A prospective study of decline in fat free mass and skeletal muscle strength in chronic obstructive pulmonary disease

Body Composition after Endoscopic Lung Volume Reduction with Endobronchial Valves: A Prospective Study

INTRODUCTION

Patients with chronic obstructive pulmonary disease (COPD) and emphysema experience malnutrition and pulmonary cachexia. Endoscopic lung volume reduction (ELVR) with endobronchial valves has not only improved lung function, exercise capacity, and quality of life but also influenced body weight. Only a few data are available on body composition changes after ELVR.

METHODS

This single-center prospective study of patients with advanced COPD investigates body composition before and after endoscopic valve treatment using multifrequency bioelectrical impedance analysis (BIA). The following parameters were evaluated in addition to clinical data and routine tests: body weight, body mass index (BMI), basal metabolic rate, total body water, body fat, cell percentage, phase angle, intracellular water (ICW), extracellular water (ECW), extracellular mass (ECM), body cell mass (BCM), lean body mass (ECM + BCM), and fat-free mass index.

RESULTS

A total of 23 patients (mean emphysema index 37.2 ± 7.5%, BMI 23.4 ± 4.3 kg/m2) experienced improvements in lung function and exercise capacity with ELVR. Complete lobar atelectasis was achieved in 39.1% of participants. A non-statistically significant increase in body weight and BMI was observed after ELVR (p = 0.111 and p = 0.102). BIA measurement revealed a worsening of phase angle, cell percentage and ECM/BCM and thus of body composition, but without statistical significance. This is mainly due to a statistically significant increase in ECM, ECW, and ICW (all p < 0.001).

CONCLUSION

ELVR demonstrated no beneficial changes in body composition, although patients tend to gain weight. A larger cohort is warranted to confirm these findings.

Characteristics of Skeletal Muscle Strength in Subjects With Interstitial Lung Disease

OBJECTIVES

To investigate muscle strength and the prevalence of muscle weakness in adults with interstitial lung diseases (ILDs) compared to healthy subjects.

DESIGN

Cross-sectional (description of clinical features).

SETTING

Public referral center (University Hospital).

PARTICIPANTS

One hundred and twelve adults with ILD (n=48, 60±10yr, 68% female) and healthy counterparts (control group, n=64, 57±10yr, 58% female) (N=112).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURE(S)

Muscle strength and prevalence of muscle weakness in adults with ILD. Muscle strength was assessed via maximal isometric voluntary contraction of dominant upper and lower limb muscle groups. Data from the control group were used to generate reference equations. Muscle weakness was defined as a muscle strength value below the lower limit of normal calculated using data from the control group. Data were expressed as mean ± SD or median [interquartile range] according to the data distribution.

RESULTS

Compared to the control group, adults with ILD had lower muscle strength for all muscle groups assessed (values presented as %predicted: pectoralis major 75[57-86]%; quadriceps 72[58-87]%; latissimus dorsi 76[57-103]%; deltoid 74[64-98]%; biceps brachii 78[64-91]%; triceps brachii 84[62-101]%; P≤.001 for all). Prevalence of muscle weakness in people with ILD was 40% for pectoralis major, 25% for latissimus dorsi, 16% for triceps brachii, 20% for biceps brachii, 27% for deltoid and 46% for quadriceps.

CONCLUSIONS

Adults with ILD present a generalised reduction in peripheral Muscle strength, ranging between 20% to 46% of people depending on the muscle group assessed. and it was more prevalent in lower limb muscles.

Extracellular Water Ratio and Phase Angle as Predictors of Exacerbation in Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), characterized by high-energy metabolism, often leads to malnutrition and is linked to exacerbations. This study investigates the association of malnutrition-related body composition and handgrip strength changes with exacerbation frequencies in COPD patients.

METHODS

We analyzed 77 acute exacerbation COPD (AECOPD) patients and 82 stable COPD patients, categorized as frequent and infrequent exacerbators. Assessments included body composition, handgrip strength, nutritional risk, dyspnea scale, and COPD assessment.

RESULTS

Among AECOPD patients, there were 22 infrequent and 55 frequent exacerbators. Infrequent exacerbators showed better muscle parameters, extracellular water ratio, phase angle, and handgrip strength. Significant differences in intracellular water, total cellular water, protein, and body cell mass were observed between groups. Logistic regression indicated that extracellular water ratio (OR = 1.086) and phase angle (OR = 0.396) were independently associated with exacerbation risk. Thresholds for exacerbation risk were identified as 0.393 for extracellular water ratio and 4.85° for phase angle. In stable COPD, 13 frequent and 69 infrequent exacerbators were compared, showing no significant differences in weight, muscle, and adipose parameters, but significant differences in extracellular water ratio, phase angle, and handgrip strength.

CONCLUSIONS

These findings suggest that increased exacerbations in COPD patients correlate with higher extracellular water ratios and lower phase angles.

The impact of sleep duration on physical activity in daily life in patients with idiopathic pulmonary fibrosis

BACKGROUND

Despite the high prevalence of sleep disturbances in idiopathic pulmonary fibrosis (IPF), the relationship between physical activity in daily life (PADL) and sleep in this population remains unclear.

OBJECTIVES

Investigate the impact of sleep on different domains of PADL in IPF and characterize their PADL profile.

METHODS

Sixty-seven participants (thirty-three with IPF and thirty-four healthy subjects [control group]) were included. The subjects underwent assessments of pulmonary function, exercise capacity, respiratory and peripheral muscle strength, PADL, sleep, dyspnea, and health-related quality of life. PADL and sleep measures were assessed using an activity monitor (Actigraph®, wGT3x-BT). Associations between sleep and PADL were done using correlation and regression models.

RESULTS

In the IPF, sleep duration at night associated significantly with step counts, sedentary, light, and moderate-to-vigorous physical activity (MVPA) (-0.82 ≤ R ≤ 0.43; p < .05 for all). Lung function and sleep partially explained PADL variables (0.19 ≤ R2 ≤ 0.65, p < .05 for all). Compared to controls, the IPF subjects presented lower step counts, less time spent in MVPA, standing position, and more time spent in lying position (p < .05, for all).

CONCLUSIONS

Sleep duration is associated with PADL in IPF. The PADL profile of patients is worse than in control subjects.

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

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

Bu-Fei Yi-Shen Granules Reduce Acute Exacerbations in Patients with GOLD 3-4 COPD: A Randomized Controlled Trial

Purpose

Chronic obstructive pulmonary disease (COPD) is a disease characterized by frequent acute exacerbations (AEs), especially in severe and very severe cases. We aimed to evaluate the efficacy and safety of Bu-fei Yi-shen granules (BYGs) for COPD.

Patients and Methods

We conducted a multicenter, randomized, double-blinded, placebo-controlled trial of 348 COPD patients with GOLD 3-4 COPD. The patients were randomly assigned into experimental or control groups in a 1:1 ratio. Patients in the experimental group were prescribed BYG, while those in the control group were administered a placebo, orally, twice daily, with 5 days on and 2 days off per week for 52 weeks. The outcomes included AEs, pulmonary function, clinical signs and symptoms, dyspnea scores (mMRC), quality of life scores, and a 6-minute walk test (6MWT).

Results

A total of 280 patients completed the trial, including 135 patients in the experimental group and 145 in the control group. Compared to the control group, significant differences were observed in frequencies of AEs (mean difference: -0.35; 95% CI: -0.61, -0.10; P = 0.006) and AE-related hospitalizations (-0.18; 95% CI: -0.36, -0.01; P = 0.04), 6MWD (40.93 m; 95% CI: 32.03, 49.83; P < 0.001), mMRC (-0.57; 95% CI: -0.76, -0.37; P < 0.001), total symptoms (-2.18; 95% CI: -2.84, -1.53; P < 0.001), SF-36 (11.60; 95% CI: 8.23, 14.97; P < 0.001), and mCOPD-PRO (-0.45; 95% CI: -0.57, -0.33; P < 0.001) after treatment. However, there were no significant differences in mortality, pulmonary function, and mESQ-PRO scores (P > 0.05). No obvious adverse events were observed.

Conclusion

BYG, as compared to a placebo, could significantly reduce the frequencies of AEs and AE-related hospitalizations for GOLD 3-4 COPD patients. Clinical symptoms, treatment satisfaction, quality of life, and exercise capacity improved. There was no significant improvement in mortality and pulmonary function.

Impact of acute exacerbations of COPD on patients' health status beyond pulmonary function: A scoping review

This scoping review summarized the evidence regarding the impact of acute exacerbations of COPD (AECOPD) on patients' health status beyond pulmonary function. PubMed, Embase, and Web of Science were searched. Prospective cohort studies assessing the health status of patients with COPD in a stable phase of the disease and after a follow-up period (where at least one AECOPD occurred) were included. An integrated assessment framework of health status (i.e., physiological functioning, complaints, functional impairment, quality of life) was used. Twenty-two studies were included. AECOPD acutely affected exercise tolerance, quadriceps muscle strength, physical activity levels, symptoms of dyspnoea and fatigue, and impact of the disease. Long-term effects on quadriceps muscle strength, symptoms of dyspnoea and depression, and quality of life were found. Repeated exacerbations negatively impacted the fat-free mass, levels of dyspnoea, impact of the disease and quality of life. Conflicting evidence was found regarding the impact of repeated exacerbations on exercise tolerance and physical activity levels. AECOPD have well-established acute and long-term adverse effects on health status beyond pulmonary function; nevertheless, the recovery trajectory and the impact of repeated exacerbations are still poorly studied. Further prospective research is recommended to draw firm conclusions on these aspects.

Efficacy of aerobic training and resistance training combined with external diaphragm pacing in patients with chronic obstructive pulmonary disease: A randomized controlled study

OBJECTIVE

To evaluate the efficacy of aerobic training, resistance training combined with external diaphragm pacing in patients with chronic obstructive pulmonary disease.

DESIGN

Randomized controlled trial.

SETTING

The Fourth Rehabilitation Hospital of Shanghai, China.

PARTICIPANTS

82 (67.0  ±  6.5 years, 59.8% male) patients with stable chronic obstructive pulmonary disease were randomized to intervention group 1 (n  =  27), intervention group 2 (n  =  28), and control group (n  =  27).

INTERVENTION

Intervention group 1 received aerobic and resistance training, while intervention group 2 received additional external diaphragm pacing. Control group received aerobic training only.

MAIN MEASURES

1-year follow-up of physical activity, body composition, respiratory function and diaphragm function.

RESULTS

Intervention groups 1 and 2 showed statistically improvements in the difference value compared with control group in terms of 6-min walk distance (-95.28  ±  20.09 and -101.92  ±  34.91 vs -63.58  ±  23.38), forced expiratory volume in 1 s (-0.042  ±  0.027 and -0.130  ±  0.050 vs -0.005  ±  0.068), fat-free mass (-2.11  ±  3.74 and -3.82  ±  3.74vs 0.28  ±  1.49) and chronic obstructive pulmonary disease assessment test value (2.16  ±  0.85 and 2.38  ±  1.02 vs 1.50  ±  0.93). Intervention group 2 showed significant difference in arterial oxygen pressure (-4.46  ±  3.22 vs -1.92  ±  3.45), diaphragm excursion during deep breaths (-0.82  ±  0.74 vs -0.38  ±  0.29), and diaphragm thickness fraction (-8.77  ±  3.22 vs -4.88  ±  2.69) compared with control group.

CONCLUSION

The combination of aerobic training, resistance training, and external diaphragm pacing obtained significant improvements in physical activity, respiratory function, body composition, arterial oxygen pressure, and diaphragm function in patients with chronic obstructive pulmonary disease.

TRIAL REGISTRATION

ChiCTR1800020257, www.chictr.org.cn/index.aspx.

Comparison of Physical Activity Patterns among Three Major Chronic Respiratory Diseases

Although the level of physical activity in daily life (PADL) plays a vital role concerning the health of subjects with chronic lung diseases, it remains uncertain how PADL patterns compare among different conditions. This study's objective was to compare the PADL levels of subjects with COPD, asthma and idiopathic pulmonary fibrosis (IPF); and to investigate PADL behaviour in different diseases' severity. Stable subjects who had not undergone pulmonary rehabilitation in the previous year were included. Subjects were divided into two subgroups according to disease severity: mild/moderate and severe/very severe. The primary outcome was time spent in moderate-to-vigorous physical activities (MVPA) (Actigraph GT3x) measured during one week over 12 h/day; other assessments included pulmonary function, peripheral muscle strength and exercise capacity. Comparisons among subgroups were corrected for age, BMI and sex. The analysis involved 119 subjects (47 asthma, 48 COPD and 24 IPF). Subjects with asthma had higher PADL levels than those with COPD and IPF (MVPA 18(14-22) vs. 8(4-12) vs. 7(1-12) min/day, respectively; p ancova = 0.002). Subjects with severe/very severe IPF had the lowest PADL level among all subgroups. Adult subjects with asthma have higher PADL levels than those with COPD and IPF, whereas patients with severe and very severe IPF are the most physically inactive subjects.

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.

Muscle Power in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

This study aimed to review the impact of training on muscle power in patients with chronic obstructive pulmonary disease (COPD). Randomized controlled trials evaluating the effects of exercise-based interventions on limbs muscle power and rate of force development in COPD patients were investigated. Five international databases were searched until October 2022. Meta-analyses were performed calculating the mean difference or standardized mean difference. Risk of bias in studies was assessed using Cochrane Risk of Bias tool 2.0. A total of nine studies were included in the analysis. There were concerns about risk of bias in seven out of nine studies. Comparison of exercising and non-exercising groups showed a significant effect of exercise in improving muscle power (P=0.0004) and rate of force development (P<0.001), in five and three trials, respectively. Four studies comparing different trainings showed no significant results on muscle power (P=0.45). Eight to 16 weeks of exercise-based intervention versus no intervention might be beneficial to enhance upper and lower limbs muscle power and rate of force development in people with COPD. In contrast, muscle power did not improve when different training modalities were compared. Future studies performing power training in COPD patients are encouraged.

Impact of Body Composition and Sarcopenia on Mortality in Chronic Obstructive Pulmonary Disease Patients

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) have alterations in body composition, such as low cell integrity, body cell mass, and disturbances in water distribution evidenced by higher impedance ratio (IR), low phase angle (PhA), as well as low strength, low muscle mass, and sarcopenia. Body composition alterations are associated with adverse outcomes. However, according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2), the impact of these alterations on mortality in COPD patients is not well-established. Our aims were to evaluate whether low strength, low muscle mass, and sarcopenia impacted mortality in COPD patients.

METHODS

A prospective cohort study performance was conducted with COPD patients. Patients with cancer, and asthma were excluded. Body composition was assessed by bioelectrical impedance analysis. Low strength and muscle mass, and sarcopenia were defined according to EWGSOP2.

RESULTS

240 patients were evaluated, of whom 32% had sarcopenia. The mean age was 72.32 ± 8.24 years. The factors associated with lower risk of mortality were handgrip strength (HR:0.91, CI 95%; 0.85 to 0.96, p = 0.002), PhA (HR:0.59, CI 95%; 0.37 to 0.94, p = 0.026) and exercise tolerance (HR:0.99, CI 95%; 0.992 to 0.999, p = 0.021), while PhA below the 50th percentile (HR:3.47, CI 95%; 1.45 to 8.29, p = 0.005), low muscle strength (HR:3.49, CI 95%; 1.41 to 8.64, p = 0.007) and sarcopenia (HR:2.10, CI 95%; 1.02 to 4.33, p = 0.022) were associated with a higher risk of mortality.

CONCLUSION

Low PhA, low muscle strength, and sarcopenia are independently associated with poor prognosis in COPD patients.

Chronic disease relapses: A cross-sectional study of the associated factors and socioeconomic inequalities during the COVID-19 pandemic in Peru

OBJECTIVES

To investigate the prevalence, associated factors and socioeconomic inequalities in chronic disease relapses (CDR) during 2020 in Peru.

METHODS

A secondary analysis was made of the National Household Survey on Living Conditions and Poverty (ENAHO) 2020. Participants older than 18 years who suffered from a chronic disease and with information about the occurrence of a CDR in the last 4 weeks prior to the survey were included. Adjusted prevalence ratios (aPRs) were estimated to determine the associated factors. Socioeconomic inequality in CDR was estimated using concentration curves (CC) and the Erreygers concentration index (ECI).

RESULTS

Data from 38,662 participants were analyzed; the prevalence of CDR in the last 4 weeks prior to the survey was 16.5% (95% CI: 15.8-17.2). Being female (aPR 1.29; 95% CI: 1.21-1.37), with regards to being male; being 30-39 (aPR 1.22; 95% CI: 1.05-1.42), 40-49 (aPR 1.29; 95% CI: 1.12-1.48), 50-59 (aPR 1.60; 95% CI: 1.41-1.82), and 60 years or older (aPR 1.80; 95% CI: 1.58-2.04), compared to 18-29; reaching up to primary (aPR 1.18; 95% CI: 1.07-1.31), or secondary education (aPR 1.13; 95% CI: 1.02-1.24), in contrast to tertiary education; presenting some physical, psychological or cognitive limitation (aPR 1.33; 95% CI: 1.21-1.46), with respect to experiencing no limitations; and being affiliated to a health insurance (aPR 1.18; CI 95%: 1.09-1.29), opposed to not having health insurance; were associated with a higher probability of CDR. Residing in the natural region of the coastal area (aPR 0.83; 95% CI: 0.74-0.92) was associated with a lower probability of relapse compared to residing in the jungle area. In people with limitations and residents of the jungle areas, the prevalence of CDR was concentrated in those with higher per capita spending.

CONCLUSIONS

Approximately 1 in 6 Peruvians with chronic diseases had a relapse within the last 4 weeks prior to the survey of 2020 and certain geographic and sociodemographic factors were found to be associated with CDR. It was also found that a higher concentration of CDR was observed in the population with the highest per capita spending with some limitations, as well as in residents of the jungle, implying the need for appropriate policy interventions that address CDR with a special focus on these populations.

CT Attenuation and Cross-Sectional Area of the Pectoralis Are Associated With Clinical Characteristics in Chronic Obstructive Pulmonary Disease Patients

Purpose: Muscle wasting is associated with prognosis in patients with chronic obstructive pulmonary disease (COPD). Computed tomography (CT) could serve as a method for muscle assessment due to its ability to measure both muscle quantity (e.g., cross-sectional muscle area) and muscle quality (e.g., muscle attenuation). Our study aimed to compare the differences in CT-derived pectoralis muscle cross-sectional area (PMA) and pectoralis muscle attenuation (PMT) between COPD patients and healthy controls and explore the association between PMA and PMT measurements and clinical characteristics in patients with COPD.

Methods: A total of 252 participants included in our analysis consisted of 80 healthy controls and 172 patients with COPD. PMA and PMT were measured from a single axial slice of the CT scan above the aortic arch. Linear regression analysis was used to determine the correlation between PMA and PMT measurements and clinical characteristics in patients with COPD. Associations were adjusted for age, sex, BMI, FEV₁%pred, smoking pack-years, current smoking status, emphysema percentage, and total airway count (TAC) of the right upper lobe apical bronchus (RB1).

Results: PMA and PMT were lower in COPD patients, especially those with acute exacerbation, than in healthy controls. PMA and PMT were significantly associated with the severity of emphysema and the TAC of RB1 (p < 0.05). Patients with stable COPD, who had lower PMA and lower PMT, had significantly worse pulmonary function, poorer exercise tolerance, decreased quality of life, and worse dyspnea scores. In addition, patients with acute COPD exacerbation, who had lower PMA and lower PMT, had a higher risk of respiratory failure on admission.

Conclusion: CT-derived measurements of the pectoralis muscle may be helpful in detecting declines in muscle quantity and quality and predicting disease severity in patients with COPD.

The Association between Fat-Free Mass and Exercise Test Outcomes in People with Chronic Obstructive Pulmonary Disease: A Systematic Review

People with chronic obstructive pulmonary disease (COPD) tend to have abnormally low levels of fat-free mass (FFM), which includes skeletal muscle mass as a central component. The purpose of this systematic review was to synthesise available evidence on the association between FFM and exercise test outcomes in COPD. MEDLINE, Cochrane Library, EMBASE, Web of Science, and Scopus were searched. Studies that evaluated exercise-related outcomes in relation to measures of FFM in COPD were included. Eighty-three studies, containing 18,770 (39% female) COPD participants, were included. Considerable heterogeneity was identified in the ways that FFM and exercise test outcomes were assessed; however, higher levels of FFM were generally associated with greater peak exercise capacity. This association was stronger for some exercise test outcomes (e.g. peak rate of oxygen consumption during incremental cycle exercise testing) than others (e.g. six-minute walking distance). This review identified heterogeneity in the methods used for measuring FFM and exercise capacity. There was, in general, a positive association between FFM and exercise capacity in COPD. There was also an identified lack of studies investigating associations between FFM and temporal physiological and perceptual responses to exercise. This review highlights the significance of FFM as a determinant of exercise capacity in COPD.

Physical Tests Are Poorly Related to Patient-Reported Outcome Measures during Severe Acute Exacerbations of COPD

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have a negative impact on patients' health status, including physical function and patient-reported outcomes. We aimed to explore the associations between physical tests and patient-reported outcome measures (PROMs) in hospitalised patients for an AECOPD. Patients were assessed on the day of discharge. Quadriceps force, handgrip strength, short physical performance battery (SPPB), five-repetition sit-to-stand test (5STS), four-meter gait speed test (4MGS), balance test, six-minute walk test (6MWT), COPD Assessment Test (CAT), London Chest Activity of Daily Living scale (LCADL), modified Medical Research Council (mMRC) dyspnea scale, Checklist of Individual Strength (CIS)-fatigue subscale, and Patient Health Questionnaire (PHQ-9) were collected. Sixty-nine patients with an AECOPD were included (54% female; age 69 ± 9 years; FEV1 39.2 (28.6-49.1%) predicted). Six-minute walk distance was strongly correlated with mMRC (ρ: -0.64, p < 0.0001) and moderately correlated with LCADL total score, subscales self-care and household activities (ρ ranging from -0.40 to -0.58, p < 0.01). Moreover, 4MGS was moderately correlated with mMRC (ρ: -0.49, p < 0.0001). Other correlations were weak or non-significant. During a severe AECOPD, physical tests are generally poorly related to PROMs. Therefore, a comprehensive assessment combining both physical tests and PROMs needs to be conducted in these patients to understand their health status.

Validation of the Brazilian Portuguese version of the University of California San Diego Shortness of Breath Questionnaire in patients with interstitial lung disease

OBJECTIVE

To investigate the reliability, internal consistency and validity of the Brazilian Portuguese version of the University of California San Diego Shortness of Breath Questionnaire (UCSD SOBQ) in patients with interstitial lung disease (ILD).

METHODS

Patients with ILD completed the questionnaire at three different time points, one week apart, with the assistance of two independent assessors. Intra- and inter-rater reliability were analysed via the intraclass correlation coefficient (ICC). Internal consistency was assessed with the Cronbach's alpha coefficient. For the validity analysis, associations between variables were assessed with Spearman's or Pearson's correlation coefficient.

RESULTS

Thirty patients with ILD (idiopathic pulmonary fibrosis, connective tissue disease-associated pulmonary fibrosis, sarcoidosis, asbestosis or non-specific interstitial pneumonia) were included (15 men; mean age, 59 ± 10 years; DLCO: 46 [33-64] % predicted). UCSD SOBQ scores showed excellent agreement and internal consistency in the intra-rater analysis (ICC: 0.93 [0.85-0.97]; Cronbach alpha: 0.95) and in the inter-rater analysis (ICC: 0.95 [0.89-0.97]; Cronbach alpha: 0.95), as well as correlating significantly with dyspnoea (as assessed by the Medical Research Council scale; r = 0.56); Medical Outcomes Study 36-item Short-Form Health Survey domains bodily pain, general health, vitality and physical functioning (-0.40 ≤ r ≤ -0.74); six-minute walk distance (r = -0.38); and quadriceps muscle strength (r = -0.41).

CONCLUSIONS

The Brazilian Portuguese version of the UCSD SOBQ is valid, is reliable and has internal consistency in patients with ILD in Brazil.

Effects of Nutritional Interventions in Individuals with Chronic Obstructive Lung Disease: A Systematic Review of Randomized Controlled Trials

Background

The role of nutrition and dietary patterns has been widely investigated in cancer, cardiovascular disease, and diabetes, but there are limited data on nutritional impact on COPD. This systematic review (PROSPERO-reg. no: CRD42020172712) aimed to investigate the effect of nutritional interventions on pulmonary and physical function, inflammation, and health-related quality of life among individuals with COPD.

Methods

Systematic searches were conducted in Medline, Embase, and Cochrane, resulting in 3861 references. Studies focusing exclusively on inpatient-stays, underweight or obese patients were excluded. Double screening, extraction and bias assessment were conducted. Bias was assessed according to the Cochrane risk of bias tool for randomized controlled trials. Thirteen randomized controlled trials with 916 participants were included.

Results

These trials investigated effects of protein supplementation, beetroot juice, increased fruit and vegetable intake, black seed oil, Tualang honey, Chlorella vulgaris-extract, whey-peptide containing nutritional drink, and increased macronutrient intake. The durations of the interventions were from weeks to a few months, and only one with duration >1 year (investigating increased fruit/vegetable intake). The intervention increasing fruit/vegetables found improvement in pulmonary function tests. Some interventions observed effects on systemic inflammation, health-related quality of life and physical function, although with some mixed results. Five were classified as poor, five as fair, and three as good in terms of risk of bias and quality.

Conclusion

Increasing intake of fruits and vegetables over prolonged periods might have positive effects on lung function in individuals with COPD. Some nutritional interventions also observed effects on systemic inflammation, health-related quality of life, and physical function, although with some mixed results. Many of the trials were underpowered, had high dropout rates, or had a high risk of bias. Further research should investigate effect of prolonged dietary interventions.

Isolated Resistance Training Programs to Improve Peripheral Muscle Function in Outpatients with Chronic Obstructive Pulmonary Diseases: A Systematic Review

This systematic review aims to establish which isolated resistance training (RT) programs have been used in outpatients with chronic obstructive pulmonary disease (COPD) and their impact on all aspects of peripheral skeletal muscle function. Electronic databases were systematically searched up to June 2021. The eligibility criteria were: (1) randomized controlled trials investigating the effects of supervised and isolated RT programs in outpatients with COPD and (2) RT programs lasting 8-12 weeks, (3) including at least one outcome measure related to trainable muscle characteristics. Initially, 6576 studies were identified, whereas 15 trials met the inclusion criteria. All the included trials reported that isolated RT improved both upper and lower limbs' maximal strength. Muscle endurance and power also increased after RT but received less attention in the analysis. Furthermore, few studies assessed the effect of RT on muscle mass and cross-sectional area, reporting only limited improvement. Isolated RT programs carried out 2-3 days a week for 8-12 weeks improved skeletal muscle function in individuals with COPD. The RT program should be specifically focused to the trainable muscle characteristic to be improved. For this reason, we further encourage the introduction of a detailed assessment of muscle function and structure during the pulmonary rehabilitation practice.

Reliability of Quadriceps Femoris Muscle Strength Assessment Using a Portable Dynamometer and Protocol Tolerance in Patients With Chronic Obstructive Pulmonary Disease

OBJECTIVE

This study aimed to evaluate the intrarater and interrater reliability of isometric quadriceps strength (IQS) using a portable dynamometer in individuals with chronic obstructive pulmonary disease (COPD) and to verify their tolerance to the protocol.

METHODS

A cross-sectional reliability study was conducted with 50 individuals with stable COPD (34 men and 16 women; mean age = 70 years [SD = 8]). The main outcome measure was obtained using a portable dynamometer (Microfet 2) to assess IQS. Two masked raters performed 2 assessments in the dominant lower limb on 2 nonconsecutive days. The intraclass correlation coefficient (ICC) was used to verify the intrarater and interrater reliability and was considered excellent when >0.90, with a 5% significance level.

RESULTS

Rater 1 and 2 intrarater reliability was as follows: ICC = 0.96 (95% CI = 0.94 to 0.98) and ICC = 0.97 (95% CI = 0.95 to 0.98), respectively. The interrater reliability was as follows: ICC = 0.96 (95% CI = 0.93 to 0.98). The minimum detectable difference was 4 to 5 peak isometric strength, in mean, for intrarater and interrater reliability. Not all patients presented relevant changes in physiological responses, dyspnea, and lower limb fatigue.

CONCLUSION

There was an excellent intrarater and interrater reliability for IQS, and the participants tolerated the protocol.

IMPACT

This tool can be used to assess quadriceps strength in clinical practice in patients with COPD.

Psoas Muscle Density Evaluated by Chest CT and Long-Term Mortality in COPD Patients

RATIONALE

Poor muscle quality in COPD patients relates to exercise intolerance and mortality. Muscle quality can be estimated on computed tomography (CT) by estimating psoas density (PsD). We tested the hypothesis that PsD is lower in COPD patients than in controls and relates to all-cause mortality.

METHODS

At baseline, PsD was measured using axial low-dose chest CT images in 220 COPD patients, 80% men, who were 65±8 years old with mild to severe airflow limitation and in a control group of 58 subjects matched by age, sex, body mass index (BMI) and body surface area (BSA). COPD patients were prospectively followed for 76.5 (48-119) months. Anthropometrics, smoking history, BMI, dyspnoea, lung function, exercise capacity, BODE index and exacerbations history were recorded. Cox proportional risk analysis determined the factors more strongly associated with long-term mortality.

RESULTS

PsD was lower in COPD patients than in controls (40.5 vs 42.5, p=0.045). During the follow-up, 54 (24.5%) deaths occurred in the COPD group. PsD as well as age, sex, pack-year history, FEV₁%, 6MWD, mMRC, BODE index, were independently associated with mortality. Multivariate analysis showed that age (HR 1.06; 95% CI 1.02-1.12, p=0.006) and CT-assessed PsD (HR 0.97; 95%CI 0.94-0.99, p=0.023) were the variables independently associated with all-cause mortality.

CONCLUSIONS

In COPD patients with mild to severe airflow limitation, chest CT-assessed psoas muscle density was lower than in matched controls and independently associated with long-term mortality. Muscle quality using the easy to evaluate psoas muscle density from chest CT may provide clinicians with important prognostic information in COPD.

Translation, cross-cultural adaptation, and measurement properties of the Brazilian-Portuguese version of the idiopathic pulmonary fibrosis-specific version of the Saint George's Respiratory Questionnaire (SGRQ-I) for patients with interstitial lung disease

BACKGROUND

The idiopathic pulmonary fibrosis-specific version of the St George's Respiratory Questionnaire (SGRQ-I) is a valid tool to assess health-related quality of life in patients with interstitial lung diseases (ILDs).

OBJECTIVE

To translate and cross-culturally adapt the SGRQ-I to Brazilian-Portuguese, and to assess its measurement properties.

METHODS

Phase one consisted of the translation and cross-cultural adaptation of the questionnaire. In phase two, intra- and inter-assessor reliability (intraclass correlation coefficient [ICC]), internal consistency (Cronbach's α), minimal detectable change (MDC), ceiling/floor effects, convergent validity (correlation with SF-36 questionnaire), and discriminative validity (according to clinical characteristics) were investigated.

RESULTS

No significant adaptations were needed during the translation process of the SGRQ-I. In phase two, 30 patients with ILD were included (15 men; age 59 ± 10 years; Forced Vital Capacity 73 [61-80]%predicted). The total score on the SGRQ-I presented excellent intra-assessor (ICC: 0.93; 95%CI: 0.85, 0.97]) and inter-assessor (ICC: 0.88; 95%CI: 0.77, 0.94) agreement. Internal consistency was considered adequate for the domains impact, activity, and total score (0.79<α<0.88) but not for symptoms (α=0.43). MDC was 12.8 points and ceiling/floor effects were found in only 3% of patients. No discriminative validity was observed, but there was adequate convergent validity.

CONCLUSION

The results provide preliminary evidence of adequate measurement properties and validity of the Brazilian-Portuguese version of the SGRQ-I for patients with ILDs.

Effects of cigarette smoke exposure on pulmonary physiology, muscle strength and exercise capacity in a retrospective cohort with 30,000 subjects

BACKGROUND

The effects of long-term cigarette smoke exposure on pulmonary physiology and how those effects lead to reduced exercise capacity are not well established.

METHODS

We retrospectively analyzed the spirometry, single-breath gas transfer (DLCO), peripheral muscle strength, and maximum exercise capacity data in patients referred to McMaster University Medical Centre for cardiopulmonary exercise testing between 2000 and 2012.

RESULTS

29,441 subjects underwent CPET and had a recorded smoking history [58% male, mean age 51.1 years (S.D.±19.6), BMI 27.4 kg/m2(±5.8)]. 7081 (24%) were current or former smokers and were divided into 4 categories by packs years (mean ±S.D.): <10 (5.8±3.3), 10-20 (17.1±2.9), 20-30 (27.1±2.8), 30-40 (37.3±2.8), and >40 (53.9±12.8). Patients with greater cigarette smoke exposure had lower expiratory flow rates (FEV1, FEF50, FEF75, PEFR), DLCO, and maximum power output (MPO) during exercise. There was no association between smoke exposure and muscle strength. Modeling MPO (kpm/min) output as a function of demographic and physiologic variables showed that the data are well explained by muscle strength (kg), FEV1 (L), and DLCO (mmHg/min/mL) in similar magnitude (MPO = 42.7*Quads0.34*FEV10.34 * DLCO0.43; r = 0.84).

CONCLUSIONS

Long-term cigarette smoke exposure is associated with small airway narrowing and impaired diffusion capacity but not with peripheral muscle weakness. The effects of smoking, age, and gender on maximum power output are mediated by reductions in FEV1, muscle strength and DLCO. Exercise capacity in smokers may benefit from therapies targeting all 3 variables.

The correlation between quadriceps muscle strength and endurance and exercise performance in patients with COPD

To determine the association between quadriceps muscle strength (QMS) and endurance (QME) and exercise capacity in patients with COPD after stratification for sex and resting lung function (LF). Data were collected from 3,246 patients with COPD (60% men, 64 ± 9 yr), including measures of exercise capacity [peak aerobic capacity (peakV̇o₂), 6-min walk distance (6MWD)] and isokinetic QMS and QME. Patients were stratified for sex, forced expiratory volume in 1 s (>50/≤50% predicted), single breath carbon monoxide diffusing capacity (>50/≤50% predicted), and residual volume (>140/≤140% predicted). After stratification for resting LF, QMS and QME were significantly associated with peakV̇o₂ (r range: 0.47-0.61 and 0.49-0.65 for men and 0.53-0.66 and 0.48-0.67 for women, respectively) and 6MWD (r range: 0.29-0.42 and 0.44-0.55 for men and 0.25-0.54 and 0.34-0.55 for women, respectively) (P < 0.001). Regression models demonstrated that QMS and QME were significant determinants of peakV̇o₂ (explained variance R² range: 35.6%-48.8% for men and 36.8%-49.0% for women) and 6MWD (R² range: 24.3%-43.3% for men and 28.4%-40.3% for women), independent of age and fat-free mass. Quadriceps muscle function was significantly associated with peakV̇o₂ and 6MWD in male and female patients with COPD after stratification for resting LF, in which QME appear to be a more important determinant than QMS. This underlines the importance of systematically evaluating both quadriceps muscle strength and endurance in in all patients with COPD.NEW & NOTEWORTHY Our findings identified quadriceps muscle function as an important determinant of exercise capacity across a wide spectrum of lung function. Quadriceps muscle endurance appears to be a more important determinant than quadriceps muscle strength, underlining the importance of including both the measurement of quadriceps muscle strength and endurance in routine assessment for all patient with COPD.

Longitudinal changes in total and regional body composition in patients with chronic obstructive pulmonary disease

Background and objective

Low fat‐free mass (FFM) is common in patients with chronic obstructive pulmonary disease (COPD) and contributes to morbidity and mortality. Few studies have evaluated longitudinal changes in body composition in patients with COPD compared with non‐COPD controls. This study aimed to compare longitudinal changes in total and regional body composition between patients with COPD and non‐COPD controls and investigate predictors of changes in body composition in COPD.

Methods

Patients with COPD and non‐COPD controls participating in the Individualized COPD Evaluation in relation to Ageing (ICE‐Age) study, a single‐centre, longitudinal, observational study, were included. Subjects were assessed at baseline and after 2 years of follow‐up. Among other procedures, body composition was measured by dual‐energy X‐ray absorptiometry scan. The number of exacerbations/hospitalizations 1 year before inclusion and during follow‐up were assessed in patients with COPD.

Results

A total of 405 subjects were included (205 COPD, 87 smoking and 113 non‐smoking controls). Patients with COPD and smoking controls presented a significant decline in total FFM (mean [95% CI]: −1173 [−1527/−820] g and −486 [−816/−156] g, respectively) while body composition remained stable in non‐smoking controls. In patients with COPD, the decline in FFM was more pronounced in legs (−174 [−361/14] g) and trunk (−675 [−944/406] g) rather than in arms (54 [−19/126] g). The predictors of changes in total and regional FFM in patients with COPD were gender, number of previous hospitalizations, baseline values of FFM and BMI.

Conclusion

Patients with COPD present a significant decline in FFM after 2 years of follow‐up, this decline is more pronounced in their legs and trunk.

Patients with chronic obstructive pulmonary disease (COPD) present a significant decline in total, leg and trunk low fat‐free mass (FFM), while arms FFM remains stable after 2 years of follow‐up. We identified a subgroup of patients with preserved FFM at baseline and history of previous hospitalizations that present greater decline in total and leg FFM compared to other patients with COPD.

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Handgrip Strength as a Reflection of General Muscle Strength in Chronic Obstructive Pulmonary Disease

Muscle dysfunction is one of the main features in individuals with chronic obstructive pulmonary disease (COPD). Handgrip strength (HS) has been used as a representation of general muscle strength in various populations, and a few studies found correlation between HS and other measures of upper and lower limbs' muscle strength in the general population, although this was not yet studied in depth in COPD. The aims of this study were to verify if HS is cross-sectionally well correlated with upper and lower limbs' muscle strength in individuals with COPD, and to identify a new cutoff for handgrip weakness in this population. HS was assessed by a dynamometer, whereas other muscle strength assessments comprised maximal voluntary contraction (MVC) of the quadriceps femoris and 1-repetition maximum (1RM) of biceps and triceps brachii, pectoralis major, latissimus dorsi and quadriceps femoris. Additional assessments included pulmonary function and volumes, body composition and exercise capacity. Fifty individuals with COPD were studied (65 ± 7 years; FEV₁ 51 ± 14%pred). HS showed moderate-to-strong correlations with all 1-RM assessments (0.62<r < 0.75) and especially with MVC of the quadriceps femoris (r = 0.83) (p < 0.05 for all). Correlations were stronger for male than female individuals, and the assessment performed on right, left or dominant hand did not present significant differences. A cutoff of 0.3892 for HS/weight yielded an AUC = 0.90 to identify weakness. In conclusion, HS is a good reflection of upper and lower limbs' muscle strength in individuals with COPD. Its usefulness as a surrogate for more complex assessments must be based on the settings and conditions.

Functional performance tests in interstitial lung disease: Impairment and measurement properties

BACKGROUND

There is limited information regarding impairment in functional performance tests and their measurement properties in ILD. The present study aimed to verify the impairment and measurement properties of functional performance tests in ILD.

METHODS

ILD and healthy individuals underwent assessments of pulmonary function, peripheral muscle strength (handgrip force and maximum isometric contraction of quadriceps femoris - MIVCq) and exercise capacity (6-min walk test - 6MWT). Functional performance was assessed by timed-up-and-go with usual (TUGu) and fast (TUGf) gait speeds, 4-m gait speed (4MGS), sit-to-stand in 30 s (30sec-STS), 1 min (1min-STS) and with 5 repetition (5rep-STS) and Short Physical Performance Battery (SPPB). Functional performance was compared between groups, validity (correlation with 6MWT and MIVCq) and reliability of tests were checked in subjects with ILD (intra- and inter-rater agreement analysis).

RESULTS

Seventy-six participants (40 ILD [25 women, 61 ± 11 years, FVC 75 ± 17 %pred] and 36 healthy [22 women, 61 ± 9 years, FVC 97 ± 11 %pred]) were included. Functional performance in ILD was worse than in healthy individuals in all tests, except for the 30sec-STS (p = 0.13). Pre-specified validity criteria were reached for TUGu, TUGf, 4MGS and 5rep-STS (-0.69 < r < 0.55; p < 0.05 for all). Except for 4MGS and SPPB, all tests showed good to excellent inter-rater (0.85 < ICC<0.93; p < 0.05 for all) and all tests showed good to excellent intra-rater (0.83 < ICC< 0.94; p < 0.05 for all) reliability.

CONCLUSIONS

Subjects with ILD present worse functional performance than healthy individuals. According to reliability and validity results, TUGu, TUGf and 5rep-STS seem to be the most appropriate tests to evaluate functional performance in ILD.

Psoas Muscle Density Evaluated by Chest CT and Long-Term Mortality in COPD Patients

RATIONALE

Poor muscle quality in COPD patients relates to exercise intolerance and mortality. Muscle quality can be estimated on computed tomography (CT) by estimating psoas density (PsD). We tested the hypothesis that PsD is lower in COPD patients than in controls and relates to all-cause mortality.

METHODS

At baseline, PsD was measured using axial low-dose chest CT images in 220 COPD patients, 80% men, who were 65±8 years old with mild to severe airflow limitation and in a control group of 58 subjects matched by age, sex, body mass index (BMI) and body surface area (BSA). COPD patients were prospectively followed for 76.5 (48-119) months. Anthropometrics, smoking history, BMI, dyspnoea, lung function, exercise capacity, BODE index and exacerbations history were recorded. Cox proportional risk analysis determined the factors more strongly associated with long-term mortality.

RESULTS

PsD was lower in COPD patients than in controls (40.5 vs 42.5, p=0.045). During the follow-up, 54 (24.5%) deaths occurred in the COPD group. PsD as well as age, sex, pack-year history, FEV1%, 6MWD, mMRC, BODE index, were independently associated with mortality. Multivariate analysis showed that age (HR 1.06; 95% CI 1.02-1.12, p=0.006) and CT-assessed PsD (HR 0.97; 95%CI 0.94-0.99, p=0.023) were the variables independently associated with all-cause mortality.

CONCLUSIONS

In COPD patients with mild to severe airflow limitation, chest CT-assessed psoas muscle density was lower than in matched controls and independently associated with long-term mortality. Muscle quality using the easy to evaluate psoas muscle density from chest CT may provide clinicians with important prognostic information in COPD.

Respiratory exacerbations are associated with muscle loss in current and former smokers

OBJECTIVES

Muscle wasting is a recognised extra-pulmonary complication in chronic obstructive pulmonary disease and has been associated with increased risk of death. Acute respiratory exacerbations are associated with reduction of muscle function, but there is a paucity of data on their long-term effect. This study explores the relationship between acute respiratory exacerbations and long-term muscle loss using serial measurements of CT derived pectoralis muscle area (PMA).

DESIGN AND SETTING

Participants were included from two prospective, longitudinal, observational, multicentre cohorts of ever-smokers with at least 10 pack-year history.

PARTICIPANTS

The primary analysis included 1332 (of 2501) participants from Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) and 4384 (of 10 198) participants from Genetic Epidemiology of COPD (COPDGene) who had complete data from their baseline and follow-up visits.

INTERVENTIONS

PMA was measured on chest CT scans at two timepoints. Self-reported exacerbation data were collected from participants in both studies through the use of periodic longitudinal surveys.

MAIN OUTCOME MEASURES

Age-related and excess muscle loss over time.

RESULTS

Age, sex, race and body mass index were associated with baseline PMA. Participants experienced age-related decline at the upper end of reported normal ranges. In ECLIPSE, the exacerbation rate over time was associated with an excess muscle area loss of 1.3% (95% CI 0.6 to 1.9, p<0.001) over 3 years and in COPDGene with an excess muscle area loss of 2.1% (95% CI 1.2 to 2.8, p<0.001) over 5 years. Excess muscle area decline was absent in 273 individuals who participated in pulmonary rehabilitation.

CONCLUSIONS

Exacerbations are associated with accelerated skeletal muscle loss. Each annual exacerbation was associated with the equivalent of 6 months of age-expected decline in muscle mass. Ameliorating exacerbation-associated muscle loss represents an important therapeutic target.

Effect of Bronchoscopic Lung Volume Reduction in Advanced Emphysema on Energy Balance Regulation

BACKGROUND

Hypermetabolism and muscle wasting frequently occur in patients with severe emphysema. Improving respiratory mechanics by bronchoscopic lung volume reduction (BLVR) might contribute to muscle maintenance by decreasing energy requirements and alleviating eating-related dyspnoea.

OBJECTIVE

The goal was to assess the impact of BLVR on energy balance regulation.

DESIGN

Twenty emphysematous subjects participated in a controlled clinical experiment before and 6 months after BLVR. Energy requirements were assessed: basal metabolic rate (BMR) by ventilated hood, total daily energy expenditure (TDEE) by doubly labelled water, whole body fat-free mass (FFM) by deuterium dilution, and physical activity by accelerometry. Oxygen saturation, breathing rate, and heart rate were monitored before, during, and after a standardized meal via pulse oximetry and dyspnoea was rated.

RESULTS

Sixteen patients completed follow-up, and among those, 10 patients exceeded the minimal clinically important difference of residual volume (RV) reduction. RV was reduced with median (range) 1,285 mL (-2,430, -540). Before BLVR, 90% of patients was FFM-depleted despite a normal BMI (24.3 ± 4.3 kg/m2). BMR was elevated by 130%. TDEE/BMR was 1.4 ± 0.2 despite a very low median (range) daily step count of 2,188 (739, 7,110). Following BLVR, the components of energy metabolism did not change significantly after intervention compared to before intervention, but BLVR treatment decreased meal-related dyspnoea (4.1 vs. 1.7, p = 0.019).

CONCLUSIONS

Impaired respiratory mechanics in hyperinflated emphysematous patients did not explain hypermetabolism. Clinical Trial Registry Number: NCT02500004 at www.clinicaltrial.gov.

Hypercapnic Respiratory Failure-Driven Skeletal Muscle Dysfunction: It Is Time for Animal Model-Based Mechanistic Research

Dysfunction of locomotor muscles is frequent in chronic pulmonary diseases and strongly associated with worse outcomes including higher mortality. Although these associations have been corroborated over the last decades, there is poor mechanistic understanding of the process, in part due to the lack of adequate animal models to investigate this process. Most of the mechanistic research has so far been accomplished using relevant individual stimuli such as low oxygen or high CO₂ delivered to otherwise healthy animals as surrogates of the phenomena occurring in the clinical setting. This review advocates for the development of a syndromic model in which skeletal muscle dysfunction is investigated as a comorbidity of a well-validated pulmonary disease model, which could potentially allow discovering meaningful mechanisms and pathways and lead to more substantial progress to treat this devastating condition.

Role of acute exacerbations in skeletal muscle impairment in COPD

Introduction: Muscle impairments are prevalent in COPD and have adverse clinical implications in terms of physical performance capacity, disease burden, quality of life and even mortality. During acute exacerbations of COPD (AECOPDs) the respiratory symptoms worsen and this might also apply to the muscle impairments. Areas covered: This report includes a review of both clinical and pre-clinical peer-reviewed literature of the past 20 years found in PubMed providing a comprehensive view on the role of AECOPD in muscle dysfunction in COPD, the putative underlying mechanisms and the treatment perspectives. Expert opinion: The contribution of AECOPD and its recurrent nature to muscle impairment in COPD cannot be ignored and can be attributed to the acutely intensifying and converging disease-related drivers of muscle deterioration, in particular disuse, systemic inflammation and corticosteroid treatment. The search for novel treatment options should focus on the AECOPD-enhanced drivers of muscle dysfunction as well as on the underlying, mainly catabolic, mechanisms. Considering the impact of AECOPD on muscle function, and that of muscle impairment on the recurrence of exacerbations, counteracting muscle deterioration in AECOPD provides an unprecedented therapeutic opportunity.

AMP-Activated Protein Kinase (AMPK) at the Crossroads Between CO2 Retention and Skeletal Muscle Dysfunction in Chronic Obstructive Pulmonary Disease (COPD)

Skeletal muscle dysfunction is a major comorbidity in chronic obstructive pulmonary disease (COPD) and other pulmonary conditions. Chronic CO2 retention, or hypercapnia, also occur in some of these patients. Both muscle dysfunction and hypercapnia associate with higher mortality in these populations. Over the last years, we have established a mechanistic link between hypercapnia and skeletal muscle dysfunction, which is regulated by AMPK and causes depressed anabolism via reduced ribosomal biogenesis and accelerated catabolism via proteasomal degradation. In this review, we discuss the main findings linking AMPK with hypercapnic pulmonary disease both in the lungs and skeletal muscles, and also outline potential avenues for future research in the area based on knowledge gaps and opportunities to expand mechanistic research with translational implications.

Skeletal Muscle Dysfunction in Chronic Obstructive Pulmonary Disease. What We Know and Can Do for Our Patients

Skeletal muscle dysfunction occurs in patients with chronic obstructive pulmonary disease (COPD) and affects both ventilatory and nonventilatory muscle groups. It represents a very important comorbidity that is associated with poor quality of life and reduced survival. It results from a complex combination of functional, metabolic, and anatomical alterations leading to suboptimal muscle work. Muscle atrophy, altered fiber type and metabolism, and chest wall remodeling, in the case of the respiratory muscles, are relevant etiological contributors to this process. Muscle dysfunction worsens during COPD exacerbations, rendering patients progressively less able to perform activities of daily living, and it is also associated with poor outcomes. Muscle recovery measures consisting of a combination of pulmonary rehabilitation, optimized nutrition, and other strategies are associated with better prognosis when administered in stable patients as well as after exacerbations. A deeper understanding of this process' pathophysiology and clinical relevance will facilitate the use of measures to alleviate its effects and potentially improve patients' outcomes. In this review, a general overview of skeletal muscle dysfunction in COPD is offered to highlight its relevance and magnitude to expert practitioners and scientists as well as to the average clinician dealing with patients with chronic respiratory diseases.

Effects of a comprehensive, inpatient pulmonary rehabilitation programme in a cachectic patient with very severe COPD and chronic respiratory failure

A cachectic patient with very severe COPD and chronic respiratory failure may benefit from comprehensive and personalised pulmonary rehabilitation including neuromuscular electrical stimulation, noninvasive ventilation and anabolic steroids http://bit.ly/31Ss7WZ.

Deterioration of Limb Muscle Function during Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Important features of both stable and acute exacerbation of chronic obstructive pulmonary disease (COPD) are skeletal muscle weakness and wasting. Limb muscle dysfunction during an exacerbation has been linked to various adverse outcomes, including prolonged hospitalization, readmission, and mortality. The contributing factors leading to muscle dysfunction are similar to those seen in stable COPD: disuse, nutrition/energy balance, hypercapnia, hypoxemia, electrolyte derangements, inflammation, and drugs (i.e., glucocorticoids). These factors may be the trigger for a downstream cascade of local inflammatory changes, pathway process alterations, and structural degradation. Ultimately, the clinical effects can be wide ranging and include reduced limb muscle strength. Current therapies, such as pulmonary/physical rehabilitation, have limited impact because of low participation rates. Recently, novel drugs have been developed in similar disorders, and learnings from these studies can be used as a foundation to facilitate discovery in patients hospitalized with a COPD exacerbation. Nevertheless, investigators should approach this patient population with knowledge of the limitations of each intervention. In this Concise Clinical Review, we provide an overview of acute muscle dysfunction in patients hospitalized with acute exacerbation of COPD and a strategic approach to drug development in this setting.

Healthcare costs and utilization associated with muscle weakness diagnosis codes in patients with chronic obstructive pulmonary disease: a United States claims analysis

AIMS

Muscle weakness (MW)-attributable healthcare resource utilization (HCRU) and costs in patients with chronic obstructive pulmonary disease (COPD) have not been well-characterized in US insurance claims databases. The primary objective of this study was to estimate HCRU in patients with evidence of COPD with and without MW diagnosis codes.

MATERIALS AND METHODS

This retrospective analysis used the MarketScan^® Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases. Between January 2007 and March 2016, we identified patients aged ≥40 years with diagnosis codes for COPD (≥1 emergency department or inpatient claim or ≥2 outpatient claims within 1 year). The cohort was divided into patients with and without ≥1 MW diagnosis code. Propensity score matching was used to generate pairs of patients with and without MW (1:1). Multivariable regression analyses were used to estimate adjusted incremental costs and utilization attributable to the presence of MW diagnosis codes among patients with COPD.

RESULTS

Of 427,131 patients who met the study inclusion criteria, 14% had evidence of MW. After matching, 107,420 unique patients remained equally distributed across MW status. Patients with MW diagnosis codes had greater predicted annual HCRU, $2,465 greater total predicted annual COPD-related costs, and $15,179 greater total all-cause costs than those without MW diagnosis codes. Overall, <1% of patients received COPD-related pulmonary rehabilitation services.

LIMITATIONS

Study limitations include the potential for undercoding of MW and lack of information on severity of MW in claims data.

CONCLUSION

The presence of MW diagnosis codes yielded higher HCRU in this COPD population and suggests that the burden of MW affects both all-cause and COPD-related care. However, utilization of pulmonary rehabilitation, a known effective treatment for MW, remains low. Future research should expand on our results by assessing data sources that allow for clinical confirmation of MW among patients with COPD.

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.

Altered protein turnover signaling and myogenesis during impaired recovery of inflammation-induced muscle atrophy in emphysematous mice

Exacerbations in Chronic obstructive pulmonary disease (COPD) are often accompanied by pulmonary and systemic inflammation, and are associated with an increased susceptibility to weight loss and muscle wasting. As the emphysematous phenotype in COPD appears prone to skeletal muscle wasting, the aims of this study were to evaluate in emphysematous compared to control mice following repetitive exacerbations (1) changes in muscle mass and strength and, (2) whether muscle mass recovery and its underlying processes are impaired. Emphysema was induced by intra-tracheal (IT) elastase instillations, followed by three weekly IT-LPS instillations to mimic repetitive exacerbations. Loss of muscle mass and strength were measured, and related to analyses of muscle protein turnover and myogenesis signaling in tissue collected during and following recovery. Emphysematous mice showed impaired muscle mass recovery in response to pulmonary inflammation-induced muscle atrophy. Proteolysis and protein synthesis signaling remained significantly higher in emphysematous mice during recovery from LPS. Myogenic signaling in skeletal muscle was altered, and fusion capacity of cultured muscle cells treated with plasma derived from LPS-treated emphysematous mice was significantly decreased. In conclusion, repetitive cycles of pulmonary inflammation elicit sustained muscle wasting in emphysematous mice due to impaired muscle mass recovery, which is accompanied by aberrant myogenesis.

Repetitive TLR3 activation in the lung induces skeletal muscle adaptations and cachexia

Due to immunosenescence, older adults are particularly susceptible to lung-based viral infections, with increased severity of symptoms in those with underlying chronic lung disease. Repeated respiratory viral infections produce lung maladaptations, accelerating pulmonary dysfunction. Toll like 3 receptor (TLR3) is a membrane protein that senses exogenous double-stranded RNA to activate the innate immune response to a viral infection. Polyinosinic-polycytidylic acid [poly(I:C)] mimics double stranded RNA and has been shown to activate TLR3. Utilizing an established mouse viral exacerbation model produced by repetitive intranasal poly(I:C) administration, we sought to determine whether repetitive poly(I:C) treatment induced negative muscle adaptations (i.e. atrophy, weakness, and loss of function). We determined skeletal muscle morphological properties (e.g. fiber-type, fiber cross-sectional area, muscle wet mass, etc.) from a treated group ((poly(I:C), n = 9) and a sham-treated control group (PBS, n = 9); age approximately 5 months. In a subset (n = 4 for both groups), we determined in vivo physical function (using grip test for strength, rotarod for overall motor function, and treadmill for endurance) and muscle contractile properties with in vitro physiology (in the EDL, soleus and diaphragm). Our findings demonstrate that poly(I:C)-treated mice exhibit both muscle morphological and functional deficits. Changes of note when comparing poly(I:C)-treated mice to PBS-treated controls include reductions in fiber cross-sectional area (-27% gastrocnemius, -25% soleus, -16% diaphragm), contractile dysfunction (soleus peak tetanic force, -26%), muscle mass (gastrocnemius -19%, soleus -23%), physical function (grip test -34%), body mass (-20%), and altered oxidative capacity (140% increase in succinate dehydrogenase activity in the diaphragm, but 66% lower in the gastrocnemius). Our data is supportive of a new model of cachexia/sarcopenia that has potential for future research into the mechanisms underlying muscle wasting.

Can muscle protein metabolism be specifically targeted by exercise training in COPD?

Patients with stable chronic obstructive pulmonary disease (COPD) frequently exhibit unintentional accentuated peripheral muscle loss and dysfunction. Skeletal muscle mass in these patients is a strong independent predictor of morbidity and mortality. Factors including protein anabolism/catabolism imbalance, hypoxia, physical inactivity, inflammation, and oxidative stress are involved in the initiation and progression of muscle wasting in these patients. Exercise training remains the most powerful intervention for reversing, in part, muscle wasting in COPD. Independently of the status of systemic or local muscle inflammation, rehabilitative exercise training induces up-regulation of key factors governing skeletal muscle hypertrophy and regeneration. However, COPD patients presenting similar degrees of lung dysfunction do not respond alike to a given rehabilitative exercise stimulus. In addition, a proportion of patients experience limited clinical outcomes, even when exercise training has been adequately performed. Consistently, several reports provide evidence that the muscles of COPD patients present training-induced myogenic activity limitation as exercise training induces a limited number of differentially expressed genes, which are mostly associated with protein degradation. This review summarises the nature of muscle adaptations induced by exercise training, promoted both by changes in the expression of contractile proteins and their function typically controlled by intracellular signalling and transcriptional responses. Rehabilitative exercise training in COPD patients stimulates skeletal muscle mechanosensitive signalling pathways for protein accretion and its regulation during muscle contraction. Exercise training also induces synthesis of myogenic proteins by which COPD skeletal muscle promotes hypertrophy leading to fusion of myogenic cells to the myofiber. Understanding of the biological mechanisms that regulate exercise training-induced muscle growth and regeneration is necessary for implementing therapeutic strategies specifically targeting myogenesis and hypertrophy in these patients.

Comparison of Effects of Endurance and Strength Training Programs in Patients with COPD

Comparisons between endurance and strength training in chronic obstructive pulmonary disease (COPD) patients have produced equivocal findings when examining physical function and health-related quality of life (HRQL). One reason for these differences may be due to individual patient responses to the different training modalities.

PURPOSE

To compare changes in physical function and HRQL in a group of COPD patients completing both an endurance and a strength training program.

METHODS

Eleven mildly diseased patients completed a three month endurance training program and, approximately 5 years later, completed a three month strength training program. Changes in 6 minute walk distance (6 MW), time to rise from a chair five times (CRT), and the total score and subscores from the SF-36 and Chronic Respiratory Disease Questionnaire (CRQ) were examined.

RESULTS

The forced expiratory volume as a percent of predicted remained relatively constant over the 5 years (61.1 ± 5.9 vs. 60.0 ± 10.3). Endurance and strength training increased 6 MW by 48.2 ± 11.2 (p = 0.008) and 39.8 ± 9.8 (p = 0.001) meters, respectively. Endurance and strength training decreased CRT by 4.8 ± 0.7 (p = 0.001) and 1.3 ± 1.2 (p = 0.056) seconds, respectively. Endurance training resulted in greater improvements in HRQL as compared to strength training.

CONCLUSION

These results show that walk distance improves as a result of participating in either an endurance or a strength training program. However, an endurance training program leads to greater improvements in both general and disease specific measures of HRQL.

Body composition and sarcopenia in patients with chronic obstructive pulmonary disease

PURPOSE

Changes in body composition are commonly present in chronic obstructive pulmonary disease (COPD). The main aim of this study were to evaluate changes in body composition and the prevalence of pre-sarcopenia and sarcopenia in patients with COPD, compared with two control groups and correlate these parameters with indices of COPD severity (VEF1 and GOLD) and prognosis (BODE).

METHODS

This was a cross-sectional study in COPD patients (DG) that undergone body composition assessment by DXA. Two control groups were used, smokers individuals without COPD (smokers group, SG), and healthy never smokers individuals (never smokers group, NSG).

RESULTS

DG comprised 121 patients (65 women, mean age 67.9 ± 8.6 years). The percentage of total body fat mass (TFM) was significantly lower in DG in both genders, despite no difference in BMI. Both BMI and relative skeletal muscle mass index (RSMI) decreased according to the worsening of GOLD in men and women, as well as the TFM and total lean mass (TLM) in men. As BODE get worse, BMI and RSMI decreased in both sexes, as well as TLM in men. The prevalence of pre-sarcopenia in the DG was 46.3% and no different with controls. In DG 12.4% were sarcopenic. Patients with sarcopenia were older and had worse prognosis. Higher BODE prognostic index, higher the prevalence of sarcopenia (OR 3.5, 95% CI 1.06-11.56, p = 0.035).

CONCLUSIONS

This study showed alterations in body composition parameters in patients with COPD. A high prevalence of sarcopenia and the association with worse prognostic index.