Physiological and clinical characteristics of patients with COPD admitted to an inpatient pulmonary rehabilitation program: A real-life study

Sleep disordered breathing: OSA-COPD overlap

INTRODUCTION

Sleep has important effects on breathing and gas exchange that may have negative consequences in patients with chronic obstructive pulmonary disease (COPD). COPD and obstructive sleep apnea (OSA) are highly prevalent and may coexist, which is referred to as the overlap syndrome.

AREAS COVERED

The probability of OSA-COPD overlap represents the balance of protective and promoting factors such as hyperinflation and fluid retention; thus, different clinical COPD phenotypes influence the likelihood of comorbid OSA. The clinical presentation of OSA-COPD overlap is nonspecific, and the diagnosis requires clinical awareness to identify patients needing overnight studies. Both COPD and OSA are associated with a range of overlapping physiological and biological disturbances including hypoxia and inflammation that contribute to cardiovascular comorbidities. The management of OSA-COPD overlap patients differs from those with COPD alone and the survival of overlap patients treated with positive airway pressure (PAP) is superior to those untreated.

EXPERT OPINION

The recognition of OSA-COPD overlap has important clinical relevance because of its impact on outcomes and management. Management of the overlap should address both sleep quality and disordered gas exchange. PAP therapy has demonstrated reductions in COPD exacerbations, hospitalizations, healthcare costs and mortality in overlap patients.

Functional capacity using sit-to-stand tests in people with chronic obstructive pulmonary disease and its relationship with disease severity-a cross-sectional study with matched controls

BACKGROUND

Functional capacity impairment is a crucial consequence of chronic obstructive pulmonary disease (COPD). Although it can be identified with simple tests, such as the sit-to-stand tests, its prevalence, relation with disease severity, and the characteristics of people presenting this impairment remain unknown.

OBJECTIVE

To explore the functional capacity of people with COPD.

METHODS

A cross-sectional study with people with COPD and age-/sex-matched healthy controls was conducted. Functional capacity was assessed with the 5-repetitions (5-STS) and the 1-minute (1-minSTS) sit-to-stand tests. People with COPD were grouped according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classifications. Comparisons between people with COPD and healthy controls, and among GOLD groups were established. Associations between symptoms, muscle strength, quality of life, and measures of functional capacity were explored.

RESULTS

302 people with COPD [79% male; mean (SD) 68 (10) years old] and 304 healthy controls [75% male; 66 (9) years old] were included. 23% of people with COPD presented impairment in the 5-STS and 33% in the 1-minSTS. People with COPD from all GOLD classifications presented significantly lower functional capacity than healthy controls (5-STS: COPD median [1st quartile; 3rd quartile] 8.4 [6.7; 10.6] versus healthy 7.4 [6.2; 9.3] s; 1-minSTS: COPD 27 [21; 35] vs healthy 35 [29; 43] reps). Correlations with symptoms, muscle strength, and quality of life were mostly weak (5-STS: rs [-0.34; 0.33]; 1-minSTS: rs [-0.47; 0.40]).

CONCLUSION

People with COPD have decreased functional capacity independently of their GOLD classifications. The prevalence of functional impairment is 23-33%. Because impaired functional capacity is a treatable trait not accurately reflected by other outcomes, comprehensive assessment and management is needed.

Airflow grades, outcome measures and response to pulmonary rehabilitation in individuals after an exacerbation of severe chronic obstructive pulmonary disease

BACKGROUND

Individuals with COPD may be staged according to symptoms and exacerbation history (GOLD groups: A-D) and on airflow obstruction (GOLD grades: 1-4). Guidelines recommend pulmonary rehabilitation (PR) for these individuals, including those recovering from an exacerbation (ECOPD) OBJECTIVE: To evaluate whether in individuals with clinically severe COPD, recovering from an ECOPD, the effect size of an in-hospital PR program would be affected by airflow severity grades and assessed outcome measures.

METHODS

Retrospective, multicentre study. Participants were compared according to different GOLD airflow grades. In addition to the MRC dyspnoea scale, six-minute walking distance test and COPD assessment test (CAT), Barthel dyspnoea index (Bid), and Short Physical Performance Battery (SPPB) were assessed, evaluating the proportion of individuals reaching the minimum clinically important difference (MCID) (responders).

RESULTS

Data of 479 individuals, completing the program were evaluated. Most of the participants were allocated in GOLD grades 4, (57.6%) and 3 (22.1%). All outcome measures significantly improved after PR (p < 0.05), without any significant difference in the proportion of responders in any measure.

CONCLUSIONS

in individuals with severe COPD, recovering from ECOPD the success rate of PR does not depend on airflow severity, or outcome measure assessed. In addition to the most used outcome measures, also Bid and SPPB are sensitive to PR.

Effect of pulmonary rehabilitation on heart rate recovery in adult individuals with asthma or chronic obstructive pulmonary disease

Introduction: Heart rate recovery (HRR) after exercise is a marker of disease severity and prognosis in cardiovascular and respiratory disorders. More than 30% of adult individuals with asthma may show a slow HRR. Pulmonary rehabilitation improves exercise capacity in individuals with asthma or chronic obstructive pulmonary disease (COPD).

Aim: The study aimed to evaluate the effect of pulmonary rehabilitation on HRR in individuals with asthma as compared to those with COPD.

Methods: Retrospective analysis of HRR one minute after the six-minute walking test (6MWT) was performed before and after an exercise training program. The COPD Assessment Test (CAT), Barthel Index-Dyspnea (BI-D), Medical Research Council (MRC) score for dyspnea, and the Five-Times-Sit-to-Stand test (5STS) were also assessed as secondary outcome measures.

Results: Slow HRR prevalence was significantly lower in individuals with asthma than with COPD (29.1 vs. 46.7%, respectively: p = 0.003). Post-program HRR did not change in more than 70% of individuals in either population and improved in 16% of both populations, whereas it actually worsened in 12 and 10% of individuals with asthma and COPD, respectively. The outcome measures significantly improved in both populations, irrespective of baseline HRR.

Conclusion: In individuals with asthma or COPD, exercise training does not significantly improve HRR.

Heart rate recovery in adult individuals with asthma

Slow heart rate recovery (HRR) after exercise is a predictor of overall mortality in individuals with and without cardiovascular or respiratory disorders. No data on adults with asthma are available. The purpose of the study is to evaluate the prevalence of slow HRR in these individuals as compared with those with chronic obstructive pulmonary disease (COPD). We performed a retrospective analysis of baseline characteristics and physiological response to the six-minute walking distance test of stable individuals with asthma or COPD. Slow HRR was defined as HRpeak - HR at 1 minute after end exercise <12 bpm. Individuals with asthma walked significantly longer (median (IQR): 455 (385-512) vs 427 (345-485) meters; p=0.005) with a lower prevalence of slow HRR (30.3% vs 49.0%, respectively: p<0.001) than those with COPD. Individuals with asthma and slow HRR were older and walked less than those with normal HRR, without any difference in airway obstruction or in disease severity. Multivariate analysis showed that only the difference HRpeak - baseline HR (∆HR), was a predictor of slow HRR in both groups. More than 30% of adult individuals with asthma may show slow HRR. Only exercise ∆HR but no baseline characteristic seems to predict the occurrence of slow HRR.

Respiratory rehabilitation for patients with COVID-19 infection and chronic respiratory failure: a real-life retrospective study by a Lombard network

The Lombardy region has been one of the areas most affected by the COVID-19 pandemic since the first months of 2020, providing real-life experiences in the acute phase. It is unclear how the respiratory rehabilitation network responded to this emergency. The aims of this retrospective study were: i) to analyze clinical, functional, and disability data at admission; ii) describe assessment tools and rehabilitative programs; iii) evaluate improvement after rehabilitation. The study was conducted on data collected from ten pulmonary rehabilitation centers in Lombardy, between the period of March 1st 2020 to March 1st 2021, in patients with respiratory failure recovering from COVID-19 both at admission and discharge. The study included demographics, comorbidities, nutritional status, risk of falls, disability status (Barthel index; Short Physical Performance Battery (SPPB); 6 minutes walking test (6MWT), symptoms (dyspnoea with Barthel Dyspnoea and MRC Dyspnoea Scale), length of stay, discharge destination, need for mechanical ventilation, respiratory function, assessment/outcomes indices, and prescribed rehabilitative programs. 413 patients were analyzed. Length of stay in acute and rehabilitative units was less than 30 days. Fifty % of patients used non-invasive ventilation during their stay. Functional status was mildly compromised for forced volumes and oxygenation, while severely compromised for diffusion capacity. Independency was low while physical performance status very low.  At discharge, 318 (77%) patients were sent home, 83 (20.1%) were transferred to an acute unit and 12 (2.9%) passed away. Barthel Index and 6MWT were the most used, while MRC score was the least used outcome parameter. The 5 main rehabilitative activities were walking (90.8 %), transfer from bed to armchair (77.5%), limb mobilization in bed (76%), balance (71.2%), and cycle-ergometer or treadmill (43.1%). A huge difference was found in admission, discharge, and delta change among different rehabilitative centers. When available, all outcomes showed a significant improvement. With the limitation of a retrospective study with a clear amount of missing data, COVID-19 subjects admitted to rehabilitative centers presented a reduced physical performance, symptoms of dyspnoea, and severe disability. The 6MWT and Barthel index were the most used measurement.

Clusters of Survivors of COVID-19 Associated Acute Respiratory Failure According to Response to Exercise

COVID-19 survivors are associated with acute respiratory failure (ARF) and show a high prevalence of impairment in physical performance. The present studied aimed to assess whether we may cluster these individuals according to an exercise test. The presented study is a retrospective analysis of 154 survivors who were admitted to two hospitals of Istituti Clinici Scientifici Maugeri network, Italy. Clinical characteristics, walked distance, heart rate (HR), pulse oximetry (SpO₂), dyspnoea, and leg fatigue (Borg scale: Borg-D and Borg-F, respectively) while performing the six-minute walking test (6MWT) were entered into unsupervised clustering analysis. Multivariate linear regression identified variables that were informative for the set of variables used for cluster definition. Cluster 1 (C1: 86.4% of participants) and Cluster 2 (C2: 13.6%) were identified. Compared to C1, the individuals in C2 were significantly older, showed significantly higher increase in fatigue and in dyspnoea, greater reduction in SpO₂, and a lower HR_peak during the test. The need of walking aids, time from admission to acute care hospitals, age, body mass index, endotracheal intubation, baseline HR and baseline Borg-D, and exercise-induced SpO₂ change were significantly associated with the variables that were used for cluster definition. Different characteristics and physiological parameters during the 6MWT characterise survivors of COVID-19-associated ARF. These results may help in the management of the long-term effects of the disease.

Time course of exercise capacity in patients recovering from COVID-19-associated pneumonia

Objective:

High prevalences of muscle weakness and impaired physical performance in hospitalized patients recovering from COVID-19-associated pneumonia have been reported. Our objective was to determine whether the level of exercise capacity after discharge would affect long-term functional outcomes in these patients.

Methods:

From three to five weeks after discharge from acute care hospitals (T₀), patients underwent a six-minute walk test (6MWT) and were divided into two groups according to the distance walked in percentage of predicted values: <75% group and ≥75% group. At T₀ and three months later (T₁), patients completed the Short Physical Performance Battery and the Euro Quality of Life Visual Analogue Scale, and pulmonary function and respiratory muscle function were assessed. In addition, a repeat 6MWT was also performed at T₁.

Results:

At T₀, 6MWD values and Short Physical Performance Battery scores were lower in the <75% group than in the ≥75% group. No differences were found in the Euro Quality of Life Visual Analogue Scale scores, pulmonary function variables, respiratory muscle function variables, length of hospital stay, or previous treatment. At T₁, both groups improved their exercise capacity, but only the subjects in the <75% group showed significant improvements in dyspnea and lower extremity function. Exercise capacity and functional status values returned to predicted values in all of the patients in both groups.

Conclusions:

Four weeks after discharge, COVID-19 survivors with exercise limitation showed no significant differences in physiological or clinical characteristics or in perceived health status when compared with patients without exercise limitation. Three months later, those patients recovered their exercise capacity.

Exercise capacity and comorbidities in patients with obstructive sleep apnea

STUDY OBJECTIVES

There are few studies evaluating (1) exercise capacity as assessed by the 6-minute walking distance (6MWD) test in large populations with obstructive sleep apnea (OSA); and (2) correlations with patients' comorbidities.

METHODS

This study presents a cluster analysis performed on the data of 1,228 patients. Severity of exercise limitation was defined on the basis of 6MWD.

RESULTS

Sixty-one percent showed exercise limitation (29.2% and 31.9% mild and severe exercise limitation, respectively). About 60% and 40% of patients were included in cluster 1 (CL1) and 2 (CL2), respectively. CL1 included younger patients with high prevalence of apneas, desaturations, and hypertension with better exercise tolerance. CL2 included older patients, all with chronic obstructive pulmonary disease (COPD), high prevalence of chronic respiratory failure (CRF), fewer apneas but severe mean desaturation, daytime hypoxemia, more severe exercise limitation, and exercise-induced desaturations. Only CRF and COPD significantly (P < .001) correlated with 6MWD < 85% of predicted value. 6MWD correlated positively with apnea-hypopnea index, oxygen desaturation index, nocturnal pulse oxygen saturation (SpO₂), resting arterial oxygen tension, mean SpO₂ on exercise, and negatively with age, body mass index, time spent during night with SpO₂ < 90%, mean nocturnal desaturation, arterial carbon dioxide tension, and number of comorbidities. Patients without severe comorbidities had higher exercise capacity than those with severe comorbidities, (P < .001). Exercise limitation was significantly worse in OSA severity class I when compared to other classes (P < .001).

CONCLUSIONS

A large number of patients with OSA experience exercise limitation. Older age, comorbidities such as COPD and CRF, OSA severity class I, severe mean nocturnal desaturation, and daytime hypoxemia are associated with worse exercise tolerance.

The respiratory rehabilitation Maugeri network service reconfiguration after 1 year of COVID-19

As part of the Italian Health Service the respiratory ICS Maugeri network were reconfigured and several in-hospital programs were suspended to be substituted by workforce and facilities reorganization for acute and post-acute COVID-19 care need. The present review shows the time course variation of respiratory ICS network in terms of admissions diagnosis and outcomes. A comparative review of the admissions and outcome measures data (anthropometric, admission diagnosis, provenience, comorbidities, disability, symptoms, effort tolerance, disease impact, length of stay and discharge destinations) over 1 year period (March 2020-March 2021) was undertaken and compared to retrospective data from a corresponding 1 year (March 2019-March 2020) period to determine the impact of the network relocation on the delivery of pulmonary specialist rehabilitation to patients with complex needs during the pandemic episode. One of the changes implemented at the respiratory Maugeri network was the relocation of the Pulmonary Rehabilitation units from its 351 beds base to a repurposed 247 beds and a reduction in total number of admitted patients (n=3912 in pre-COVID time; n=2089 in post COVID time). All respiratory diagnosis, except COVID sequelae, decreased (chronic respiratory failure-CRF, COPD, obstructive sleep apnoea syndrome-OSAS, interstitial lung disease-ILD, tracheostomized patients and other mixed diseases decreased of 734, 705, 157, 87, 79 and 326 units respectively). During the pandemic time, 265 post COVID sequelae with CRF were admitted for rehabilitation (12.62%), % of patients coming from acute hospital increased, LOS and NIV use remained stable while CPAP indication decreased. Disease impact, dyspnea and effort tolerance as their improvements after rehabilitation, were similar in the two periods.  Only baseline disability, expressed by Barthel index, seems higher in the 2° observation time as its improvement. Hospital deaths and transfers to acute hospitals were higher during pandemic crisis while home destination decreased. This review demonstrated impact of coronavirus pandemic situation, specifically the relocation of the respiratory inpatient rehabilitation wards in a huge Italian network.

Pulmonary rehabilitation in patients with interstitial lung diseases: Correlates of success

BACKGROUND AND AIM

Benefits of pulmonary rehabilitation in Interstitial Lung Diseases (ILD) have been reported. The aim of this large multicenter study was to identify the success predictors of pulmonary rehabilitation in a real-life setting.

METHODS

Data of 240 in-patients (110 idiopathic pulmonary fibrosis (IPF), 106 ILD other than IPF and 24 undetermined ILD) undergoing pulmonary rehabilitation in a 10-year period were retrospectively evaluated. Six minute walking distance (6MWT), body weight-walking distance product tests, dyspnoea and arterial blood gases were assessed at admission and discharge. Differences in post rehabilitation changes in outcome measures as function of baseline characteristics were evaluated.

RESULTS

After rehabilitation, patients showed improvements in all outcome measures (p < 0.05), regardless of the underlying diagnosis or disease severity. Patients needing oxygen therapy at rest showed reduced benefits. Baseline 6MWD inversely correlated with its changes at discharge. Non-significant greater benefits after rehabilitation were found in IPF patients under antifibrotic therapy. In a subset of 50 patients assessed on average 10.3 ± 3.5 months after discharge, the benefits in 6MWD were not maintained (312.9 ± 139.4, 369.7 ± 122.5 and 310.8 ± 139.6 m at admission, discharge and follow up respectively: p < 0.0001).

CONCLUSION

Pulmonary rehabilitation may improve dyspnoea, exercise capacity and fatigue in patients with ILD of different aethiologies and level of severity. The long-term effects need to be established.

The severity of acute exacerbations of COPD and the effectiveness of pulmonary rehabilitation

BACKGROUND AND AIM

Pulmonary rehabilitation is effective also in patients recovering from acute exacerbations of COPD (AECOPD). We aimed to evaluate whether levels of dyspnoea affect the outcome of pulmonary rehabilitation in patients recovering from AECOPD requiring different levels of care.

MATERIALS AND METHODS

Retrospective data analysis of 1057 patients recovering from AECOPD requiring either hospital (Hospital group: 291) or home management (Home group: 766), undergone post AECOPD in-patient pulmonary rehabilitation. The 6-min walking distance (6MWD) test was the primary outcome, stratified by the Barthel index Dyspnoea (Bid). Data of modified Medical Research Council scale, Short Physical Performance Battery, COPD Assessment Test were also analysed, when available.

RESULTS

In overall population 6MWD improved significantly from 278 (129) to 335 (139) meters (p < 0.001). As compared to Home, 6MWD improved more in Hospital group [by 81.9 (79.6) vs 48.9 (94.4) meters respectively, p < 0.001] also when stratified by Bid levels (all: p < 0.01). In Hospital group, 6MWD improved significantly more in patients with Bid level 3 than levels 4 and 5 (p < 0.05). Hospital group showed a greater proportion of patients reaching the Minimal Clinically Important Difference for 6MWD (75.9 vs 56.7% in Hospital and Home group respectively p < 0.001). All other available outcome measures significantly (p < 0.01) improved independent of the Bid levels. There was no significant correlation between baseline severity of airflow obstruction and effect of the program.

CONCLUSIONS

In-patient pulmonary rehabilitation results in clinically meaningful improvement in patients recovering from AECOPD, independent of severity of dyspnoea. However, the levels of dyspnoea severity and the care required by AECOPD influenced the magnitude of success.

The Maugeri daily activity profile: a tool to assess physical activity in patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) report reduced physical activity (PA). There are only few tools available to assess PA and sedentary behavior in these patients, and none of them aims to differentiate between sedentary and active patterns. The aim of the study was to evaluate an easy tool to profile daily activity time in a cohort of patients with COPD, compared to healthy subjects; the study was set at the Istituti Clinici Scientifici Maugeri (ICS), IRCCS of Tradate and Lumezzane, Italy, and at the Ente Ospedaliero Cantonale Novaggio, Switzerland (Italian Speaking). The populations were inpatients with COPD, healthy subjects. The items of the Maugeri Daily Activity (MaDA) profile were chosen based on literature, interviews with patients and health professionals. Time spent during sleep (ST), when awake (AT), active (ACT) or in sedentary behavior (SET) were recorded. Lung function tests, arterial blood gases, the modified Medical Research Council (mMRC), the six-minute walking distance test (6MWD), the COPD Assessment Test (CAT), and the body-mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index were also assessed in patients. Sixty patients with COPD and 60 healthy controls filled in the questionnaire. As compared to controls, patients showed longer AT and SET. Active time of patients was significantly correlated with mMRC, CAT, Bode Index and 6MWD, but not with demographics, anthropometrics or stages of disease. Using this tool, we found that patients with COPD spent longer time awake and in sedentary behavior. The MaDA may be useful to evaluate PA in patients with COPD.

Pulmonary Rehabilitation in Patients Recovering from COVID-19

BACKGROUND

In hospitalized patients recovering from the SARS-coronavirus-2 disease 19 (COVID-19), high prevalence of muscle weakness and physical performance impairment has been observed.

OBJECTIVES

The aim of this study was to evaluate the effectiveness of pulmonary rehabilitation in these subjects in a real-life setting.

METHODS

Retrospective data analysis of patients recovering from COVID-19, including those requiring assisted ventilation or oxygen therapy, consecutively admitted to an in-patient pulmonary rehabilitation program between April 1 and August 15, 2020. Short Physical Performance Battery (SPPB: primary outcome), Barthel Index (BI), and six-min walking distance were assessed as outcome measures.

RESULTS

Data of 140 patients were analyzed. After rehabilitation, patients showed improvements in SPPB {from: (median [IQR]) 0.5 (0-7) to 7 (4-10), p < 0.001} and BI (from 55 [30-90] to 95 [65-100], p < 0.001), as well as in other assessed outcome measures. The proportion of patients unable at admission to stand, rise from a chair and walk was significantly reduced (p < 0.00).

CONCLUSIONS

Pulmonary rehabilitation is possible and effective in patients recovering from COVID-19. Our findings may be useful to guide clinicians taking care of patients surviving COVID-19 infection.

Minimal Clinically Important Difference in Barthel Index Dyspnea in Patients with COPD

Background

The Barthel Index dyspnea (BId) is responsive to physiological changes and pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD). However, the minimum clinically important difference (MCID) has not been established yet.

Aim

To identify the MCID of BId in patients with COPD stratified according to the presence of chronic respiratory failure (CRF) or not.

Materials and Methods

Using the Medical Research Council (MRC) score as an anchor, receiver operating characteristic curves and quantile regression were retrospectively evaluated before and after pulmonary rehabilitation in 2327 patients with COPD (1151 of them with CRF).

Results

The median post-rehabilitation changes in BId for all patients were −10 (interquartile range = −17 to −3, p<0.001), correlating significantly with changes in MRC (r = 0.57, 95% CI = 0.53 to 0.59, p<0.001). Comparing different methods of assessment, the MCID ranged from −6.5 to −9 points for patients without and −7.5 to −12 points for patients with CRF.

Conclusion

The most conservative estimate of the MCID is −9 points in patients with COPD, without and −12 in those with CRF. This estimate may be useful in the clinical interpretation of data, particularly in response to intervention studies.

Therapist Driven Rehabilitation Protocol for Patients with Chronic Heart and Lung Diseases: A Real-Life Study

Therapist driven protocols may help to tailor rehabilitation programs to individual patients. We aimed to test the feasibility, safety, and clinical usefulness of a therapist driven protocol for rehabilitation including exercise training of patients with heart or lung diseases. An internal audit elaborated the Cardio-Respiratory Exercise Maugeri Algorithm (CREMA) based on: (a) standardized baseline assessments, (b) decision-making pathways, and (c) frequency/intensity/time/type (FITT) of prescription for each exercise. Outpatients (n = 620) with chronic heart disease (CHD), recent myocardial revascularization (REVASC), chronic airway (Obstructive), and restrictive lung (Restrictive) diseases underwent exercise training according to CREMA during 4 years. Peripheral muscle strengthening was the most prescribed exercise (83.6%), while arm endurance training was the least frequently (0.75%). Exercise prescription varied widely among the disease groups (interval training 19-47%, balance 35-49%, lower limb muscle training 6-15%). After training, REVASC patients were the best improvers in the 6 min walking distance (+48.7 (56.1) m), maximal inspiratory pressure (+9.6 (15.4) cmH2O), and daily steps (+1087.2 (3297.1) n/day). Quadriceps and biceps strength, maximal expiratory pressure, and balance improved in all groups, without significant differences. Minor side effects were observed in 11.2% of the patients. The CREMA therapist driven protocol was feasible, safe, and useful for prescribing tailored training programs. Exercise prescriptions and training response differed among diseases.

Physical Activity in Patients with Chronic Obstructive Pulmonary Disease on Long-Term Oxygen Therapy: A Cross-Sectional Study

Background and aim

There are few studies evaluating physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) on long-term oxygen therapy (LTOT).

Aim

To assess PA in hypoxemic COPD patients on LTOT.

Methods

In this cross-sectional study, we compared lung function, arterial blood gases, respiratory and peripheral muscle strength, 6-min walking distance (6MWD), daily energy expenditure and steps, and health-related quality of life (HRQL) in COPD patients on LTOT (LTOT group) versus two groups of control patients not needing LTOT: with (HYPOX) and without (COPD) exercise-induced desaturations.

Results

Groups did not differ as regards demographics, anthropometrics, peripheral or respiratory muscle strength. Compared to the other groups, LTOT patients had more severe airway obstruction and lung hyperinflation, greater number and severity of comorbidities, shorter 6MWD, as well as lower mean SpO₂ during 6MWD and worse quality of life. LTOT patients had a lower daily energy expenditure, shorter time spent > 3.0 METs and longer sedentary time compared to the COPD group, and less daily steps compared to the other groups. No significant difference in any parameter of PA was found between COPD and HYPOX. In LTOT patients, daily steps showed a strong correlation with 6MWD, and a moderate correlation with airway obstruction, level of oxygenation, comorbidities and quality of life but not with peripheral and respiratory muscle strength. In COPD and HYPOX patients, daily steps were strongly correlated with 6MWD and level of oxygenation as assessed by PaO₂/FiO₂. There was no significant correlation between mean SpO₂ and 6MWD in any group.

Conclusion

COPD patients on LTOT perform less physical activity than patients not needing LTOT, both with and without exercise-induced desaturations. Patients with exercise-induced desaturations do not perform less physical activity than those without.