The 6-min walk distance: change over time and value as a predictor of survival in severe COPD

Five-Repetition Sit-to-Stand Test as Predictor of Mortality in High Risk COPD Patients

OBJECTIVE

To determine if adding performance on the five-repetition sit-to-stand test (5-STS) to chronic obstructive pulmonary disease (COPD) high-risk criteria, proposed by the Spanish COPD guidelines (GesEPOC), affects mortality prognosis.

METHODS

Observational study of COPD outpatients involved prospective follow-up for 5 years. Patients were classified based on 5-STS performance and risk criteria proposed by GesEPOC version 2021. Outcome measures were 5-year mortality timing and rate. Kaplan-Meier curves and univariate and multivariate Cox proportional-hazard analyses, analysis of variance, and univariate and multivariate linear and logistic regression models were used.

RESULTS

One hundred and thirty-seven patients were included. Mean age was 66±8.3 years, and 87.6% were men. Of them, 115 (83.9%) were classified as high risk, 43 (34.4%) of whom had poor performance on the 5-STS. Overall mortality at 5 years was 27% and was significantly higher in the high-risk (29.6%) compared with the low-risk (13.6%) group. Among high-risk patients, mortality at 5 years was significantly worse with poor 5-STS performance (60.5%) compared with non-poor performance (11.1%). Poor performance on the 5-STS was independently associated with increased 5-year mortality risk (HR 4.70; 95% CI: 1.96-11.27) in a model adjusted for history of heart disease and dyspnea.

CONCLUSION

Among high-risk COPD patients, those with poor performance on the 5-STS have a significantly higher mortality at 5 years than those with non-poor 5-STS performance.

Widening the selection criteria for lung volume reduction surgery

Lung emphysema is a chronic disease that strongly impairs the patient's quality of life and survival. In well-selected patients with severe emphysema, who are breathless despite maximal medical care, lung volume reduction (LVR) can improve lung function and exercise capacity to alleviate symptoms and potentially delay or prevent lung transplantation [1, 2]. The main goal of LVR is to reduce hyperinflation by targeting the excess residual volume (RV), increasing dynamic lung volumes and breathing reserve capacity [2]. Patients should be selected by a specialised multidisciplinary team following thorough functional and morphological assessment [3]. The general accepted selection criteria for lung volume reduction surgery (LVRS) originate from expert recommendations in the NETT trial and include forced expiratory volume in 1 s (FEV1) 20–45% of predicted, total lung capacity >100% pred, RV >150% pred, diffusing capacity for carbon monoxide (D LCO) ≥20% pred, 6-min walking distance (6MWD) 140–450 m, and absence of coronary artery disease or moderate to severe pulmonary hypertension (mean pulmonary arterial pressure <35 mmHg) [4]. Over the past years, expert centres have challenged the lower inclusion limits by reporting successful outcomes in patients with more severe disease (FEV1 <20% pred and D LCO <20% pred) and less favourable morphology in the presence of significant hyperinflation [5–7]. In contrast to these often-challenging cases, to our knowledge, no data is published on LVRS in symptomatic patients exceeding the upper-limit criteria, once deemed “too good” for LVRS. We hypothesise that these patients with a major impact on functional capacity and quality of life due to hyperinflation could benefit from LVRS.

Severely hyperinflated patients with a heterogeneous morphology could be considered for lung volume reduction surgery when surpassing the upper limit criteria for FEV1 and 6MWD, resulting in significant clinical benefits with minimal postoperative risks https://bit.ly/4eWTNy8

The usefulness of Charlson Comorbidity Index (CCI) scoring in predicting all-cause mortality in Outpatients with Clinical Diagnoses of COPD

Background

Since comorbid conditions are frequently present in chronic obstructive pulmonary disease (COPD) and affect outcome, a composite scoring system to quantify comorbidity might be helpful in assessing mortality risk.

Methods

We tested the hypothesis that the Charlson Comorbidity Index (CCI) score at the time of an outpatient medical clinic encounter for COPD predicts all-cause mortality. Cox Proportional Hazards analyses were used in 200 randomly selected patients to relate CCI scores to all-cause mortality out to 5 years.

Results

Mean age was 62 ± 10 years, 56% were female, FEV1 was 62%, CCI was 3.08 ± 2.30, and 30% had a CCI ≥ 4, indicating 3 or more comorbid conditions. All-cause mortality was 8.5% and 20% at 3 and 5 years, respectively. In univariate testing, the CCI score and hospitalizations predicted mortality, but FEV1 did not. In multivariable testing, which included covariates of age, sex, socioeconomic status, race, FEV1 percent-predicted, and all-cause hospitalizations in the preceding year, CCI expressed as a continuous variable strongly predicted mortality: hazard ratio (HR) 1.38 for each unit increase in the score (p < 0.0001). While 1 or 2 comorbid conditions were not significantly related to mortality, 3 or more comorbid conditions (compared to none) strongly predicted mortality: HR 9.80, 95% CI 3.80 to 25.00.

Conclusion

Comorbidity, assessed with the CCI, is strongly predictive of mortality in outpatients with a clinical diagnosis of COPD, and this relationship appears to be non-linear. This instrument may be useful in determining prognosis in this population.

Lower mean corpuscular hemoglobin levels as a predictive factor of future exacerbations in patients with chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a pulmonary and systemic inflammatory disease, and the management of systemic comorbidities is important. We previously reported that a lower mean corpuscular hemoglobin concentration (MCHC) at admission was an independent prognostic factor for death in patients with COPD exacerbation. This study aimed to determine the association between MCHC levels and prognosis in patients with stable COPD.

METHODS

Overall, 200 stable patients with COPD (mean age; 71.0 ± 8.4 years, male; 93.5%) from January 2014 to March 2020 who were followed up for 4.6 ± 0.7 years were included. During the observation period, 70 patients experienced COPD exacerbations.

RESULTS

Significantly lower body mass index and more severe pulmonary function were observed in patients with COPD exacerbations than those without. The serum levels of aspartate aminotransferase and alanine aminotransferase, lymphocyte counts, and hemoglobin and MCHC levels in peripheral blood in patients with COPD exacerbation were significantly lower than those in patients without exacerbations. Multiple logistic regression analysis revealed that a lower MCHC level was an independent predictive factor of COPD exacerbations during the observation period, even after adjusting age, BMI, ACO merger, COPD grade, and emphysema severity, which were significantly different in univariate logistic regression analysis.

CONCLUSION

MCHC levels are a significant biomarker for assessing the future risk of exacerbations in patients with COPD, indicating usefulness of measurement of MCHC levels in the management of patients with COPD.

Prediction of spirometry outcome in Croatian patients with chronic obstructive pulmonary disease

The current study offers an extensive examination of the influence of 29 diverse parameters on spirometry measurement variables in a cohort of 534 patients with chronic obstructive pulmonary disease (COPD) from five different centers in Croatia. The study elucidates both the magnitude and direction of the effect exerted by the 29 predictors on forced vital capacity (FVC), forced expiratory volume in one second (FEV1), the ratio FEV1/FVC, and predicted forced expiratory flow at 50% of FVC. Additionally, the development of prediction models for these parameters has been undertaken using several statistical methods. The study identifies fat-free mass index, 6-minute walk distance, predicted diffusing capacity of the lung for carbon monoxide, arterial partial pressure of oxygen, and both arterial and tissue hemoglobin oxygen saturation percentage as robust positive predictors for all four spirometry parameters. Body mass index is recognized as a weak positive predictor for FEV1 and FEV1/FVC, commonly observed in COPD patients. As expected, smoking years is identified as a strong negative predictor for all four spirometry parameters, while age and illness duration exhibit strong predictive negative associations. Furthermore, modified medical research council, arterial partial pressure carbon dioxide, St George's respiratory questionnaire, COPD assessment test, depression anxiety stress scales, and nutritional risk screening are identified as weak negative predictors. Charlson comorbidity index, phase angle, and number of comorbidities do not exhibit a significant impact on spirometry variables. Ultimately, the performed factorial analysis categorized the 29 parameters into five groups, which were identified as relating to lung function, health status, nutritional status, age, and smoking. Multiple regression analysis, including four newly derived parameters based on the results of factorial analysis, identified nutritional status as a positive predictor for spirometry readings, while smoking, poor health status, and age were identified as negative predictors in successive order.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Efficacy and safety of Supine Daoyin in the treatment of acute exacerbation of chronic obstructive pulmonary disease: A randomized controlled trial

AIM

This study aimed to develop and evaluate the efficacy and safety of Supine Daoyin, a TCM PR technique, in hospitalized patients with AECOPD.

METHODS

This is a multicenter, prospective, randomized, controlled trial involving AECOPD inpatients recruited from April 2021 to December 2023 in five tertiary hospitals in China. Participants were randomly assigned to 14 days of Supine Daoyin group or control group and evaluated at days 3, 7, and 14 (posttreatment). The primary outcomes were LOS and CCQ and secondary outcomes were 6MWD, 30-STS, BI, Borg CR10, time on mechanical ventilation, SGRQ, mCOPD-PRO, and mESQ-COPD.

RESULTS

Out of 369 participants screened, 228 were randomly assigned (Supine Daoyin group: n = 114; control group: n = 114). For primary outcomes, there was no significant between-group difference in LOS (p > 0.05), but for CCQ the Supine Daoyin was superior to control at days 7 (p < 0.01) and 14 (p < 0.01). For secondary outcomes, Supine Daoyin groups showed robust and superior improvements in 6MWD, 30-STS, BI, Borg CR10, SGRQ, mCOPD-PRO, and mESQ-COPD (all p < 0.05), but for time on mechanical ventilation there was no significant difference in two groups (p > 0.05).

CONCLUSION

Supine Daoyin, a novel TCM PR technique, demonstrates safety and efficacy for AECOPD inpatients, yielding clinically meaningful improvements in health status, exercise capacity, and quality of life. This study offers a viable PR option for AECOPD patients with severe symptoms and limited mobility.

Efficacy of a student-led interprofessional health clinic in regional Australia for preventing and managing chronic disease

Increasing chronic disease rates in regional Australian communities necessitates innovative models of healthcare. We evaluated the efficacy of an interprofessional chronic disease program, delivered within a regional student-led nursing and allied health clinic in Southern Queensland, Australia. Changes to anthropometric, aerobic fitness and strength, and quality of life outcomes were examined at four time points spanning 16 months: intake, program transition (4 months), 6 and 12 months (post-transition). Our primary aim was to investigate whether the health improvements achieved during the program were sustained at 12 months in a subset of participants who provided complete data. Significant improvements were found in 6 of 11 measures, including the 6-minute walk test, grip strength, and self-reported quality of life across physical and psychosocial dimensions, with these improvements maintained to final review. No significant changes were found in body mass index (BMI), waist circumference, fat mass, or muscle mass. This is the first health clinic in regional Australia to deliver a student-led model of interprofessional and collaborative service to tackle the increasing burden of chronic disease in the community. The cost-effectiveness of this service and other potential clinical and social benefits remain to be investigated.

Identifying COPD patients with poor health status and low exercise tolerance through the five-repetition sit-to-stand test and modified Medical Research Council Dyspnea Score

BACKGROUND

The objective of this study was to determine whether the concomitant presence of poor health status (COPD Assessment Test, CAT ≥ 10 points) and low exercise tolerance (6-Minute Walking Test, 6MWT < 350 m) is associated with worse clinical characteristics in patients with COPD. In addition, we aimed to develop a readily applicable diagnostic model to discriminate COPD patients with these conditions.

METHODS

A cross-sectional multicenter study involving 208 stable COPD patients (FEV1/FVC < 0.7, smoking history of at least 10 pack-years, and chronic respiratory symptoms) was carried out. The outcome measures were the 6MWT, CAT score, 5-repetition sit-to-stand test (5STS) and modified Medical Research Council Dyspnea Scale (mMRC). Patients were categorized into three groups: no condition (6MWT ≥ 350 m and CAT < 10 points), one condition (6MWT < 350 m or CAT ≥ 10 points), and both conditions (6MWT < 350 m and CAT ≥ 10 points).

RESULTS

A total of 26 patients (12,5%) presented both conditions. These patients experienced a higher degree of dyspnea (p = 0.001), smoking pack-years (p = 0.011), severe obstruction (p = 0.006), and time on 5STS (p = 0.001). The probability of having both conditions directly increased with the time spent on the 5STS (β=0.188; p = 0.010) and the degree of dyspnea (β=1.920; p < 0.001) (R2=0.413). The scoring system, using the 5STS and dyspnea as surrogate measures, demonstrated adequate calibration between the predicted and observed risk (linear R2=0.852).

CONCLUSIONS

COPD patients with concurrent conditions have worse clinical status. The diagnostic model developed to discriminate these patients shows good internal validation.

Pulmonary function test results are correlated with 6-minute walk distance, distance-saturation product, and 6-minute walk work in patients with lymphangioleiomyomatosis

BACKGROUND AND OBJECTIVE

Lymphangioleiomyomatosis (LAM) is a rare multicystic lung disease. Although a correlation between pulmonary function test (PFT) results and exercise capacity appears probable, it has not yet been demonstrated. The aim of this study was to assess whether PFT results correlate with 6-minute walk test (6MWT) results in patients with LAM.

METHODS

We conducted a retrospective study of all patients with a diagnosis of LAM followed in a French reference centre over a 13-year period. PFT and 6MWT data were collected. Distance-saturation product (DSP) and 6-minute walk work (6MWORK) were calculated.

RESULTS

A total of 62 patients were included. Their median forced expiratory volume in 1 s (FEV1) was 82.7 % predicted and their median forced vital capacity (FVC) was 96.7 % predicted. The median diffusing capacity of the lungs for carbon monoxide (DLCO) was 58.5 % predicted and was decreased in 79 % of the patients. The median 6-minute walk distance was 535 m, which was 90.9 % of the 602 m predicted distance. The median DSP was 497.4 m % and the median 6MWORK was 32,910 kg.m. The distance walked during the 6MWT was significantly correlated with FVC%predicted (R = 0.435), FEV1 %predicted (R = 0.303), TLC%predicted (R = 0.345), FRC%predicted (R = 0.262), RV/TLC ratio (R = -0.271), and DLCO%predicted (R = 0.279). DSP and 6MWORK were each significantly correlated with different PFT results.

CONCLUSION

The present study shows that PFT results are potential predictors of the exercise capacity in patients with LAM. Additional studies are required to evaluate the interest of DSP and 6MWORK in LAM.

Prevalence and prognostic importance of exercise limitation and physical inactivity in COPD

Exercise limitation and physical inactivity are separate, but related constructs. Both are commonly present in individuals with COPD, contribute to disease burden over and above the respiratory impairments, and are independently predictive of adverse outcomes. Because of this, clinicians should consider assessing these variables in their patients with COPD. Field tests of exercise performance such as the 6-min walk test and the incremental and endurance shuttle walk tests require limited additional resources, and results correlate with negative outcomes. Laboratory measures of exercise performance using a treadmill or cycle ergometer assess exercise capacity, provide prognostic information and have the advantage of explaining physiological mechanisms (and their interactions) underpinning exercise limitation. Limitations in exercise capacity (i.e. "cannot do") and physical inactivity (i.e. "do not do") are both associated with mortality; exercise limitation appears to be the more important driver of this outcome.

Clinical utilization of airway inflammatory biomarkers in the prediction and monitoring of clinical outcomes in patients with chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) accounts for 545 million people living with chronic respiratory disorders and is the third leading cause of morbidity and mortality around the world. COPD is a progressive disease, characterized by episodes of acute worsening of symptoms such as cough, dyspnea, and sputum production.

AREAS COVERED

Airway inflammation is a prominent feature of COPD. Chronic airway inflammation results in airway structural remodeling and emphysema. Persistent airway inflammation is a treatable trait of COPD and plays a significant role in disease development and progression. In this review, the authors summarize the current and emerging biomarkers that reveal the heterogeneity of airway inflammation subtypes, clinical outcomes, and therapeutic response in COPD.

EXPERT OPINION

Airway inflammation can be broadly categorized as eosinophilic (type 2 inflammation) and non-eosinophilic (non-type 2 inflammation) in COPD. Currently, blood eosinophil counts are incorporated in clinical practice guidelines to identify COPD patients who are at a higher risk of exacerbations and lung function decline, and who are likely to respond to inhaled corticosteroids. As new therapeutics are being developed for the chronic management of COPD, it is essential to identify biomarkers that will predict treatment response.

Impacts of regular physical activity on hospitalisation in chronic obstructive pulmonary disease: a nationwide population-based study

INTRODUCTION

Studies that comprehensively evaluate the association between physical activity (PA) levels, particularly by quantifying PA intensity, and healthcare use requiring emergency department (ED) visit or hospitalisation in patients with chronic obstructive pulmonary disease (COPD) are limited in Korea.

METHODS

The risk of all-cause and respiratory ED visit or hospitalisation according to the presence or absence of COPD and the level of PA was evaluated in a retrospective nationwide cohort comprising 3308 subjects with COPD (COPD cohort) and 293 358 subjects without COPD (non-COPD cohort) from 2009 to 2017.

RESULTS

The COPD group exhibited a higher relative risk of all-cause and respiratory ED visit or hospitalisation across all levels of PA compared with the highly active control group (≥1500 metabolic equivalents (METs)-min/week). Specifically, the highest risk was observed in the sedentary group (adjusted HR (aHR) (95% CI) = 1.70 (1.59 to 1.81) for all-cause ED visit or hospitalisation, 5.45 (4.86 to 6.12) for respiratory ED visit or hospitalisation). A 500 MET-min/week increase in PA was associated with reductions in all-cause and respiratory ED visit or hospitalisation in the COPD cohort (aHR (95% CI) = 0.92 (0.88 to 0.96) for all-cause, 0.87 (0.82 to 0.93) for respiratory cause).

CONCLUSIONS

Compared with the presumed healthiest cohort, the control group with PA>1500 METs-min/week, the COPD group with reduced PA has a higher risk of ED visit or hospitalisation.

Natural Killer Cells as a Further Insight into the Course of Chronic Obstructive Pulmonary Disease

The role of natural killer (NK) cells in chronic obstructive pulmonary disease (COPD) pathogenesis has been discussed but is not yet clearly understood. This current study aimed to evaluate the associations between immunophenotypes, degrees of maturity, and the expression level of functional receptors of NK cells in the lung environment present in bronchoalveolar lavage fluid (BALF), and an attempt was made to determine their relationship in the course and progression of COPD. A total of 15 COPD patients and 14 healthy smokers were included. The clinical parameters of COPD were evaluated. In both groups, NK cells using monoclonal antibodies directly conjugated with fluorochromes in flow cytometry were assessed in the peripheral blood. Additionally, NK cells using the same method were assessed in BALF in the COPD subgroup. The blood's NK cells differed from the estimated group's maturity and receptor expression. Functional receptors CD158b+, CD314+, and CD336+ expressed by NK cells were significantly interlinked with age, RV, TLC, 6MWT, smoking, and the number of exacerbations. These results confirm the essential role of NK cells in COPD pathogenesis. Additionally, the relationship between clinical parameters and NK cell expression may indicate its participation in the disease progression and exacerbation and allow for a better understanding of NK cell biology in COPD.

Pulmonary Rehabilitation Is Associated With Decreased Exacerbation and Mortality in Patients With COPD: A Nationwide Korean Study

BACKGROUND

Poor uptake to pulmonary rehabilitation (PR) is still challenging around the world. There have been few nationwide studies investigating whether PR impacts patient outcomes in COPD. We investigated the change of annual PR implementation rate, medical costs, and COPD outcomes including exacerbation rates and mortality between 2015 and 2019.

RESEARCH QUESTION

Does PR implementation improve outcomes in patients with COPD in terms of direct cost, exacerbation, and mortality?

STUDY DESIGN AND METHODS

Data of patients with COPD extracted from a large Korean Health Insurance Review and Assessment service database (2015-2019) were analyzed to determine the trends of annual PR implementation rate and direct medical costs of PR. Comparison of COPD exacerbation rates between pre-PR and post-PR, and the time to first exacerbation and mortality rate according to PR implementation, were also assessed.

RESULTS

Among all patients with COPD in South Korea, only 1.43% received PR. However, the annual PR implementation rate gradually increased from 0.03% to 1.4% during 4 years, especially after health insurance coverage commencement. The direct medical cost was significantly higher in the PR group than the non-PR group, but the costs in these groups showed decreasing and increasing trends, respectively. Both the incidence rate and frequency of moderate-to-severe and severe exacerbations were lower during the post-PR period compared with the pre-PR period. The time to the first moderate-to-severe and severe exacerbations was longer in the PR group than the non-PR group. Finally, PR implementation was associated with a significant decrease in mortality.

INTERPRETATION

We concluded that health insurance coverage increases PR implementation rates. Moreover, PR contributes toward improving outcomes including reducing exacerbation and mortality in patients with COPD. However, despite the well-established benefits of PR, its implementation rate remains suboptimal.

Dietary nitrate supplementation to enhance exercise capacity in patients with COPD: Evidence from a meta-analysis of randomized controlled trials and a network pharmacological analysis

OBJECTIVE

The potential effects of nitrate in patients with chronic obstructive pulmonary disease (COPD) have attracted increased research interest. However, previous clinical trials have reported inconsistent results, and consecutive meta-analyses have failed to reach a consensus. Since some randomized controlled trials have recently been conducted that can provide more evidence, we performed an updated meta-analysis.

METHODS

A comprehensive literature search was conducted using PubMed, the Cochrane Library, Embase, and Web of Science databases to identify trials that assessed the efficacy and safety of nitrate in patients with COPD. The Revman 5.3 software was used for data analysis. Mean difference (MD) or standardized mean difference (SMD) with 95 % confidence interval (CI) was used as the effect measure, and forest plots were used to display individual and pooled results. Network pharmacology analysis was conducted to investigate the potential mechanisms of nitrate action in COPD.

RESULTS

Eleven studies involving 287 patients were included in this meta-analysis. The results indicated that dietary nitrate supplementation increased plasma nitrate and nitrite concentrations and fractional exhaled nitric oxide in patients with COPD. Nitrate improved exercise capacity [SMD = 0.38, 95 % CI = 0.04-0.72] and endothelial function [MD = 9.41, 95 % CI = 5.30-13.52], and relieved dyspnea in patients with COPD. Network pharmacology identified AKT1, IL1B, MAPK3, and CASP3 as key treatment targets.

CONCLUSION

Dietary nitrate supplementation could be used as a potential treatment for patients with COPD, especially to increase their exercise capacity. The underlying mechanisms may be related to AKT1, IL1B, MAPK3, and CASP3.

Influence of physical activity on the prognosis of COPD patients: the HADO.2 score - health, activity, dyspnoea and obstruction

Objective

The aim of this study was to create a prognostic instrument for COPD with a multidimensional perspective that includes physical activity (PA). The score also included health status, dyspnoea and forced expiratory volume in 1 s (HADO.2 score).

Methods

A prospective, observational, non-intervention study was carried out. Patients were recruited from the six outpatient clinics of the respiratory service of a single university hospital. The component variables of the HADO.2 score and BODE index were studied, and PA was measured using an accelerometer. The outcomes for the HADO.2 score were mortality and hospitalisations during follow-up and an exploration of the correlation with health-related quality of life at the moment of inclusion in the study.

Results

401 patients were included in the study and followed up for three years. The HADO.2 score showed good predictive capacity for mortality: C-index 0.79 (0.72-0.85). The C-index for hospitalisations was 0.72 (0.66-0.77) and the predictive ability for quality of life, as measured by R2, was 0.63 and 0.53 respectively for the Saint George's Respiratory Questionnaire and COPD Assessment Test.

Conclusions

There was no statistically significant difference between the mortality predictive capacity of the HADO.2 score and the BODE index. Adding PA to the original BODE index significantly improved the predictive capacity of the index. The HADO.2 score, which includes PA as a key variable, showed good predictive capacity for mortality and hospitalisations. There were no differences in the predictive capacity of the HADO.2 score and the BODE index.

Utility of Cardiopulmonary Exercise Testing in Chronic Obstructive Pulmonary Disease: A Review

Chronic obstructive pulmonary disease (COPD) is a disease defined by airflow obstruction with a high morbidity and mortality and significant economic burden. Although pulmonary function testing is the cornerstone in diagnosis of COPD, it cannot fully characterize disease severity or cause of dyspnea because of disease heterogeneity and variable related and comorbid conditions affecting cardiac, vascular, and musculoskeletal systems. Cardiopulmonary exercise testing (CPET) is a valuable tool for assessing physical function in a wide range of clinical conditions, including COPD. Familiarity with measurements made during CPET and its potential to aid in clinical decision-making related to COPD can thus be useful to clinicians caring for this population. This review highlights pulmonary and extrapulmonary impairments that can contribute to exercise limitation in COPD. Key elements of CPET are identified with an emphasis on measurements most relevant to COPD. Finally, clinical applications of CPET demonstrated to be of value in the COPD setting are identified. These include quantifying functional capacity, differentiating among potential causes of symptoms and limitation, prognostication and risk assessment for operative procedures, and guiding exercise prescription.

Can static hyperinflation predict exercise capacity in COPD?

INTRODUCTION

The diagnosis and severity assessment of COPD relies on spirometry, and in particular the FEV1. However, it has been proposed that hyperinflation and air-trapping are better predictors of exercise capacity and mortality than the FEV1.

RESEARCH

QUESTION: Does static hyperinflation predict exercise capacity?

METHODS

We conducted an observational prospective study. Patients with COPD referred to the lung function laboratory were consecutively recruited. Patients with hyperinflation (the experimental group) were compared to patients without hyperinflation (the control group). The sample sizes were determined assuming an effect size of 0.5 and a power of 0.80.

RESULTS

We recruited 124 participants, of whom 87% were male, the mean age was 66.1 ± 8.8 years. 67% were symptomatic (GOLD B or D). Airflow limitation was moderate to severe in the majority of patients (median FEV1 47%, IQR 38-65%) and 43% of patients had static hyperinflation. The median 6MWD was 479 meters (404-510) and peak workload in CPET was 64 watts (46-88) with peak VO2 1.12 L/min, 0.89-1.31 L/min. Patients with lower FEV1, DLCO and IC/TLC and higher RV/TLC had reduced exercise capacity in both 6MWT and CPET, measured as lower distance, greater desaturation and ∆Borg dyspnoea, and reduced workload, peak VO2 and peak VE and higher desaturation and ventilatory limitation (VE/MVV). An IC/TLC < 0.33 predicted reduced exercise performance (peak O2 <60%). Dyspnoea assessed by mMRC and QoL measured by CAT and CCQ were also worse in the hyperinflation in COPD patients.

CONCLUSION

In COPD patients, IC/TLC and RV/TLC are valuable predictors of exercise performance in both 6MWT and CPET and PRO.

Time-Course of Changes in Multidimensional Fatigue and Functional Exercise Capacity and Their Associations during a Short Inpatient Pulmonary Rehabilitation Program

This study aimed to assess the time-course of changes in multidimensional fatigue and functional exercise capacity and their associations during an inpatient pulmonary rehabilitation (PR) program. Seventy COPD patients from three centres were enrolled for a four-week PR program and were evaluated before (T0) and at the end of each week (T1, T2, T3, and T4). Weekly change in multidimensional fatigue was assessed by the multidimensional inventory questionnaire (MFI-20) and functional exercise capacity by the 6-minute walking distance (6MWD). Reaction time (RT) and heart rate variability (HRV) were also assessed as complementary markers of fatigue. HRV did not change during the study (all p > 0.05). MFI-20 score and RT decreased during the first part of the program (p < 0.001) and levelled off at T2 (all p > 0.05 compared with each preceding time). While 6MWD improved by almost 70% during the first part of the PR, it continued to increase, albeit at a greatly reduced pace, between T2 and T4 (p < 0.05). In parallel, a negative association was found between MFI-20 score and 6MWD at each evaluation time (r ranged from 0.43 to 0.71), with a significantly stronger T3 correlation compared with the other time periods (all p < 0.05). The strengthening of the association between fatigue and functional exercise capacity at T3, which occurred concomitantly with the slowdown of functional exercise capacity improvement, is consistent with a role for fatigue in the limitation of performance changes during PR. The limitation of fatigue during PR is thus an interesting aspect to improve the magnitude of performance changes.

Breathless and Blue in the Canadian Longitudinal Study on Aging: Incident and Recurrent Depression Among Older Adults with COPD During the COVID-19 Pandemic

Background and Objectives

The COVID-19 pandemic and related public health measures intensified risk factors for depression and concurrently heightened numerous health-related stressors for individuals with Chronic Obstructive Pulmonary Disease (COPD). Utilizing a comprehensive longitudinal sample of Canadian older adults, this study examined the incidence and recurrence of depression among older adults with COPD, and identified factors that were associated with depression during the pandemic among this population.

Methods

Data came from four phases of the Canadian Longitudinal Study on Aging (CLSA) (n=875 with COPD). The primary outcome of interest was a positive screen for depression based on the CES-D-10, during autumn of 2020. Bivariate and multivariate logistic regression analyses were performed to identify factors that were associated with depression.

Results

Approximately 1 in 6 (17%) respondents with COPD and no lifetime history of depression developed depression for the first time during the early stages of the pandemic. Approximately 1 in 2 (52%) participants with COPD and a history of depression experienced a recurrence of depressive symptoms during this period. Loneliness, functional limitations, and family conflict were associated with a higher risk of both incident and recurrent depression. The risk of incident depression only was higher among those who had difficulty accessing healthcare resources. The risk of recurrent depression only was higher among women, those with a post-secondary education, and those with more adverse childhood experiences.

Conclusion

Screening and interventions aimed at individuals with COPD, both with and without a history of depression, are warranted to potentially mitigate the mental health impacts of the COVID-19 pandemic.

A computational musculoskeletal arm model for assessing muscle dysfunction in chronic obstructive pulmonary disease

Computational models have been used extensively to assess diseases and disabilities effects on musculoskeletal system dysfunction. In the current study, we developed a two degree-of-freedom subject-specific second-order task-specific arm model for characterizing upper-extremity function (UEF) to assess muscle dysfunction due to chronic obstructive pulmonary disease (COPD). Older adults (65 years or older) with and without COPD and healthy young control participants (18 to 30 years) were recruited. First, we evaluated the musculoskeletal arm model using electromyography (EMG) data. Second, we compared the computational musculoskeletal arm model parameters along with EMG-based time lag and kinematics parameters (such as elbow angular velocity) between participants. The developed model showed strong cross-correlation with EMG data for biceps (0.905, 0.915) and moderate cross-correlation for triceps (0.717, 0.672) within both fast and normal pace tasks among older adults with COPD. We also showed that parameters obtained from the musculoskeletal model were significantly different between COPD and healthy participants. On average, higher effect sizes were achieved for parameters obtained from the musculoskeletal model, especially for co-contraction measures (effect size = 1.650 ± 0.606, p < 0.001), which was the only parameter that showed significant differences between all pairwise comparisons across the three groups. These findings suggest that studying the muscle performance and co-contraction, may provide better information regarding neuromuscular deficiencies compared to kinematics data. The presented model has potential for assessing functional capacity and studying longitudinal outcomes in COPD.

The six-minute walk test - a reliable test for detection of exercise-related desaturation in patients with chronic obstructive pulmonary disease

INTRODUCTION

Exercise-induced desaturation is common in patients with moderate to severe chronic obstructive pulmonary disease (COPD). It provides additional information about physical capacity and disease evolution, and it is an important predictor of mortality.

Reference standards for the 6-min walk test in Croatian older adults

Introduction: The 6-min walk test (6MWT) is commonly used to assess the level of functional capacity of individuals with respiratory diseases. Although previous evidence has provided reference standards for the 6MWT in unhealthy older adults, no data have been provided for the Croatian healthy older populations. Therefore, the main purposes of the study were to define sex- and age-specific references for the 6MWT in older adults. Methods: Six-hundred and forty-three older adults (260 men and 383 women) aged 60-80 years were recruited in this observational cross-sectional study. The participants were instructed to walk the maximal distance possible for 6 min. The main outcome was the final score in the 6MWT conducted at a 30-m straight corridor. Results: Men exhibited longer walking distance, compared to women (678.3 ± 59.1 vs. 653.8 ± 49.9 m, p < 0.001) and younger men and women performed better, than their older counterparts (p < 0.001). However, the sex*age interaction effect showed no significant differences between men and women in the same age range (p = 0.865). Discussion: This is the first study with the purpose of providing reference standards for the 6MWT in a large sample of Croatian older adults. Older men and women in lower percentiles may be treated as a "risky group" of individuals with a special attention of implementing interventions to enhance the performance.

Early Desaturation During 6-Minute Walk Test is a Predictor of Mortality in COPD

BACKGROUND

Oxygen desaturation during exercise is mainly observed in severe cases of chronic obstructive pulmonary disease (COPD) and is associated with a worse prognosis, but little is known about the type of desaturation that causes the greatest risk of mortality.

MATERIAL AND METHODS

We studied all of the 6-min walk tests performed periodically at a tertiary hospital over a period of 12 years in patients with moderate or severe COPD. We classified patients as non-desaturators if they did not suffer a drop in oxygen saturation (SpO2 < 88%) during the test, early desaturators if the time until desaturation was < 1 min, and non-early desaturators if it was longer than 1 min. The average length of follow-up per patient was 5.6 years.

RESULTS

Of the 319 patients analyzed, 126 non-desaturators, 91 non-early desaturators and 102 early desaturators were identified. The mortality analysis showed that early desaturators had a mortality of 73%, while it was 38% for non-early desaturators and 28% for non-desaturators, with a survival of 5.9 years compared to 7.5 years and 9.6 years, respectively (hazard ratio of 3.50; 95% CI 2.3-5.3; p < 0.0001).

CONCLUSIONS

The early desaturation seen in patients with chronic obstructive pulmonary disease is associated with greater mortality and is likely responsible for the poor prognosis shown globally in patients who desaturate. The survival of patients with early desaturation is almost 4 years less with respect to non-desaturators, and they, thus, require closer observation.

Improved exercise capacity results in a survival benefit after endobronchial valve treatment

BACKGROUND

Bronchoscopic lung volume reduction using endobronchial valves (EBV) is a treatment option for selected patients with advanced emphysema. The treatment significantly improves pulmonary function, exercise capacity, quality of life, and potentially improves survival. Our main aim was to assess whether treatment response significantly influences survival time after EBV treatment.

METHODS

We evaluated treatment response at 6-week and 1-year follow-up of all patients treated with EBVs between 2008 and 2020. Survival status was retrieved on December 1, 2021. Patients were defined as responders or non-responders based on known minimal important differences for FEV₁, residual volume (RV), RV/Total Lung Capacity (TLC) ratio, 6-min walk distance (6MWD), St. George's Respiratory Questionnaire (SGRQ), target lobe volume reduction (TLVR), and complete lobar atelectasis. Uni- and multivariate cox regression models were used to evaluate the effect of response on survival time.

RESULTS

A total of 428 patients were included. EBV treatment resulted in significant improvements in pulmonary function, exercise capacity and quality of life. Median survival was 8.2 years after treatment. SGRQ and 6MWD response were independent predictors for improved survival time (Hazard Ratio (HR) 0.50 [0.28-0.89], p = .02 and HR 0.54 [0.30-0.94], p = .03, respectively). The presence of a complete lobar atelectasis did not significantly affect survival, neither did pulmonary function improvements.

CONCLUSIONS

Our results suggest that improvement in exercise capacity and quality of life after EBV treatment are associated with a survival benefit, independent of improvements in pulmonary function, reduction in target lobe volume or the presence of complete lobar atelectasis.

Predictive equation for six-minute walk test in Indian children, adolescents, and adults

Background

Post-COVID residual dysfunction has been observed in a majority of people, with reduction in cardiopulmonary endurance emerging as a primary symptom. The Six-Minute Walk Test is a simple, reliable, and valid test that is used routinely on people with chronic respiratory dysfunction. In the current COVID-19 pandemic situation, reference values and a predictive equation developed from a large sample across a large age group, from 6 to 75 years, will enable one to establish goals of treatment for post-COVID rehabilitation.

Methods

Following institutional ethical clearance, we recruited 1369 participants for the study (685 females and 684 males). Participants were classified according to biological age into group 1 (6-12 years), group 2 (13-17 years), group 3 (18-40 years), group 4 (41-65 years), and group 5 (>65 years). Informed consent was sought and participants were screened using a health history questionnaire. Demographic features, namely, age, height, weight, and body mass index (BMI) were noted. The Six-Minute Walk Test was administered as per ATS guidelines. Clinical parameters, namely, pulse rate, respiratory rate, systolic blood pressure, diastolic blood pressure, and rate of perceived exertion were recorded.

Results

The Six-Minute Walk Test (6MWT) was significantly influenced by age and gender (r = 0.257, P = 0.00 and r = 0.501, P = 0.00, respectively). Walking distance was longest in 13-17-year-old males, whereas females demonstrated a linear decline after 12 years. In each age group, males walked a greater distance than females. Stepwise linear regression analysis was used to derive the following predictive equation: 6MWT = 491.93 - (2.148 × age) + (107.07 × gender) (females = 0, males = 1).

Conclusion

The study confirmed variability of the Six-Minute Walk Test, with age and gender being predominant predictors. Reference values, equations, and percentile charts generated from the study can be utilised to guide clinical decision-making while exercise prescription for patients with post COVID dysfunction.

Respiratory and peripheral muscle strength influence recovery of exercise capacity after severe exacerbation of COPD? An observational prospective cohort study

BACKGROUND

Patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) have decreased exercise tolerance, which may persist for months. In this context, little is known about the associations between muscle strength and recovery of exercise capacity.

OBJECTIVE

To assess whether respiratory and peripheral muscle strength influence recovery of exercise capacity in patients hospitalized due to AECOPD.

METHODS

Twenty-seven AECOPD patients (aged 69 ± 7 years, 56% male) were included. The following assessments were performed within 24 to 72 h of hospital admission: (i) respiratory muscle strength, measured by maximal inspiratory and expiratory pressures (MIP and MEP); (ii) peripheral muscle strength, assessed by handgrip and quadriceps muscle strength; and (iii) exercise capacity, measured by 6-min walking distance (6MWD). The 6MWD was reassessed 30 days later to determine the recovery of exercise capacity.

RESULTS

After 30 days, while 63% of the patients showed clinically important improvement in the 6MWD (recovery ≥ 30 m), 37% showed no change (recovery < 30 m). During hospital stay, the non-recovered group had lower quadriceps muscle strength compared to the recovered group (15 ± 5 vs. 22 ± 6 kgf; P = 0.006), with no significant difference for MIP, MEP and handgrip strength. Only quadriceps muscle strength was associated with recovery of exercise capacity (r = 0.56; P = 0.003).

CONCLUSION

AECOPD patients with quadriceps muscle weakness during hospitalization have poor recovery of exercise capacity after 30 days. This finding suggests the importance of early rehabilitation to improve quadriceps strength and accelerate functional recovery after AECOPD.

COPD: Providing the right treatment for the right patient at the right time

Chronic Obstructive Pulmonary Disease (COPD) is a common disease associated with significant morbidity and mortality that is both preventable and treatable. However, a major challenge in recognizing, preventing, and treating COPD is understanding its complexity. While COPD has historically been characterized as a disease defined by airflow limitation, we now understand it as a multi-component disease with many clinical phenotypes, systemic manifestations, and associated co-morbidities. Evidence is rapidly emerging in our understanding of the many factors that contribute to the pathogenesis of COPD and the identification of "early" or "pre-COPD" which should provide exciting opportunities for early treatment and disease modification. In addition to breakthroughs in our understanding of the origins of COPD, we are optimizing treatment strategies and delivery of care that are showing impressive benefits in patient-centered outcomes and healthcare utilization. This special issue of Respiratory Medicine, "COPD: Providing the Right Treatment for the Right Patient at the Right Time" is a summary of the proceedings of a conference held in Stresa, Italy in April 2022 that brought together international experts to discuss emerging evidence in COPD and Pulmonary Rehabilitation in honor of a distinguished friend and colleague, Claudio Ferdinando Donor (1948-2021). Claudio was a true pioneer in the field of pulmonary rehabilitation and the comprehensive care of individuals with COPD. He held numerous leadership roles in in the field, provide editorial stewardship of several respiratory journals, authored numerous papers, statement and guidelines in COPD and Pulmonary Rehabilitation, and provided mentorship to many in our field. Claudio's most impressive talent was his ability to organize spectacular conferences and symposia that highlighted cutting edge science and clinical medicine. It is in this spirit that this conference was conceived and planned. These proceedings are divided into 4 sections which highlight crucial areas in the field of COPD: (1) New concepts in COPD pathogenesis; (2) Enhancing outcomes in COPD; (3) Non-pharmacologic management of COPD; and (4) Optimizing delivery of care for COPD. These presentations summarize the newest evidence in the field and capture lively discussion on the exciting future of treating this prevalent and impactful disease. We thank each of the authors for their participation and applaud their efforts toward pushing the envelope in our understanding of COPD and optimizing care for these patients. We believe that this edition is a most fitting tribute to a dear colleague and friend and will prove useful to students, clinicians, and researchers as they continually strive to provide the right treatment for the right patient at the right time. It has been our pleasure and a distinct honor to serve as editors and oversee such wonderful scholarly work.

Associations of the distance-saturation product and low-attenuation area percentage in pulmonary computed tomography with acute exacerbation in patients with chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) has high global health concerns, and previous research proposed various indicators to predict mortality, such as the distance-saturation product (DSP), derived from the 6-min walk test (6MWT), and the low-attenuation area percentage (LAA%) in pulmonary computed tomographic images. However, the feasibility of using these indicators to evaluate the stability of COPD still remains to be investigated. Associations of the DSP and LAA% with other COPD-related clinical parameters are also unknown. This study, thus, aimed to explore these associations.

Methods

This retrospective study enrolled 111 patients with COPD from northern Taiwan. Individuals' data we collected included results of a pulmonary function test (PFT), 6MWT, life quality survey [i.e., the modified Medical Research Council (mMRC) scale and COPD assessment test (CAT)], history of acute exacerbation of COPD (AECOPD), and LAA%. Next, the DSP was derived by the distance walked and the lowest oxygen saturation recorded during the 6MWT. In addition, the DSP and clinical phenotype grouping based on clinically significant outcomes by previous study approaches were employed for further investigation (i.e., DSP of 290 m%, LAA% of 20%, and AECOPD frequency of ≥1). Mean comparisons and linear and logistic regression models were utilized to explore associations among the assessed variables.

Results

The low-DSP group (<290 m%) had significantly higher values for the mMRC, CAT, AECOPD frequency, and LAA% at different lung volume scales (total, right, and left), whereas it had lower values of the PFT and 6MWT parameters compared to the high-DSP group. Significant associations (with high odds ratios) were observed of the mMRC, CAT, AECOPD frequency, and PFT with low- and high-DSP groupings. Next, the risk of having AECOPD was associated with the mMRC, CAT, DSP, and LAA% (for the total, right, and left lungs).

Conclusion

A lower value of the DSP was related to a greater worsening of symptoms, more-frequent exacerbations, poorer pulmonary function, and more-severe emphysema (higher LAA%). These readily determined parameters, including the DSP and LAA%, can serve as indicators for assessing the COPD clinical course and may can serve as a guide to corresponding treatments.

Efficacy of Nasal High-Flow Oxygen Therapy in Chronic Obstructive Pulmonary Disease Patients in Long-Term Oxygen and Nocturnal Non-Invasive Ventilation during Exercise Training

High-flow oxygen therapy (HFOT) improves gas exchange and dead space washout and reduces the level of work required for breathing. This study aimed to evaluate pulmonary rehabilitation (PR) combined with HFOT in COPD patients treated with nocturnal non-invasive ventilation (NIV) and long-term oxygen therapy (LTOT). In particular, we sought to discover whether the addition of HFOT during exercise training could improve patients’ performance, mainly with regard to their Six-Minute Walking Test (6MWT) outcomes, and reduce the exacerbation rates, periods of rehospitalization or need to resort to unscheduled visits. Thirty-one COPD subjects (13 female) who used nocturnal NIV were included in a randomized controlled trial and allocated to one of two groups: the experimental group (EG), with 15 subjects, subjected to PR with HFOT; and the control group (CG), with 16 subjects, subjected to PR without HFOT. The primary outcome of the study was the observation of changes in the 6MWT. The secondary outcome of the study was related to the rate of exacerbation and hospitalization. Data were collected at baseline and after one, two and three cycles of cycle-ergometer exercise training performed in 20 supervised sessions of 40 min thrice per week, with a washout period of 3 months between each rehabilitation cycle. Statistical significance was not found for the 6MWT distance (W = 0.974; p = 0.672) at the last follow-up, but statistical significance was found for the Borg scale in regard to dyspnea (W = 2.50; p < 0.001) and fatigue (W = 2.00; p < 0.001). HFOT may offer a positive option for dyspnea-affected COPD patients in the context of LTOT and nocturnal NIV.

Predicting 6-minute walking test outcomes in patients with chronic obstructive pulmonary disease without physical performance measures

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) requires a multifactorial assessment, evaluating the airflow limitation and symptoms of the patients. The 6-min walk test (6MWT) is commonly used to evaluate the functional exercise capacity in these patients. This study aims to propose a novel predictive model of the major 6MWT outcomes for COPD assessment, without physical performance measurements.

METHODS

Cardiopulmonary and clinical parameters were obtained from fifty COPD patients. These parameters were used as inputs of a Bayesian network (BN), which integrated three multivariate models including the 6-min walking distance (6MWD), the maximum HR (HR_max) after the walking, and the HR decay 3 min after (HRR₃). The use of BN allows the assessment of the patients' status by predicting the 6MWT outcomes, but also inferring disease severity parameters based on actual patient's 6MWT outcomes.

RESULTS

Firstly, the correlation obtained between the estimated and actual 6MWT measures was strong (R = 0.84, MAPE = 8.10% for HR_max) and moderate (R = 0.58, MAPE = 15.43% for 6MWD and R = 0.58, MAPE = 32.49% for HRR₃), improving the classical methods to estimate 6MWD. Secondly, the classification of disease severity showed an accuracy of 78.3% using three severity groups, which increased up to 84.4% for two defined severity groups.

CONCLUSIONS

We propose a powerful two-way assessment tool for COPD patients, capable of predicting 6MWT outcomes without the need for an actual walking exercise. This model-based tool opens the way to implement a continuous monitoring system for COPD patients at home and to provide more personalized care.

Swetha, Prasanth G., Sakthi Sangeetha V., V. Gangadharan. Correlation between six-minute walk test and sit-to-stand test in COPD patients

Introduction and Aim: Six Minute Walk Test (6MWT) and spirometry are commonly used tests to assess the functional status of the Chronic Obstructive Pulmonary Diseases (COPD) patients. However, many other simpler tests like Sit to Stand Test (STST) are also available. This study is done to assess the utility of STST in comparison to 6MWT to evaluate the functional status of COPD patients in our hospital.   Materials and Methods: This study is a prospective and an observational study conducted on 50 COPD patients. Each patient underwent spirometry and subjected to 6MWT and STST. Quadriceps femoris muscle powers are measured for every patient before start of study. During the test, dyspnoea grade, Pulse rate, respiratory rate, saturation and blood pressure were measured.   Results: In this study group mean age was 60.38±11.09 years, mean FEV1 55.24% ±16.18% and then 6MWT and STST were correlating with each other. On comparing parameters hemodynamic parameters before and after performing 6MWT and STST for 30 seconds. There is significant correlation between 6MWT and STST using Pearson’s correlation. However, there is a negative correlation between FEV1 and both 6MWT and  STST.   Conclusion: Sit to stand test is less time consuming, repeatable and easy to perform. STST can also determine the functional status of COPD patient similar to Spirometry and Six-minute walk test. Hence, STST can be an alternative test for Spirometry and 6MWT in COPD patients in a limited resource facility.

Regulatory T cells, damage-associated molecular patterns, and myeloid-derived suppressor cells in bronchoalveolar lavage fluid interlinked with chronic obstructive pulmonary disease severity: An observational study

The role of regulatory T cells (Tregs), damage-associated molecular patterns (DAMPs), and myeloid-derived suppressor cells (MDSCs) in the mechanism of innate and adaptive immune responses in chronic obstructive pulmonary disease (COPD) is not well understood.Evaluating the presence of Tregs in the bronchoalveolar lavage fluid (BALF) and peripheral blood in patients with COPD, and assessment of the relationship between Tregs, MDSCs, and DAMPs as factors activating innate and adaptive immune responses. Description of the association between immune and clinical parameters in COPD.Thirty-one patients with COPD were enrolled. Clinical parameters (forced expiratory volume in one second [FEV1], forced vital capacity, total lung capacity [TLC], diffusion capacity of carbon monoxide, and B-BMI, O-obstruction, D-dyspnea, E-exercise [BODE]) were assessed. Tregs and MDSCs were investigated in the BALF and blood using monoclonal antibodies directly conjugated with fluorochromes in flow cytometry. The levels of defensin (DEF2), galectin-1 (Gal-1), galectin-3 (Gal-3), galectin-9 (Gal-9), heat shock protein-27 (HSP27), and surfactant protein A were assessed via sandwich enzyme-linked immunosorbent assay.The percentage of Tregs was significantly higher in the blood than in the BALF, in contrast to the mean fluorescence intensity of forkhead box P3 (FoxP3). Significant associations were observed between Tregs and HSP27 (r = 0.39), Gal-1 (r = 0.55), Gal-9 (r = -0.46), and MDSCs (r = -0.50), and between FoxP3 and Gal-1 (r = -0.42), Gal-3 (r = -0.39), and MDSCs (r = -0.43). Tregs and clinical parameters, including FEV1%pred (r = 0.39), residual volume (RV)%pred (r = -0.56), TLC%pred (r = -0.55), RV/TLC (r = -0.50), arterial oxygen saturation (r = -0.38), and arterial oxygen pressure (r = -0.39) were significantly correlated. FoxP3 was significantly interlinked with RV/TLC (r = -0.52), arterial oxygen pressure (r = 0.42), and BODE index (r = -0.57).The interaction between innate and adaptive immune responses in patients with COPD was confirmed. The expression of Tregs in BALF may have prognostic value in patients with COPD. The conversion of immune responses to clinical parameters appears to be associated with disease severity.

Deep Learning Prediction of Survival in Patients with Chronic Obstructive Pulmonary Disease Using Chest Radiographs

Background Preexisting indexes for predicting the prognosis of chronic obstructive pulmonary disease (COPD) do not use radiologic information and are impractical because they involve complex history assessments or exercise tests. Purpose To develop and to validate a deep learning-based survival prediction model in patients with COPD (DLSP) using chest radiographs, in addition to other clinical factors. Materials and Methods In this retrospective study, data from patients with COPD who underwent postbronchodilator spirometry and chest radiography from 2011-2015 were collected and split into training (n = 3475), validation (n = 435), and internal test (n = 315) data sets. The algorithm for predicting survival from chest radiographs was trained (hereafter, DLSP_CXR), and then age, body mass index, and forced expiratory volume in 1 second (FEV₁) were integrated within the model (hereafter, DLSP_integ). For external test, three independent cohorts were collected (n = 394, 416, and 337). The discrimination performance of DLSP_CXR was evaluated by using time-dependent area under the receiver operating characteristic curves (TD AUCs) at 5-year survival. Goodness of fit was assessed by using the Hosmer-Lemeshow test. Using one external test data set, DLSP_integ was compared with four COPD-specific clinical indexes: BODE, ADO, COPD Assessment Test (CAT), and St George's Respiratory Questionnaire (SGRQ). Results DLSP_CXR had a higher performance at predicting 5-year survival than FEV₁ in two of the three external test cohorts (TD AUC: 0.73 vs 0.63 [P = .004]; 0.67 vs 0.60 [P = .01]; 0.76 vs 0.77 [P = .91]). DLSP_CXR demonstrated good calibration in all cohorts. The DLSP_integ model showed no differences in TD AUC compared with BODE (0.87 vs 0.80; P = .34), ADO (0.86 vs 0.89; P = .51), and SGRQ (0.86 vs 0.70; P = .09), and showed higher TD AUC than CAT (0.93 vs 0.55; P < .001). Conclusion A deep learning model using chest radiographs was capable of predicting survival in patients with chronic obstructive pulmonary disease. © RSNA, 2022 Online supplemental material is available for this article.

Treatment with JianPiYiFei II granules for patients with moderate to very severe chronic obstructive pulmonary disease: A 52-week randomised, double-blinded, placebo-controlled, multicentre trial

BACKGROUND

Complementary and alternative therapy is widely used to treat chronic obstructive pulmonary disease (COPD). A Chinese herbal medicine, JianPiYiFei (JPYF) II granules, have been shown to improve COPD patients' quality of life, however long-term effectiveness has not been examined.

PURPOSE

To investigate whether long-term treatment with JPYF II granules is effective and safe for patients with stable, moderate to very severe COPD.

STUDY DESIGN AND METHODS

A multicentre, randomised, double-blinded, placebo-controlled trial was conducted. Eligible participants from six hospitals were randomly assigned 1:1 to receive either JPYF II granules or placebo for 52 weeks. The primary outcome was the change in St. George's Respiratory Questionnaire (SGRQ) score during treatment. Secondary outcomes included the frequency of acute exacerbations during treatment, COPD Assessment Test (CAT), 6-minute walking test (6MWT), lung function, body mass index, airflow obstruction, dyspnoea, exercise capacity (BODE) index, and peripheral capillary oxygen saturation (SpO₂) at the end of treatment.

RESULTS

A total of 276 patients (138 in each group) were included in the analysis. JPYF II granules led to a significantly greater reduction in SGRQ score (-7.33 points, 95% CI -10.59 to -4.07; p < 0.0001) which reflects improved quality of life. JPYF II granules improved CAT (-3.49 points, 95% CI -5.12 to -1.86; p < 0.0001) and 6MWT (45.61 metres, 95% CI 20.26 to 70.95; p = 0.0005), compared with placebo. Acute exacerbations were less frequent with JPYF II granules than with placebo (0.87 vs. 1.34 events per patient; p = 0.0043). There were no significant differences between the groups in lung function, BODE index and SpO₂. JPYF II granules were well tolerated and no significant adverse effects were noted.

CONCLUSIONS

Long-term treatment with JPYF II granules is effective in moderate to very severe COPD, improving quality of life and exercise capacity, decreasing the risk of acute exacerbation, and relieving symptoms.

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.

Predictors of mortality in chronic obstructive pulmonary disease: a systematic review and meta-analysis

Background

Better insight in patients’ prognosis can help physicians to timely initiate advance care planning (ACP) discussions with patients with chronic obstructive pulmonary disease (COPD). We aimed to identify predictors of mortality.

Methods

We systematically searched databases Embase, PubMed, MEDLINE, Web of Science, and Cochrane Central in April 2020. Papers reporting on predictors or prognostic models for mortality at 3 months and up to 24 months were assessed on risk-of-bias. We performed a meta-analysis with a fixed or random-effects model, and evaluated the discriminative ability of multivariable prognostic models.

Results

We included 42 studies (49–418,251 patients); 18 studies were included in the meta-analysis. Significant predictors of mortality within 3–24 months in the random-effects model were: previous hospitalization for acute exacerbation (hazard ratio [HR] 1.97; 95% confidence interval [CI] 1.32–2.95), hospital readmission within 30 days (HR 5.01; 95% CI 2.16–11.63), cardiovascular comorbidity (HR 1.89; 95% CI 1.25–2.87), age (HR 1.48; 95% CI 1.38–1.59), male sex (HR 1.68; 95% CI 1.38–1.59), and long-term oxygen therapy (HR 1.74; 95% CI 1.10–2.73). Nineteen previously developed multicomponent prognostic models, as examined in 11 studies, mostly had moderate discriminate ability.

Conclusion

Identified predictors of mortality may aid physicians in selecting COPD patients who may benefit from ACP. However, better discriminative ability of prognostic models or development of a new prognostic model is needed for further large-scale implementation.

Registration: PROSPERO (CRD42016038494), https://www.crd.york.ac.uk/prospero/.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01911-5.

Samba, deep water, and poles: a framework for exercise prescription in Parkinson's disease

Parkinson's disease is a brain disorder that leads to tremor, slowness, muscle stiffness, and other movement disorders. The benefits of exercise for reducing disability in individuals with Parkinson’s disease are numerous. However, not much is known about the designing and prescription of exercise in neurodegenerative diseases. A brief review and indications for exercise prescription and evaluation are discussed throughout. In this scoping review, we specifically aimed to describe the applicability of walking tests (6-min/10-m) for the prescription of exercise in individuals with Parkinson’s disease and to propose training (undulating periodized) designs in three exercise modalities, Brazilian dance rhythms (Samba and Forró), deep-water exercises, and Nordic walking. These training models and evaluation methods may assist coaches and therapists in organizing exercise programs adequate to people with Parkinson’s disease, and are essential steps toward a comprehensive and more detailed understanding of the training loads in motor disorders and disease states.

How is the organisational settings, content and availability of comprehensive multidisciplinary pulmonary rehabilitation for people with COPD in primary healthcare in Norway: a cross-sectional study

OBJECTIVE

To examine the organisational settings, content and availability of comprehensive multidisciplinary pulmonary rehabilitation (PR) programmes for people with chronic obstructive pulmonary disease (COPD) in primary healthcare in Norway.

DESIGN

This was a cross-sectional survey study examining the content, organisational settings and availability of comprehensive multidisciplinary PR for people with COPD.

SETTING AND PARTICIPANTS

When the survey was conducted, Norway had 436 municipalities/primary healthcare services who were invited to participate.

OUTCOME MEASURES

The main outcome was the question related to accessibility to a PR programme in primary healthcare. We also examined in what degree the single interventions which are a part of a PR programme were one of the municipalities services and if there were regional differences regarding PR.

RESULTS

Of the 436 municipalities, 158 answered the survey (36% response rate), and the survey covered for 45% of the total population in Norway. Five per cent of the responders reported having multidisciplinary PR for patients with COPD. The most frequently reported single interventions that can be a part of a multidisciplinary PR programme were reported as follows: group exercise training for all diagnoses (27%), reablement (25%) and home-care treatment by a physiotherapist and/or occupational therapist (24%). Southern-Eastern Norway had a significantly lower number of these interventions than Western Norway, Central Norway, and Northern Norway (p<0.001).

CONCLUSION

Only 5% of the Norwegian primary healthcare services (municipalities) had a multidisciplinary PR programme for patients with COPD. PR is the most important and cost-effective treatment within integrated care of patients with COPD. National strategies are therefore needed to increase the availability of PR for patients with COPD in Norwegian municipalities.

Cut-off values of 6-min walk test and sit-to-stand test for determining symptom burden in atrial fibrillation

Background

Since symptomatology is a major predictor of quality of life and an endpoint for the management of atrial fibrillation (AF), practical approaches for objectively interpreting symptom burden and functional impairment are needed.

Aims

We aimed to provide cut-off values for two frequently used field tests to be able to objectively interpret symptom burden in atrial fibrillation.

Methods

One hundred twenty-five patients with AF were evaluated with European Heart Rhythm Association (EHRA) score, 6-min walk test (6MWT), 30 s sit-to-stand test (30 s-STST), Short-Form 36 (SF-36), International Physical Activity Questionnaire-Short Form (IPAQ-SF), and spirometry. Patients with EHRA 1 were classified as “asymptomatic”, and those with EHRA 2–4 as “symptomatic”. Cut-off values of 6MWT and 30 s-STST for discriminating between these patients were calculated.

Results

The optimal cut-off value was “450 m” for 6MWT (sensitivity: 0.71; specificity of 0.79) and “11 repetitions” for 30 s-STST (sensitivity 0.77; specificity of 0.70). Area under ROC curve was 0.75 for both tests (p < 0.001). Discriminative properties of the two tests were similar, and they were significantly correlated (r = 0.58; p < 0.001). Subgroup analysis revealed patients below cut-off values also had worse outcomes in SF-36, IPAQ-SF, and spirometry.

Conclusions

In patients with AF, walking < 450 m in 6MWT or performing < 11 repetitions in 30 s-STST indicates increased symptom burden, as well as impaired exercise capacity, quality of life, physical activity participation, and pulmonary function. These cut-off values may help identifying patients who may require adjustments in their routine treatment or who may benefit from additional rehabilitative approaches.

Changes in health-related quality of life as a marker in the prognosis in COPD patients

Chronic obstructive pulmonary disease (COPD) is understood as a complex, heterogeneous and multisystem airway obstructive disease. The association of deterioration in health-related quality of life (HRQoL) with mortality and hospitalisation for COPD exacerbation has been explored in general terms. The specific objectives of this study were to determine whether a change in HRQoL is related, over time, to mortality and hospitalisation. Overall, 543 patients were recruited through Galdakao Hospital's five outpatient respiratory clinics. Patients were assessed at baseline, and the end of the first and second year, and were followed up for 3 years. At each assessment, measurements were made of several variables, including HRQoL using the St George's Respiratory Questionnaire (SGRQ). The cohort had moderate obstruction (forced expiratory volume in 1 s 55% of the predicted value). SGRQ total, symptoms, activity and impact scores at baseline were 39.2, 44.5, 48.7 and 32.0, respectively. Every 4-point increase in the SGRQ was associated with an increase in the likelihood of death: "symptoms" domain odds ratio 1.04 (95% CI 1.00-1.08); "activity" domain OR 1.12 (95% CI 1.08-1.17) and "impacts" domain OR 1.11 (95% CI 1.06-1.15). The rate of hospitalisations per year was 5% (95% CI 3-8%) to 7% (95% CI 5-10%) higher for each 4-point increase in the separate domains of the SGRQ. Deterioration in HRQoL by 4 points in SGRQ domain scores over 1 year was associated with an increased likelihood of death and hospitalisation.

Exertional Desaturation Has Higher Mortality Than Non-Desaturation in COPD

Background and objectives: Exertional desaturation (ED) is often overlooked in chronic obstructive pulmonary disease (COPD). We aim to investigate the impact of ED on mortality and the predictors of ED in COPD. Materials andmethods: A cohort of COPD patients with clinically stable, widely ranging severities were enrolled. ED is defined as oxyhemoglobin saturation by pulse oximetry (SpO2) < 90% or a drop of ΔSpO2 ≥ 4% during a six-minute walk test (6MWT). Cox regression analysis is used to estimate the hazard ratio (HR) for three-year mortality. Results: A total of 113 patients were studied, including ED (N = 34) and non-ED (N = 79) groups. FVC (% of predicted value), FEV1/FVC (%), FEV1 (% of predicted value), DLCO (%), maximal inspiratory pressure, SpO2 during the 6MWT, GOLD stage, and COPD severity were significantly different between the ED and non-ED groups in univariate analysis. Low minimal SpO2 (p < 0.001) and high maximal heart rate (p = 0.04) during the 6MWT were significantly related to ED in multivariate analysis. After adjusting for age, gender, body mass index, 6MWD, FEV1, mMRC, GOLD staging, exacerbation, hs-CRP, and fibrinogen, the mortality rate of the ED group was higher than that of the non-ED group (p = 0.012; HR = 4.12; 95% CI 1.37–12.39). For deaths, the average survival time of ED was shorter than that of the non-ED group (856.4 days vs. 933.8 days, p = 0.033). Conclusions: ED has higher mortality than non-ED in COPD. COPD should be assessed for ED, especially in patients with low minimal SpO2 and high maximal HR during the 6MWT.

Ultrasound assessment of the rectus femoris in patients with chronic obstructive pulmonary disease predicts poor exercise tolerance: an exploratory study

Background

Reduced exercise tolerance is an important clinical feature of chronic obstructive pulmonary disease (COPD) and is associated with poor prognosis. The 6-min walk test (6MWT) is widely used to assess exercise capacity; however, it is not commonly administered in primary medical institutions because it requires a suitable site and professional training. Ultrasound has great potential for evaluating skeletal muscle dimensions in COPD. However, whether skeletal muscle ultrasound can predict impaired exercise tolerance is unclear.

Methods

The study included 154 stable patients with COPD, who were randomly divided into a development set and a validation set. The thickness (RF_thick) and cross-sectional area (RF_csa) of the rectus femoris were measured using ultrasound. Standardized RF_thick (STD- RF_thick) and Standardized RF_csa (STD-RFcsa) were obtained via standardization of RF_thick and RF_csa by patients' height.

Results

Strong correlations were observed between the 6MWD and RF_thick (r = 0.84, p < 0.001) and between the 6MWD and RF_csa (r = 0.81, p < 0.001). In the development set, the optimal cut-off values for men and women for predicting poor exercise tolerance were < 3.098 cm/m and < 3.319 cm/m for STD-RF_thick and < 4.052 cm²/m and < 4.366 cm²/m for STD-RF_csa, respectively. In the validation set, the area under the curve (AUC) values for the prediction of a 6MWD < 350 by STD-RF_thick and STD-RF_csa were 0.881 and 0.903, respectively. Finally, the predictive efficacy of STD-RF_thick (AUC: 0.922), STD-RF_csa (AUC: 0.904), and the derived nomogram model (AUC: 0.98) for exercise tolerance was superior to that of the sit-to-stand test and traditional clinical features.

Conclusions

Rectus femoris ultrasound has potential clinical application to predict impaired exercise tolerance in patients with COPD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01663-8.

The effectiveness and safety of Chuna manual therapy adjuvant to Western medicine in patients with chronic obstructive pulmonary disease: Study protocol for a randomized, single-blind, investigator-initiated, pilot trial

BACKGROUND

In chronic obstructive pulmonary disease (COPD) management, greater emphasis has been placed on symptomatic improvement and enhanced quality of life in patients. Manual therapy among respiratory rehabilitation programs has received much attention recently, with the publication of numerous studies. In South Korea, a method known as Chuna Manual Therapy (CMT) has been applied in the management of COPD patients and in clinical practice, but the clinical basis for safety and effectiveness is yet to be established. Therefore, rigorously designed randomized controlled trials are required. We aimed to evaluate the feasibility of assessing the add-on effect and safety of CMT administered with standard Western medicine therapy for the treatment of COPD.

METHODS

This is a randomized, single-blind, single-center clinical pilot trial. Patients with COPD receiving standard drug therapy are randomly divided into an experimental group (n = 20) and a control group (n = 20) at a 1:1 ratio. The experimental group receives CMT adding to the standard medical therapy once a week for 8 weeks. The control group receives only the standard drug treatment. The trial is conducted with an outcome assessor and statistician blinding. The primary outcome is the 6-minute walk test. The secondary outcomes include the pulmonary function test, the Modified Medical Research Council, visual analog scale for dyspnea, COPD assessment test, quality of life using the St. George's respiratory questionnaire, EuroQOL five dimensions questionnaire, and Korean pattern identification questionnaire. Adverse events are also be evaluated.

CONCLUSIONS

The results of this study will provide the feasibility of a large-scale clinical trial to establish high-quality clinical evidence of CMT for COPD.

TRIAL REGISTRATION

Korean Clinical Trial Registry (http://cris.nih.go.kr; registration number: KCT0006119).

Normative data for the 6-min walk test in 11-14 year-olds: a population-based study

BACKGROUND

The 6-min walk test (6MWT) has become an established measure for assessing exercise capacity in children with chronic diseases. However, little evidence has been provided regarding population-based normal data in healthy children. The main purpose of the study was to provide normative data in a large sample of children.

METHODS

In this cross-sectional study, 4352 children between 11 and 14 years were recruited (66% girls). The main outcome measure was the distance walked for six minutes. Sex- and age-specific percentile values (5th, 15th, 25th, 50th, 75th, 85th and 95th) for the 6MWT were created and the differences and correlations were examined by the analysis of variance and Pearson's coefficient of correlation.

RESULTS

The mean distance walked in 6 min was 576 ± 93 m in boys and 545 ± 92 m in girls, respectively. The mean walking speed for boys and girls was 98 ± 5 m/min and 91 ± 6 m/min. Older boys and girls performed better, compared to their younger counterparts (p for age < 0.001). The 6MWT was significantly correlated with age (r = 0.24, p < 0.001), height (r = 0.09, p < 0.001), weight (r =  - 0.13, p < 0.001) and body-mass index (r =  - 0.26, p < 0.001).

CONCLUSIONS

This is the first population-based study aiming to provide normative data for the 6MWT in healthy children between 11 to 14 years. Children in lower percentiles are 'target groups' for special intervention aiming to enhance the performance.

Integrated disease management interventions for patients with chronic obstructive pulmonary disease

BACKGROUND

People with chronic obstructive pulmonary disease (COPD) show considerable variation in symptoms, limitations, and well-being; this often complicates medical care. A multi-disciplinary and multi-component programme that addresses different elements of care could improve quality of life (QoL) and exercise tolerance, while reducing the number of exacerbations.

OBJECTIVES

To compare the effectiveness of integrated disease management (IDM) programmes versus usual care for people with chronic obstructive pulmonary disease (COPD) in terms of health-related quality of life (QoL), exercise tolerance, and exacerbation-related outcomes.

SEARCH METHODS

We searched the Cochrane Airways Group Register of Trials, CENTRAL, MEDLINE, Embase, and CINAHL for potentially eligible studies. Searches were current as of September 2020.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared IDM programmes for COPD versus usual care were included. Interventions consisted of multi-disciplinary (two or more healthcare providers) and multi-treatment (two or more components) IDM programmes of at least three months' duration.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. If required, we contacted study authors to request additional data. We performed meta-analyses using random-effects modelling. We carried out sensitivity analyses for the quality of included studies and performed subgroup analyses based on setting, study design, dominant intervention components, and region.

MAIN RESULTS

Along with 26 studies included in the 2013 Cochrane Review, we added 26 studies for this update, resulting in 52 studies involving 21,086 participants for inclusion in the meta-analysis. Follow-up periods ranged between 3 and 48 months and were classified as short-term (up to 6 months), medium-term (6 to 15 months), and long-term (longer than 15 months) follow-up. Studies were conducted in 19 different countries. The mean age of included participants was 67 years, and 66% were male. Participants were treated in all types of healthcare settings, including primary (n =15), secondary (n = 22), and tertiary care (n = 5), and combined primary and secondary care (n = 10). Overall, the level of certainty of evidence was moderate to high. We found that IDM probably improves health-related QoL as measured by St. George's Respiratory Questionnaire (SGRQ) total score at medium-term follow-up (mean difference (MD) -3.89, 95% confidence interval (CI) -6.16 to -1.63; 18 RCTs, 4321 participants; moderate-certainty evidence). A comparable effect was observed at short-term follow-up (MD -3.78, 95% CI -6.29 to -1.28; 16 RCTs, 1788 participants). However, the common effect did not exceed the minimum clinically important difference (MCID) of 4 points. There was no significant difference between IDM and control for long-term follow-up and for generic QoL. IDM probably also leads to a large improvement in maximum and functional exercise capacity, as measured by six-minute walking distance (6MWD), at medium-term follow-up (MD 44.69, 95% CI 24.01 to 65.37; 13 studies, 2071 participants; moderate-certainty evidence). The effect exceeded the MCID of 35 metres and was even greater at short-term (MD 52.26, 95% CI 32.39 to 72.74; 17 RCTs, 1390 participants) and long-term (MD 48.83, 95% CI 16.37 to 80.49; 6 RCTs, 7288 participants) follow-up. The number of participants with respiratory-related admissions was reduced from 324 per 1000 participants in the control group to 235 per 1000 participants in the IDM group (odds ratio (OR) 0.64, 95% CI 0.50 to 0.81; 15 RCTs, median follow-up 12 months, 4207 participants; high-certainty evidence). Likewise, IDM probably results in a reduction in emergency department (ED) visits (OR 0.69, 95%CI 0.50 to 0.93; 9 RCTs, median follow-up 12 months, 8791 participants; moderate-certainty evidence), a slight reduction in all-cause hospital admissions (OR 0.75, 95%CI 0.57 to 0.98; 10 RCTs, median follow-up 12 months, 9030 participants; moderate-certainty evidence), and fewer hospital days per person admitted (MD -2.27, 95% CI -3.98 to -0.56; 14 RCTs, median follow-up 12 months, 3563 participants; moderate-certainty evidence). Statistically significant improvement was noted on the Medical Research Council (MRC) Dyspnoea Scale at short- and medium-term follow-up but not at long-term follow-up. No differences between groups were reported for mortality, courses of antibiotics/prednisolone, dyspnoea, and depression and anxiety scores. Subgroup analysis of dominant intervention components and regions of study suggested context- and intervention-specific effects. However, some subgroup analyses were marked by considerable heterogeneity or included few studies. These results should therefore be interpreted with caution.

AUTHORS' CONCLUSIONS

This review shows that IDM probably results in improvement in disease-specific QoL, exercise capacity, hospital admissions, and hospital days per person. Future research should evaluate which combination of IDM components and which intervention duration are most effective for IDM programmes, and should consider contextual determinants of implementation and treatment effect, including process-related outcomes, long-term follow-up, and cost-effectiveness analyses.

Frailty Impact during and after Pulmonary Rehabilitation

Frailty is a condition of reduced physiologic reserve common in COPD candidates to pulmonary rehabilitation, however no study has investigated whether frailty impacts the decline that a great part of COPD patients face after the completion of the rehabilitation program. Study objectives are to verify frailty impact on pulmonary rehabilitation outcomes during and after the program. This is a secondary analysis of a longitudinal study. Stable COPD patients GOLD I-III were randomized to a three-month endurance versus endurance and resistance training. Participants performed a multidimensional assessment at baseline, at the end of the rehabilitation program and after six months. Frailty was defined using a two-step approach including PRISMA-7 and Timed "Up and Go" test. Frailty interaction with time was evaluated using generalized least-squared regression models for repeated measures, correcting for potential confounders. Of the 53 participants with a mean age of 73 (SD:8) years 38 (72%) were frail. The mean 6MWD and V'O2_peak increased in frail and no frail patients during pulmonary rehabilitation and declined after its completion, while CAT score showed a steep decline during the training, and a mild decline later. Frailty showed a significant interaction with time in terms of 6MWD variation during (β adj:43.6 meters, p-value:0.01) and after (β adj:-47 meters, p-value:0.02) pulmonary rehabilitation; no significant interaction was found in terms of V'O2_peak and CAT score variation. In conclusion, frail COPD patients have a higher potential to benefit from pulmonary rehabilitation, but a higher risk to have a steeper decline later.Supplemental data for this article is available online at https://doi.org/10.1080/15412555.2021.1967915 .

Multidimensional indices in the assessment of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a very common disease, is the third leading cause of death worldwide. Due to the significant heterogeneity of clinical phenotypes of COPD there is no single method suitable for predicting patients' health status and outcomes, and therefore multidimensional indices, assessing different components of the disease, were developed and are recommended for clinical practice by international guidelines. Several indices have been widely accepted: BODE and its modifications, ADO, DOSE, CODEX, COTE. They differ in their composition and aim, while they are more accurate and better validated in specific settings and populations. We review the characteristics, strengths and limitations of these indices, and we discuss their role in routine management of patients with COPD, as well as in specific clinical scenarios, such as resuscitation and ceiling of care, or decisions to offer more invasive treatments. This analysis may help clinicians to use those indexes in a more practical and appropriate way.

Adaptive Capacities and Complexity of Heart Rate Variability in Patients With Chronic Obstructive Pulmonary Disease Throughout Pulmonary Rehabilitation

Introduction

The complexity of bio-signals, like R-R intervals, is considered a reflection of the organism's capacity to adapt. However, this association still remains to be consolidated. We investigated whether the complexity of R-R intervals at rest and during perturbation [6-minute walking test (6MWT)], yielded information regarding adaptive capacities in Chronic Obstructive Pulmonary Disease (COPD) patients during pulmonary rehabilitation (PR).

Methods

In total, 23 COPD patients (64 ± 8 years, with forced expiratory volume in 1 s of 55 ± 19% predicted) were tested three times at the start (T1), middle (T2), and end (T3) of 4 weeks PR. Each time, R-R intervals were measured at rest and during 6MWT. The complexity of R-R intervals was assessed by evenly spaced Detrended Fluctuations Analysis and evaluated by the fractal exponent α and deviation from maximal complexity |1-α|.

Results

The 6MWT distance was significantly increased at T2 and T3 compared to T1. Neither α nor |1-α| at rest and during perturbation significantly changed throughout PR, nor were they consistently associated with 6MWT distances at each time. Throughout the PR program, complexity during the 6MWT was significantly lower compared to the rest. The level of α during 6MWT at T1 was positively correlated with the improvement of the 6MWT distance throughout the PR program.

Discussion

Reduced complexity in COPD patients during acute perturbation at the beginning of PR supports a decreased improvement of the 6MWT distance throughout PR. This result seems consistent with the notion that the complexity reflects the patients' adaptive capacities and could therefore become a clinical indicator in an applied perspective.