Systemic and pulmonary inflammation is independent of skeletal muscle changes in patients with chronic obstructive pulmonary disease

Association Between Anthropometric Indices and Skeletal-Muscle Atrophy in Chinese Patients with Stable Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study

Purpose

Anthropometric indices are simple indicators of patient nutritional status. However, the association between these indices and skeletal-muscle atrophy in patients with stable chronic obstructive pulmonary disease (COPD) has not been fully investigated. In this study, we evaluated this association.

Patients and Methods

We recruited 123 outpatients with stable COPD from a general hospital in China from 2020 to 2021. We recorded their demographic characteristics, including age, sex, course of illness, dyspnea score, body mass index (BMI), force expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), smoking status, and severity grading. In addition, patients' anthropometric indices, including fat-free mass index (FFMI) and appendicular skeletal-muscle mass index (ASMI), were measured using a body composition analyzer, and measurements were taken of the triceps skinfold (TSF), midarm circumference (MAC), and calf circumference (CC). We drew and analyzed a receiver operating characteristic (ROC) curve to identify the best intercept point value for the assessment of skeletal-muscle atrophy.

Results

The TSF, MAC, CC, FFMI, and ASMI of COPD patients were 1.08 ± 0.44 cm, 26.39 ± 2.92 cm, 34.5 ± 3.06 cm, 17.49 ± 1.86 kg/m², and 8.17 ± 0.90 kg/m², respectively. These anthropometric indices had a significant positive correlation with skeletal-muscle mass (correlation values, 0.481-0.820). CC was strongly correlated with both FFMI and ASMI. The ROC curve showed an area-under-the-curve (AUC) value of 0.873-0.959.

Conclusion

Anthropometric indices were correlated with skeletal-muscle mass. CC showed the best diagnostic value in COPD patients, suggesting its effectiveness as a simple method for assessing skeletal-muscle atrophy and identifying patients with a noticeable reduction in muscle mass. Such patients require early, multidisciplinary intervention.

Sarcopenia in COPD: a systematic review and meta-analysis

COPD is associated with a progressive loss of muscle mass and function. However, there is an unmet need to define and standardise methods to estimate the prevalence of sarcopenia in COPD patients.

We performed a systematic review and meta-analysis of the prevalence of this extrapulmonary manifestation in COPD patients. We searched Embase, Medline (Ovid), CINAHL (EBSCO), Web of Science, Scopus and Google Scholar for studies published up to January 17, 2019, assessing sarcopenia in COPD patients based on low muscle mass and decreased muscle function. Interventional studies, in vitro experiments, protocols or reviews and meta-analyses were excluded. We estimated heterogeneity (I²) and assessed significance (Q) using a Chi-squared test for estimates obtained from random-effects models.

4465 articles were initially identified. After removing the duplicates and applying the selection criteria, we reviewed 62 full-text articles. Finally, 10 articles (n=2565 COPD patients) were included in this systematic review and meta-analyses. Overall, the prevalence of sarcopenia in patients with COPD was 21.6% (95% CI 14.6–30.9%, I²=94%), ranging from 8% in population-based to 21% in clinic-based studies, and 63% in COPD patients residing in nursing homes.

Sarcopenia is frequently observed in COPD patients, with varying prevalence across population settings. Sarcopenia in COPD should be assessed using standardised tests and cut-off points from sarcopenia consensus criteria for clinical practice and international comparisons.

We confirmed a high prevalence of sarcopenia in COPD patients, with varying prevalence across population settings. We recommend adhering to the sarcopenia consensus criteria to systematically evaluate the muscle health of COPD patients.http://bit.ly/2KA6weh

It's more than low BMI: prevalence of cachexia and associated mortality in COPD

BACKGROUND

Cachexia is associated with increased mortality risk among chronic obstructive pulmonary disease (COPD) patients. However, low body mass index (BMI) as opposed to cachexia is often used, particularly when calculating the BODE (BMI, Obstruction, Dyspnea and Exercise) index. For this reason, we examined mortality using a consensus definition and a weight-loss definition of cachexia among COPD cases and compared two new COPD severity indices with BODE.

METHODS

In the current report, the consensus definition for cachexia incorporated weight-loss > 5% in 12-months or low BMI in addition to 3/5 of decreased muscle strength, fatigue, anorexia, low FFMI and inflammation. The weight-loss definition incorporated weight-loss > 5% or weight-loss > 2% (if low BMI) in 12-months. The low BMI component in BODE was replaced with the consensus definition to create the CODE (Consensus cachexia, Obstruction, Dyspnea and Exercise) index and the weight-loss definition to create the WODE (Weight loss, Obstruction, Dyspnea and Exercise) index. Mortality was assessed using Kaplan-Meier survival and Cox Regression. Performance of models was compared using C-statistics.

RESULTS

Among 1483 COPD cases, the prevalences of cachexia by the consensus and weight-loss definitions were 4.7 and 10.4%, respectively. Cachectic patients had a greater than three-fold increased mortality by either the consensus or the weight-loss definition of cachexia independent of BMI and lung function. The CODE index predicted mortality slightly more accurately than the BODE and WODE indices.

CONCLUSIONS

Cachexia is associated with increased mortality among COPD patients. Monitoring cachexia using weight-loss criteria is relatively simple and predictive of mortality among COPD cases who may be missed if only low BMI is used.

The feasibility of early pulmonary rehabilitation and activity after COPD exacerbations: external pilot randomised controlled trial, qualitative case study and exploratory economic evaluation

BACKGROUND

Chronic obstructive pulmonary disease (COPD) affects > 3 million people in the UK. Acute exacerbations of COPD (AECOPD) are the second most common reason for emergency hospital admission in the UK. Pulmonary rehabilitation is usual care for stable COPD but there is little evidence for early pulmonary rehabilitation (EPR) following AECOPD, either in hospital or immediately post discharge.

OBJECTIVE

To assess the feasibility of recruiting patients, collecting data and delivering EPR to patients with AECOPD to evaluate EPR compared with usual care.

DESIGN

Parallel-group, pilot 2 × 2 factorial randomised trial with nested qualitative research and an economic analysis.

SETTING

Two acute hospital NHS trusts. Recruitment was carried out from September 2015 to April 2016 and follow-up was completed in July 2016.

PARTICIPANTS

Eligible patients were those aged ≥ 35 years who were admitted with AECOPD, who were non-acidotic and who maintained their blood oxygen saturation level (SpO₂) within a prescribed range. Exclusions included the presence of comorbidities that affected the ability to undertake the interventions.

INTERVENTIONS

(1) Hospital EPR: muscle training delivered at the patient's hospital bed using a cycle ergometer and (2) home EPR: a pulmonary rehabilitation programme delivered in the patient's home. Both interventions were delivered by trained physiotherapists. Participants were allocated on a 1 : 1 : 1 : 1 ratio to (1) hospital EPR (n = 14), (2) home EPR (n = 15), (3) hospital EPR and home EPR (n = 14) and (4) control (n = 15). Outcome assessors were blind to treatment allocation; it was not possible to blind patients.

MAIN OUTCOME MEASURES

Feasibility of recruiting 76 participants in 7 months at two centres; intervention delivery; views on intervention/research acceptability; clinical outcomes including the 6-minute walk distance (6WMD); and costs. Semistructured interviews with participants (n = 27) and research health professionals (n = 11), optimisation assessments and an economic analysis were also undertaken.

RESULTS

Over 7 months 449 patients were screened, of whom most were not eligible for the trial or felt too ill/declined entry. In total, 58 participants (76%) of the target 76 participants were recruited to the trial. The primary clinical outcome (6MWD) was difficult to collect (hospital EPR, n = 5; home EPR, n = 6; hospital EPR and home EPR, n = 5; control, n = 5). Hospital EPR was difficult to deliver over 5 days because of patient discharge/staff availability, with 34.1% of the scheduled sessions delivered compared with 78.3% of the home EPR sessions. Serious adverse events were experienced by 26 participants (45%), none of which was related to the interventions. Interviewed participants generally found both interventions to be acceptable. Home EPR had a higher rate of acceptability, mainly because patients felt too unwell when in hospital to undergo hospital EPR. Physiotherapists generally found the interventions to be acceptable and valued them but found delivery difficult because of staffing issues. The health economic analysis results suggest that there would be value in conducting a larger trial to assess the cost-effectiveness of the hospital EPR and hospital EPR plus home EPR trial arms and collect more information to inform the hospital cost and quality-adjusted life-year parameters, which were shown to be key drivers of the model.

CONCLUSIONS

A full-scale randomised controlled trial using this protocol would not be feasible. Recruitment and delivery of the hospital EPR intervention was difficult. The data obtained can be used to design a full-scale trial of home EPR. Because of the small sample and large confidence intervals, this study should not be used to inform clinical practice.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN18634494.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 11. See the NIHR Journals Library website for further project information.

Elevated serum Activin A in chronic obstructive pulmonary disease with skeletal muscle wasting

OBJECTIVE

Muscle wasting contributes to the reduced quality of life and increased mortality in chronic obstructive pulmonary disease (COPD). Muscle atrophy in mice with cachexia was caused by Activin A binding to ActRIIB. The role of circulating Activin A leading to muscle atrophy in COPD remains elusive.

METHODS

In the present study, we evaluated the relationship between serum levels of Activin A and skeletal muscle wasting in COPD patients. The expression levels of serum Activin A were measured in 78 stable COPD patients and in 60 healthy controls via ELISA, which was also used to determine the expression of circulating TNF-α levels. Total skeletal muscle mass (SMM) was calculated according to a validated formula by age and anthropometric measurements. The fat-free mass index (FFMI) was determined as the fat-free mass (FFM) corrected for body surface area.

RESULTS

Compared to the healthy controls, COPD patients had upregulated Activin A expression. The elevated levels of Activin A were correlated with TNF-α expression, while total SMM and FFMI were significantly decreased in COPD patients. Furthermore, serum Activin A expression in COPD patients was negatively associated with both FFMI and BMI.

CONCLUSION

The above results showed an association between increased circulating Activin A in COPD patients and the presence of muscle atrophy. Given our previous knowledge, we speculate that Activin A contributes to skeletal muscle wasting in COPD.

The sarcopenia index: A novel measure of muscle mass in lung transplant candidates

BACKGROUND

Frailty, including low muscle mass, is an emerging risk factor for poor outcomes after lung transplant. The sarcopenia index (SI)-(serum creatinine value/cystatin C value) × 100-is a novel blood test to approximate muscle mass. We sought to validate SI among lung transplant patients.

METHODS

We retrospectively identified adult lung transplant recipients from 2000 through 2012 at our institution who underwent computed tomography within 1 year before transplant and had preserved blood samples. Creatinine and cystatin C values were measured using the samples and used to calculate SI. Muscle mass was estimated by computed tomographic measurement of skeletal muscle cross-sectional surface area (SA) at the L1 to L3 vertebral levels. Correlation between SI and SA was evaluated.

RESULTS

Of 28 patients meeting eligibility criteria, most were white (96%) and men (54%). Median (interquartile range) body mass index, SI, and SA were 25.9 (22-30) kg/m² , 106 (91-119), and 157 (113-195) cm2, respectively. The Pearson correlation coefficient between SI and SA was significant at L2 (0.43; P = .02) and L3 (0.41; P = .03).

CONCLUSION

Sarcopenia index is a potentially objective measure for estimating muscle mass that is noninvasive and less expensive. Sarcopenia index could be considered in lung transplant candidate selection following prospective validation in larger cohorts.

Soluble guanylate cyclase stimulation reduces oxidative stress in experimental Chronic Obstructive Pulmonary Disease

Objective

Soluble guanylate cyclase (sGC) is a key enzyme of the nitric oxide–cyclic guanosine 3′,5′-monophosphate (NO–cGMP) signaling pathway, and its pharmacological stimulation has been shown to prevent the development of emphysema and pulmonary vascular remodeling in animal models of chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the effects of sGC stimulation on oxidative stress in the plasma of guinea pigs chronically exposed to cigarette smoke (CS).

Methods and results

Guinea pigs were exposed to CS or sham for three months, and received either the sGC stimulator BAY 41–2272 or vehicle. Body weight was measured weekly; and markers of oxidative stress in plasma, and airspace size and inflammatory cell infiltrate in lung tissue were analyzed at the end of the study. Compared to sham-exposed guinea pigs, CS-exposed animals gained less body weight and showed higher plasma levels of nitrated tyrosine residues (3-NT), 4-hydroxynonenal (4-HNE), and 8-hydroxydeoxyguanosine (8-OHdG). Treatment with the sGC stimulator led to a body weight gain in the CS-exposed guinea pigs similar to non-exposed and attenuated the increase in 3-NT and 4-HNE. Plasma levels of 3-NT correlated with the severity of inflammatory cell infiltrate in the lung.

Conclusion

Stimulation of sGC prevents oxidative stress induced by CS exposure and is associated with an attenuated inflammatory response in the lung.

COPD and osteoporosis: links, risks, and treatment challenges

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease associated with various systemic comorbidities including osteoporosis. Osteoporosis and its related fractures are common and have significant impacts on quality of life and even respiratory function in patients with COPD. COPD-associated osteoporosis is however extremely undertreated. Recent studies have suggested that both decreased bone mineral density (BMD) and impaired bone quality contribute to bone fragility, causing fractures in COPD patients. Various clinical risk factors of osteoporosis in COPD patients, including older age, emaciation, physical inactivity, and vitamin D deficiency, have also been described. It is critically important for pulmonologists to be aware of the high prevalence of osteoporosis in COPD patients and evaluate them for such fracture risks. Routine screening for osteoporosis will enable physicians to diagnose COPD patients with comorbid osteoporosis at an early stage and give them appropriate treatment to prevent fracture, which may lead to improved quality of life as well as better long-term prognosis.

Relation between systemic inflammatory markers, peripheral muscle mass, and strength in limb muscles in stable COPD patients

The aim of this study was to investigate the association between systemic inflammatory mediators and peripheral muscle mass and strength in COPD patients. Fifty-five patients (69% male; age: 64±9 years) with mild/very severe COPD (defined as forced expiratory volume in the first second [FEV1] =54%±23%) were evaluated. We evaluated serum concentrations of IL-8, CRP, and TNF-α. Peripheral muscle mass was evaluated by computerized tomography (CT); midthigh cross-sectional muscle area (MTCSA) and midarm cross-sectional muscle area (MACSA) were obtained. Quadriceps, triceps, and biceps strength were assessed through the determination of the one-repetition maximum. The multiple regression results, adjusted for age, sex, and FEV1%, showed positive significant association between MTCSA and leg extension (0.35 [0.16, 0.55]; P=0.001), between MACSA and triceps pulley (0.45 [0.31, 0.58]; P=0.001), and between MACSA and biceps curl (0.34 [0.22, 0.47]; P=0.001). Plasma TNF-α was negatively associated with leg extension (-3.09 [-5.99, -0.18]; P=0.04) and triceps pulley (-1.31 [-2.35, -0.28]; P=0.01), while plasma CRP presented negative association with biceps curl (-0.06 [-0.11, -0.01]; P=0.02). Our results showed negative association between peripheral muscle mass (evaluated by CT) and muscle strength and that systemic inflammation has a negative influence in the strength of specific groups of muscles in individuals with stable COPD. This is the first study showing association between systemic inflammatory markers and strength in upper limb muscles.