Quadriceps strength predicts mortality in patients with moderate to severe chronic obstructive pulmonary disease

BACKGROUND

Prognosis in chronic obstructive pulmonary disease (COPD) is poorly predicted by indices of air flow obstruction, because other factors that reflect the systemic nature of the disease also influence prognosis.

OBJECTIVE

To test the hypothesis that a reduction in quadriceps maximal voluntary contraction force (QMVC) is a useful predictor of mortality in patients with COPD.

METHODS

A mortality questionnaire was sent to the primary care physician of 184 patients with COPD who had undergone quadriceps strength measurement over the past 5 years. QMVC was expressed as a percentage of the patient's body mass index. The end point measured was death or lung transplantation, and median (range) follow-up was 38 (1-54) months.

RESULTS

Data were obtained for 162 patients (108 men and 54 women) with a mean (SD) percentage of forced expiratory volume in 1 s (FEV1) predicted of 35.6 (16.2), giving a response rate of 88%. Transplant-free survival of the cohort was 93.5% at 1 year and 87.1% at 2 years. Cox regression models showed that the mortality risk increased with increasing age and with reducing QMVC. Only age (HR 1.72 (95% CI 1.14 to 2.6); p = 0.01) and QMVC (HR 0.91 (95% CI 0.83 to 0.99); p = 0.036) continued to be significant predictors of mortality when controlled for other variables in the multivariate analysis.

CONCLUSION

QMVC is simple and provides more powerful prognostic information on COPD than that provided by age, body mass index and forced expiratory volume in 1 s.

Minimum clinically important difference for the COPD Assessment Test: a prospective analysis

BACKGROUND

The COPD Assessment Test (CAT) is responsive to change in patients with chronic obstructive pulmonary disease (COPD). However, the minimum clinically important difference (MCID) has not been established. We aimed to identify the MCID for the CAT using anchor-based and distribution-based methods.

METHODS

We did three studies at two centres in London (UK) between April 1, 2010, and Dec 31, 2012. Study 1 assessed CAT score before and after 8 weeks of outpatient pulmonary rehabilitation in patients with COPD who were able to walk 5 m, and had no contraindication to exercise. Study 2 assessed change in CAT score at discharge and after 3 months in patients admitted to hospital for more than 24 h for acute exacerbation of COPD. Study 3 assessed change in CAT score at baseline and at 12 months in stable outpatients with COPD. We focused on identifying the minimum clinically important improvement in CAT score. The St George's Respiratory Questionnaire (SGRQ) and Chronic Respiratory Questionnaire (CRQ) were measured concurrently as anchors. We used receiver operating characteristic curves, linear regression, and distribution-based methods (half SD, SE of measurement) to estimate the MCID for the CAT; we included only patients with paired CAT scores in the analysis.

FINDINGS

In Study 1, 565 of 675 (84%) patients had paired CAT scores. The mean change in CAT score with pulmonary rehabilitation was -2·5 (95% CI -3·0 to -1·9), which correlated significantly with change in SGRQ score (r=0·32; p<0·0001) and CRQ score (r=-0·46; p<0·0001). In Study 2, of 200 patients recruited, 147 (74%) had paired CAT scores. Mean change in CAT score from hospital discharge to 3 months after discharge was -3·0 (95% CI -4·4 to -1·6), which correlated with change in SGRQ score (r=0·47; p<0·0001). In Study 3, of 200 patients recruited, 164 (82%) had paired CAT scores. Although no significant change in CAT score was identified after 12 months (mean 0·6, 95% CI -0·4 to 1·5), change in CAT score correlated significantly with change in SGRQ score (r=0·36; p<0·0001). Linear regression estimated the minimum clinically important improvement for the CAT to range between -1·2 and -2·8 with receiver operating characteristic curves consistently identifying -2 as the MCID. Distribution-based estimates for the MCID ranged from -3·3 to -3·8.

INTERPRETATION

The most reliable estimate of the minimum important difference of the CAT is 2 points. This estimate could be useful in the clinical interpretation of CAT data, particularly in response to intervention studies.

FUNDING

Medical Research Council and UK National Institute of Health Research.

Effect of Home Noninvasive Ventilation With Oxygen Therapy vs Oxygen Therapy Alone on Hospital Readmission or Death After an Acute COPD Exacerbation: A Randomized Clinical Trial

IMPORTANCE

Outcomes after exacerbations of chronic obstructive pulmonary disease (COPD) requiring acute noninvasive ventilation (NIV) are poor and there are few treatments to prevent hospital readmission and death.

OBJECTIVE

To investigate the effect of home NIV plus oxygen on time to readmission or death in patients with persistent hypercapnia after an acute COPD exacerbation.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial of patients with persistent hypercapnia (Paco2 >53 mm Hg) 2 weeks to 4 weeks after resolution of respiratory acidemia, who were recruited from 13 UK centers between 2010 and 2015. Exclusion criteria included obesity (body mass index [BMI] >35), obstructive sleep apnea syndrome, or other causes of respiratory failure. Of 2021 patients screened, 124 were eligible.

INTERVENTIONS

There were 59 patients randomized to home oxygen alone (median oxygen flow rate, 1.0 L/min [interquartile range {IQR}, 0.5-2.0 L/min]) and 57 patients to home oxygen plus home NIV (median oxygen flow rate, 1.0 L/min [IQR, 0.5-1.5 L/min]). The median home ventilator settings were an inspiratory positive airway pressure of 24 (IQR, 22-26) cm H2O, an expiratory positive airway pressure of 4 (IQR, 4-5) cm H2O, and a backup rate of 14 (IQR, 14-16) breaths/minute.

MAIN OUTCOMES AND MEASURES

Time to readmission or death within 12 months adjusted for the number of previous COPD admissions, previous use of long-term oxygen, age, and BMI.

RESULTS

A total of 116 patients (mean [SD] age of 67 [10] years, 53% female, mean BMI of 21.6 [IQR, 18.2-26.1], mean [SD] forced expiratory volume in the first second of expiration of 0.6 L [0.2 L], and mean [SD] Paco2 while breathing room air of 59 [7] mm Hg) were randomized. Sixty-four patients (28 in home oxygen alone and 36 in home oxygen plus home NIV) completed the 12-month study period. The median time to readmission or death was 4.3 months (IQR, 1.3-13.8 months) in the home oxygen plus home NIV group vs 1.4 months (IQR, 0.5-3.9 months) in the home oxygen alone group, adjusted hazard ratio of 0.49 (95% CI, 0.31-0.77; P = .002). The 12-month risk of readmission or death was 63.4% in the home oxygen plus home NIV group vs 80.4% in the home oxygen alone group, absolute risk reduction of 17.0% (95% CI, 0.1%-34.0%). At 12 months, 16 patients had died in the home oxygen plus home NIV group vs 19 in the home oxygen alone group.

CONCLUSIONS AND RELEVANCE

Among patients with persistent hypercapnia following an acute exacerbation of COPD, adding home noninvasive ventilation to home oxygen therapy prolonged the time to readmission or death within 12 months.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00990132.

An official European Respiratory Society statement on physical activity in COPD

This European Respiratory Society (ERS) statement provides a comprehensive overview on physical activity in patients with chronic obstructive pulmonary disease (COPD). A multidisciplinary Task Force of experts representing the ERS Scientific Group 01.02 "Rehabilitation and Chronic Care" determined the overall scope of this statement through consensus. Focused literature reviews were conducted in key topic areas and the final content of this Statement was agreed upon by all members. The current knowledge regarding physical activity in COPD is presented, including the definition of physical activity, the consequences of physical inactivity on lung function decline and COPD incidence, physical activity assessment, prevalence of physical inactivity in COPD, clinical correlates of physical activity, effects of physical inactivity on hospitalisations and mortality, and treatment strategies to improve physical activity in patients with COPD. This Task Force identified multiple major areas of research that need to be addressed further in the coming years. These include, but are not limited to, the disease-modifying potential of increased physical activity, and to further understand how improvements in exercise capacity, dyspnoea and self-efficacy following interventions may translate into increased physical activity. The Task Force recommends that this ERS statement should be reviewed periodically (e.g. every 5-8 years).

The prevalence of quadriceps weakness in COPD and the relationship with disease severity

Quadriceps strength relates to exercise capacity and prognosis in chronic obstructive pulmonary disease (COPD). We wanted to quantify the prevalence of quadriceps weakness in COPD and hypothesised that it would not be restricted to patients with severe airflow obstruction or dyspnoea. Predicted quadriceps strength was calculated using a regression equation (incorporating age, sex, height and fat-free mass), based on measurements from 212 healthy subjects. The prevalence of weakness (defined as observed values 1.645 standardised residuals below predicted) was related to Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage and Medical Research Council (MRC) dyspnoea score in two cohorts of stable COPD outpatients recruited from the UK (n = 240) and the Netherlands (n = 351). 32% and 33% of UK and Dutch COPD patients had quadriceps weakness. A significant proportion of patients in GOLD stages 1 and 2, or with an MRC dyspnoea score of 1 or 2, had quadriceps weakness (28 and 26%, respectively). These values rose to 38% in GOLD stage 4, and 43% in patients with an MRC Score of 4 or 5. Quadriceps weakness was demonstrable in one-third of COPD patients attending hospital respiratory outpatient services. Quadriceps weakness exists in the absence of severe airflow obstruction or breathlessness.

Sarcopenia in COPD: prevalence, clinical correlates and response to pulmonary rehabilitation

BACKGROUND

Age-related loss of muscle, sarcopenia, is recognised as a clinical syndrome with multiple contributing factors. International European Working Group on Sarcopenia in Older People (EWGSOP) criteria require generalised loss of muscle mass and reduced function to diagnose sarcopenia. Both are common in COPD but are usually studied in isolation and in the lower limbs.

OBJECTIVES

To determine the prevalence of sarcopenia in COPD, its impact on function and health status, its relationship with quadriceps strength and its response to pulmonary rehabilitation (PR).

METHODS

EWGSOP criteria were applied to 622 outpatients with stable COPD. Body composition, exercise capacity, functional performance, physical activity and health status were assessed. Using a case-control design, response to PR was determined in 43 patients with sarcopenia and a propensity score-matched non-sarcopenic group.

RESULTS

Prevalence of sarcopenia was 14.5% (95% CI 11.8% to 17.4%), which increased with age and Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) stage, but did not differ by gender or the presence of quadriceps weakness (14.9 vs 13.8%, p=0.40). Patients with sarcopenia had reduced exercise capacity, functional performance, physical activity and health status compared with patients without sarcopenia (p<0.001), but responded similarly following PR; 12/43 patients were no longer classified as sarcopenic following PR.

CONCLUSIONS

Sarcopenia affects 15% of patients with stable COPD and impairs function and health status. Sarcopenia does not impact on response to PR, which can lead to a reversal of the syndrome in select patients.

Determinants and outcomes of physical activity in patients with COPD: a systematic review

BACKGROUND

The relationship between physical activity, disease severity, health status and prognosis in patients with COPD has not been systematically assessed. Our aim was to identify and summarise studies assessing associations between physical activity and its determinants and/or outcomes in patients with COPD and to develop a conceptual model for physical activity in COPD.

METHODS

We conducted a systematic search of four databases (Medline, Embase, CINAHL and Psychinfo) prior to November 2012. Teams of two reviewers independently selected articles, extracted data and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to assess quality of evidence.

RESULTS

86 studies were included: 59 were focused on determinants, 23 on outcomes and 4 on both. Hyperinflation, exercise capacity, dyspnoea, previous exacerbations, gas exchange, systemic inflammation, quality of life and self-efficacy were consistently related to physical activity, but often based on cross-sectional studies and low-quality evidence. Results from studies of pharmacological and non-pharmacological treatments were inconsistent and the quality of evidence was low to very low. As outcomes, COPD exacerbations and mortality were consistently associated with low levels of physical activity based on moderate quality evidence. Physical activity was associated with other outcomes such as dyspnoea, health-related quality of life, exercise capacity and FEV1 but based on cross-sectional studies and low to very low quality evidence.

CONCLUSIONS

Physical activity level in COPD is consistently associated with mortality and exacerbations, but there is poor evidence about determinants of physical activity, including the impact of treatment.

Respiratory muscle strength and ventilatory failure in amyotrophic lateral sclerosis

Although ventilatory failure is the most common cause of death in amyotrophic lateral sclerosis (ALS) and measurement of respiratory muscle strength (RMS) has been shown to have prognostic value, no single test of strength can predict the presence of hypercapnia reliably. RMS was measured in 81 ALS patients to evaluate the relationship between tests of RMS and the presence of ventilatory failure, defined as a carbon dioxide tension > or = 6 kPa. We studied the predictive value of vital capacity (VC), static inspiratory and expiratory mouth pressures (MIP, MEP), maximal sniff oesophageal (sniff P(oes)), transdiaphragmatic (sniff P(di)) and nasal (SNP) pressure, cough gastric (cough P(gas)) pressure and transdiaphragmatic pressure after bilateral cervical magnetic phrenic nerve stimulation (CMS P(di)) to identify the risk of ventilatory failure in the whole group and in subgroups of patients with and without significant bulbar involvement. For patients without significant bulbar involvement, sniff P(di) had greatest predictive power [odds ratio (OR) 57] with specificity, sensitivity and positive and negative predictive values (PPV, NPV) of 87, 90, 74 and 95%, respectively Of the less invasive tests, per cent predicted SNP had greater overall predictive power (OR 25, specificity 85%, sensitivity 81%) than per cent predicted VC (9, 89%, 53%) and per cent predicted MIP (6, 83%, 55%). No test had significant predictive power for the presence of hypercapnia when used to measure RMS in a subgroup of patients with significant bulbar weakness. Thirty-five patients underwent polysomnography. CMS P(di), sniff P(di) and per cent predicted SNP were significantly correlated with the apnoea/hypopnoea index (AHI) (P = 0.035, 0.042 and 0.026, respectively). The correlations between AHI and per cent predicted MIP and VC were less strong (both non-significant). In ALS patients without significant bulbar involvement, novel tests of RMS have greater predictive power than conventional tests to predict hypercapnia. In particular, the non-invasive SNP is more sensitive than VC and MIP, suggesting that it could usefully be included in tests of respiratory muscle strength in ALS and will be helpful in assessing the risk of ventilatory failure. In patients with significant bulbar involvement, tests of respiratory muscle strength do not predict hypercapnia. Sleep-disordered breathing is correlated with RMS and the novel tests of RMS having the strongest relationship with the degree of sleep disturbance.

Bronchoscopic lung volume reduction with endobronchial valves for patients with heterogeneous emphysema and intact interlobar fissures (the BeLieVeR-HIFi study): a randomised controlled trial

BACKGROUND

Lung volume reduction surgery improves survival in selected patients with emphysema, and has generated interest in bronchoscopic approaches that might achieve the same effect with less morbidity and mortality. Previous trials with endobronchial valves have yielded modest group benefits because when collateral ventilation is present it prevents lobar atelectasis.

METHODS

We did a single-centre, double-blind sham-controlled trial in patients with both heterogeneous emphysema and a target lobe with intact interlobar fissures on CT of the thorax. We enrolled stable outpatients with chronic obstructive pulmonary disease who had a forced expiratory volume in 1 s (FEV1) of less than 50% predicted, significant hyperinflation (total lung capacity >100% and residual volume >150%), a restricted exercise capacity (6 min walking distance <450 m), and substantial breathlessness (MRC dyspnoea score ≥3). Participants were randomised (1:1) by computer-generated sequence to receive either valves placed to achieve unilateral lobar occlusion (bronchoscopic lung volume reduction) or a bronchoscopy with sham valve placement (control). Patients and researchers were masked to treatment allocation. The study was powered to detect a 15% improvement in the primary endpoint, the FEV1 3 months after the procedure. Analysis was on an intention-to-treat basis. The trial is registered at controlled-trials.com, ISRCTN04761234.

FINDINGS

50 patients (62% male, FEV1 [% predicted] mean 31·7% [SD 10·2]) were enrolled to receive valves (n=25) or sham valve placement (control, n=25) between March 1, 2012, and Sept 30, 2013. In the bronchoscopic lung volume reduction group, FEV1 increased by a median 8·77% (IQR 2·27-35·85) versus 2·88% (0-8·51) in the control group (Mann-Whitney p=0·0326). There were two deaths in the bronchoscopic lung volume reduction group and one control patient was unable to attend for follow-up assessment because of a prolonged pneumothorax.

INTERPRETATION

Unilateral lobar occlusion with endobronchial valves in patients with heterogeneous emphysema and intact interlobar fissures produces significant improvements in lung function. There is a risk of significant complications and further trials are needed that compare valve placement with lung volume reduction surgery.

FUNDING

Efficacy and Mechanism Evaluation Programme, funded by the Medical Research Council (MRC) and managed by the National Institute for Health Research (NIHR) on behalf of the MRC-NIHR partnership.

Ultrasound measurement of rectus femoris cross-sectional area and the relationship with quadriceps strength in COPD

BACKGROUND

Quadriceps weakness and loss of muscle mass predict mortality in chronic obstructive pulmonary disease (COPD). It was hypothesised that a reduced quadriceps cross-sectional area could be detected by ultrasound in patients with COPD compared with healthy subjects, and that measurements relate to strength and fat-free mass (FFM).

METHODS

Rectus femoris muscle cross-sectional area (RF(CSA)) was measured by ultrasound and whole-body FFM estimated using electrical bioimpedance. Quadriceps strength was measured by maximum voluntary contraction and twitch tension (TwQ) following magnetic femoral nerve stimulation.

RESULTS

26 healthy volunteers of mean (SD) age 63 (9) years and 30 patients with COPD of mean (SD) age 67 (9) years and percentage predicted forced expiratory volume in 1 s (FEV(1)) 48.0 (20.8)% with a similar FFM (46.9 (9.3) kg vs 46.1 (7.3) kg, p = 0.193) participated in the study. Mean RF(CSA) was reduced in patients with COPD by 25% of the mean value in healthy subjects(-115 mm(2); 95% CI -177 to -54, p = 0.001) and was related to MRC dyspnoea scale score, independent of FFM or sex. Maximum voluntary contraction strength was linearly related to RF(CSA) in patients with COPD (r = 0.78, p<0.001). TwQ force per unit of RF(CSA) was similar in both healthy individuals and those with COPD (mean (SD) 17 (4) g/mm(2) vs 18 (3) g/mm(2), p = 0.657). Voluntary contraction strength per unit of RF(CSA) was dependent on central quadriceps activation and peripheral oxygen saturation in COPD.

CONCLUSION

Ultrasound measurement of RF(CSA) is an effort-independent and radiation-free method of measuring quadriceps muscle cross-sectional area in patients with COPD that relates to strength.

ERS statement on respiratory muscle testing at rest and during exercise

Assessing respiratory mechanics and muscle function is critical for both clinical practice and research purposes. Several methodological developments over the past two decades have enhanced our understanding of respiratory muscle function and responses to interventions across the spectrum of health and disease. They are especially useful in diagnosing, phenotyping and assessing treatment efficacy in patients with respiratory symptoms and neuromuscular diseases. Considerable research has been undertaken over the past 17 years, since the publication of the previous American Thoracic Society (ATS)/European Respiratory Society (ERS) statement on respiratory muscle testing in 2002. Key advances have been made in the field of mechanics of breathing, respiratory muscle neurophysiology (electromyography, electroencephalography and transcranial magnetic stimulation) and on respiratory muscle imaging (ultrasound, optoelectronic plethysmography and structured light plethysmography). Accordingly, this ERS task force reviewed the field of respiratory muscle testing in health and disease, with particular reference to data obtained since the previous ATS/ERS statement. It summarises the most recent scientific and methodological developments regarding respiratory mechanics and respiratory muscle assessment by addressing the validity, precision, reproducibility, prognostic value and responsiveness to interventions of various methods. A particular emphasis is placed on assessment during exercise, which is a useful condition to stress the respiratory system.

Quadriceps wasting and physical inactivity in patients with COPD

Quadriceps weakness is an important complication of advanced chronic obstructive pulmonary disease (COPD) but few data exist concerning muscle bulk in early disease. We hypothesised that quadriceps bulk, measured by ultrasound rectus femoris cross-sectional area (USRF(CSA)), would be reduced in mild, as well as advanced, COPD compared with controls, and would correlate with physical activity. 161 patients with stable COPD and 40 healthy subjects had a measurement of USRF(CSA) and wore a multisensor armband to record physical activity. USRF(CSA) was reduced in Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I patients compared with healthy subjects (p=0.0002). Stage II-IV patients had reduced USRF(CSA) (p<0.0001) compared with controls but were not significantly different from those with stage I disease. Physical activity level was reduced in stage I (p=0.002) and stage II-IV disease compared with controls. Using regression analysis, physical activity level was independently associated with USRF(CSA) in stage I (p=0.01) but not stage II-IV disease, where residual volume to total lung capacity ratio was the only independent predictor of physical activity level. Quadriceps wasting exists in patients with mild, as well as advanced, COPD, and is independently associated with physical inactivity in GOLD stage I disease. The identification of these patients may guide early lifestyle and therapeutic interventions.

The COPD assessment test (CAT): response to pulmonary rehabilitation. A multicentre, prospective study

BACKGROUND

The COPD (chronic obstructive pulmonary disease) assessment test (CAT) is a recently introduced, simple to use patient-completed quality of life instrument that contains eight questions covering the impact of symptoms in COPD. It is not known how the CAT score performs in the context of clinical pulmonary rehabilitation (PR) programmes or what the minimum clinically important difference is.

METHODS

The introduction of the CAT score as an outcome measure was prospectively studied by PR programmes across London. It was used alongside other measures including the St George's Respiratory Questionnaire, the Chronic Respiratory Disease Questionnaire, the Clinical COPD Questionnaire, the Hospital Anxiety and Depression score, the Medical Research Council (MRC) dyspnoea score and a range of different walking tests. Patients completed a 5-point anchor question used to assess overall response to PR from 'I feel much better' to 'I feel much worse'.

RESULTS

Data were available for 261 patients with COPD participating in seven programmes: mean (SD) age 69.0 (9.0) years, forced expiratory volume in 1 s (FEV(1)) 51.1 (18.7) % predicted, MRC score 3.2 (1.0). Mean change in CAT score after PR was 2.9 (5.6) points, improving by 3.8 (6.1) points in those scoring 'much better' (n=162), and by 1.3(4.5) in those who felt 'a little better' (n=88) (p=0.002). Only eight individuals reported no difference after PR and three reported feeling 'a little worse', so comparison with these smaller groups was not possible.

CONCLUSION

The CAT score is simple to implement as an outcome measure, it improves in response to PR and can distinguish categories of response.

Physical frailty and pulmonary rehabilitation in COPD: a prospective cohort study

Background

Frailty is an important clinical syndrome that is consistently associated with adverse outcomes in older people. The relevance of frailty to chronic respiratory disease and its management is unknown.

Objectives

To determine the prevalence of frailty among patients with stable COPD and examine whether frailty affects completion and outcomes of pulmonary rehabilitation.

Methods

816 outpatients with COPD (mean (SD) age 70 (10) years, FEV₁% predicted 48.9 (21.0)) were recruited between November 2011 and January 2015. Frailty was assessed using the Fried criteria (weight loss, exhaustion, low physical activity, slowness and weakness) before and after pulmonary rehabilitation. Predictors of programme non-completion were identified using multivariate logistic regression, and outcomes were compared using analysis of covariance, adjusting for age and sex.

Results

209/816 patients (25.6%, 95% CI 22.7 to 28.7) were frail. Prevalence of frailty increased with age, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, Medical Research Council (MRC) score and age-adjusted comorbidity burden (all p≤0.01). Patients who were frail had double the odds of programme non-completion (adjusted OR 2.20, 95% CI 1.39 to 3.46, p=0.001), often due to exacerbation and/or hospital admission. However, rehabilitation outcomes favoured frail completers, with consistently better responses in MRC score, exercise performance, physical activity level and health status (all p<0.001). After rehabilitation, 71/115 (61.3%) previously frail patients no longer met case criteria for frailty.

Conclusions

Frailty affects one in four patients with COPD referred for pulmonary rehabilitation and is an independent predictor of programme non-completion. However, patients who are frail respond favourably to rehabilitation and their frailty can be reversed in the short term.

Pharmacologic Management of Chronic Obstructive Pulmonary Disease. An Official American Thoracic Society Clinical Practice Guideline

Background: This document provides clinical recommendations for the pharmacologic treatment of chronic obstructive pulmonary disease (COPD). It represents a collaborative effort on the part of a panel of expert COPD clinicians and researchers along with a team of methodologists under the guidance of the American Thoracic Society.

Methods: Comprehensive evidence syntheses were performed on all relevant studies that addressed the clinical questions and critical patient-centered outcomes agreed upon by the panel of experts. The evidence was appraised, rated, and graded, and recommendations were formulated using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

Results: After weighing the quality of evidence and balancing the desirable and undesirable effects, the guideline panel made the following recommendations: 1) a strong recommendation for the use of long-acting β₂-agonist (LABA)/long-acting muscarinic antagonist (LAMA) combination therapy over LABA or LAMA monotherapy in patients with COPD and dyspnea or exercise intolerance; 2) a conditional recommendation for the use of triple therapy with inhaled corticosteroids (ICS)/LABA/LAMA over dual therapy with LABA/LAMA in patients with COPD and dyspnea or exercise intolerance who have experienced one or more exacerbations in the past year; 3) a conditional recommendation for ICS withdrawal for patients with COPD receiving triple therapy (ICS/LABA/LAMA) if the patient has had no exacerbations in the past year; 4) no recommendation for or against ICS as an additive therapy to long-acting bronchodilators in patients with COPD and blood eosinophilia, except for those patients with a history of one or more exacerbations in the past year requiring antibiotics or oral steroids or hospitalization, for whom ICS is conditionally recommended as an additive therapy; 5) a conditional recommendation against the use of maintenance oral corticosteroids in patients with COPD and a history of severe and frequent exacerbations; and 6) a conditional recommendation for opioid-based therapy in patients with COPD who experience advanced refractory dyspnea despite otherwise optimal therapy.

Conclusions: The task force made recommendations regarding the pharmacologic treatment of COPD based on currently available evidence. Additional research in populations that are underrepresented in clinical trials is needed, including studies in patients with COPD 80 years of age and older, those with multiple chronic health conditions, and those with a codiagnosis of COPD and asthma.

Validity of physical activity monitors during daily life in patients with COPD

Symptoms during physical activity and physical inactivity are hallmarks of chronic obstructive pulmonary disease (COPD). Our aim was to evaluate the validity and usability of six activity monitors in patients with COPD against the doubly labelled water (DLW) indirect calorimetry method. 80 COPD patients (mean ± sd age 68 ± 6 years and forced expiratory volume in 1 s 57 ± 19% predicted) recruited in four centres each wore simultaneously three or four out of six commercially available monitors validated in chronic conditions for 14 consecutive days. A priori validity criteria were defined. These included the ability to explain total energy expenditure (TEE) variance through multiple regression analysis, using TEE as the dependent variable with total body water (TBW) plus several physical activity monitor outputs as independent variables; and correlation with activity energy expenditure (AEE) measured by DLW. The Actigraph GT3X (Actigraph LLC, Pensacola, FL, USA), and DynaPort MoveMonitor (McRoberts BV, The Hague, the Netherlands) best explained the majority of the TEE variance not explained by TBW (53% and 70%, respectively) and showed the most significant correlations with AEE (r=0.71, p<0.001 and r=0.70, p<0.0001, respectively). The results of this study should guide users in choosing valid activity monitors for research or for clinical use in patients with chronic diseases such as COPD.

Community pulmonary rehabilitation after hospitalisation for acute exacerbations of chronic obstructive pulmonary disease: randomised controlled study

OBJECTIVE

To evaluate the effects of an early community based pulmonary rehabilitation programme after hospitalisation for acute exacerbations of chronic obstructive pulmonary disease (COPD).

DESIGN

A single centre, randomised controlled trial.

SETTING

An inner city, secondary and tertiary care hospital in London.

PARTICIPANTS

42 patients admitted with an acute exacerbation of COPD.

INTERVENTION

An eight week, pulmonary rehabilitation programme for outpatients, started within 10 days of hospital discharge, or usual care.

MAIN OUTCOME MEASURES

Incremental shuttle walk distance, disease specific health status (St George's respiratory questionnaire, SGRQ; chronic respiratory questionnaire, CRQ) and generic health status (medical outcomes short form 36 questionnaire, SF-36) at three months after hospital discharge.

RESULTS

Early pulmonary rehabilitation, compared with usual care, led to significant improvements in median incremental shuttle walk distance (60 metres, 95% confidence interval 26.6 metres to 93.4 metres, P = 0.0002), mean SGRQ total score (-12.7, -5.0 to -20.3, P = 0.002), all four domains of the CRQ (dyspnoea 5.5, 2.0 to 9.0, P = 0.003; fatigue 5.3, 1.9 to 8.8, P = 0.004; emotion 8.7, 2.4 to 15.0, P = 0.008; and mastery 7.5, 4.2 to 10.7, P < 0.001) and the mental component score of the SF-36 (20.1, 3.3 to 36.8, P = 0.02). Improvements in the physical component score of the SF-36 did not reach significance (10.6, -0.3 to 21.6, P = 0.057).

CONCLUSION

Early pulmonary rehabilitation after admission to hospital for acute exacerbations of COPD is safe and leads to statistically and clinically significant improvements in exercise capacity and health status at three months.

Cough augmentation with mechanical insufflation/exsufflation in patients with neuromuscular weakness

Adults and children with neuromuscular disease exhibit weak cough and are susceptible to recurrent chest infections, a major cause of morbidity and mortality. Mechanical insufflation/exsufflation may improve cough efficacy by increasing peak cough flow. It was hypothesised that mechanical insufflation/exsufflation would produce a greater increase in peak cough flow than other modes of cough augmentation. The acceptability of these interventions was also compared. Twenty-two patients aged 10-56 yrs (median 21 yrs) with neuromuscular disease and 19 age-matched controls were studied. Spirometry was performed and respiratory muscle strength measured. Peak cough flow was recorded during maximal unassisted coughs, followed in random order by coughs assisted by physiotherapy, noninvasive ventilation, insufflation and exsufflation, and exsufflation alone. Subjects rated strength of cough, distress and comfort on a visual analogue scale. In the neuromuscular disease group, mean +/- SD forced expiratory volume in one second was 0.8 +/- 0.6 L x s(-1), forced vital capacity 0.9 +/- 0.8 L, maximum inspiratory pressure 25 +/- 16 cmH2O, maximum expiratory pressure 26 +/- 22 cmH2O and unassisted peak cough flow 169 +/- 90 L x min(-1). The greatest increase in peak cough flow was observed with mechanical insufflation/exsufflation at 235 +/- 111 L x min(-1) (p<0.01). All techniques showed similar patient acceptability. Mechanical insufflation/exsufflation produces a greater increase in peak cough flow than other standard cough augmentation techniques in adults and children with neuromuscular disease.

Physical activity is increased by a 12-week semiautomated telecoaching programme in patients with COPD: a multicentre randomised controlled trial

Rationale

Reduced physical activity (PA) in patients with COPD is associated with a poor prognosis. Increasing PA is a key therapeutic target, but thus far few strategies have been found effective in this patient group.

Objectives

To investigate the effectiveness of a 12-week semiautomated telecoaching intervention on PA in patients with COPD in a multicentre European randomised controlled trial.

Methods

343 patients from six centres, encompassing a wide spectrum of disease severity, were randomly allocated to either a usual care group (UCG) or a telecoaching intervention group (IG) between June and December 2014. This 12-week intervention included an exercise booklet and a step counter providing feedback both directly and via a dedicated smartphone application. The latter provided an individualised daily activity goal (steps) revised weekly and text messages as well as allowing occasional telephone contacts with investigators. PA was measured using accelerometry during 1 week preceding randomisation and during week 12. Secondary outcomes included exercise capacity and health status. Analyses were based on modified intention to treat.

Main results

Both groups were comparable at baseline in terms of factors influencing PA. At 12 weeks, the intervention yielded a between-group difference of mean, 95% CI (lower limit – upper limit; ll-ul) +1469, 95% CI (971 to 1965) steps/day and +10.4, 95% CI (6.1 to 14.7) min/day moderate PA; favouring the IG (all p≤0.001). The change in 6-min walk distance was significantly different (13.4, 95% CI (3.40 to 23.5) m, p<0.01), favouring the IG. In IG patients, an improvement could be observed in the functional state domain of the clinical COPD questionnaire (p=0.03) compared with UCG. Other health status outcomes did not differ.

Conclusions

The amount and intensity of PA can be significantly increased in patients with COPD using a 12-week semiautomated telecoaching intervention including a step counter and an application installed on a smartphone.

Trial registration number:

NCT02158065.

Predicting outcomes from 6-minute walk distance in chronic obstructive pulmonary disease

BACKGROUND

Exercise tolerance is an important clinical aspect of chronic obstructive pulmonary disease that can be easily and reliably measured with the 6-minute walking test (6MWT). To improve the utility of the 6MWT for patient and health care system management, the interpretation of the functional status measure in relation to death and hospitalization should be elucidated.

METHODS

Three-year, prospective, multicenter observational study to evaluate the predictive power of 6MWD for death or exacerbation-related hospitalization and to evaluate the factors that help determine 6MWD.

RESULTS

We measured 6MWD at baseline and annually in 2110 patients with clinically stable Global Initiative for Obstructive Lung Disease (GOLD) stage II-IV COPD and recorded exacerbation-related hospitalizations and all-cause mortality. During the study, 200 patients died and 650 were hospitalized. Using receiver operating characteristics, the best predictive thresholds of the 6MWD were 334 m for increased risk of death and 357 m for exacerbation-related hospitalization (area under the curve 0.67 and 0.60 respectively); however, the discriminatory thresholds, especially for mortality, were influenced by age. The mean (SE) 6MWD declined by 1.6 (1.2) m per year in GOLD II, 9.8 (1.3) m per year in GOLD III, and 8.5 (2.4) m per year in GOLD IV.

CONCLUSION

The 6MWD provides prognostic information that may be useful for identifying high-risk patients with COPD.

Exercise-induced respiratory muscle fatigue: implications for performance

It is commonly held that the respiratory system has ample capacity relative to the demand for maximal O2and CO2transport in healthy humans exercising near sea level. However, this situation may not apply during heavy-intensity, sustained exercise where exercise may encroach on the capacity of the respiratory system. Nerve stimulation techniques have provided objective evidence that the diaphragm and abdominal muscles are susceptible to fatigue with heavy, sustained exercise. The fatigue appears to be due to elevated levels of respiratory muscle work combined with an increased competition for blood flow with limb locomotor muscles. When respiratory muscles are prefatigued using voluntary respiratory maneuvers, time to exhaustion during subsequent exercise is decreased. Partially unloading the respiratory muscles during heavy exercise using low-density gas mixtures or mechanical ventilation can prevent exercise-induced diaphragm fatigue and increase exercise time to exhaustion. Collectively, these findings suggest that respiratory muscle fatigue may be involved in limiting exercise tolerance or that other factors, including alterations in the sensation of dyspnea or mechanical load, may be important. The major consequence of respiratory muscle fatigue is an increased sympathetic vasoconstrictor outflow to working skeletal muscle through a respiratory muscle metaboreflex, thereby reducing limb blood flow and increasing the severity of exercise-induced locomotor muscle fatigue. An increase in limb locomotor muscle fatigue may play a pivotal role in determining exercise tolerance through a direct effect on muscle force output and a feedback effect on effort perception, causing reduced motor output to the working limb muscles.

Bronchoscopic volume reduction with valve implants in patients with severe emphysema

Eight patients with severe emphysema entered a pilot study of unilateral volume reduction by endobronchial valve insertion. Five patients had emphysema judged too severe for volume reduction surgery and three refused the operation. After valve insertions, the median forced expiratory volume in 1 s (FEV1) increased from 0.79 L (range 0.61-1.07) to 1.06 L (0.75-1.22) (difference 34%, p=0.028) and the median diffusing capacity (TL(CO)) increased from 3.05 mL/min/mm Hg (2.35-4.71) to 3.92 mL/min/mm Hg (2.89-5.40) (difference 29%, p=0.017). CT scans showed a substantial reduction in regional volume in four of the eight patients. Two patients developed a transient pneumothorax (one requiring drainage) but we recorded no other important adverse effects during follow-up. Lung-volume reduction can be achieved with unilateral bronchoscopically placed valve implants in patients with severe emphysema with acceptable short-term safety and worthwhile functional benefits.