Distance-saturation product of the 6-minute walk test predicts mortality of patients with non-cystic fibrosis bronchiectasis

Change in the 6-min walk test among 71 patients with cystic fibrosis treated with elexacaftor/tezacaftor/ivacaftor

BACKGROUND

Elexacaftor/tezacaftor/ivacaftor (ETI) has led to substantial improvements in the clinical outcome of people with cystic fibrosis (pwCF). However, its effects on exercise capacity remain uncertain.

METHODS

This retrospective cohort study included 71 pwCF who started ETI between March 2020 and September 2022. The best performance on the 6-min walk test (6MWT), defined as the peak walking distance achieved, was compared between the 12 months preceding ETI initiation and the first 14 months of treatment. Pulmonary function tests (PFT) and Cystic Fibrosis Questionnaire-Revised (CFQ-R) were analyzed at treatment initiation and after 12 months.

RESULTS

After starting ETI, the 6MWT was performed at a median interval of 356 [296-380] days. The mean 6-min walk distance (6MWD) was 641 m ± 85.5 at baseline. After treatment, the 6MWD showed a significant absolute increase of 15.8 m (P = 0.007). Improvement was greater in pwCF with a percent predicted FEV1 (ppFEV1) ≤40, showing a mean increase of 37.8 m (P = 0.009), and in those without prior CFTR modulator therapy with an increase of 21.6 m (P = 0.016). After 12 months, the absolute increase in ppFEV1 was 15.8 (P < 0.001). The absolute changes from baseline in CFQ-R physical and respiratory scores were 17.9 (P < 0.001) and 27 points (P < 0.001), respectively. No correlation was found between changes in 6MWT and changes in PFT results.

CONCLUSIONS

ETI improved exercise capacity in pwCF, as evidenced by a significant increase in the 6MWD. ETI was also associated with improvements in physical-related quality of life. Changes in PFT results cannot predict changes in 6MWT results after ETI therapy.

Heart rate recovery after the 6-min walk test in people with bronchiectasis

Background

The cardiac autonomic response to exercise and during recovery has been poorly explored in bronchiectasis.

Methods

A longitudinal study was conducted in adults with bronchiectasis. Sociodemographic and clinical data were collected at baseline and after 12 months of follow-up. The heart rate recovery after the first (HRR1) and second minute (HRR2) of recovery in the six-min walk test (6MWT) was estimated in both assessments. Adjusted regression models were used to identify predictors of a delayed HRR1 (HRR1≤14).

Results

104 participants with a mean±sd age of 64±13 years and mostly women (67%) were included. A delayed HRR1 after the baseline 6MWT was identified in 36% of participants. These participants presented a higher proportion of males, increased body mass index, higher disease severity, more likely to require hospitalisation, more impact on quality of life, lower exercise capacity, lower heart rate at the end of the 6MWT and lower HRR2. Disease severity (β, 95% CI) (moderate and severe versus mild, -0.47 (-0.94 to -0.01)) and distance walked (0.34 (0.11 to 0.56)) were the independent variables associated with HRR1. Of the 45 participants who completed the entire follow-up period, 24% exhibited delayed HRR1. The presence of at least two exacerbations during the follow-up period (OR 16.89, 95% CI 1.44 to 197.48) was the only predictor of a delayed HRR1 in the assessment completed at the end of the study.

Conclusion

HRR1 is related to disease severity and is mainly affected by having severe exacerbations in people with bronchiectasis.

Evaluation of novel indices of walking performance taking oxygen desaturation into account during six-minute walk test in cardiovascular disease patients

In pulmonary disease patients since oxygen desaturation during 6-min walk test (6MWT) affects walk distance (6MWD), some novel indices such as desaturation/distance ratio [DDR, oxygen desaturation area (DAO2)/6MWD] and distance-saturation product [DSP, 6MWD × minimum peripheral oxygen saturation (SpO2)] are evaluated. However, there has been no study examining these indices that consider exercise-induced desaturation (EID) in patients with cardiovascular disease. In 94 cardiovascular disease patients without pulmonary complications, 6MWT and echocardiography were performed at the entry of cardiac rehabilitation. SpO2 was measured during 6MWT using a continuously monitorable pulse oximeter, and DSP and DDR were calculated using minimum SpO2 and DAO2 [sum of (100-SpO2) per second during 6MWT], respectively. EID was defined as SpO2 decrease of ≥ 4% or minimum SpO2 of < 90% during 6MWT. DSP was slightly lower and DDR was markedly higher in patients with EID than in those without. When examining correlations of DSP and DDR with their components, DSP was correlated with 6MWD much closely than minimum SpO2, while DDR was correlated as closely with DAO2 as 6MWD. Furthermore, DAO2, but not minimum SpO2, had a direct correlation with 6MWD. As for associations with cardiac function, DSP was correlated with several cardiac parameters, but DDR was not correlated with any of these parameters. Our findings suggest that oxygen desaturation during 6MWT affects walking distance in cardiovascular disease patients even without pulmonary complications and that DDR is more appropriate than DSP as an index of walking performance that takes EID into consideration, independently of cardiac function.

Pulmonary Rehabilitation Program Is an Effective Treatment Approach for Post-COVID-19 Syndrome Patients

Background/Objectives: Patients with post-COVID-2019 syndrome may have reduced functional capacity and physical activity levels. The pulmonary rehabilitation program (PRP)-an exercise training program-is designed to restore these functions and has been shown to improve dyspnea, exercise capacity, and other measures in these patients. This study aimed to analyze the effects of the RP on post-COVID-19 syndrome patients with respect to objective and subjective functional capacity, balance, and musculoskeletal strength. Methods: A prospective interventional trial was conducted before and after this phase. Patients were referred to the hospital with a confirmed diagnosis of SARS-CoV-2 and subsequently directed to the RP. These patients underwent an 8-week pulmonary rehabilitation program (45-min sessions 3 times/week). Each session consisted of stationary cycle-ergometer and resistance musculoskeletal exercises tailored to individuals' performance. They were evaluated pre- and post-PRP using the maximal handgrip strength (HGS) test, timed up-and-go test, 6-min walk test and its derived variables, and Duke Activity Status Index questionnaire. Results: From 142 hospitalized patients admitted with a diagnosis of SARS-CoV-2 infection, 60 completed the program, with an attendance rate of 85%. Nineteen patients were categorized as severe/critical, with a significantly higher hospital stay, compared to mild/moderate patients, and there were no differences in terms of sex distribution, age, or BMI between groups. Compared to the pre-PRP evaluation, both groups showed significant (p < 0.001) improvements in TUG, HGS, DASI D6MWT, 6MWS, and DSP variables after the PRP conduction. In addition, the groups exhibited similar improvement patterns following PRP (intragroup analysis), with no intergroup differences. Conclusions: RPs promote both objective and subjective functional capacity in patients with post-COVID-19 syndrome, with no difference in improvement regardless of the severity of the initial infection.

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.

Six-minute walking distance and desaturation-distance ratio in allogeneic stem cell transplantation

BACKGROUND

Most patients with haematological malignancies who undergo allogeneic haematopoietic stem cell transplant (HSCT) receive chemotherapy before the transplant to control the disease. Certain chemotherapy drugs can cause lung toxicity. Conversely, in patients with chronic respiratory conditions, the 6-min walking test (6MWT) and the desaturation-distance ratio (DDR) have demonstrated prognostic significance. Our objective was to determine whether the 6MWD and DDR, assessed prior to HSCT, have a prognostic impact on survival at 24 months post-HSCT.

METHODS

A prospective experimental study was conducted in consecutive patients referred for allogeneic HSCT at Hospital Clinic, Barcelona, Spain. A complete functional respiratory study, including the 6MWT and DDR, was conducted prior to admission. The area under the curve (AUC) and cut-off points were calculated. Data on patients' characteristics, HSCT details, main events, with a focus on lung complications, and survival at 24 months were analysed.

RESULTS

One hundred and seventy-five patients (39% women) with mean age of 48 ± 13 years old were included. Before HSCT, forced vital capacity and forced expiratory volume in the first second were 96% ± 13% predicted and 92% ± 14% predicted, respectively; corrected diffusing capacity for carbon monoxide 79% ± 15% predicted; 6MWD was 568 ± 83 m and DDR of .27 (.20-.41). The cut-off points for 6MWD and DDR were 566 m, [.58 95% CI (.51-.64)], p = .024 and .306, [.63 95% CI (.55-.70)], p = .0005, respectively. The survival rate at 24 months was 55%.

CONCLUSION

Our results showed that individuals who exhibit a 6MWD shorter than 566 ms or a decline in DDR beyond .306 experienced reduced survival rates at 24 months after HSCT.

Do Causes Influence Functional Aspects and Quality of Life in Patients with Nonfibrocystic Bronchiectasis?

Background

The denomination of noncystic fibrosis bronchiectasis (NCFB) includes several causes, and differences may be expected between the patient subgroups regarding age, comorbidities, and clinical and functional evolution. This study sought to identify the main causes of NCFB in a cohort of stable adult patients and to investigate whether such conditions would be different in their clinical, functional, and quality of life aspects.

Methods

Between 2017 and 2019, all active patients with NCFB were prospectively evaluated searching for clinical data, past medical history, dyspnea severity grading, quality of life data, microbiological profile, and lung function (spirometry and six-minute walk test).

Results

There was a female predominance; mean age was 54.7 years. Causes were identified in 82% of the patients, the most frequent being postinfections (n = 39), ciliary dyskinesia (CD) (n = 32), and chronic obstructive pulmonary disease (COPD) (n = 29). COPD patients were older, more often smokers (or former smokers) and with more comorbidities; they also had worse lung function (spirometry and oxygenation) and showed worse performance in the six-minute walk test (6MWT) (walked distance and exercise-induced hypoxemia). Considering the degree of dyspnea, in the more symptomatic group, patients had higher scores in the three domains and total score in SGRQ, besides having more exacerbations and more patients in home oxygen therapy.

Conclusions

Causes most identified were postinfections, CD, and COPD. Patients with COPD are older and have worse pulmonary function and more comorbidities. The most symptomatic patients are clinically and functionally more severe, besides having worse quality of life.

Assessment of Exercise Capacity in Post-COVID-19 Patients: How Is the Appropriate Test Chosen?

There is a wide range of sequelae affecting COVID-19 survivors, including impaired physical capacity. These sequelae can affect the quality of life and return to work of the active population. Therefore, one of the pillars of following-up is the evaluation of physical capacity, which can be assessed with field tests (such as the six-minute walk test, the one-minute standing test, the Chester step test, and the shuttle walking test) or laboratory tests (such as the cardiopulmonary exercise test). These tests can be performed in different contexts and have amply demonstrated their usefulness in the assessment of physical capacity both in post-COVID-19 patients and in other chronic respiratory, metabolic, cardiologic, or neurologic diseases. However, when traditional tests cannot be performed, physical function can be a good substitute, especially for assessing the effects of an intervention. For example, the Short Physical Performance Battery assessment and the Timed Up and Go assessment are widely accepted in older adults. Thus, the test should be chosen according to the characteristics of each subject.

Does arterial oxygenation during exercise add prognostic value in pulmonary arterial hypertension?

BACKGROUND

The 6-min walking distance (6MWD) is often used to assess prognosis in pulmonary arterial hypertension (PAH) patients. Whether or not changes in arterial oxygen saturation (SpO₂) during exercise add prognostic value to the 6MWD in these patients is unclear. The objective of this study was to investigate if SpO₂ changes during exercise adds prognostic value to the 6MWD in PAH patients.

METHODS

Ambispective study that includes 137 patients with PAH: 38 idiopathic/heritable (i/h PAH), 42 with connective tissue disease (CTD-PAH), 34 with porto-pulmonary hypertension (PoPH), 21 with HIV-associated PAH and 2 with pulmonary venous occlusive disease (PVOD). Patients were characterized and, treated according to international recommendations, and were followed-up for 5 years. To integrate SpO₂ changes during exercise, we calculated the desaturation distance ratio (DDR) either in its original form (from a maximal theoretical value of 100%) or the actual resting SpO₂ value of the patient (new DDR) as well as the distance saturation product (DSP).

RESULTS

(1) during follow-up, 40 patients died (29.2%); (2) results confirmed the prognostic value of the 6MWD (AUC 0.913 [IQR 0.868-0.958]; p < 0.0001), original DDR (AUC 0.923 [0.881-0.966]; p < 0.001), New DDR (AUC 0.917 [0.872-0.961], p < 0.001), and DSP (AUC 0.914 [0.869-0.959], p < 0.001); and, (3) neither the original or new DDR or DSP added significant prognostic value to 6MWD in these patients.

CONCLUSIONS

Consideration of three different composite indices of arterial oxygenation changes during exercise does not add prognostic value to that of the 6MWD in patients with PAH.

Effects of Pulmonary Rehabilitation on Systemic Inflammation and Exercise Capacity in Bronchiectasis: A Randomized Controlled Trial

INTRODUCTION

Bronchiectasis is a chronic condition that is becoming a global health concern.

OBJECTIVE

To examine the effects of pulmonary rehabilitation (PR) on systemic inflammation, exercise capacity, and quality of life in participants with bronchiectasis.

METHODS

Participants were randomized to receive PR (outpatient, three weekly sessions for 3 months) or control intervention (usual care + airway clearance therapy + breathing exercises). Data on laboratory (fibrinogen level) and patient-centered outcomes such as physical fitness [6-min walk test (6MWT)] and quality of life were collected.

RESULTS

A total of 41 participants were evaluated (20 in the intervention group and 21 in the control group). The magnitude of change between baseline and the end of study was greater in the PR group than in the control group-the 6MWT distance increased by a mean of 54 m (54 vs 12 m; p < 0.01), fibrinogen showed a significant reduction (fibrinogen - 92.8 versus - 47.1 mg/dl; p < 0.01), and quality of life improved according to Saint George's Respiratory Questionnaire (SGRQ) (- 7.5 vs 3.2; p < 0.01), which exceeded the minimal clinically important difference of 4 points.

CONCLUSION

PR effectively improved physical fitness, quality of life, and the degree of systemic inflammation, as reflected by changes in 6 MWT, fibrinogen levels and SGRQ scores. This study supports the inclusion of people with bronchiectasis in supervised PR programs.

Influence of Comorbidities and Airway Clearance on Mortality and Outcomes of Patients With Severe Bronchiectasis Exacerbations in Taiwan

Bronchiectasis is characterized by systemic inflammation and multiple comorbidities. This study aimed to investigate the clinical outcomes based on the bronchiectasis etiology comorbidity index (BACI) score in patients hospitalized for severe bronchiectasis exacerbations. We included non-cystic fibrosis patients hospitalized for severe bronchiectasis exacerbations between January 2008 and December 2016 from the Chang Gung Research Database (CGRD) cohort. The main outcome was the 1-year mortality rate after severe exacerbations. We used the Cox regression model to assess the risk factors of 1-year mortality. Of 1,235 patients who were hospitalized for severe bronchiectasis exacerbations, 641 were in the BACI < 6 group and 594 in the BACI ≥ 6 group. The BACI ≥ 6 group had more previous exacerbations and a lower FEV₁. Pseudomonas aeruginosa (19.1%) was the most common bacterium, followed by Klebsiella pneumoniae (7.5%). Overall, 11.8% of patients had respiratory failure and the hospital mortality was 3.0%. After discharge, compared to the BACI < 6 group, the BACI ≥ 6 group had a significantly higher cumulative incidence of respiratory failure and mortality in a 1-year follow-up. The risk factors for 1-year mortality in a multivariate analysis include age [hazard ratio (HR) 4.38, p = 0.01], being male (HR 4.38, p = 0.01), and systemic corticosteroid usage (HR 6.35, p = 0.001), while airway clearance therapy (ACT) (HR 0.50, p = 0.010) was associated with a lower mortality risk. An increased risk of respiratory failure and mortality in a 1-year follow-up after severe exacerbations was observed in bronchiectasis patients with multimorbidities, particularly older age patients, male patients, and patients with a history of systemic corticosteroid use. ACT could effectively improve the risk for 1-year mortality.

The 6-minute walk test predicts mortality in a pulmonary nontuberculous mycobacteria-predominant bronchiectasis cohort

Background

Bronchiectasis is a chronic lung condition frequently associated with nontuberculous mycobacteria pulmonary (NTM) disease. Persons with these conditions are at increased risk of mortality. Patient reported outcome (PRO) instruments and the 6-minute walk test (6MWT) have been shown to predict mortality for several lung conditions, but these measures have not been fully evaluated for bronchiectasis and NTM.

Methods

We conducted a retrospective cohort study among adult patients enrolled in a natural history study of bronchiectasis at the National Heart, Lung, and Blood Institute. Electronic medical records were queried for demographic, clinical, microbiologic, radiographic, and PRO instrument data: St. George’s Respiratory Questionnaire (SGRQ), Medical Research Council Dyspnea Scale, and the Pulmonary Symptom Severity Score (PSSS). The study baseline date was defined as the patient’s first visit after January 1st, 2015 with a SGRQ or 6MWT completed. Follow-up was defined as the interval between the study baseline visit and date of death or December 31st, 2019. Sex-stratified Cox proportional-hazards regression was conducted to identify predictors of mortality. Separate models were run for each PRO and 6MWT measure, controlling for age, body mass index (BMI), fibrocavitary disease status, and M. abscessus infection.

Results

In multivariable Cox proportional-hazards regression models, the PSSS-severity (aHR 1.29, 95% CI 1.04–1.59), the 6MWT total distance walked (aHR 0.938, 95% CI 0.896–0.981) and distance saturation product (aHR 0.930, 95% CI 0.887–0.974) independently predicted mortality. In addition, BMI was significantly predictive of mortality in all models.

Conclusions

The 6MWT and a PRO instrument capturing symptom severity are independently predictive of mortality in our cohort of bronchiectasis patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07054-6.

Predicting mortality in non-cystic fibrosis bronchiectasis patients using distance-saturation product

BACKGROUND

The bronchiectasis severity index (BSI) and FACED score are currently used in predicting outcomes of non-cystic fibrosis bronchiectasis (NCFB). Distance-saturation product (DSP), the product of distance walked, and lowest oxygen saturation during the 6-min walk test showed strong predictive power of mortality in non-CF bronchiectasis patients. This study aimed to compare the efficacy of these scores and DSP in predicting mortality.

METHODS AND PATIENTS

Our retrospective study included NCFB patients from January 2004 to December 2017. We recorded the basic data, pulmonary function, radiologic studies, sputum culture results, acute exacerbations (AE), emergency department (ED) visits, hospitalization, and mortality.

RESULTS

A total 130 NCFB patients were analysed. The mean BSI score, FACED score, and DSP were 8.8 ± 4.9, 3.4 ± 1.7, and 413.1 ± 101.5 m%, respectively. BSI and FACED scores had comparable predictive power for AE (p=.011; p=.010, respectively). The BSI score demonstrated a significant correlation with ED visits (p=.0003). There were 12 deaths. Patients were stratified using a DSP cut-off value of 345 m% according to the best area under receiver operator characteristic curve (AUC) value in mortality. DSP was not correlated with AE and ED visits. BSI, FACED scores, and DSP demonstrated statistically significant correlations with hospitalization (p<.0001; p<.0001; p=.0007, respectively). The AUC for overall mortality was similar for BSI, FACED score, and DSP (0.80 versus 0.85, p=.491; 0.85 versus 0.83, p=.831).

CONCLUSION

DSP had comparable predictive power for mortality as the well-validated BSI and FACED scores and is relatively easy to use in clinical practice.KEY MESSAGEDistance-saturation product (DSP) comprised with the product of distance walked, and lowest oxygen saturation during the 6-min walk test, which is common used in clinical practice.DSP demonstrated strong and comparable predictive power of mortality as the well-validated BSI and FACED scores in non-CF bronchiectasis patients.

Reference Values for 7 Different Protocols of Simple Functional Tests: A Multicenter Study

OBJECTIVES

To establish reference values and equations (ages 20-80y) for 7 simple functional tests based on a multicenter study.

DESIGN

Cross-sectional data collection in 4 research centers across different regions of a continental dimension country.

SETTING

Healthy subjects from general community were assessed in different research laboratories.

PARTICIPANTS

Data collection of 296 volunteer subjects (N=296; 45% men; aged 50±18y, forced expiratory volume in the first second 95±13% pred, body mass index 26.9±4.5 kg/m²) aged 20-80 years; representing both sexes; with the ability to understand and perform all proposed assessments; and with no severe and/or unstable condition that could limit functional assessments occurred simultaneously in all centers.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

All participants randomly performed the following 7 functional tests twice: (1) the 4-meter gait speed test at usual walking speed; (2) the 4-meter gait speed test at maximal walking speed; (3) the Sit-to-Stand test performed with 5 repetitions; (4) the Sit-to-Stand test performed in 30 seconds; (5) the Sit-to-Stand test performed in 1 minute; (6) the Timed Up and Go test at usual speed; and (7) the Timed Up and Go test at maximal speed. Spirometry, quality of life, depression, anxiety, physical activity, and comorbidities were also assessed to better characterize the sample. The best performance of each test was used to propose reference values for men and women and reference equations for all.

RESULTS

Participants similarly distributed by age groups from the 4 centers were included. All tests were correlated with age (0.34<r<0.53) and body mass index (0.24<r< 0.31; P<.05 for all). Reference values with limits of normality were provided by each 10-year age group and regression models identified reference equations for all tests. Reliability of the reference equations were confirmed in an independent sample.

CONCLUSIONS

Reference values and equations for 7 widely used simple functional tests were provided in this study and might help researchers and clinicians to identify and quantify functional impairments using easy-to-perform assessments.

Phenotypic Clustering in Non-Cystic Fibrosis Bronchiectasis Patients: The Role of Eosinophils in Disease Severity

Whether high blood eosinophil counts may define a better phenotype in bronchiectasis patients, as shown in chronic obstructive pulmonary disease (COPD), remains to be investigated. Differential phenotypic characteristics according to eosinophil counts were assessed using a biostatistical approach in a large cohort study from the Spanish Online Bronchiectasis Registry (RIBRON). The 906 patients who met the inclusion criteria were clustered into two groups on the basis of their eosinophil levels. The potential differences according to the bronchiectasis severity index (BSI) score between two groups (Mann–Whitney U test and eosinophil count threshold: 100 cells/µL) showed the most balanced cluster sizes: above-threshold and below-threshold groups. Patients above the threshold exhibited significantly better clinical outcomes, lung function, and nutritional status, while showing lower systemic inflammation levels. The proportion of patients with mild disease was higher in the above-threshold group, while the below-threshold patients were more severe. Two distinct clinical phenotypes of stable patients with non-cystic fibrosis (CF) bronchiectasis of a wide range of disease severity were established on the basis of blood eosinophil counts using a biostatistical approach. Patients classified within the above-threshold cluster were those exhibiting a mild disease, significantly better clinical outcomes, lung function, and nutritional status while showing lower systemic inflammatory levels. These results will contribute to better characterizing bronchiectasis patients into phenotypic profiles with their clinical implications.

Association Between Non-Cystic Fibrosis Bronchiectasis and Quality of Life: A Single-Center Cross-Sectional Study

Introduction

Bronchiectasis is a chronic respiratory disease that can affect patients of all ages and significantly impact the quality of life (QOL) in patients who suffer from it. In spite of its widespread prevalence, and the significant impact on QOL, data on the quantitative impact of bronchiectasis on QOL is lacking. The Quality of Life-Bronchiectasis (QOL-B) is a self-administered patient-reported outcome measure, that was recently developed as a response to the emergent need for such measurement tools to study the impact of bronchiectasis on QOL.

Methods

We conducted a single-center cross-sectional study to study the correlation between QOL and various other outcome parameters such as exercise capacity, lung functions, co-morbidities, inflammatory markers, and body mass index (BMI). The secondary outcome was to find out various determinants of quality of life in non-cystic fibrosis bronchiectasis (NCFB).

Results

Forty-four patients who determined the pre-determined criteria for NCFB were enrolled in this study. This study demonstrated a significant impact on the QOL of NCFB patients based on the QOL-B scoring system. Almost all domains of QOL-B were found to be adversely impacted as measured by one or more of the outcome parameters but the FEV1, age, colonization, extension, dyspnea (FACED) score, bronchiectasis severity index (BSI) score, six-minute walk test (6MWD), and FEV1 showed associations across most scales while the other outcome parameters showed varying associations.

Conclusions

The QOL is significantly reduced in NCFB and it may be quantified using the QOL-B questionnaire. The impact on QOL in NCFB may be assessed using validated tools such as the FACED and BSI scoring systems, as well as other well-established outcome parameters like 6MWD and FEV1 predicted.

Cardiorespiratory coupling is associated with exercise capacity in patients with chronic obstructive pulmonary disease

Background

The interaction between the pulmonary function and cardiovascular mechanics is a crucial issue, particularly when treating patients with chronic obstructive pulmonary disease (COPD). Synchrogram index is a new parameter that can quantify this interaction and has the potential to apply in COPD patients. Our objective in this study was to characterize cardiorespiratory interactions in terms of cardiorespiratory coupling (CRC) using the synchrogram index of the heart rate and respiratory flow signals in patients with chronic obstructive pulmonary disease.

Methods

This is a cross-sectional and preliminary data from a prospective study, which examines 55 COPD patients. K-means clustering analysis was applied to cluster COPD patients based on the synchrogram index. Linear regression and multivariable regression analysis were used to determine the correlation between the synchrogram index and the exercise capacity assessed by a six-minute walking test (6MWT).

Results

The 55 COPD patients were separated into a synchronized group (median 0.89 (0.64–0.97), n = 43) and a desynchronized group (median 0.23 (0.02–0.51), n = 12) based on K-means clustering analysis. Synchrogram index was correlated significantly with six minutes walking distance (r = 0.42, p = 0.001) and distance saturation product (r = 0.41, p = 0.001) assessed by 6MWT, and still was an independent variable by multivariable regression analysis.

Conclusion

This is the first result studying the heart–lung interaction in terms of cardiorespiratory coupling in COPD patients by the synchrogram index, and COPD patients are clustered into synchronized and desynchronized groups. Cardiorespiratory coupling is associated with exercise capacity in patients with COPD.

Clinical Determinants of the Six-Minute Walk Test (6MWT) in Stable Non-Cystic Fibrosis Bronchiectasis Patients

BACKGROUND

The six-minute walk test (6MWT) is a suitable tool for the assessment of functional capacity in patients with chronic pulmonary diseases. This study aimed to assess the clinical determinants of the six-minute walk distance (6MWD), exercise-induced desaturation (EID), and pretest saturation of arterial oxygen (Sat_aO₂) in patients with diffuse non-cystic fibrosis (CF) bronchiectasis.

MATERIALS AND METHODS

In this cross-sectional study, a total of 57 clinically stable patients with diffuse non-CF bronchiectasis were enrolled. Anthropometric measurements (body mass index [BMI], mid-arm muscle circumference [MAMC], and triceps skinfold thickness [TSF]), spirometric indices (forced expiratory volume in one second [FEV1], forced vital capacity [FVC], and FEV1/FVC ratio), imaging assessment (CT scan), and bacteriological sputum studies were performed, and then, 6MWT was carried out.

RESULTS

The mean 6MWD was measured to be 447.11±94.59 m. The average walked distance in patients with severe, moderate, and mild bronchiectasis was 427.73±92.07, 439.63±102.65, and 485.87±80.47 m, respectively, with no significant difference. The pretest Sat_aO₂ was 88.92±5.59%, 93.75±3.36%, and 94.87±2.88% in the severe, moderate, and mild bronchiectasis groups (P<0.001). A significant inverse correlation was observed between the distance walked and BMI (r=-0.434, P=0.001).

CONCLUSION

The predictors of 6MWD in stable non-CF bronchiectasis patients were FVC, Sat_aO₂ at rest, BMI, and MAMC. The FEV1, FEV1/FVC, and BMI were independent predictors of Sat_aO₂ at rest. The extension of bronchiectasis was the only predictor of EID during the test.

Factors Associated with Exercise-Induced Desaturation in Patients with Chronic Obstructive Pulmonary Disease

Purpose

The 6-min walk test (6MWT) is a useful tool to assess the physiologic function in patients with chronic obstructive pulmonary disease (COPD). The recent study showed that patients with COPD with oxygen desaturation during the 6MWT had an increased risk of exacerbation and death compared with those without oxygen desaturation. This study aimed to explore the potential risk factors for exercise-induced desaturation (EID) in patients with COPD.

Patients and Methods

Adult patients with COPD were enrolled from the Chang Gung Research Database between January 2013 and January 2017. Age, sex, body mass index, underlying diseases, medications, and results of the pulmonary function tests and 6MWT were retrospectively collected and analyzed.

Results

Among 1768 patients with COPD, 932 (52.7%) had oxygen desaturation, and the other 836 (47.3%) had no desaturation during the 6MWT. The patients with EID had a shorter 6-min walk distance than those without desaturation (352.08±120.29 vs 426.56±112.56, p<0.0001). In the multivariate logistic regression analysis, older age, female sex, lower forced expiratory volume in 1 s, and comorbidity with atrial fibrillation (AF) were associated with oxygen desaturation during the 6MWT. Patients with EID had higher exacerbation frequency than those without desaturation in the 1-year follow-up period (0.59±1.50 vs 0.34±1.26, p<0.0001). Patients with COPD with AF also had a higher rate of exacerbation requiring emergency department visit or hospitalization in the 1-year follow-up.

Conclusion

This study demonstrates that older age, low FEV1, and female sex are risk factors for EID. Desaturation during 6MWT is related to frequent acute exacerbation of COPD in the 1-year follow-up.

Prognostic ability of the distance-saturation product in the 6-minute walk test in patients with chronic obstructive pulmonary disease

INTRODUCTION

The product (DSP) of the distance walked (meters) and minimum oxygen saturation obtained during the 6-minute walk test (6MWT) has been proposed as a predictor of mortality in idiopathic pulmonary fibrosis and in bronchiectasis not related to cystic fibrosis.

OBJECTIVE

The aim of this study was to determine the DSP's ability to predict mortality in patients with chronic obstructive pulmonary disease (COPD) at the outpatient level and compare it to the BODE index and meters walked in the 6MWT.

MATERIAL AND METHODS

Descriptive observational study in a cohort of patients with COPD being treated at outpatient pulmonology clinics. Each of the patients completed the 6MWT following ATS/ERS protocols and their BODE index and DSP were calculated.

RESULTS

About 103 patients were included. The average length of follow-up was 36 months. Patients who died showed a lower number of meters walked in the 6MWT (P < 0.001), as well as a lower DSP (P < 0.001). A 6MWT < 334 m, a DSP < 290 and a BODE ≥ 4 showed good prognostic ability at 3 years (AUC 71%, 69% and 70.4%, respectively). The 6MWT was superior to the BODE index in predicting mortality during the first year of follow-up (P = 0.023). We did not find any differences between DSP and meters walked in the 6MWT.

CONCLUSIONS

The DSP is a good predictor of mortality, although it does not offer a better prognostic ability than that of meters walked in the 6MWT.

Maintenance Negative Pressure Ventilation Improves Survival in COPD Patients with Exercise Desaturation

Negative pressure ventilation (NPV), when used as an adjuvant to pulmonary rehabilitation, improves lung function, increases exercise capacity, and reduces exacerbations. The aim of this study was to determine whether maintenance NPV improves long-term clinical outcomes and reduces mortality in patients with chronic obstructive pulmonary disease (COPD). Between 2003 and 2009, 341 patients were treated for COPD either with or without hospital-based NPV. We measured forced expiratory volume in one second (FEV₁), 6-min walking distance (6MWD), and oxygen saturation by pulse oximetry (SpO₂) during a 6-min walk test (6MWT) every 3–6 months. Desaturation (D) during the 6MWT was defined as a reduction in SpO₂ of ≥10% from baseline. The NPV group had a better survival outcome than the Non-NPV group. The 8-year survival probabilities for the NPV and Non-NPV groups were 60% and 20%, respectively (p < 0.01). Baseline desaturation was a significant risk factor for death, and the risk of death increased with desaturation severity (SpO₂ 80~89: hazard ratios (HR) 2.7, 95% confidence interval (CI) 1.4–5.3; SpO₂ < 80: HR 3.1, 95% CI 1.3–7.4). The NPV group had a slower decline in lung function and 6MWD. The NPV + D and Non-NPV+D had a threefold and fourfold increase in the risks of all-cause mortality compared with the NPV-ND, respectively. Maintenance non-invasive NPV reduced long-term mortality in COPD patients. The desaturating COPD patients had an increased mortality risk compared with non-desaturating COPD patients.

Oxygen desaturation during the 6-min walk test as a risk for osteoporosis in non-cystic fibrosis bronchiectasis

BACKGROUND

Osteoporosis is a common comorbidity in non-cystic fibrosis (non-CF) bronchiectasis patients. We determined whether desaturation during 6-min walk test (6MWT) can be a predictor for osteoporosis risk.

METHODS

This was a retrospective cross-sectional study. Sixty-six non-CF bronchiectasis patients were enrolled. Lung function, walking distance, the lowest oxygen saturation (SpO₂), the fall in SpO₂ (ΔSpO₂), and the distance-saturation product (DSP) were determined during the 6MWT. Desaturators (n = 45) were defined as those with ΔSpO₂ > 10% or the lowest SpO₂ < 88%. Bone mineral density (BMD) was determined through dual-energy X-ray absorptiometry. The severity of non-CF bronchiectasis was evaluated using high-resolution computed tomography.

RESULTS

Osteoporosis was evident in more desaturators (82%) than non-desaturators (43%, p < 0.01). BMD at the level of the femoral neck was significantly lower in desaturators than in non-desaturators (- 3.6 ± 1.1 vs. - 2.4 ± 0.9, p < 0.01). BMD was correlated positively with the lowest SpO₂ and negatively with ΔSpO₂ and severe exacerbations. In multivariate linear regression analysis, desaturation during 6MWT was the most significant predictive factor for osteoporosis (95% confidence interval - 1.60 to - 0.26, p = 0.01). Other risk factors included old age, low body mass index and severe exacerbation.

CONCLUSIONS

Exertional desaturation during the 6MWT was a significant predictive factor for osteoporosis in Asian non-CF bronchiectasis patients. The 6MWT may be useful in identifying the osteoporotic phenotype of non-CF bronchiectasis and increasing clinician awareness to promote early intervention.

Cardiorespiratory Responses to Glittre ADL Test in Bronchiectasis: A Cross-Sectional Study

Background

Bronchiectasis is a chronic respiratory condition characterised by chronic sputum production, fatigue, and dyspnoea. These symptoms will lead to reduced exercise capacity and a reduced ability to carry out activities of daily living. Glittre ADL test is a valid and reliable test which evaluates the activities of daily living.

Aim

To investigate whether the Glittre ADL test can differentiate the functional capacity and cardiorespiratory responses of patients with bronchiectasis from those healthy individuals using the six-minute test as a functional performance standard.

Methods

This study included 30 subjects: 15 bronchiectasis and 15 age- and gender-matched healthy subjects. The patients and healthy subjects were made to perform the Glittre ADL and six-minute test on two consecutive days. Parameters such as time taken, distance walked, HR, RR, SpO₂, and dyspnoea were recorded before and after the tests.

Results

The performance of bronchiectasis was worse than the healthy group on the Glittre ADL test (4.78 ± 1.33 min, 3.94 ± 0.82 min, p=0.04). Distance walked in the six-minute walk test by the bronchiectasis was 42 meters lesser than the healthy (400.33 ± 77.99, 442 ± 89.21, p=0.18). The Glittre ADL test was correlated with 6MWT when the total sample was analysed (r=−0.41, p=0.05). There was moderate positive correlation between heart rate variation, dyspnoea, respiratory rate, and peripheral saturation (SpO₂) between the tests (Glittre heart rate versus six-minute walk test heart rate (r=0.55, p=0.001); Glittre (Borg) versus six-minute walk test (Borg) (r=0.72, p=0.00); Glittre respiratory rate versus six-minute walk test RR (r=0.62, p=0.00); Glittre SpO₂ versus six-minute walk test SpO₂ (r=0.40, p=0.02)). The bronchiectasis group had a statistically significant higher (p=0.08, p=0.46) increase in dyspnoea and RR than the controls in both the Glittre ADL test and six-minute walk test (p=0.009, p=0.03), with the similar HR variation in both the groups (p > 0.05). There was statistical difference in peripheral oxygen saturation in bronchiectasis in the six-minute walk test (p=0.03).

Conclusion

The Glittre ADL test induced similar cardiorespiratory responses when compared to the six-minute walk test. So, the Glittre ADL test can be used as an assessment tool besides the six-minute walk test for the more complete evaluation of functional capacity and activities of daily living.

Paediatric and adult bronchiectasis: Monitoring, cross-infection, role of multidisciplinary teams and self-management plans

Bronchiectasis is a chronic lung disease associated with structurally abnormal bronchi, clinically manifested by a persistent wet/productive cough, airway infections and recurrent exacerbations. Early identification and treatment of acute exacerbations is an integral part of monitoring and annual review, in both adults and children, to minimize further damage due to infection and inflammation. Common modalities used to monitor disease progression include clinical signs and symptoms, frequency of exacerbations and/or number of hospital admissions, lung function (forced expiratory volume in 1 s (FEV₁ )% predicted), imaging (radiological severity of disease) and sputum microbiology (chronic infection with Pseudomonas aeruginosa). There is good evidence that these monitoring tools can be used to accurately assess severity of disease and predict prognosis in terms of mortality and future hospitalization. Other tools that are currently used in research settings such as health-related quality of life (QoL) questionnaires, magnetic resonance imaging and lung clearance index can be burdensome and require additional expertise or resource, which limits their use in clinical practice. Studies have demonstrated that cross-infection, especially with P. aeruginosa between patients with bronchiectasis is possible but infrequent. This should not limit participation of patients in group activities such as pulmonary rehabilitation, and simple infection control measures should be carried out to limit the risk of cross-transmission. A multidisciplinary approach to care which includes respiratory physicians, chest physiotherapists, nurse specialists and other allied health professionals are vital in providing holistic care. Patient education and personalized self-management plans are also important despite limited evidence it improves QoL or frequency of exacerbations.

Fatigue in Chronic Respiratory Diseases: Theoretical Framework and Implications For Real-Life Performance and Rehabilitation

Fatigue is a primary disabling symptom in chronic respiratory diseases (CRD) with major clinical implications. However, fatigue is not yet sufficiently explored and is still poorly understood in CRD, making this symptom underdiagnosed and undertreated in these populations. Fatigue is a dynamic phenomenon, particularly in such evolving diseases punctuated by acute events which can, alone or in combination, modulate the degree of fatigue experienced by the patients. This review supports a comprehensive inter-disciplinary approach of CRD-related fatigue and emphasizes the need to consider both its performance and perceived components. Most studies in CRD evaluated perceived fatigue as a trait characteristic using multidimensional scales, providing precious information about its prevalence and clinical impact. However, these scales are not adapted to understand the complex dynamics of fatigue in real-life settings and should be augmented with ecological assessment of fatigue. The state level of fatigue must also be considered during physical tasks as severe fatigue can emerge rapidly during exercise. CRD patients exhibit alterations in both peripheral and central nervous systems and these abnormalities can be exacerbated during exercise. Laboratory tests are necessary to provide mechanistic insights into how and why fatigue develops during exercise in CRD. A better knowledge of the neurophysiological mechanisms underlying perceived and performance fatigability and their influence on real-life performance will enable the development of new individualized countermeasures. This review aims first to shed light on the terminology of fatigue and then critically considers the contemporary models of fatigue and their relevance in the particular context of CRD. This article then briefly reports the prevalence and clinical consequences of fatigue in CRD and discusses the strengths and weaknesses of various fatigue scales. This review also provides several arguments to select the ideal test of performance fatigability in CRD and to translate the mechanistic laboratory findings into the clinical practice and real-world performance. Finally, this article discusses the dose-response relationship to training and the feasibility and validity of using the fatigue produced during exercise training sessions in CRD to optimize exercise training efficiency. Methodological concerns, examples of applications in selected diseases and avenues for future research are also provided.