body mass index on mortality in COPD: an updated dose-response meta-analysis

BACKGROUND AND OBJECTIVE

The obesity paradox is a well-established clinical conundrum in COPD patients. This study aimed to provide an updated analysis of the relationship between body mass index (BMI) and mortality in this population.

METHODS

A systematic search was conducted through Embase, PubMed, and Web of Science. International BMI cut-offs were employed to define underweight, overweight and obesity. The primary outcome was all-cause mortality, and the secondary outcome was respiratory and cardiovascular mortality.

RESULTS

120 studies encompassed a total of 1 053 272 patients. Underweight status was associated with an increased risk of mortality, while overweight and obesity were linked to a reduced risk of mortality. A nonlinear U-shaped relationship was observed between BMI and all-cause mortality, respiratory mortality and cardiovascular mortality. Notably, an inflection point was identified at BMI 28.75 kg·m-2 (relative risk 0.83, 95% CI 0.80-0.86), 30.25 kg·m-2 (relative risk 0.51, 95% CI 0.40-0.65) and 27.5 kg·m-2 (relative risk 0.76, 95% CI 0.64-0.91) for all-cause, respiratory and cardiovascular mortality, respectively, and beyond which the protective effect began to diminish.

CONCLUSION

This study augments the existing body of evidence by confirming a U-shaped relationship between BMI and mortality in COPD patients. It underscores the heightened influence of BMI on respiratory and cardiovascular mortality compared to all-cause mortality. The protective effect of BMI was lost when BMI values exceeded 35.25 kg·m-2, 35 kg·m-2 and 31 kg·m-2 for all-cause, respiratory and cardiovascular mortality, respectively.

Nocturnal Hypoxemia Is Associated with Sarcopenia in Patients with Chronic Obstructive Pulmonary Disease

Rationale: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. Our previous studies have identified that nocturnal hypoxemia causes skeletal muscle loss (i.e., sarcopenia) in in vitro models of COPD. Objectives: We aimed to extend our preclinical mechanistic findings by analyzing a large sleep registry to determine whether nocturnal hypoxemia is associated with sarcopenia in patients with COPD. Methods: Sleep studies from patients with COPD (n = 479) and control subjects without COPD (n = 275) were analyzed. Patients with obstructive sleep apnea, as defined by apnea-hypopnea index ⩾ 5, were excluded. Pectoralis muscle cross-sectional area (PMcsa) was quantified using computed tomography scans performed within 1 year of the sleep study. We defined sarcopenia as less than the lowest 20% residuals for PMcsa of control subjects, which was adjusted for age and body mass index (BMI) and stratified by sex. Youden's optimal cut-point criteria were used to predict sarcopenia based on mean oxygen saturation during sleep. Additional measures of nocturnal hypoxemia were analyzed. The pectoralis muscle index (PMI) was defined as PMcsa normalized to BMI. Results: On average, males with COPD had a 16.6% lower PMI than control males (1.41 ± 0.44 vs. 1.69 ± 0.56 cm2/BMI; P < 0.001), whereas females with COPD had a 9.4% lower PMI than control females (0.96 ± 0.27 vs. 1.06 ± 0.33 cm2/BMI; P < 0.001). Males with COPD with nocturnal hypoxemia had a 9.5% decrease in PMI versus COPD with normal O2 (1.33 ± 0.39 vs. 1.47 ± 0.46 cm2/BMI; P < 0.05) and a 23.6% decrease compared with control subjects (1.33 ± 0.39 vs. 1.74 ± 0.56 cm2/BMI; P < 0.001). Females with COPD with nocturnal hypoxemia had an 11.2% decrease versus COPD with normal O2 (0.87 ± 0.26 vs. 0.98 ± 0.28 cm2/BMI; P < 0.05) and a 17.9% decrease compared with control subjects (0.87 ± 0.26 vs. 1.06 ± 0.33 cm2/BMI; P < 0.001). These findings were largely replicated using multiple measures of nocturnal hypoxemia. Conclusions: We defined sarcopenia in the pectoralis muscle using residuals that take into account age, BMI, and sex. We found that patients with COPD have a lower PMI than patients without COPD and that nocturnal hypoxemia was associated with an additional decrease in the PMI of patients with COPD. Additional prospective analyses are needed to determine a protective threshold of oxygen saturation to prevent or reverse sarcopenia due to nocturnal hypoxemia in COPD.

IA-Body Composition CT at T12 in Idiopathic Pulmonary Fibrosis: Diagnosing Sarcopenia and Correlating with Other Morphofunctional Assessment Techniques

BACKGROUND

Body composition (BC) techniques, including bioelectrical impedance analysis (BIVA), nutritional ultrasound® (NU), and computed tomography (CT), can detect nutritional diagnoses such as sarcopenia (Sc). Sc in idiopathic pulmonary fibrosis (IPF) is associated with greater severity and lower survival. Our aim was to explore the correlation of BIVA, NU and functional parameters with BC at T12 level CT scans in patients with IPF but also its relationship with degree of Sc, malnutrition and mortality.

METHODS

This bicentric cross-sectional study included 60 IPF patients (85.2% male, 70.9 ± 7.8 years). Morphofunctional assessment (MFA) techniques included BIVA, NU, CT at T12 level (T12-CT), handgrip strength, and timed up and go. CT data were obtained using FocusedON®. Statistical analysis was conducted using JAMOVI version 2.3.22 to determine the cutoff points for Sc in T12-CT and to analyze correlations with other MFA techniques.

RESULTS

the cutoff for muscle area in T12-CT was ≤77.44 cm2 (area under the curve (AUC) = 0.734, sensitivity = 41.7%, specificity = 100%). The skeletal muscle index (SMI_T12CT) cutoff was ≤24.5 cm2/m2 (AUC = 0.689, sensitivity = 66.7%, specificity = 66.7%). Low SMI_T12CT exhibited significantly reduced median survival and higher risk of mortality compared to those with normal muscle mass (SMI cut off ≥ 28.8 cm/m2). SMI_T12CT was highly correlated with body cell mass from BIVA (r = 0.681) and rectus femoris cross-sectional area (RF-CSA) from NU (r = 0.599). Cronbach's α for muscle parameters across different MFA techniques and CT was 0.735, confirming their validity for evaluating muscle composition.

CONCLUSIONS

T12-CT scan is a reliable technique for measuring low muscle mass in patients with IPF, specifically when the L3 vertebrae are not captured. An SMI value of <28.8 is a good predictor of low lean mass and 12-month mortality in IPF patients.

Lower skeletal muscle density and airway structure on computed tomography in asthma

BACKGROUND

Lower skeletal muscle density may reflect muscle adiposity and metabolic dysregulation that potentially impair disease control and lung function independent of high body mass index (BMI) in patients with asthma.

OBJECTIVE

To investigate whether the lower density of pectoralis muscles (PMs) and erector spinae muscles (ESMs) on chest computed tomography was associated with airway structural changes in patients with asthma.

METHODS

Consecutive patients with asthma and healthy controls undergoing chest computed tomography were retrospectively analyzed. The ESM and PM density, areas of subcutaneous adipose tissue near the PM and epicardial adipose tissue, wall area percent of the airways, and airway fractal dimension (AFD) were quantified on computed tomography.

RESULTS

The study included 179 patients with asthma (52% women) and 88 controls (47% women). All the controls were 60 years old or younger. The PM and ESM density in female patients with asthma who were 60 years old or younger were significantly lower than those in controls after adjustment for BMI. In female patients with asthma at all ages, lower PM and ESM density (but not subcutaneous or epicardial adipose tissue area) was associated with greater wall area percent of the airways and lower AFD after adjusting for age, height, BMI, smoking status, blood eosinophil count, and oral corticosteroid use. The only association between ESM density and AFD was found in male patients with asthma.

CONCLUSION

Lower skeletal muscle density may be associated with airway wall thickening and less complexity of the airway luminal tree in female patients with asthma.

Increased adiposity-to-muscle ratio and severity of sinusitis affect quality of life in asthma: Computed tomographic analysis

Background

Deteriorated sinusitis and increased adiposity relative to muscle mass may affect quality of life in patients with asthma. However, whether these effects are observed regardless of intrapulmonary pathology is unknown.

Objectives

We evaluated the correlation of the cross-sectional ratio of abdominal visceral fat (VF) to erector spinae muscle (ESM) and sinus findings based on Lund-Mackey scoring system (LMS) on computed tomography (CT) with the impaired score of the Asthma Quality of Life Questionnaire (AQLQ), regardless of airway and parenchymal disease, in patients with asthma.

Methods

We recruited participants from the Hokkaido-based severe asthma cohort who had completed AQLQ and CT examination at the entry. The participants were divided into high (highest) and low (other quartiles) groups on the bases of the extrapulmonary indices. Multivariate analysis examined the association of VF/ESM for the adiposity-to-muscle ratio and LMS with AQLQ after adjusting for the airway fractal dimension for airway index and percentage of low attenuation volume to lung volume for parenchymal index.

Results

No significant differences were observed in VF/ESM and LMS in terms of sex. The AQLQ score in the high VF/ESM group and high LMS group was lower than those in low VF/ESM group and low LMS group (63 male and 100 female subjects). High VF/ESM (estimate [95% confidence interval] (-0.43 [-0.61, -0.25]) and high LMS scores (-0.22 [-0.41, -0.03]) were associated with low AQLQ scores when adjusted for age, body mass index, smoking status, blood eosinophil count, and intrapulmonary CT indices.

Conclusions

Increased VF relative to ESM mass and high LMS may deteriorate asthma-related quality of life, regardless of presence of intrapulmonary disease.

Association between Muscle Mass Index and Neurological Outcomes of Patients with Out-of-Hospital Cardiac Arrest

Muscle mass depletion is associated with unfavorable outcomes in many diseases. However, its relationship with cardiac arrest outcomes has not been explored. This retrospective single-center study determined the relationship between muscle mass depletion and the neurological outcomes of patients with out-of-hospital cardiac arrest (OHCA) by measuring muscle mass at various locations. Adult patients with OHCA, who were treated with target temperature management, and who underwent abdominal or chest computed tomography (CT) within 3 months of the cardiac arrest were included. Skeletal muscle index (SMI) was measured at the third lumbar vertebra (L3) level, psoas muscle, fourth thoracic vertebra (T4) level, and pectoralis muscle. The Youden index was used to determine a low SMI based on sex-specific cutoff values. The outcome variables were "good neurological outcome" and "survival" at hospital discharge. Multivariable analyses revealed that patients with low T4 SMI level were significantly associated with good neurological outcomes at hospital discharge (odds ratio = 0.26, 95% confidence interval: 0.07-0.88, p = 0.036). However, no significant differences were observed between good neurological outcomes and low SMI at the L3 level and psoas and pectoralis muscles; SMIs were not associated with survival at hospital discharge. T4 level SMI depletion was inversely associated with good neurological outcomes in patients with OHCA. Thoracic muscle depletion may be crucial for predicting the neurological outcomes in patients with OHCA and further investigation in larger prospective study is warranted.

Longitudinal assessment of interstitial lung abnormalities on CT in patients with COPD using artificial intelligence-based segmentation: a prospective observational study

BACKGROUND

Interstitial lung abnormalities (ILAs) on CT may affect the clinical outcomes in patients with chronic obstructive pulmonary disease (COPD), but their quantification remains unestablished. This study examined whether artificial intelligence (AI)-based segmentation could be applied to identify ILAs using two COPD cohorts.

METHODS

ILAs were diagnosed visually based on the Fleischner Society definition. Using an AI-based method, ground-glass opacities, reticulations, and honeycombing were segmented, and their volumes were summed to obtain the percentage ratio of interstitial lung disease-associated volume to total lung volume (ILDvol%). The optimal ILDvol% threshold for ILA detection was determined in cross-sectional data of the discovery and validation cohorts. The 5-year longitudinal changes in ILDvol% were calculated in discovery cohort patients who underwent baseline and follow-up CT scans.

RESULTS

ILAs were found in 32 (14%) and 15 (10%) patients with COPD in the discovery (n = 234) and validation (n = 153) cohorts, respectively. ILDvol% was higher in patients with ILAs than in those without ILA in both cohorts. The optimal ILDvol% threshold in the discovery cohort was 1.203%, and good sensitivity and specificity (93.3% and 76.3%) were confirmed in the validation cohort. 124 patients took follow-up CT scan during 5 ± 1 years. 8 out of 124 patients (7%) developed ILAs. In a multivariable model, an increase in ILDvol% was associated with ILA development after adjusting for age, sex, BMI, and smoking exposure.

CONCLUSION

AI-based CT quantification of ILDvol% may be a reproducible method for identifying and monitoring ILAs in patients with COPD.

Factors associated with changes in activities of daily living from admission to discharge among older patients with pneumonia

INTRODUCTION

It has not been fully elucidated that nutritional parameters affect the change of activities of daily living (ADL) during pneumonia treatment. This study assessed the impact of nutritional status, including erector spinae muscle (ESM) size on ADL changes from admission to discharge among older patients with community-acquired pneumonia (CAP).

METHODS

We retrospectively included patients (age: ≥65 years) who were admitted to the hospital for CAP and underwent chest computed tomography (CT) on admission. ADL was evaluated using the Barthel index, and patients were divided into the maintained or improved ADL group and the declined ADL group from admission through discharge. The ESM cross-sectional area was measured on a single-slice CT image. Logistic regression models were applied for assessing factors associated with changes in ADL.

RESULTS

A total of 523 patients hospitalized for CAP (median age 86 years) were evaluated. The declined group had significantly higher ADL levels on admission, a greater frequency of smoking history and malignancy, and a lower frequency of cerebrovascular disease and dementia. No significant difference in ESM size was observed between the groups. Multivariate analysis revealed that higher ADL levels on admission (odds ratio 1.034, interquartile range 1.026-1.043) and malignancy (3.002, 1.150-7.836) were associated with a decline in ADL, whereas cerebrovascular disease (0.579, 0.373-0.900) was related to improvement or maintenance of ADL.

CONCLUSIONS

Although nutritional status might not affect the change of ADL among older patients hospitalized with pneumonia, a cerebrovascular disease history may be a good predictor for ADL improvement.

Current advances in pulmonary functional imaging

Recent advances in imaging analysis have enabled evaluation of ventilation and perfusion in specific regions by chest computed tomography (CT) and magnetic resonance imaging (MRI), in addition to modalities including dynamic chest radiography, scintigraphy, positron emission tomography (PET), ultrasound, and electrical impedance tomography (EIT). In this review, an overview of current functional imaging techniques is provided for each modality. Advances in chest CT have allowed for the analysis of local volume changes and small airway disease in addition to emphysema, using the Jacobian determinant and parametric response mapping with inspiratory and expiratory images. Airway analysis can reveal characteristics of airway lesions in chronic obstructive pulmonary disease (COPD) and bronchial asthma, and the contribution of dysanapsis to obstructive diseases. Chest CT is also employed to measure pulmonary blood vessels, interstitial lung abnormalities, and mediastinal and chest wall components including skeletal muscle and bone. Dynamic CT can visualize lung deformation in respective portions. Pulmonary MRI has been developed for the estimation of lung ventilation and perfusion, mainly using hyperpolarized 129Xe. Oxygen-enhanced and proton-based MRI, without a polarizer, has potential clinical applications. Dynamic chest radiography is gaining traction in Japan for ventilation and perfusion analysis. Single photon emission CT can be used to assess ventilation-perfusion (V˙/Q˙) mismatch in pulmonary vascular diseases and COPD. PET/CT V˙/Q˙ imaging has also been demonstrated using "Galligas". Both ultrasound and EIT can detect pulmonary edema caused by acute respiratory distress syndrome. Familiarity with these functional imaging techniques will enable clinicians to utilize these systems in clinical practice.

Impact of changes in skeletal muscle mass and quality during the waiting time on outcomes of lung transplantation

INTRODUCTION

The association of changes in skeletal muscle mass and quality during the waiting time with outcomes of lung transplantation (LT) remains unclear. We aimed to examine the association of changes in skeletal muscle mass and quality during the waiting time, as well as preoperative skeletal muscle mass and quality, with outcomes of LT.

METHODS

This study included individuals who underwent LT from brain-dead donors. Skeletal muscle mass (cm2 /m2 ) and quality (mean Hounsfield units [HU]) of the erector spinae muscle at the 12th thoracic level were evaluated using computed tomography. Preoperative skeletal muscle mass and quality, and their changes during the waiting time were calculated. We evaluated the associations among mechanical ventilation (MV) duration, intensive care unit (ICU) length of stay (LOS), hospital LOS, 6-minute walk distance at discharge, and 5-year survival after LT.

RESULTS

This study included 98 patients. The median waiting time was 594.5 days (interquartile range [IQR], 355.0-913.0). The median changes in skeletal muscle mass and quality were -4.4% (IQR, -13.3-3.1) and -2.9% (IQR, -16.0-4.1), respectively. Severe low skeletal muscle mass at LT was associated with prolonged ICU LOS (B = 8.46, 95% confidence interval [CI]: .51-16.42) and hospital LOS (B = 36.00, 95% CI: 3.23-68.78). Pronounced decrease in skeletal muscle mass during the waiting time was associated with prolonged MV duration (B = 7.85, 95% CI: .89-14.81) and ICU LOS (B = 7.97, 95% CI: .83-15.10).

CONCLUSION

Maintaining or increasing skeletal muscle mass during the waiting time would be beneficial to improve the short-term outcomes of LT.

Prognostic value of the serum creatinine/cystatin C ratio in patients with chronic obstructive pulmonary disease

BACKGROUND

Sarcopenia, characterized by skeletal muscle atrophy and physical inactivity, is a manifestation of chronic obstructive pulmonary disease (COPD) and is associated with a poor prognosis. The serum creatinine (Cr)/cystatin C (CysC) ratio has been proposed as a marker of sarcopenia, given its correlation with total skeletal muscle mass, and as a prognostic indicator in COPD. This study aimed to evaluate the usefulness of the serum Cr/CysC ratio as a prognostic determinant in these patients.

METHODS

A total of 124 outpatients with COPD were enrolled in this study. Their serum Cr and CysC levels were measured. Survival time analyses were conducted to compare mortality rates between the low and high serum Cr/CysC ratio groups. Multivariate analysis was performed to investigate the association between various factors.

RESULTS

Using a serum Cr/CysC cut-off value of 0.885, the mortality rate (per 1000 person-years) for overall mortality was significantly higher in the low serum Cr/CysC ratio group (69.2 versus 28.6; hazard ratio, 2.47; 95% confidence interval, 1.06-5.79; p < 0.05). Similarly, the mortality rate due to respiratory disease was also higher (37.8 versus 8.2; hazard ratio, 4.68; 95% confidence interval, 1.05-20.9; p < 0.05). Multivariate Cox proportional hazards analysis revealed that serum Cr/CysC was an independent risk factor for respiratory disease mortality, regardless of age and airflow limitations.

CONCLUSIONS

The serum Cr/CysC ratio could be a valuable clinical parameter for identifying sarcopenia and severe airflow obstruction. The study findings highlight the utility of this ratio as a prognostic predictor in patients with COPD.

Perioperative changes in radiographic density in erector spinae muscle and mortality after lung transplantation

RATIONALE

The radiographic density of the erector spinae muscle (ESM) is often decreased early after lung transplantation (LTx). The prognostic impact of this change has not been elucidated.

OBJECTIVE

To investigate whether the decrease in the radiographic density of ESMs early after LTx is associated with a poor prognosis.

METHODS

This study is a single center retrospective cohort study. Routine follow-up chest computed tomography scan data just before and 12 weeks after LTx were retrospectively retrieved for adult patients who underwent primary LTx at Kyoto University Hospital. The radiographic density of ESM was quantitatively evaluated as the mean attenuation of the ESM (ESMct), and the impact of the decreased ESMct during the 12 weeks after LTx on overall survival (OS) was examined by Cox proportional hazard regression.

RESULTS

A total of 151 recipients (94 cadaveric LTx, 57 living-donor lobar LTx) were included in this study. The median duration of postoperative observation was 4.4 years, during which time 39 recipients (26%) died. Decreased postoperative ESMct was significantly associated with poor OS (HR, 1.64; 95% CI, 1.14-2.35, P = 0.008 per 1 Z score decrease) in the multivariate model adjusted for age, sex, episodes of acute rejection, and preoperative ESMct. Similar results were obtained when the subjects were limited to those with cadaveric LTx.

CONCLUSION

A decreased perioperative ESMct was strongly associated with a poor prognosis after LTx in addition to low preoperative ESMct. Maintaining postoperative muscle radiographic density, which reflects muscle quality, may be important for a better prognosis after LTx.

Association between muscular atrophy and mortality risk in patients with COPD: a systematic review

BACKGROUND

Muscular atrophy often can be seen at the end of stage in many chronic diseases. It will also negatively influence patients' outcomes. Different studies showed that the association between muscular atrophy and mortality in patients with chronic obstructive pulmonary disease (COPD) was unclear. This study will continue to assess the influence of muscular atrophy on mortality in patients with COPD.

OBJECTIVES

To systematically evaluate the association between muscular atrophy and death in patients with COPD.

DESIGN

Systematic review.

METHODS AND DATA SOURCES

A systematic review and meta-analysis was conducted. Databases including PubMed, Web of Science, Embase, the Cochrane Library, the China Biomedical Literature Service System, China Biomedical Literature Service System (CINAHL), China National Knowledge Infrastructure, the Wanfang database, and the WeiPu (VIP) were systematically searched for cohort studies on muscular atrophy and COPD from inception to July 1st, 2023. Two reviewers independently review, assess, and extract data from the included studies. Meta-analysis was performed using RevMan 5.4 software.

RESULTS

Thirteen cohort studies were ultimately included, involving 10,528 patients with COPD. There were seven cohort studies included in the meta-analysis, including 3,458 COPD patients. The meta-analysis showed that patients with COPD combined with muscular atrophy had a higher mortality risk (HR = 2.20, 95%CI (1.74, 2.79), p < 0.00001). At the same time, patients with COPD who had muscular atrophy may had longer hospital stays.

CONCLUSION

Muscular atrophy is associated with the mortality and disease prognosis of patients with COPD. The conclusion needs to be supported and validated by more high-quality studies given the limitation of the number of articles included in this study.

TRIAL REGISTRATION

This systematic review protocol was prospectively registered with PROSPERO (No. CRD42024589435).

Correlation between body composition and white matter hyperintensity in patients with acute ischemic stroke

White matter hyperintensity (WMH) burden is associated with a higher risk of ischemic stroke. The relationship between WMH and obesity is somewhat controversial which might be interfered by different body composition such as skeletal muscle, fat and bone density. However, few researchers have evaluated the relationship between WMH burden and disaggregated body constituents in acute ischemic stroke (AIS) patients systematically. A total of 352 AIS patients were enrolled in this study. The subcutaneous adipose tissue, erector spinae muscle area and bone density were evaluated on the computed tomography scanning. The burden of WMH was evaluated using the Fazekas scale based on the fluid-attenuated inversion recovery sequence. The severity of overall WMH was defined as none-mild WMH (total Fazekas score 0-2) or moderate-severe WMH (total Fazekas score 3-6). Based on the severity of periventricular WMH (P-WMH) and deep WMH, patients were categorized into either a none-mild (Fazekas score 0-1) group or a moderate-severe (Fazekas score 2-3) group. We found that patients with moderate-severe WMH showed lower bone density and smaller erector spinae muscle area and subcutaneous adipose tissue than none-mild. The logistic regression analysis showed that the bone density was independently associated with moderate-severe overall WMH (odds radio = 0.98, 95% confidence interval, 0.972-0.992, P < .001) and similar results were found in the analyses according to P-WMH (odds radio = 0.98, 95% confidence interval, 0.972-0.992, P < .001). These findings suggest that among the AIS body composition, the bone density is independently associated with the severity of overall WMH and P-WMH.

Evaluation of the relationship of the T and M stage with the erector spinae muscle area in male lung cancer patients

OBJECTIVES

Sarcopenia is very common due to cachexia and presents with a decrease in skeletal muscle mass. In this study, we aimed to investigate the relationship between the T, M category and the erector spinae muscle area (ESMa).

MATERIAL AND METHODS

The initial first thorax and high-resolution computed tomography (CT) of patients with lung cancer between 2015 and 2019 were retrospectively screened. After exclusion criterias remaining 226 male patients constituted the study group. ESMa was measured manually in the section taken from the T12 vertebra spinous process level as previously described in the literature and its relationship with the T and M stage were evaluated.

RESULTS

The mean ages of patients were 70 ± 9.57 years. The T stage was T1 in 34 (15%) patients, T2 in 46 (20.4%), T3 in 59 (26.1%), and T4 in 87 (38.5%). Metastasis was detected in 83 (36.7%) patients. The mean ESMa of the patients was 34.15 ± 7.21 mm² and did not differ according to the T stage (p = .39). ESMa was lower in the metastatic group (mean 30.42 ± 6.38 mm²) than the non-metastatic group (mean 36.32 ± 6.78 mm²) (p = .0001).

CONCLUSIONS

ESMa, one of the indicators of sarcopenia, is lower in patients with metastatic lung cancer than in nonmetastatic.

Reduced CT-derived erector spinae muscle area: a poor prognostic factor for short- and long-term outcomes in idiopathic pulmonary fibrosis patients

AIM

To assess the relationship between idiopathic pulmonary fibrosis (IPF) prognosis, baseline skeletal muscle mass, and attenuation on computed tomography (CT) and clinical parameters.

MATERIAL AND METHODS

This retrospective cohort study enrolled 195 patients. The mean follow-up duration was 42.52 months. Erector spinae muscle area (ESMA), pectoralis muscle area (PMA), and the attenuation of the erector spinae muscle at the level of T12 vertebrae were measured. Muscle indexes were obtained by adjusting the measured muscle areas to the patients' heights. The relationship between baseline CT-derived muscle metrics and clinical parameters including short- and long-term mortality were evaluated.

RESULTS

There was a moderate correlation between ESMA and PMA and pectoralis muscle index (PMI; r=0.536, p<0001 and r=0.403, p<0.001 respectively). ESMA correlated significantly with forced expiratory volume in 1 second (FEV1; hazard ratio [HR] = 0.488 p<0.001) and forced vital capacity (FVC; HR=0.501, p<0.001). Compared with PMA, ESMA was more strongly associated with 1- and 2-year mortality in patients with IPF (HR=0.957, p=0.022). The survival rate in male patients with sarcopenia was significantly worse (p=0.040).

CONCLUSION

ESMA measurements obtained from CT correlated with clinical parameters in IPF patients and were also predictors of short- and long-term survival.

Predictive Value of CT Biomarkers in Lung Transplantation Survival: Preliminary Investigation in a Diverse, Underserved, Urban Population

INTRODUCTION

Survival following lung transplant is low. With limited donor lung availability, predicting post-transplant survival is key. We investigated the predictive value of pre-transplant CT biomarkers on survival.

METHODS

In this single-center retrospective cohort study of adults in a diverse, underserved, urban lung transplant program (11/8/2017-5/20/2022), chest CTs were analyzed using TeraRecon to assess musculature, fat, and bone. Erector spinae and pectoralis muscle area and attenuation were analyzed. Sarcopenia thresholds were 34.3 (women) and 38.5 (men) Hounsfield Units (HU). Visceral and subcutaneous fat area and HU, and vertebral body HU were measured. Demographics and pre-transplant metrics were recorded. Survival analyses included Kaplan-Meier and Cox proportional hazard.

RESULTS

The study cohort comprised 131 patients, 50 women, mean age 60.82 (SD 10.15) years, and mean follow-up 1.78 (SD 1.23) years. Twenty-nine percent were White. Mortality was 32.1%. Kaplan-Meier curves did not follow the proportional hazard assumption for sex, so analysis was stratified. Pre-transplant EMR metrics did not predict survival. Women without sarcopenia at erector spinae or pectoralis had 100% survival (p = 0.007). Sarcopenia did not predict survival in men and muscle area did not predict survival in either sex. Men with higher visceral fat area and HU had decreased survival (p = 0.02). Higher vertebral body density predicted improved survival in men (p = 0.026) and women (p = 0.045).

CONCLUSION

Pre-transplantation CT biomarkers had predictive value in lung transplant survival and varied by sex. The absence of sarcopenia in women, lower visceral fat attenuation and area in men, and higher vertebral body density in both sexes predicted survival in our diverse, urban population.

The cross-sectional area of erector spinae muscle and the liver-to-spleen ratio are associated with frailty in older patients with diabetes: a cross-sectional study

BACKGROUND

Older patients with diabetes mellitus are more susceptible to frailty. Although some imaging markers of appendicular skeletal muscle mass obtained using dual-energy X-ray absorptiometry or computed tomography (CT) imaging can reflect frailty status, the association between imaging indices obtained by abdominal CT scans and frailty in older inpatients has not been reported.

METHODS

A total of 151 older inpatients with diabetes mellitus (median age, 79 years; men, 42%) who underwent abdominal CT scans close to the admission date were studied to examine the associations between abdominal CT indices and frailty. Two frailty definitions were used: the modified Cardiovascular Health Study (mCHS) criteria and Kihon Checklist (KCL) criteria. Using the imaging analysis software SYNAPSE VINCENT®, we compared the cross-sectional areas (CSA) of four truncal muscles (erector spinae, iliopsoas, rectus abdominis, and abdominal oblique muscles) and the liver-to-spleen ratio (L/S), the ratio of the CT values of the liver and spleen between frail and non-frail patients. The muscle areas that showed the strongest associations with frailty were also investigated in relation to grip strength and walking speed. Finally, multivariate binominal logistic regression analyses were performed to assess the independent associations of CSA of muscle and L/S with the prevalence of frailty.

RESULTS

The prevalence of frailty defined by the mCHS and KCL criteria was 55% and 52%, respectively. The CSA of the erector spinae muscle was most significantly associated with frailty, and was significantly smaller in both sexes of mCHS-defined frail patients and in men with KCL-defined frailty. The CSA of erector spinae muscle was also positively correlated with grip strength and walking speed. In contrast, the L/S was higher in men with KCL-defined frailty. Multivariate logistic regression analyses revealed that the CSA of the erector spinae muscle was independently associated with mCHS-defined frailty in women, and the L/S was associated with KCL-defined frailty in men.

CONCLUSIONS

The CSA of erector spinae muscle and low liver fat content could be indices of frailty in older patients with diabetes.

Cigarette smoking and disproportionate changes of thoracic skeletal muscles in low-dose chest computed tomography

Association between smoking intensity and the quantity and quality of thoracic skeletal muscles (TSMs) remains unexplored. Skeletal muscle index (SMI; skeletal muscle area/height2) and percentage of normal attenuation muscle area (NAMA%) were measured to represent the quantity and quality of the skeletal muscles, respectively, and quantification was performed in pectoralis muscle at aortic arch (AA-PM), TSM at carina (C-TSM), erector spinae muscle at T12 (T12-ESM), and skeletal muscle at L1 (L1-SM). Among the 258 men (median age, 62 years [IQR: 58-69]), 183 were current smokers (median smoking intensity, 40 pack-years [IQR: 30-46]). SMI and NAMA% of AA-PM significantly decreased with pack-year (β =  - 0.028 and - 0.076; P < 0.001 and P = 0.021, respectively). Smoking intensity was inversely associated with NAMA% of C-TSM (β =  - 0.063; P = 0.001), whereas smoking intensity showed a borderline association with SMI of C-TSM (β =  - 0.023; P = 0.057). Smoking intensity was associated with the change in NAMA% of L1-SM (β =  - 0.040; P = 0.027), but was not associated with SMI of L1-SM (P > 0.05). Neither NAMA% nor SMI of T12-ESM was affected by smoking intensity (P > 0.05). In conclusion, smoking intensity was associated with the change of TSMs. Its association varied according to the location of TSMs, with the most associated parts being the upper (AA-PM) and middle TSMs (C-TSM).

A Systematic Review of Factors Associated with Mortality among Patients with Mycobacterium avium Complex Lung Disease

PURPOSE

As the number of patients with Mycobacterium avium complex lung disease is significantly increasing worldwide, several studies have focused on the prognostic factors associated with the disease. This systematic review investigated the factors associated with mortality among patients with Mycobacterium avium complex lung disease.

METHODS

Two investigators independently identified studies that were designed to determine risk factors for mortality in patients with Mycobacterium avium complex lung disease from PubMed, the Cochrane Register of Control Trial database, and EMBASE (accessed on 25 November 2022).

RESULTS

Of the 1133 titles and abstracts screened, 54 full texts were selected for review, and 15 studies were finally included in this systematic review. The most commonly studied risk factors were advanced age and low body mass index (11 studies for each), followed by male sex (8 studies), hypoalbuminemia (5 studies), and cavity (5 studies). In each study, these factors were mostly associated with increased all-cause mortality among patients with Mycobacterium avium complex lung disease as confirmed via multivariate analysis.

CONCLUSIONS

Advanced age, male sex, low body mass index, hypoalbuminemia, and cavity are likely to be the common risk factors for all-cause mortality among patients with Mycobacterium avium complex lung disease, suggesting that patients with these factors need to be carefully monitored.

Comparison of the thickness of the erector spinae muscles between aspiration pneumonia and bacterial pneumonia patients

BACKGROUND AND AIMS

Aspiration pneumonia is generally associated with deterioration of skeletal muscle mass, which is usually evaluated by the erector spinae muscle cross-sectional area (ESMCSA); however, no report has assessed ESMCSA in patients with aspiration pneumonia. Furthermore, erector spinae muscle thickness (ESMT) was developed to be easier to measure than ESMCSA. Therefore, this study investigated the relationship between ESMT and ESMCSA in aspiration pneumonia patients compared to bacterial pneumonia patients.

METHODS

We retrospectively collected data for 164 patients with aspiration pneumonia and 480 patients with bacterial pneumonia who were hospitalized at Fukujuji Hospital between September 2018 and May 2022. We assessed the correlations between ESMCSA and ESMT and compared the data between the two groups.

RESULTS

ESMT had a strong, proportional relationship with ESMCSA in all patients (r = 0.908, p < 0.001) and those with aspiration pneumonia (r = 0.896, p < 0.001). ESMCSA (median 671.8 mm2 [range 164.0-1636.7] vs. median 1057.0 mm2 [range 161.3-2412.5], p < 0.001) and ESMT (median 17.1 mm [range 6.95-34.4] vs. median 23.8 mm [range 6.95-43.7], p < 0.001) were significantly lower in patients with aspiration pneumonia. A multivariate analysis of aspiration pneumonia diagnosis showed significant independent differences from bacterial pneumonia in ESMCSA (odds ratio 0.998 [95% CI: 0.996-0.999], p = 0.001) and ESMT (odds ratio 0.90 [95% CI: 0.84-0.96], p = 0.002).

CONCLUSION

This study demonstrates a strong correlation between ESMCSA and ESMT. ESMT can be more easily used to evaluate skeletal muscle mass and can help in diagnosing aspiration pneumonia.

Prognostic impact of the cross-sectional area of the erector spinae muscle in patients with pleuroparenchymal fibroelastosis

Pleuroparenchymal fibroelastosis (PPFE) progresses slowly but sometimes relatively quickly, leading to decreased activities of daily living (ADL) and muscle weakness. Skeletal muscle atrophy and muscle weakness in chronic obstructive pulmonary disease (COPD) patients may be caused by cachexia and are associated with reduced ADLs and increased risk of death. However, the association between skeletal muscle mass and the prognosis of PPFE patients remains unknown. We retrospectively analysed the clinical significance of the cross-sectional area of the erector spinae muscle (ESMCSA), a skeletal muscle index, and predictors of mortality within 3 years in PPFE 51 patients, idiopathic pulmonary fibrosis (IPF) 52 patients and COPD 62 patients. PPFE patients had significantly lower ESMCSA than IPF or COPD patients, and lower ESMCSA (< 22.57 cm2) was associated with prognosis within 3 years (log-rank test; p = 0.006), whereas lower body mass index (BMI) showed no association. Multivariate analysis showed that ESMCSA was an independent predictor of mortality within 3 years in PPFE patients (hazard ratio, 0.854; 95% confidence interval: 0.737-0.990, p = 0.036). These results suggest the importance of monitoring ESMCSA in PPFE patients and that assessing ESMCSA in PPFE patients could be a more useful prognostic indicator than BMI.

Incident low muscle mass is associated with greater lung disease and lower circulating leptin in a tobacco-exposed longitudinal cohort

BACKGROUND

Muscle loss is prevalent in chronic obstructive pulmonary disease (COPD). Prior studies evaluating musculoskeletal dysfunction in COPD have focused on individuals with baseline low muscle mass. Currently, there is limited data evaluating clinical characteristics and outcomes associated with progression to incident low muscle mass in a tobacco-exposed cohort of individuals with baseline normal muscle mass.

METHODS

We evaluated 246 participants from a single-center longitudinal tobacco-exposed cohort with serial spirometry, thoracic imaging, dual energy x-ray absorptiometry (DXA) measurements, walk testing, and plasma adipokine measurements. DXA-derived fat free mass index (FFMI) and appendicular skeletal mass index (ASMI) were used as surrogates for muscle mass. Participants with incident low muscle mass (LM) at follow-up were characterized by FFMI < 18.4 kg/m2 in males and < 15.4 kg/m2 in females and/or ASMI < 7.25 kg/m2 in males and < 5.67 kg/m2 in females.

RESULTS

Twenty-five (10%) participants progressed to incident low muscle mass at follow-up. At baseline, the LM subgroup had greater active smoking prevalence (60% v. 38%, p = 0.04), lower FFMI (17.8 ± 1.7 kg/m2 v. 19.7 ± 2.9 kg/m2, p = 0.002), lower ASMI (7.3 ± 0.9 kg/m2 v. 8.2 ± 1.2 kg/m2, p = 0.0003), and lower plasma leptin (14.9 ± 10.1 ng/mL v. 24.0 ± 20.9 ng/mL, p = 0.04). At follow-up, the LM subgroup had higher COPD prevalence (68% v. 43%, p = 0.02), lower FEV1/FVC (0.63 ± 0.12 v. 0.69 ± 0.12, p = 0.02), lower %DLco (66.5 ± 15.9% v. 73.9 ± 16.8%, p = 0.03), and higher annual rate of FFMI decline (-0.17 kg/m2/year v. -0.04 kg/m2/year, p = 0.006). There were no differences in age, gender distribution, pack years smoking history, or walk distance.

CONCLUSIONS

We identified a subgroup of tobacco-exposed individuals with normal baseline muscle mass who progressed to incident DXA-derived low muscle mass. This subgroup demonstrated synchronous lung disease and persistently low circulating leptin levels. Our study suggests the importance of assessing for muscle loss in conjunction with lung function decline when evaluating individuals with tobacco exposure.

Clinically defined aspiration pneumonia is an independent risk factor associated with long-term hospital stay: a prospective cohort study

BACKGROUND

Long-term hospital stay is associated with functional decline in patients with pneumonia, especially in the elderly. Among elderly patients with pneumonia, aspiration pneumonia is a major category. Clinical definition is usually used because it can occur without apparent aspiration episodes. It is still not clear whether a long-term hospital stay is due to aspiration pneumonia itself caused by underlying oropharyngeal dysfunction or simply due to functional decline in elderly patients with multiple comorbidities during acute infection. The aim of this study is to identify whether clinically defined aspiration pneumonia itself was associated with a long-term hospital stay.

METHODS

A prospective observational study on community-acquired (CAP) or healthcare-associated pneumonia (HCAP) was conducted from January 2012 through January 2014. Aspiration pneumonia was clinically defined as pneumonia not only occurring in patients after documented aspiration episodes, but also occurring in those with underlying oropharyngeal dysfunction: chronic disturbances of consciousness and/or chronic neuromuscular diseases. We defined thirty-day hospital stay as a long-term hospital stay and compared it with logistic regression analysis. Potential confounders included age, sex, HCAP, body mass index (BMI), long-term bed-ridden state, heart failure, cerebrovascular disorders, dementia, antipsychotics use, hypnotics use, and CURB score which is a clinical prediction tool used to assess the severity, standing for; C (presence of Confusion), U (high blood Urea nitrogen level), R (high Respiratory rate), and B (low Blood pressure). In a sub-analysis, we also explored factors associated with long-term hospital stay in patients with aspiration pneumonia.

RESULTS

Of 2,795 patients, 878 (31.4%) had aspiration pneumonia. After adjusting potential confounders, the aspiration pneumonia itself was significantly associated with long-term hospital stay (adjusted odds ratio 1.44; 95% confidence interval 1.09-1.89, p < 0.01), as were higher age, male sex, high CURB score, HCAP, low BMI, heart failure, cerebrovascular disease, and antipsychotics use. Sub-analysis revealed factors associated with long-term hospital stay in the aspiration pneumonia, which included male sex, and multi-lobar chest X-ray involvement.

CONCLUSIONS

Clinically defined aspiration pneumonia itself was independently associated with long-term hospital stay. This result could potentially lead to specific rehabilitation strategies for pneumonia patients with underlying oropharyngeal dysfunction.

CT-Derived Deep Learning-Based Quantification of Body Composition Associated with Disease Severity in Chronic Obstructive Pulmonary Disease

Purpose

Our study aimed to evaluate the association between automated quantified body composition on CT and pulmonary function or quantitative lung features in patients with chronic obstructive pulmonary disease (COPD).

Materials and Methods

A total of 290 patients with COPD were enrolled in this study. The volume of muscle and subcutaneous fat, area of muscle and subcutaneous fat at T12, and bone attenuation at T12 were obtained from chest CT using a deep learning-based body segmentation algorithm. Parametric response mapping-derived emphysema (PRMemph), PRM-derived functional small airway disease (PRMfSAD), and airway wall thickness (AWT)-Pi10 were quantitatively assessed. The association between body composition and outcomes was evaluated using Pearson's correlation analysis.

Results

The volume and area of muscle and subcutaneous fat were negatively associated with PRMemph and PRMfSAD (p < 0.05). Bone density at T12 was negatively associated with PRMemph (r = -0.1828, p = 0.002). The volume and area of subcutaneous fat and bone density at T12 were positively correlated with AWT-Pi10 (r = 0.1287, p = 0.030; r = 0.1668, p = 0.005; r = 0.1279, p = 0.031). However, muscle volume was negatively correlated with the AWT-Pi10 (r = -0.1966, p = 0.001). Muscle volume was significantly associated with pulmonary function (p < 0.001).

Conclusion

Body composition, automatically assessed using chest CT, is associated with the phenotype and severity of COPD.

Predictors of longitudinal changes in body weight, muscle and fat in patients with and ever-smokers at risk of COPD

BACKGROUND AND OBJECTIVE

Weight and muscle loss are predictors of poor outcomes in chronic obstructive pulmonary disease. However, to our knowledge, no study has investigated the predictors of longitudinal weight loss or its composition from functional and morphological perspectives.

METHODS

This longitudinal observational study with a median follow-up period of 5 years (range: 3.0-5.8 years) included patients with COPD and ever-smokers at risk of COPD. Using chest computed tomography (CT) images, airway and emphysematous lesions were assessed as the square root of the wall area of a hypothetical airway with an internal perimeter of 10 mm (√Aaw at Pi10) and the percentage of low attenuation volume (LAV%). Muscle mass was estimated using cross-sectional areas (CSAs) of the pectoralis and erector spinae muscles, and fat mass was estimated using the subcutaneous fat thickness at the level of the 8th rib measured using chest CT images. Statistical analyses were performed using the linear mixed-effects models.

RESULTS

In total, 114 patients were enrolled. Their body mass index remained stable during the study period while body weight and muscle CSA decreased over time and the subcutaneous fat thickness increased. Reduced forced expiratory volume in 1 s and peak expiratory flow (PEF) at baseline predicted the future decline in muscle CSA.

CONCLUSION

Severe airflow limitation predicted future muscle wasting in patients with COPD and ever-smokers at risk of COPD. Airflow limitation with a PEF slightly below 90% of the predicted value may require intervention to prevent future muscle loss.

Analytic Morphomics in Myositis-Related Interstitial Lung Disease

PURPOSE

Interstitial lung disease (ILD) is the most common non-musculoskeletal manifestation of idiopathic inflammatory myopathies (IIM). Identification of body composition change may enable early intervention to improve prognosis. We investigated muscle quantity and quality derived from cross-sectional imaging in IIM, and its relationship to ILD severity.

METHODS

A retrospective cohort study assessing IIM of ILD patients (n = 31) was conducted. Two datasets separated in time were collected, containing demographics, biochemical data, pulmonary function testing and thoracic CT data. Morphomic analysis of muscle quantity (cross-sectional area) and quality (density in Hounsfield Units) on thoracic CT were analysed utilising a web-based tool allowing segmentation of muscle and fat. Bilateral erector spinae and pectoralis muscle (ESM&PM) were measured at defined vertebral levels.

RESULTS

FVC and DLCO decreased but within acceptable limits of treatment response (FVC: 83.7-78.7%, p < 0.05, DLCO 63.4-60.6%, p < 0.05). The cross-sectional area of the PM and ESM increased (PM: 39.8 to 40.7 cm2, p = 0.491; ESM: 35.2 to 39.5 cm2, p = 0.098). Density significantly fell for both the PM and ESM (PM: 35.3-31 HU, p < 0.05; ESM: 38-33.7, p < 0.05). Subcutaneous fat area increased from 103.9 to 136.1 cm2 (p < 0.05), while the visceral fat area increased but not reaching statistical significance. The change in PM density between time points demonstrated an inverse correlation with DLCO (p < 0.05, R =  - 0.49).

CONCLUSION

Patients with IIM ILD demonstrated significant body composition changes on CT imaging unlikely to be detected by traditional measurement tools. An increase in muscle area with an inverse decrease in density suggests poor muscle quality.

Urinary titin N-fragment as a predictor of decreased skeletal muscle mass in patients with interstitial lung diseases

This study aimed to examine the validity of urinary N-terminal titin fragment/creatinine (urinary N-titin/Cr) reflecting muscle damage biomarker in patients with interstitial lung disease. This retrospective study enrolled patients with interstitial lung disease. We measured urinary N-titin/Cr. Furthermore, we measured the cross-sectional areas of the pectoralis muscles above the aortic arch (PMCSA) and erector spinae muscles of the 12th thoracic vertebra muscles (ESMCSA) to assess muscle mass until 1 year. We examined the correlation between urinary N-titin/Cr and the change in muscle mass. We plotted receiver operating characteristic curves to estimate the cut-off points for urinary N-titin/Cr for distinguishing the greater-than-median and smaller-than-median reduction of muscle mass after 1 year. We enrolled 68 patients with interstitial lung disease. The median urinary N-titin/Cr value was 7.0 pmol/mg/dL. We observed significant negative correlations between urinary N-titin/Cr and changes in the PMCSA after 1 year (p < 0.001) and changes in the ESMCSA after 6 months (p < 0.001) and 1 year (p < 0.001). The cut-off points for urinary N-titin/Cr were 5.2 pmol/mg/dL and 10.4 pmol/mg/dL in the PMCSA and ESMCSA, respectively. In summary, urinary N-titin/Cr may predict muscle loss in the long-term and act as a clinically useful biomarker reflecting muscle damage.

Relationship between the thickness of erector spinae muscles and mortality in patients with pulmonary tuberculosis

BACKGROUND

Skeletal muscle mass is a known predictor of mortality in older patients. However, its relationship with tuberculosis is unclear. Skeletal muscle mass is determined by the cross-sectional area of erector spinae muscle (ESM_CSA). Additionally, the erector spinae muscle thickness (ESM_T) is an easier measurement than ESM_CSA. This study investigated the relationship of ESM_T and ESM_CSA with mortality in tuberculosis patients.

METHODS

We retrospectively collected the data of 267 older patients (age ≥65 years) who were hospitalized due to tuberculosis at the Fukujuji Hospital from January 2019 to July 2021. This included 40 patients with 60-day mortality (the death group) and 227 patients with 60-day survival (the alive group). Here, we assessed the correlations between ESM_CSA and ESM_T, and the data were compared between the two groups.

RESULTS

ESM_T had a strong proportional relationship with ESM_CSA (r = 0.991, p < 0.001). ESM_CSA (median 670.2 mm² [interquartile range (IQR): 585.1-760.9] vs. 914.3 mm² [717.6-1141.6], p < 0.001) and ESM_T (median 16.7 mm [15.4-18.6] vs. 21.1 mm [18.0-25.5], p < 0.001) were significantly lower in the patients in the death group than those of patients in the alive group. A multivariable Cox proportional hazard model for 60-day mortality showed significantly independent differences in ESM_T (hazard ratio [HR] 0.870 [95% confidence interval (Cl): 0.795-0.952], p = 0.003) and ESM_CSA (HR 0.998 [95% Cl: 0.996-0.999], p = 0.009).

CONCLUSIONS

This study demonstrated a strong correlation between ESM_CSA and ESM_T, which were risk factors for mortality in patients with tuberculosis. Therefore, using ESM_T is easier to predict mortality than ESM_CSA.

Association between thoracic and third lumbar CT-derived muscle mass and density in Caucasian patients without chronic disease: a proof-of-concept study

BACKGROUND

Computed tomography (CT) is increasingly used in the clinical workup, and existing scan contains unused body composition data, potentially useful in a clinical setting. However, there is no healthy reference for contrast-enhanced thoracic CT-derived muscle measures. Therefore, we aimed at investigating whether there is a correlation between each of the thoracic and third lumbar vertebra level (L3) skeletal muscle area (SMA), skeletal muscle index (SMI), and skeletal muscle density (SMD) at contrast-enhanced CT in patients without chronic disease.

METHODS

A proof-of-concept retrospective observational study was based on Caucasian patients without chronic disease, who received CT for trauma between 2012 and 2014. Muscle measures were assessed using a semiautomated threshold-based software by two raters independently. Pearson's correlation between each thoracic level and third lumbar and intraclass correlation between two raters and test-retest with SMA as proxy parameters were used.

RESULTS

Twenty-one patients (11 males, 10 females; median age 29 years) were included. The second thoracic vertebra (T2) had the highest median of cumulated SMA (males 314.7 cm², females 118.5 cm²) and SMI (97.8 cm²/m² and 70.4 cm²/m², respectively). The strongest SMA correlation was observed between T5 and L3 (r = 0.970), the SMI between T11 and L3 (r = 0.938), and the SMD between the T10 and L3 (r = 0.890).

CONCLUSIONS

This study suggests that any of the thoracic levels can be valid to assess skeletal muscle mass. However, the T5 may be most favourable for measuring SMA, the T11 for SMI, and T10 for SMD when using contrast-enhanced thoracic CT.

RELEVANCE STATEMENT

In COPD patients, a CT-derived thoracic muscle mass assessment may help identify who would benefit from focused pulmonary rehabilitation: thoracic contrast-enhanced CT conducted as part of the standard clinical workup can be used for this evaluation.

KEY POINTS

• Any thoracic level can be used to assess thoracic muscle mass. • Thoracic level 5 is strongly associated with the 3rd lumbar muscle area. • A strong correlation between the thoracic level 11 and the 3rd lumbar muscle index. • Thoracic level 10 is strongly associated with the 3rd lumbar muscle density.

The effect of lifestyle on the mortality associated with respiratory diseases in the general population

Lifestyle factors, including smoking habit, diet, and physical activity, affect the prognosis of various diseases. We elucidated the effect of lifestyle factors and health status on deaths from respiratory diseases in the general Japanese population using data from a community health examination database. Data of the nationwide screening program of the Specific Health Check-up and Guidance System (Tokutei-Kenshin), targeting the general population in Japan, from 2008 to 2010 were analyzed. The underlying causes of death were coded according to the International Classification of Diseases (ICD)-10. The hazard ratios of the incidence of mortality associated with respiratory disease were estimated using the Cox regression model. This study included 664,926 participants aged 40-74 years, who were followed up for 7 years. There were 8051 deaths, including 1263 (15.69%) deaths from respiratory diseases. The independent risk factors of mortality associated with respiratory diseases were male sex, older age, low body mass index, no exercise habit, slow walking speed, no drinking habit, smoking history, history of cerebrovascular diseases, high hemoglobin A1c and uric acid levels, low low-density lipoprotein cholesterol level, and proteinuria. Aging and decline of physical activity are significant risk factors for mortality associated with respiratory diseases, regardless of the smoking status.

Skeletal muscle atrophy and short-term mortality in patients with acute exacerbation of idiopathic pulmonary fibrosis: an observational cohort study

BACKGROUND

Skeletal muscle atrophy, a common complication of idiopathic pulmonary fibrosis (IPF), and its presence upon diagnosis can indicate a poor prognosis. Patients with IPF frequently experience acute exacerbations (AE), which is associated with a high mortality rate. However, the association between skeletal muscle atrophy and short-term mortality remains unknown.

METHODS

We performed a retrospective, multicenter cohort study of patients admitted for AE-IPF in Japan. The cross-sectional areas of the erector spinae muscle (ESM_CSA) and the pectoralis muscle (PM_CSA) were analyzed via single-slice computed tomography (CT). The primary outcome was 90-day mortality. Survival probability was estimated using the Kaplan-Meier method, and the log-rank test was used between the low and high groups of ESM_CSA and PM_CSA. We used multivariable Cox proportional-hazards models to evaluate the association between ESM_CSA and PM_CSA and prognosis.

RESULTS

Of the 212 patients included, 94 (44%) died during the observation period. The low ESM_CSA group (<25.6 cm²) had a significantly worse prognosis than that of the high ESM_CSA group (≥25.6 cm²) (hazard ratio (HR) [95% confidence interval (CI)]: 1.52 [1.00-2.33], P = 0.049). Multivariable analyses showed that all-cause mortality was associated with low ESM_CSA (model 1, adjusted HR [95% CI]: 1.59 [0.98-2.60]; model 2, 1.55 [0.95-2.56], and model 3, 1.67 [1.00-2.78], respectively). The adjusted HR of low PM_CSA (<20.4 cm²) vs. high PM_CSA (≥20.4 cm²) was 1.39 (95% CI: 0.88-2.20).

CONCLUSIONS

Low ESM_CSA on CT images is associated with a high 90-day mortality rate in patients with AE-IPF.