Effects of Asthma on the Performance of Activities of Daily Living: A Retrospective Study

The study aim was to identify the most problematic self--reported activities of daily living (ADLs). In a retrospective study, 1935 problematic ADLs were reported by 538 clients with 95% experiencing two or more problematic ADLs. Problematic ADLs were assessed by occupational therapists using the Canadian Occupational Performance Measure with walking (67%), household activities (41%), and climbing the stairs (41%) identified as the most prevalent problematic ADLs. Significant but weak associations were found between clinical determinants (e.g. physical, psychosocial) and problematic ADLs. The wide variety of problematic ADLs and the absence of a strong association with clinical determinants emphasizes the need for using individualized interview-based performance measures in clients with asthma.

Treatable traits in advanced emphysema patients eligible for bronchoscopic lung volume reduction with endobronchial valves

INTRODUCTION

Patients with advanced emphysema eligible for bronchoscopic lung volume reduction (BLVR) using endobronchial valves (EBV) are characterized by severe static lung hyperinflation, which can be considered a treatable trait. Other treatable traits (TTs), which are assumed to be present in this highly selected patient group, have not been studied in detail nor how they may affect health-related quality of life (HRQL).

AIMS

We aimed to evaluate a spectrum of TTs in COPD patients eligible for EBV treatment and their association with HRQL.

METHODS

The SoLVE study (NCT03474471) was a prospective multicenter randomized controlled trial to examine the impact of pulmonary rehabilitation in COPD patients receiving EBV. The presence/absence of 16 TTs was based on pre-defined thresholds. HRQL was assessed with the St. George's Respiratory Questionnaire (SGRQ). Subjects were stratified into two groups, using the median split method, into higher or lower SGRQ total score. Logistic regression assessed the odds ratio (OR) of having a higher SGRQ total score per TT.

RESULTS

Ninety-seven subjects were included, the mean number of TTs per patient was 8.1 ± 2.5. Low physical activity (95%), poor exercise capacity (94%) and severe fatigue (75%) were the most prevalent TTs. The sum of TTs present in a subject was associated with the SGRQ total score (r = 0.53; p < 0.001). Severe fatigue, depression, and anxiety were predictors of having a higher SGRQ total score.

CONCLUSIONS

A high prevalence and co-occurrence of multiple TTs were identified in emphysema patients eligible for EBV. Patients with a higher number of TTs were more likely to have worse HRQL.

Fatigue and symptom-based clusters in post COVID-19 patients: a multicentre, prospective, observational cohort study

BACKGROUND

In the Netherlands, the prevalence of post COVID-19 condition is estimated at 12.7% at 90-150 days after SARS-CoV-2 infection. This study aimed to determine the occurrence of fatigue and other symptoms, to assess how many patients meet the Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) criteria, to identify symptom-based clusters within the P4O2 COVID-19 cohort and to compare these clusters with clusters in a ME/CFS cohort.

METHODS

In this multicentre, prospective, observational cohort in the Netherlands, 95 post COVID-19 patients aged 40-65 years were included. Data collection at 3-6 months after infection included demographics, medical history, questionnaires, and a medical examination. Follow-up assessments occurred 9-12 months later, where the same data were collected. Fatigue was determined with the Fatigue Severity Scale (FSS), a score of ≥ 4 means moderate to high fatigue. The frequency and severity of other symptoms and the percentage of patients that meet the ME/CFS criteria were assessed using the DePaul Symptom Questionnaire-2 (DSQ-2). A self-organizing map was used to visualize the clustering of patients based on severity and frequency of 79 symptoms. In a previous study, 337 Dutch ME/CFS patients were clustered based on their symptom scores. The symptom scores of post COVID-19 patients were applied to these clusters to examine whether the same or different clusters were found.

RESULTS

According to the FSS, fatigue was reported by 75.9% of the patients at 3-6 months after infection and by 57.1% of the patients 9-12 months later. Post-exertional malaise, sleep disturbances, pain, and neurocognitive symptoms were also frequently reported, according to the DSQ-2. Over half of the patients (52.7%) met the Fukuda criteria for ME/CFS, while fewer patients met other ME/CFS definitions. Clustering revealed specific symptom patterns and showed that post COVID-19 patients occurred in 11 of the clusters that have been observed in the ME/CFS cohort, where 2 clusters had > 10 patients.

CONCLUSIONS

This study shows persistent fatigue and diverse symptomatology in post COVID-19 patients, up to 12-18 months after SARS-CoV-2 infection. Clustering showed that post COVID-19 patients occurred in 11 of the clusters that have been observed in the ME/CFS cohort.

Baseline dependent minimally important differences for clinical outcomes of pulmonary rehabilitation in people with COPD

INTRODUCTION

Minimally important differences (MIDs) for common outcomes of pulmonary rehabilitation are well documented for people with chronic obstructive pulmonary disease (COPD). It is not known whether MIDs differ based on COPD disease characteristics. This study aimed to estimate MIDs for clinical outcomes of pulmonary rehabilitation dependent upon baseline characteristics.

METHODS

A database containing 2791 people with COPD was split into derivation (n=2245; age 66±9 years; 50% males; FEV1 47±20% predicted) and comparator (n=546; age 66±9 years; 47% males; FEV1 46±21% predicted) cohorts. MIDs were estimated using 0.5 x SD (symmetrically distributed) or 0.5 x IQR (non-symmetrically distributed) for: 6-minute walk test (6MWT), constant work rate test (CWRT), COPD assessment test (CAT), St. George's respiratory questionnaire (SGRQ), hospital anxiety and depression scale (HADS), and fat-free mass index (FFMI). MIDs were estimated based on baseline outcome scores, lung function, modified medical research council (mMRC) grade and FFMI.

RESULTS

MID estimates were comparable to previously reported values. MIDs for SGRQ domains (Symptom=8.7 points, Activity=7.1 points, Impact=8.1 points) and FFMI were produced (0.36kg/m2). There was greater variation of change in 6MWT, SGRQ-activity, SGRQ-impact, HADS and FFMI on which the MIDs were determined when categorising for baseline values (all, p<0.05). Greater variation of change in 6MWT on which the MIDs were determined was evident with COPD disease severity grouping (p<0.05). The magnitude of change in 6MWT, CAT, CWRT, SGRQ-activity, and FFMI with baseline mMRC score categorisation resulted in greater variation on which the MIDs were determined (all, p<0.05). Baseline stratification for FFMI resulted in greater variation of change in CWRT (p<0.001) and HADS-depression (p = 0.043) on which MIDs were determined.

DISCUSSION

Findings suggest that baseline presentation should be considered for people with COPD when assessing the efficacy of pulmonary rehabilitation. However, clinical significance of the variation underpinning MIDs is yet to be determined.

Recent advances in bronchoscopic lung volume reduction for severe COPD patients

PURPOSE OF REVIEW

Bronchoscopic lung volume reduction (BLVR) is a novel and effective treatment for a specific phenotype of chronic obstructive pulmonary disease (COPD) characterized by advanced emphysema with static lung hyperinflation and severe breathlessness. This review aims to provide an overview of the recent advances made in BLVR.

RECENT FINDINGS

For achieving optimal outcomes with BLVR, patient selection and target lobe identification is crucial. BLVR has recently also been established to improve pulmonary function, exercise capacity and quality of life in COPD patients falling outside the standard treatment criteria, including patients with moderate hyperinflation, chronic hypercapnic failure or with very low diffusion capacity. In a cluster analysis, target lobe characteristics like emphysema destruction, air trapping and perfusion were found to be important discriminators between responders and non-responders. A potential survival benefit has been demonstrated in BLVR-treated patients when compared to non-treated patients. Long-term outcomes showed sustained outcomes of BLVR; however, effects decline over time, probably due to disease progression.

SUMMARY

BLVR using one-way endobronchial valves has become a guideline treatment offered in specialized intervention centres for a specific subgroup of COPD patients. Recent studies further characterize responders, describe extrapulmonary effects of BLVR and show positive long-term outcomes and a potential survival benefit.

Test-retest reliability, construct validity and determinants of 6-minute walk test performance in adult patients with asthma

INTRODUCTION AND OBJECTIVES

Current knowledge regarding the measurement properties of the 6-minute walk test (6MWT) in patients with asthma is limited. Therefore, the aim of this study was to assess the test-retest reliability, measurement error and construct validity of the 6MWT and identify determinants of 6-minute walk distance (6MWD) in patients with asthma.

PATIENTS AND METHODS

201 asthma patients referred for pre-pulmonary rehabilitation assessment, were retrospectively analyzed (age 61±12 years, 42% male, FEV1 78±27% predicted). Patients performed two 6MWTs on subsequent days using a 30 m straight walking course. Other measurements included resting dyspnea, maximal exercise capacity, body composition, pulmonary function, pulmonary and quadriceps muscle strength and symptoms of anxiety and depression. Measurement error (absolute reliability) was tested using standard error of measurement (SEM), minimal detectable change at 95% confidence interval (MDC95%) and Bland and Altman 95% limits of agreement, whereas test-retest reliability (relative reliability) and construct validity were assessed using the intra-class correlation coefficient (ICC2,1) and correlations, respectively.

RESULTS

The 6MWD showed excellent test-retest reliability (ICC2,1: 0.91). The mean change in 6MWD after the second 6MWT was 18m (95%CI 11-24m), with 73% of the patients walking further in the second test. The SEM and MDC95% for the 6MWT were 35 m and 98 m, respectively. The best 6MWD correlated strongly with peak oxygen uptake during CPET and resting dyspnea (r = 0.61-0.64) and had no-to-moderate correlations with body composition, pulmonary function, respiratory and quadriceps muscle strength and symptoms of anxiety and depression (r = 0.02-0.45). Multiple linear regression was able to identify maximal workload, BMI, rollator use, maximal expiratory pressure, FEV1 and DLCO as independent determinants of the best 6MWD (R2 = 0.58).

CONCLUSIONS

The 6MWT was considered to be reliable and valid in patients with asthma, which strengthens its clinical utility. However, the majority of patients demonstrated a considerable learning effect in the second 6MWT, providing a strong rationale for performing two 6MWTs.

Reference values for six-minute walk distance and six-minute walk work in Caucasian adults

RATIONALE

The six-minute walk test (6MWT) is a practical and simple field-based test to assess physical capacity. Several reference equations for six-minute walking distance (6MWD, m) exist, but have a number of limitations that decrease their clinical utility. In addition, no reference equations exist for the 6MWT-derived outcome six-minute walk work (6MWORK, kg.m).

OBJECTIVES

To establish new reference equations for 6MWD and 6MWORK on a 20 m course using data from the population-based Canadian Cohort Obstructive Lung Disease study.

METHODS AND MEASUREMENTS

A total of 335 participants without obstructive or restrictive pulmonary function, with normal self-reported health status, normal exercise capacity, and <30 pack years cigarette smoking history were selected to create a representative sample of Canadian adults aged ≥40 years. All participants performed two 6MWTs. Reference equations were derived using multiple regression analyses.

MAIN RESULTS

On average, 6MWD and 6MWORK were 541±98 m and 41.3 ± 11.2 kg.m, respectively. All outcomes were significantly greater in males than females. Sex-specific reference equations were derived from the results of 6MWD and 6MWORK with an explained variance of 24 to 35%.

CONCLUSIONS

This study established reference equations for 6MWD and 6MWORK on a 20 m course in Caucasian males and females aged ≥40 years with normal pulmonary function, self-reported health status and exercise capacity. These newly derived reference equations add value to the assessment of functional capacity in clinical practice.

Differential Response to 12 Weeks of Once-Daily Tiotropium/Olodaterol Fixed Dose Combination in Patients with COPD: A Multidimensional Response Profiling in the TORRACTO Study

Purpose

Long-acting bronchodilators (LABD), in general, reduce respiratory symptoms, improve exercise endurance time and pulmonary function in patients with chronic obstructive pulmonary disease (COPD). However, there might be heterogeneity in improvement for several outcomes on an individual level. Therefore, we aimed to profile the multidimensional response in patients receiving tiotropium/olodaterol (T/O) using self-organizing maps (SOM).

Materials and Methods

This is a secondary analysis of the TORRACTO study: a multicenter, multinational, randomized, double-blind, placebo-controlled, parallel-group trial to evaluate the effects of T/O (2.5/5 and 5/5 μg) compared with placebo after 6 and 12 weeks of treatment in patients with COPD. In the current study, we used endurance time, forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), inspiratory capacity (IC) at rest and IC at isotime (ICiso) to identify clusters by means of SOM in patients treated with T/O.

Results

Six clusters with distinct response profiles were generated at week 12 in COPD patients receiving T/O (n = 268). Patients in cluster 1 improved significantly on all outcomes, whilst cluster 5 showed strong improvement in endurance time (357s); contrarily, FEV1, FVC, ICrest and ICiso decreased when compared to baseline.

Conclusion

Individual responses on endurance time and pulmonary function after 12 weeks of T/O are heterogeneous. This study identified clusters in COPD patients with markedly different multidimensional response on LABD.

Symptom-based clusters in people with ME/CFS: an illustration of clinical variety in a cross-sectional cohort

BACKGROUND

Myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is a complex, heterogenous disease. It has been suggested that subgroups of people with ME/CFS exist, displaying a specific cluster of symptoms. Investigating symptom-based clusters may provide a better understanding of ME/CFS. Therefore, this study aimed to identify clusters in people with ME/CFS based on the frequency and severity of symptoms.

METHODS

Members of the Dutch ME/CFS Foundation completed an online version of the DePaul Symptom Questionnaire version 2. Self-organizing maps (SOM) were used to generate symptom-based clusters using severity and frequency scores of the 79 measured symptoms. An extra dataset (n = 252) was used to assess the reproducibility of the symptom-based clusters.

RESULTS

Data of 337 participants were analyzed (82% female; median (IQR) age: 55 (44-63) years). 45 clusters were identified, of which 13 clusters included ≥ 10 patients. Fatigue and PEM were reported across all of the symptom-based clusters, but the clusters were defined by a distinct pattern of symptom severity and frequency, as well as differences in clinical characteristics. 11% of the patients could not be classified into one of the 13 largest clusters. Applying the trained SOM to validation sample, resulted in a similar symptom pattern compared the Dutch dataset.

CONCLUSION

This study demonstrated that in ME/CFS there are subgroups of patients displaying a similar pattern of symptoms. These symptom-based clusters were confirmed in an independent ME/CFS sample. Classification of ME/CFS patients according to severity and symptom patterns might be useful to develop tailored treatment options.

Endothelial function in patients with COPD: an updated systematic review of studies using flow-mediated dilatation

INTRODUCTION

Cardiovascular disease is a significant cause of morbidity and mortality in COPD. Endothelial dysfunction is suggested to be involved in cardiovascular disease pathogenesis, and multiple studies report endothelial dysfunction in COPD. This article summarized the current knowledge on endothelial function in COPD patients.

AREAS COVERED

Databases were screened until November 2022 for studies using ultrasound-based flow-mediated dilation in patients with stable COPD. Pooled effect sizes were calculated using random effects model. Meta-regression analyses assessed the effects of demographic and clinical variables.

EXPERT OPINION

34 studies were identified (1365 COPD patients; 617 controls). Pooled analysis demonstrated an impaired endothelial-dependent (-2.33%; 95%CI -3.30/-1.35; p < 0.001) and endothelial-independent dilation (-3.11%; 95%CI -5.14/-1.08; p = 0.003) in COPD patients when compared to non-COPD controls. Meta-regression identified that higher age, worse severity of airflow obstruction, and current smoking were significantly associated with impaired endothelial function. Studies evaluating the effects of pharmacological and non-pharmacological interventions on endothelial function in COPD patients demonstrated conflicting results.

Design and recruitment of a large-scale cohort study on prevalence, risk factors and impact evaluation of post-COVID-19 condition and its wider long-term social, mental, and physical health impact: The PRIME post-COVID study

Background

Persistent symptoms, described as long COVID or post-COVID-19 condition, pose a potential public health problem. Here, the design and recruitment of the PRIME post-COVID study is described. PRIME post-COVID is a large-scale population-based observational study that aims to improve understanding of the occurrence, risk factors, social, physical, mental, emotional, and socioeconomic impact of post-COVID-19 condition.

Methods

An observational open cohort study was set up, with retrospective and prospective assessments on various health-conditions and health-factors (medical, demographic, social, and behavioral) based on a public health COVID-19 test and by self-report (using online questionnaires in Dutch language). Invited for participation were, as recorded in a public health registry, adults (18 years and older) who were tested for COVID-19 and had a valid Polymerase Chain Reaction (PCR) positive or negative test result, and email address. In November 2021, 61,655 individuals were invited by email to participate, these included all eligible adults who tested PCR positive between 1 June 2020 and 1 November 2021, and a sample of adults who tested negative (2:1), comparable in distribution of age, sex, municipality of residence and year-quarter of testing. New recruitment periods are planned as well. Participants are followed over time by regular follow-up measurements. Data are analyzed using the appropriate data-analyses methods.

Discussion

The PRIME post-COVID study will provide insights into various health-related aspects of post-COVID-19 condition in the context of various stages of the COVID-19 pandemic. Results will inform practical guidance for society, clinical and public health practice for the prevention and care for long-term impact of COVID-19.

Trial registration ClinicalTrialsgov identifier

NCT05128695.

Physical and mental fatigue in people with non-communicable chronic diseases

BACKGROUND

Fatigue is frequently reported in people with a non-communicable chronic disease. More insight in the nature of this symptom may enhance targeted treatment of fatigue. In this study, we aimed to gain more insight in the prevalence of different types of fatigue and in current prescribed treatment strategies to reduce fatigue in non-communicable chronic diseases.

METHODS

People with non-communicable chronic diseases were contacted via public, non-profit, disease-specific health funds and patient associations and invited to complete a web-based survey. The survey included a general question about the experience ("Do you now or have you ever had complaints of fatigue?") and nature of fatigue (physically/mentally/combination), the Checklist Individual Strength-subscale subjective fatigue (CIS-Fatigue; 8-56 points), self-constructed questions for the distinction between physical and mental fatigue (both 3-21 points) and questions on prescribed treatments for fatigue.

RESULTS

In total, 4199 participants (77% females) completed the online survey. 3945 participants (94.0%) reported experiencing fatigue, of which 64.4% reported a combination of both physical and mental fatigue. Median CIS-Fatigue score was 41 (32-48) points, with 68% of the participants reporting severe fatigue (≥36 points). Median scores for physical and mental fatigue were 15 (11-18) and 12 (8-16) points, respectively. In 55% of the participants, fatigue was only occasionally or never discussed with the healthcare professional, and only 23% of the participants were prescribed a treatment for fatigue. Participants often reported no effect or even an increase in fatigue after treatment.

CONCLUSIONS

Findings indicate that both physical and mental fatigue are often experienced simultaneously in people with non-communicable chronic diseases, but can also occur separately. Fatigue is often only occasionally or never discussed, let alone treated, highlighting the need to raise awareness among healthcare professionals. Future studies are needed to gain more insight in underlying factors of fatigue in non-communicable chronic diseases, its impact on daily life and development and evaluation of targeted treatment strategies.Key messages:Both physical and mental fatigue are frequently present in people with non-communicable chronic diseases.Fatigue is often only occasionally or never discussed during consultation with the physician, highlighting the need to raise awareness among healthcare professionals for adequate screening and evaluating of fatigue in people with non-communicable chronic diseases.Only less than a quarter of the people with non-communicable chronic diseases who reported to experience fatigue were prescribed a treatment for fatigue, which was often experienced as ineffective.

International perspectives on outcome measurement in pulmonary rehabilitation of people with COPD: A qualitative study

BACKGROUND

There is high heterogeneity of outcomes and measures reported in the literature for pulmonary rehabilitation (PR), which might limit benchmarking and an effective evidence synthesis. A core outcome set (COS) can minimise this problem. It is however unclear which outcomes and measures are most important and suitable for different stakeholders.

METHODS

A multicentre qualitative study with one-to-one semi-structured interviews with people with chronic obstructive pulmonary disease (COPD), healthcare professionals (HCPs), researchers and policy makers was conducted. Manifest content analysis was conducted to explore the frequency of outcomes viewed as crucial or not. Thematic analysis was performed to better understand stakeholders' views.

RESULTS

37 participants (17 people with COPD and 20 HCPs/researchers/policy makers) from 14 countries and 4 continents were included. Participants expressed that i) core outcomes need to be meaningful to people with COPD and show PR benefits; ii) there should be comprehensive assessment and similar outcomes across settings; iii) a balance between optimal and practical measures is needed; iv) the COS is needed to benchmark PR and advance knowledge; and v) reluctance to change outcomes/measures used by HCPs and using the COS as a maximum set of outcomes might be the pitfalls. 28 outcomes were identified as crucial, and 12 as not crucial.

CONCLUSIONS

This study provided important insights into outcome measurement in PR from the perspectives of different key international stakeholders and a list of outcomes that will inform a future consensus study.

Differences in Pulmonary and Extra-Pulmonary Traits between Women and Men with Chronic Obstructive Pulmonary Disease

Background: Evidence suggests sex-related differences in chronic obstructive pulmonary disease (COPD). Whether these differences are reflected in the prevalence of treatable traits remains unknown. Methods: Two samples of patients referred to secondary (n = 530) or tertiary care (n = 2012) were analyzed. Men and women were matched for age, forced expiratory volume in 1 s and body mass index. Sex-related differences were tested using t-tests, Mann-Whitney U, or chi-square tests. Results: Frequent exacerbations (30.5 vs. 19.7%), high cardiovascular risk (88.1 vs. 66.2%) and activity-related severe dyspnea (50.9 vs. 34.8%) were more prevalent in women in secondary care (p < 0.05). Severe hyperinflation (43.0 vs. 25.4%), limited diffusing capacity (79.6 vs. 70.1%), impaired mobility (44.0 vs. 28.7%), frequent exacerbations (66.8 vs. 57.4%), frequent hospitalizations (47.5 vs. 41.6%), severe activity-related dyspnea (89.1 vs. 85.0%), symptoms of anxiety (56.3 vs. 42.0%) and depression (50.3 vs. 44.8%), and poor health status (79.9 vs. 71.0%) were more prevalent in women in tertiary care (p < 0.05). Severe inspiratory muscle weakness (14.6 vs. 8.2%) and impaired exercise capacity (69.1 vs. 59.6%) were more prevalent among men (p < 0.05) in tertiary care. Conclusions: Sex-related differences were found, with most traits more prevalent and severe among women. Care providers should be aware of these differences to adjust treatment.

"Can Do, Do Do" Quadrants and 6-Year All-Cause Mortality in Patients With COPD

BACKGROUND

Physical capacity (PC; "can do") and physical activity (PA; "do do") are prognostic indicators in COPD and can be used to subdivide patients with COPD into four exclusive subgroups (the so-called "can do, do do" quadrants). This concept may be useful to understand better the impact of PC and PA on all-cause mortality in patients with COPD.

RESEARCH QUESTION

What is the 6-year all-cause mortality risk of the "can do, do do" quadrants of patients with COPD?

STUDY DESIGN AND METHODS

This retrospective study used data from patients with COPD who underwent a comprehensive assessment at their first-ever outpatient consultation. PC was assessed using the 6-min walk distance and physical activity was assessed using an accelerometer (steps per day). All-cause mortality data were obtained from the Municipal Personal Records Database. Receiver operating characteristic curves were used to determine threshold values for PC and PA to predict 6-year all-cause mortality. Using the derived threshold values, male and female patients were divided into the four "can do, do do" quadrants.

RESULTS

Data from 829 patients were used for analyses. Best discriminatory values for 6-year mortality were 404 m and 4,125 steps/day for men and 394 m and 4,005 steps/day for women. During a median follow-up of 55 months (interquartile range, 37-71 months), 129 patients (15.6%) died. After controlling for established prognostic factors, patients in the "can do, don't do" quadrant and "can do, do do" quadrant showed significantly lower mortality risk compared with patients in the "can't do, don't do" quadrant: hazard ratios of 0.36 (95% CI, 0.14-0.93) and 0.24 (95% CI, 0.09-0.61) for men and 0.37 (95% CI, 0.38-0.99) and 0.29 (95% CI, 0.10-0.87) for women, respectively. No significant differences were found between the "can't do, do do" and "can't do, don't do" quadrants.

INTERPRETATION

Patients with COPD with a preserved PC seem to have a significantly lower 6-year mortality risk compared with patients with a decreased PC, regardless of physical activity level.

The Impact of Long COVID-19 on Mental Health: Observational 6-Month Follow-Up Study

BACKGROUND

The psychological impact of COVID-19 can be substantial. However, knowledge about long-term psychological outcomes in patients with COVID-19 is scarce.

OBJECTIVE

In this longitudinal, observational study, we aimed to reveal symptoms of posttraumatic stress disorder (PTSD) and symptoms of anxiety and depression up to 6 months after the onset of COVID-19-related symptoms in patients with confirmed COVID-19 and persistent complaints. To demonstrate the impact in nonhospitalized patients, we further aimed to compare these outcomes between nonhospitalized and hospitalized patients.

METHODS

Demographics, symptoms of PTSD (Trauma Screening Questionnaire [TSQ] ≥6 points) and symptoms of anxiety and depression (Hospital Anxiety and Depression Scale [HADS] ≥8 points) were assessed at 3 and 6 months after the onset of COVID-19-related symptoms in members of online long COVID-19 peer support groups.

RESULTS

Data from 239 patients with confirmed COVID-19 (198/239, 82.8% female; median age: 50 [IQR 39-56] years) were analyzed. At the 3-month follow-up, 37.2% (89/239) of the patients had symptoms of PTSD, 35.6% (85/239) had symptoms of anxiety, and 46.9% (112/239) had symptoms of depression, which remained high at the 6-month follow-up (64/239, 26.8%, P=.001; 83/239, 34.7%, P=.90; 97/239, 40.6%, P=.08, respectively; versus the 3-month follow-up). TSQ scores and HADS anxiety and depression scores were strongly correlated at the 3- and 6-month follow-ups (r=0.63-0.71, P<.001). Symptoms of PTSD, anxiety, and depression were comparable between hospitalized (n=62) and nonhospitalized (n=177) patients.

CONCLUSIONS

A substantial percentage of patients with confirmed COVID-19 and persistent complaints reported symptoms of PTSD, anxiety, or depression 3 and 6 months after the onset of COVID-19-related symptoms. The prevalence rates of symptoms of PTSD, anxiety, and depression were comparable between hospitalized and nonhospitalized patients and merely improved over time. Health care professionals need to be aware of these psychological complications and intervene on time in post-COVID-19 patients with persistent complaints.

TRIAL REGISTRATION

Netherlands Trial Register NTR8705; https://www.trialregister.nl/trial/8705.

A pilot study on the feasibility and effectiveness of treadmill-based perturbations for assessing and improving walking stability in chronic obstructive pulmonary disease

BACKGROUND

Falls risk is elevated in chronic obstructive pulmonary disease (COPD). However, there is a lack of evidence regarding the contributing factors. Here, we examined the feasibility of, and initial responses to, large walking perturbations in COPD, as well as the adaptation potential of people with COPD to repeated walking perturbations that might indicate potential for perturbation-based balance training in COPD.

METHODS

12 participants with COPD undergoing inpatient pulmonary rehabilitation and 12 age-gender-matched healthy control participants walked on an instrumented treadmill and experienced repeated treadmill-belt acceleration perturbations (leading to a forward balance loss). Three-dimensional motion capture was used to quantify the stability of participants body position during perturbed walking. Feasibility, stability following the initial perturbations and adaptation to repeated perturbations were assessed.

FINDINGS

Using perturbations in this manner was feasible in this population (no harness assists and participants completed the minimum number of perturbations). No clear, specific deficit in reactive walking stability in COPD was found (no significant effects of participant group on stability or recovery step outcomes). There were mixed results for the adaptability outcomes which overall indicated some adaptability to repeated perturbations, but not to the same extent as the healthy control participants.

INTERPRETATION

Treadmill-based perturbations during walking are feasible in COPD. COPD does not appear to result in significant deficits in stability following sudden perturbations and patients do demonstrate some adaptability to repeated perturbations. Perturbation-based balance training may be considered for fall prevention in research and practice in people with COPD.

Isokinetic testing of quadriceps function in COPD: feasibility, responsiveness, and minimal important differences in patients undergoing pulmonary rehabilitation

•

Evaluation of isokinetic quadriceps testing in COPD is needed to assess its efficacy.

•

Isokinetic testing was performed incorrectly in a quarter of patients with COPD.

•

Quadriceps peak torque and total work improved following pulmonary rehabilitation.

•

Minimal important differences for peak torque and total work were determined.

Background

Isokinetic testing of peripheral muscle function is valid and reliable in patients with chronic obstructive pulmonary disease (COPD).

Objective

To evaluate whether and to what extent isokinetic testing of quadriceps function meets pre-defined test criteria in patients with COPD; to determine the response to pulmonary rehabilitation (PR), and to calculate minimal important differences (MIDs) of isokinetic quadriceps function.

Methods

Retrospective analysis of 2033 patients with COPD (age: 65±9 years, body mass index: 26±6 kg/m², FEV₁: 49±22% predicted) who followed a comprehensive PR program. Pre and post PR isokinetic quadriceps function was assessed with 30 maximal extension-flexion contractions at an angular speed of 90°/s on a computerized dynamometer. The chosen anchors were 6-min walk test and COPD assessment test.

Results

Pre PR, 27% of the patients performed the isokinetic test incorrectly. In male and female patients with a correct pre and post PR isokinetic test, peak torque (Δ=10±13 Nm or 9% and Δ=7±9 Nm or 10%, respectively) and total work (Δ=263±270 J or 14% and Δ=198±190 J or 15%, respectively) improved significantly. There was no change in work fatigue index following PR. Using distribution-based calculations, MID estimates for peak torque and total work ranged between 6–7 Nm and 97–135 J in males and between 4–5 Nm and 62–99 J in females.

Conclusions

Based on the current test criteria, three in four patients with COPD performed the isokinetic quadriceps test correctly during baseline PR assessment. Furthermore, peak torque and total work, but not work fatigue index, were responsive to PR and sex-specific MIDs were established.

Implementation of Bronchoscopic Lung Volume Reduction Using One-Way Endobronchial Valves: A Retrospective Single-Centre Cohort Study

BACKGROUND

Bronchoscopic lung volume reduction (BLVR) using 1-way endobronchial valves (EBV) has become a guideline treatment in patients with advanced emphysema. Evidence from this minimally invasive treatment derives mainly from well-designed controlled trials conducted in high-volume specialized intervention centres. Little is known about real-life outcome data in hospitals setting up this novel treatment and which favourable conditions are required for a continuous successful program.

OBJECTIVES

In this study, we aim to evaluate the eligibility rate for BLVR and whether the implementation of BLVR in our academic hospital is feasible and yields clinically significant outcomes.

METHOD

A retrospective evaluation of patients treated with EBV between January 2016 and August 2019 was conducted. COPD assessment test (CAT), forced expiratory volume in 1 s (FEV1), residual volume (RV), and 6-min walking test (6MWT) were measured at baseline and 3 months after intervention. Paired sample t tests were performed to compare means before and after intervention.

RESULTS

Of 350 subjects screened, 283 (81%) were not suitable for intervention mostly due to lack of a target lobe. The remaining 67 subjects (19%) underwent bronchoscopic assessment, and if suitable, valves were placed in the same session. In total, 55 subjects (16%) were treated with EBV of which 10 did not have complete follow-up: 6 subjects had their valves removed because of severe pneumothorax (n = 2) or lack of benefit (n = 4) and the remaining 4 had missing follow-up data. Finally, 45 patients had complete follow-up at 3 months and showed an average change ± SD in CAT -4 ± 6 points, FEV1 +190 ± 140 mL, RV -770 ± 790 mL, and +37 ± 65 m on the 6MWT (all p < 0.001). After 1-year follow-up, 34 (76%) subjects had their EBV in situ.

CONCLUSION

Implementing BLVR with EBV is feasible and effective. Only 16% of screened patients were eligible, indicating that this intervention is only applicable in a small subset of highly selected subjects with advanced emphysema, and therefore a high volume of COPD patients is essential for a sustainable BLVR program.

Objectively Measured Physical Activity in Patients with COPD: Recommendations from an International Task Force on Physical Activity

Physical activity (PA) is of key importance for health among healthy persons and individuals with chronic obstructive pulmonary disease (COPD). PA has multiple dimensions that can be assessed and quantified objectively using activity monitors. Moreover, as shown in the published literature, variable methodologies have been used to date to quantify PA among individuals with COPD, precluding clear comparisons of outcomes across studies. The present paper aims to provide a summary of the available literature for the rationale behind using objectively measured PA and proposes a standardized methodology for assessment, including standard operating procedures for future research. The present paper, therefore, describes the concept of PA, reports on the importance of PA, summarizes the dimensions of PA, provides a standard operating procedure on how to monitor PA using objective assessments, and describes the psychometric properties of objectively measured PA. The present international task force recommends implementation of the standard operating procedure for PA data collection and reporting in the future. This should further clarify the relationship between PA and clinical outcomes, test the impact of treatment interventions on PA in individuals with COPD, and successfully propose a PA endpoint for regulatory qualification in the future.

Severe Fatigue in Long COVID: Web-Based Quantitative Follow-up Study in Members of Online Long COVID Support Groups

Background

Fatigue is the most commonly reported symptom in patients with persistent complaints following COVID-19 (ie, long COVID). Longitudinal studies examining the intensity of fatigue and differentiating between physical and mental fatigue are lacking.

Objective

The objectives of this study were to (1) assess the severity of fatigue over time in members of online long COVID peer support groups, and (2) assess whether members of these groups experienced mental fatigue, physical fatigue, or both.

Methods

A 2-wave web-based follow-up study was conducted in members of online long COVID peer support groups with a confirmed diagnosis approximately 3 and 6 months after the onset of infectious symptoms. Demographics, COVID-19 diagnosis, received health care (from medical professionals or allied health care professionals), fatigue (Checklist Individual Strength–subscale subjective fatigue [CIS-Fatigue]; 8-56 points), and physical and mental fatigue (self-constructed questions; 3-21 points) were assessed. Higher scores indicated more severe fatigue. A CIS-Fatigue score ≥36 points was used to qualify patients as having severe fatigue.

Results

A total of 239 patients with polymerase chain reaction/computed tomography–confirmed COVID-19 completed the survey 10 weeks (SD 2) and 23 weeks (SD 2) after onset of infectious symptoms, respectively (T1 and T2). Of these 239 patients, 198 (82.8%) were women; 142 (59.4%) had no self-reported pre-existing comorbidities; 208 (87%) self-reported being in good health before contracting COVID-19; and 62 (25.9%) were hospitalized during acute infection. The median age was 50 years (IQR 39-56). The vast majority of patients had severe fatigue at T1 and T2 (n=204, 85.4%, and n=188, 78.7%, respectively). No significant differences were found in the prevalence of normal, mild, and severe fatigue between T1 and T2 (P=.12). The median CIS-Fatigue score was 48 points (IQR 42-53) at T1, and it decreased from T1 to T2 (median change: –2 points, IQR –7 to 3; P<.001). At T1, a median physical fatigue score of 19 points (IQR 16-20) and a median mental fatigue score of 15 points (IQR 10-17) were reported; these scores were lower at T2 for physical but not for mental fatigue (median change for physical fatigue –1 point, IQR –3 to 0, P<.001; median change for mental fatigue 0 points, IQR –3 to 3, P=.52). At the time of completing the follow-up survey, 194/239 (81.2%) and 164/239 (68.6%) of all patients had received care from at least one medical professional and one allied health care professional, respectively.

Conclusions

Fatigue in members of online long COVID support groups with a confirmed COVID-19 diagnosis decreases from 10 to 23 weeks after onset of symptoms. Despite this, severe fatigue remains highly prevalent. Both physical and mental fatigue are present. It remains unclear whether and to what extent fatigue will resolve spontaneously in the longer term.

Trial Registration

Netherlands Trial Register NTR8705; https://www.trialregister.nl/trial/8705.

Analysis of retinal blood vessel diameters in patients with COPD undergoing a pulmonary rehabilitation program

BACKGROUND

Regular exercise positively affects cardiovascular physiology, translating into the adequate capacity of microvascular blood vessels to dilate in response to acute bouts of exercise. However, this remains unstudied in patients with chronic obstructive pulmonary disease (COPD), who often suffer from cardiovascular comorbidity. Therefore, we studied acute changes in retinal blood vessel diameters in response to high-intensity exercise in patients with COPD. The effect of an exercise-based 8-week pulmonary rehabilitation (PR) program was evaluated. We consider changes in these retinal metrics as an indicator of microvascular reactivity.

METHODS

Demographics and clinical characteristics of 41 patients were collected at the start and end of the PR program. Patients performed a high-intensity exercise test on a cycle ergometer at the start and end of the PR program, during which we collected retinal images. Fundus images were taken immediately before and 0, 5, 10, 15, and 30 min after the ergometer test. Widths of retinal blood vessels, represented as Central Retinal Arteriolar and Venular Equivalents (CRAE and CRVE), were calculated.

RESULTS

Thirty patients with COPD completed the study protocol (57% males; mean age: 64 ± 7 years; mean FEV₁: 45 ± 17%pred). We did not observe a change in retinal vessel widths following the ergometer test at the start of the PR program. This null result remained at the end of the 8-week PR program. Our observations did not alter when considering responders and non-responders to PR.

CONCLUSION

Retinal blood vessel diameters of patients with COPD did not change following an exercise test on an ergometer. The exercise-based PR program of eight weeks did not counteract the blunted retinal microvascular response.

Short Physical Performance Battery: Response to pulmonary rehabilitation and minimal important difference estimates in patients with chronic obstructive pulmonary disease

OBJECTIVE

To determine the response to a pulmonary rehabilitation (PR) program and minimal important differences (MIDs) for the Short Physical Performance Battery (SPPB) subtests and SPPB summary score in patients with Chronic Obstructive Pulmonary Disease (COPD).

DESIGN

Retrospective analysis using distribution- and anchor-based methods.

SETTING

PR center in the Netherlands including a comprehensive 8-week inpatient and 14-week outpatient program of 40 sessions.

PARTICIPANTS

632 patients with COPD (age: 65±8 years, 50% male, FEV₁: 43 (27-47) % predicted) INTERVENTION: Not applicable.

MAIN OUTCOME MEASURE

Baseline and post PR results of the SPPB, consisting of three balance standing tests, 4-meter gait speed (4MGS) test and 5-repetition sit-to-stand (5STS) test. The chosen anchors were 6-minute walk test and COPD Assessment Test. Patients were stratified according to their SPPB summary scores into a low-performance, moderate-performance or high-performance group.

RESULTS

5STS (∆= -1.14 (-4.20- -0.93) seconds) and SPPB summary score (∆= 1 (0-2) points) improved after PR in patients with COPD. In patients with low-performance at baseline, balance tandem and 4MGS significantly increased as well. Based on distribution-based calculations, the MID estimates range between 2.19-6.33 seconds for 5STS and 0.83-0.96 points for SPPB summary score.

CONCLUSIONS

The 5STS and SPPB summary score are both responsive to PR in patients with COPD. The balance tandem test and 4MGS are only responsive to PR in patients with COPD with a low-performance at baseline. Based on distribution-based calculations, a MID estimate of 1 point for the SPPB summary score is recommended in patients with COPD. Future research is needed to confirm MID estimates for SPPB in different centres.

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

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

The Impact of Post-COVID-19 Syndrome on Self-Reported Physical Activity

Background: A subgroup of patients recovering from COVID-19 experience persistent symptoms, decreased quality of life, increased dependency on others for personal care and impaired performance of activities of daily living. However, the long-term effects of COVID-19 on physical activity (PA) in this subgroup of patients with persistent symptoms remain unclear. Methods: Demographics, self-reported average time spent walking per week, as well as participation in activities pre-COVID-19 and after three and six months of follow-up were assessed in members of online long-COVID-19 peer support groups. Results: Two hundred thirty-nine patients with a confirmed COVID-19 diagnosis were included (83% women, median (IQR) age: 50 (39-56) years). Patients reported a significantly decreased weekly walking time after three months of follow-up (three months: 60 (15-120) min. vs. pre-COVID-19: 120 (60-240) min./week; p < 0.05). Six months after the onset of symptoms walking time was still significantly lower compared to pre-COVID-19 but significantly increased compared to three months of follow-up (three months: 60 (15-120) min. vs. six months: 90 (30-150) min.; p < 0.05). Conclusions: Patients who experience persistent symptoms after COVID-19 may still demonstrate a significantly decreased walking time six months after the onset of symptoms. More research is needed to investigate long-term consequences and possible treatment options to guide patients during the recovery fromCOVID-19.

Physiological Changes Differ between Responders and Nonresponders to Pulmonary Rehabilitation in COPD

PURPOSE

Not all patients with chronic obstructive pulmonary disease (COPD) experience similar benefits after pulmonary rehabilitation (PR). This pre-post PR study used a large sample of patients with COPD to determine whether PR-induced changes of oxygen uptake (V˙O2) kinetics and exercise responses of V˙O2, carbon dioxide output (V˙CO2), minute ventilation (V˙E), V˙E/V˙CO2, breathing frequency, and tidal volume differed between responders and nonresponders to PR.

METHODS

Responders to PR were defined as patients with a minimal clinically important increase in endurance time of 105 s. Isotime (=180 s) values of V˙O2, V˙CO2, V˙E, V˙E/V˙CO2, breathing frequency, and tidal volume; gains of V˙O2, V˙CO2, and V˙E; and V˙O2 mean response time of 183 patients with COPD (forced expiratory volume in 1 s: 56% ± 19% predicted) were compared between pre- and post-PR constant work rate tests.

RESULTS

After PR, only the group of responders significantly decreased V˙O2 mean response time (P < 0.05), V˙CO2 gain, V˙E gain, and isotime values of V˙CO2, V˙E, and V˙E/V˙CO2 (all, P < 0.001), while also improving their breathing pattern (e.g., decreased breathing frequency isotime value; P < 0.0001). These changes were not observed in the group of nonresponders. Changes in physiological exercise responses were correlated with changes in physical performance (e.g., correlation between changes in V˙O2 mean response time and endurance time: P = 0.0002, r = -0.32).

CONCLUSIONS

PR-induced changes in physiological exercise responses differed between responders and nonresponders. Physiological changes are relevant to explain the variable improvements of physical performance after PR in patients with COPD.

Recovery from COVID-19: a sprint or marathon? 6-month follow-up data from online long COVID-19 support group members

Background

It remains unknown whether and to what extent members of online “long COVID” peer support groups remain symptomatic and limited over time. Therefore, we aimed to evaluate symptoms in members of online long COVID peer support groups up to 6 months after the onset of coronavirus disease 2019 (COVID-19)-related symptoms.

Methods

Demographics, symptoms, health status, work productivity, functional status and health-related quality of life were assessed about 3 and 6 months after the onset of COVID-19-related symptoms in members of online long COVID peer support groups.

Results

Data from 239 patients with a confirmed COVID-19 diagnosis (83% women; median (interquartile range) age 50 (39–56) years) were analysed. During the infection, a median (interquartile range) of 15 (11–18) symptoms was reported, which was significantly lower 3 and 6 months later: 6 (4–9) and 6 (3–8), respectively (p<0.05). From 3 to 6 months follow-up, the proportion of patients without symptoms increased from 1.3% to only 5.4% (p<0.001). Patients also reported a significantly improved work productivity (work absenteeism and presenteeism: 73% versus 52% and 66% versus 60%, respectively), self-reported good health (9.2% versus 16.7%), functional status (mean±sd Post-COVID-19 Functional Status scale: 2.4±0.9 versus 2.2±1.0) and health-related quality of life (all p<0.05).

Conclusion

Although patients with confirmed COVID-19, who were all members of online long COVID peer support groups, reported significant improvements in work productivity, functional status and quality of life between 3 and 6 months follow-up, these data clearly highlight the long-term impact of COVID-19, as approximately 6 months after the onset of COVID-19-related symptoms a large proportion still experienced persistent symptoms, a moderate-to-poor health, moderate-to-severe functional limitations, considerable loss in work productivity, and/or an impaired quality of life. Action is needed to improve the management and healthcare of these patients.

Patients who are members of online #longCOVID peer support groups may still experience persistent symptoms about 6 months after the onset of symptoms, which can affect work productivity, functional status and quality of lifehttps://bit.ly/3vxPF2b

Understanding and Being Understood: Information and Care Needs of 2113 Patients With Confirmed or Suspected COVID-19

To become a proactive and informed partner in postacute coronavirus disease 2019 (COVID-19) management, patients need to have the knowledge, skills, and confidence to self-manage COVID-19-related health challenges. Due to several restrictions and consequently social isolation, online platforms and forums where people can share information and experiences became more popular and influential. Therefore, this study aimed to identify perceived information needs and care needs of members of 2 Facebook groups for patients with COVID-19 and persistent complaints in the Netherlands and Belgium and patients with COVID-19 who registered at a website of the Lung Foundation Netherlands. Besides demographics and clinical characteristics, the degree of satisfaction with care during and after the infection as well as satisfaction with available information were assessed. Open text fields revealed specific information needs which were summarized. Patients with confirmed or suspected COVID-19 perceive various unmet needs varying from specific information needs (eg, information about permanent lung damage) to general needs (eg, being heard and understood). These data lead to several recommendations to improve care for patients with COVID-19 and justify further development of online platforms specifically addressing these unmet needs.

Generic and Respiratory-Specific Quality of Life in Non-Hospitalized Patients with COVID-19

The impact of coronavirus disease 2019 (COVID-19) on quality of life appears to be highly underestimated, especially in patients who have not been admitted to the hospital. Therefore, our aim was to assess respiratory-specific quality of life in addition to generic quality of life in former patients with confirmed/suspected COVID-19 who have never been admitted to the hospital. Members of an online Belgian social support group for patients with confirmed/suspected COVID-19 with persistent complaints, completed an online survey. The five-level EQ-5D (EQ-5D-5L) and the Clinical COPD Questionnaire (CCQ) were used to assess generic and respiratory-specific quality of life, respectively. Data of 210 non-hospitalized patients (88% women, 45 ± 11 years, 79 ± 17 days after symptom onset) were included in the analyses. Mean EQ-5D index and visual analogue scale (EQ-VAS) score was 0.62 ± 0.19 and 50.71 ± 18.87, respectively, with 40% of the patients demonstrating an EQ-5D index that was below the fifth percentile of normative values, indicating poor generic quality of life. The mean CCQ score was 2.01 ± 0.98 points, while 123 respondents (59%) had a total score ≥1.9 points, indicating poor respiratory-specific quality of life. The correlation between EQ-5D index score/EQ-VAS score and CCQ total score was moderate (r = -0.524 and r = -0.374; both p < 0.001). In conclusion, both generic and respiratory-specific quality of life are affected in non-hospitalized patients with COVID-19, approximately three months after the onset of symptoms. The combined use of the EQ-5D and the CCQ could identify the broad impact of COVID-19 on quality of life.

Persistent symptoms 3 months after a SARS-CoV-2 infection: the post-COVID-19 syndrome?

Background

Many patients with COVID-19 did not require hospitalisation, nor underwent COVID-19 testing. There is anecdotal evidence that patients with “mild” COVID-19 may complain about persistent symptoms, even weeks after the infection. This suggests that symptoms during the infection may not resolve spontaneously. The objective of this study was to assess whether multiple relevant symptoms recover following the onset of symptoms in hospitalised and nonhospitalised patients with COVID-19.

Methods

A total of 2113 members of two Facebook groups for coronavirus patients with persistent complaints in the Netherlands and Belgium, and from a panel of people who registered on a website of the Lung Foundation Netherlands, were assessed for demographics, pre-existing comorbidities, health status, date of symptoms onset, COVID-19 diagnosis, healthcare utilisation, and the presence of 29 symptoms at the time of the onset of symptoms (retrospectively) and at follow-up (mean±sd 79±17 days after symptoms onset).

Results

Overall, 112 hospitalised patients and 2001 nonhospitalised patients (confirmed COVID-19, n=345; symptom-based COVID-19, n=882; and suspected COVID-19, n=774) were analysed. The median number of symptoms during the infection reduced significantly over time (median (interquartile range) 14 (11–17) versus 6 (4–9); p<0.001). Fatigue and dyspnoea were the most prevalent symptoms during the infection and at follow-up (fatigue: 95% versus 87%; dyspnoea: 90% versus 71%).

Conclusion

In previously hospitalised and nonhospitalised patients with confirmed or suspected COVID-19, multiple symptoms are present about 3 months after symptoms onset. This suggests the presence of a “post-COVID-19 syndrome” and highlights the unmet healthcare needs in a subgroup of patients with “mild” or “severe” COVID-19.

Previously hospitalised and nonhospitalised #COVID19 patients can still have multiple persistent symptoms 3 months after the onset of infection-related symptoms. This provides the first evidence for a “post-COVID-19 syndrome” #longCOVIDhttps://bit.ly/3h8iJ80

Care Dependency in Non-Hospitalized Patients with COVID-19

BACKGROUND

A large sample of "mild" COVID-19 patients still experience multiple symptoms months after being infected. These persistent symptoms are associated with many clinically relevant outcomes, including poor health status and impaired functional status. To date, no information is available about care dependency. Therefore, we aimed to explore the level of care dependency and the need for assistance with personal care in non-hospitalized COVID-19 patients.

METHODS

Members of two Facebook groups for COVID-19 patients with persistent complaints in The Netherlands and Belgium, and from a panel of people who registered at a website of the Lung Foundation Netherlands, were assessed for demographics, pre-existing comorbidities, health status, and symptoms. In addition, patients were asked about their dependence on others for personal care before and after the infection. The level of care dependency was assessed with the Care Dependency Scale (CDS) in members of the Belgian Facebook group (n = 210).

RESULTS

The data of 1837 non-hospitalized patients (86% women; median (IQR) age: 47 (38-54)) were analyzed. Only a small proportion of patients needed help with personal care before COVID-19, but the care need increased significantly after the infection (on average 79 ± 17 days after the onset of symptoms; 7.7% versus 52.4%, respectively; p < 0.05). The patients had a median (IQR) CDS score of 72 (67-75) points, and 31% of the patients were considered as care-dependent (CDS score ≤ 68 points).

CONCLUSIONS

COVID-19 has an important impact on care dependency in non-hospitalized patients. About three months after the onset of symptoms, a considerable proportion of non-hospitalized patients were to some degree dependent on others for personal care. This indicates that the impact of COVID-19 on patients' daily lives is tremendous, and more attention is needed to identify optimal treatment strategies to restore patients' independency.

Skin auto-fluorescence as a measure of advanced glycation end-products is associated with microvascular health in patients with COPD

BACKGROUND AND OBJECTIVES

Chronic obstructive pulmonary disease (COPD) is associated with systemic inflammation and oxidative stress. These physiological processes can lead to increased formation and accumulation of advanced glycation end-products (AGEs), that can play a role in vascular complications. In this cross-sectional study, we determined the association between skin AGEs and microvascular health in patients with COPD.

METHODS

Clinical characteristics and cardiovascular parameters, including pulmonary function, metabolic and inflammatory parameters, and blood pressure, were obtained in this observational study with patients with COPD. Skin concentrations of AGEs were assessed non-invasively by measuring skin autofluorescence (AF). Retinal vessel analysis was used as a marker of microvascular health.

RESULTS

62 patients with COPD (52% males; mean age: 64.4 ± 8.4 years; mean FEV₁: 45.0 ± 20.7%pred.) were analysed. Mean skin AF was 2.75 ± 0.64 arbitrary units. Skin AF in patients with COPD was negatively associated with retinal arteriolar diameter (β -0.021, 95% CI -0.040 to -0.002; p = 0.031) and arteriole-to-venular ratio (β -7.233, 95% CI -9.732 to -4.734; p < 0.001) and positively associated with retinal venular diameter (β 0.029, 95% CI 0.019 to 0.038; p < 0.001) after adjustment for sex, age, lung function, pack-years of smoking and conventional cardiovascular risk factors.

CONCLUSION

We document for the first time that skin AF in patients with COPD is independently associated with retinal arteriolar and venular vessel diameters, biological indicators for microvascular health. This adds to the evidence that AGEs are an accessible marker of microvascular health.

Phenotypic Characteristics of Patients With Chronic Obstructive Pulmonary Disease After Stratification for the Short Physical Performance Battery Summary Score

OBJECTIVE

To assess the phenotypic characteristics of patients with chronic obstructive pulmonary disease (COPD) after stratification for Short Physical Performance Battery (SPPB) summary scores and to determine phenotypic characteristics of the SPPB summary score at the start of pulmonary rehabilitation (PR).

DESIGN

Retrospective, cross-sectional.

SETTING

Baseline assessment for PR program.

PARTICIPANTS

Patients with COPD (n=900; age 65±8y, 52% male, forced expiratory volume in the first second of expiration, 43% [interquartile range, 31%-62%] predicted).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Patients were stratified according to their SPPB summary scores into low-performance (LP), moderate-performance (MP), or high-performance (HP) groups. Furthermore, lung function, arterial blood gases, body composition, physical capacity, lower limb muscle strength and endurance, and symptoms of anxiety and depression were assessed.

RESULTS

Generally, physical capacity and muscle function were lower and scores for symptoms of anxiety and depression were higher in LP patients than MP and HP patients (all values, P<.01). However, 25% of HP patients with COPD scored high on symptoms of anxiety and/or depression (≥10 points), and HP patients still had on average an impaired physical capacity (median, 6-minute walk test [6MWT] distance of 69% predicted). Furthermore, age and 6MWT distance (m) were the only independent predictors in a multivariate regression model, explaining 29% of the variance in SPPB summary score.

CONCLUSIONS

In COPD, LP patients have the worst physical and emotional functioning. However, HP patients can still exhibit physical and emotional impairments. Because the explained variance in SPPB summary score is low, SPPB should not be considered as a test to discriminate between patients with COPD with a low or preserved physical capacity and emotional status.

Structural analysis of retinal blood vessels in patients with COPD during a pulmonary rehabilitation program

Cardiovascular diseases are frequently present in chronic obstructive pulmonary disease (COPD). Population-based studies found associations between retinal vessel diameters and cardiovascular health, but it is unknown whether this also applies to COPD patients. Therefore, we measured retinal vessel diameters in COPD patients and aimed to determine the association with cardiovascular risk factors, lung function, and functional outcomes. In addition, we investigated whether an exercise-based pulmonary rehabilitation (PR) program would change retinal vessel diameters, as a proxy for improved microvascular health. Demographics and clinical characteristics, including pulmonary function, exercise capacity, blood pressure, blood measurements and level of systemic inflammation were obtained from 246 patients during routine assessment before and after PR. Retinal vessel diameters were measured from digital retinal images. Older age and higher systolic blood pressure were associated with narrower retinal arterioles (β: −0.224; p = 0.042 and β: −0.136; p < 0.001, respectively). Older age, higher systolic blood pressure and lower level of systemic inflammation were associated with narrower retinal venules (β: −0.654; −0.229; and −13.767, respectively; p < 0.05). No associations were found between retinal vessel diameters and lung function parameters or functional outcomes. After PR, no significant changes in retinal venular or arteriolar diameter were found. To conclude, retinal vessel diameters of COPD patients were significantly associated with systolic blood pressure and systemic inflammation, whilst there was no evidence for an association with lung function parameters, functional outcomes or other cardiovascular risk factors. Furthermore, an exercise-based PR program did not affect retinal vessel diameter.

Wearable Finger Pulse Oximetry for Continuous Oxygen Saturation Measurements During Daily Home Routines of Patients With Chronic Obstructive Pulmonary Disease (COPD) Over One Week: Observational Study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) patients can suffer from low blood oxygen concentrations. Peripheral blood oxygen saturation (SpO2), as assessed by pulse oximetry, is commonly measured during the day using a spot check, or continuously during one or two nights to estimate nocturnal desaturation. Sampling at this frequency may overlook natural fluctuations in SpO2.

OBJECTIVE

This study used wearable finger pulse oximeters to continuously measure SpO2 during daily home routines of COPD patients and assess natural SpO2 fluctuations.

METHODS

A total of 20 COPD patients wore a WristOx2 pulse oximeter for 1 week to collect continuous SpO2 measurements. A SenseWear Armband simultaneously collected actigraphy measurements to provide contextual information. SpO2 time series were preprocessed and data quality was assessed afterward. Mean SpO2, SpO2 SD, and cumulative time spent with SpO2 below 90% (CT90) were calculated for every (1) day, (2) day in rest, and (3) night to assess SpO2 fluctuations.

RESULTS

A high percentage of valid SpO2 data (daytime: 93.27%; nocturnal: 99.31%) could be obtained during a 7-day monitoring period, except during moderate-to-vigorous physical activity (MVPA) (67.86%). Mean nocturnal SpO2 (89.9%, SD 3.4) was lower than mean daytime SpO2 in rest (92.1%, SD 2.9; P<.001). On average, SpO2 in rest ranged over 10.8% (SD 4.4) within one day. Highly varying CT90 values between different nights led to 50% (10/20) of the included patients changing categories between desaturator and nondesaturator over the course of 1 week.

CONCLUSIONS

Continuous SpO2 measurements with wearable finger pulse oximeters identified significant SpO2 fluctuations between and within multiple days and nights of patients with COPD. Continuous SpO2 measurements during daily home routines of patients with COPD generally had high amounts of valid data, except for motion artifacts during MVPA. The identified fluctuations can have implications for telemonitoring applications that are based on daily SpO2 spot checks. CT90 values can vary greatly from night to night in patients with a nocturnal mean SpO2 around 90%, indicating that these patients cannot be consistently categorized as desaturators or nondesaturators. We recommend using wearable sensors for continuous SpO2 measurements over longer time periods to determine the clinical relevance of the identified SpO2 fluctuations.

Impact of pulmonary rehabilitation on activities of daily living in patients with chronic obstructive pulmonary disease

A high proportion of patients with chronic obstructive pulmonary disease (COPD) experience problems during the performance of activities of daily living (ADLs). We aimed to determine the effects of a comprehensive 8-wk pulmonary rehabilitation program on the physiologic response to and performance of ADLs in patients with COPD. Before and after pulmonary rehabilitation, 31 patients with COPD [71% men; mean age: 64.2 (SD 8.4) years; mean forced expiratory volume in the first second: 54.6 (SD 19.9) % predicted] performed physical function tests, the Canadian Occupational Performance Measure (COPM), and an ADL test consisting of the following: putting on socks, shoes, and vest; stair climbing; washing up four dishes, cups, and saucers; doing groceries and putting away groceries in a cupboard; folding eight towels; and vacuum cleaning for 4 min. Metabolic load, ventilation, and dynamic hyperinflation were assessed using an Oxycon mobile device. In addition, symptoms of dyspnea and fatigue and time to complete ADLs were recorded. After rehabilitation, patients with COPD used a significantly lower proportion of their peak aerobic capacity and ventilation to perform ADLs, accompanied by lower Borg scores for dyspnea and fatigue. Furthermore, patients needed significantly less time to complete ADLs. Dynamic hyperinflation occurred during the performance of ADLs, which did not change following pulmonary rehabilitation. Changes in physical function, including six-min walk distance, constant work rate test, quadriceps muscle strength, and COPM were significantly correlated with change in average total oxygen uptake during the performance of the ADL test. A comprehensive pulmonary rehabilitation program can improve the physiologic response to and actual performance of ADLs in patients with COPD. NEW & NOTEWORTHY A high proportion of patients with chronic obstructive pulmonary disease (COPD) experience problems during the performance of activities of daily living (ADLs). This study clearly demonstrated that a comprehensive pulmonary rehabilitation program can improve the performance of ADLs in patients with COPD, indicated by a significantly shorter time to perform ADLs and a lower metabolic load and dyspnea sensation.

Looking into the eye of patients with chronic obstructive pulmonary disease: an opportunity for better microvascular profiling of these complex patients

Chronic obstructive pulmonary disease (COPD) is a complex disease with many patients suffering from cardiovascular comorbidity. However, cardiovascular diseases remain often undiagnosed in COPD. Assessment of the retinal microvasculature can provide value in cardiovascular profiling of these patients. Retinal microvascular assessment carried out via a noninvasive eye exam represents an easy to use tool when examining patients with COPD. The purpose of this review was to provide an overview of studies assessing structural and functional changes in the retinal microvasculature of patients with COPD. Findings demonstrated that structural and functional microvascular changes were more common and severe in COPD patients as compared to non-COPD controls, although few retinal investigations have been performed in patients with COPD. As cardiovascular comorbidities are highly prevalent in COPD, we advocate more research to investigate the value of an eye exam for microvascular phenotyping of COPD patients.

Oxygen saturation measurements in telemonitoring of patients with COPD: a systematic review

INTRODUCTION

Telemonitoring applications are expected to become a key component in future healthcare. Despite the frequent use of SpO₂ measurements in telemonitoring of patients with chronic obstructive pulmonary disease (COPD), no profound overview is available about these measurements. Areas covered: A systematic search identified 71 articles that performed SpO₂ measurements in COPD telemonitoring. The results indicate that long-term follow-up of COPD patients using daily SpO₂ spot checks is practically feasible. Very few studies specified protocols for performing these measurements. In many studies, deviating SpO₂ values were used to raise alerts that led to immediate action from healthcare professionals. However, little information was available about the exact implementation and performance of these alerts. Therefore, no firm conclusions can be drawn about the real value of SpO₂ measurements. Future research could optimize performance of alerts using individualized, time-dependent thresholds or predictive algorithms to account for individual differences and SpO₂ baseline changes. Additionally, the value of performing continuous measurements should be examined. Expert commentary: Standardization of the measurements, data science techniques and advancing technology can still boost performance of telemonitoring applications. All these opportunities should be thoroughly explored to assess the real value of SpO₂ in COPD telemonitoring.

Endothelial function in patients with chronic obstructive pulmonary disease: a systematic review of studies using flow mediated dilatation

BACKGROUND

Cardiovascular disease is an important cause of morbidity and mortality in chronic obstructive pulmonary disease (COPD). Endothelial function may be involved in the pathogenesis of cardiovascular disease. In contrast to the attention given to pulmonary endothelial dysfunction, little is known about peripheral vascular changes in COPD. Therefore, we reviewed the literature on peripheral endothelial function in COPD.

METHODS

Databases were screened for studies using ultrasound-based flow-mediated dilation (FMD), the reference method for assessing peripheral endothelial function, in stable COPD patients. Pooled effect sizes were calculated using random effects model.

RESULTS

17 studies were identified, with a total of 1228 participants (724 COPD patients; 504 controls). Pooled analysis demonstrated an impaired endothelial-dependent FMD (-3.22%; 95% confidence interval (CI) -4.74 to -1.69; p < 0.001; I² = 96%) and endothelial-independent FMD (-2.86%; 95%CI -5.63 to -0.09; p = 0.04; I² = 83%) in COPD patients when compared with smoking and non-smoking controls.

CONCLUSION

This review provides evidence for impaired peripheral endothelial function in COPD. Since impaired endothelial function may contribute to cardiovascular morbidity, a more comprehensive cardiovascular phenotyping is considered important in COPD to address cardiovascular risk. A high frequency of cardiovascular comorbidity is observed in COPD patients, and therefore well-controlled, larger studies that investigate endothelial function in COPD patients are recommended.

Physical activity patterns and clusters in 1001 patients with COPD

We described physical activity measures and hourly patterns in patients with chronic obstructive pulmonary disease (COPD) after stratification for generic and COPD-specific characteristics and, based on multiple physical activity measures, we identified clusters of patients. In total, 1001 patients with COPD (65% men; age, 67 years; forced expiratory volume in the first second [FEV₁], 49% predicted) were studied cross-sectionally. Demographics, anthropometrics, lung function and clinical data were assessed. Daily physical activity measures and hourly patterns were analysed based on data from a multisensor armband. Principal component analysis (PCA) and cluster analysis were applied to physical activity measures to identify clusters. Age, body mass index (BMI), dyspnoea grade and ADO index (including age, dyspnoea and airflow obstruction) were associated with physical activity measures and hourly patterns. Five clusters were identified based on three PCA components, which accounted for 60% of variance of the data. Importantly, couch potatoes (i.e. the most inactive cluster) were characterised by higher BMI, lower FEV₁, worse dyspnoea and higher ADO index compared to other clusters (p < 0.05 for all). Daily physical activity measures and hourly patterns are heterogeneous in COPD. Clusters of patients were identified solely based on physical activity data. These findings may be useful to develop interventions aiming to promote physical activity in COPD.

Features of a Mobile Support App for Patients With Chronic Obstructive Pulmonary Disease: Literature Review and Current Applications

Background

Chronic obstructive pulmonary disease (COPD) is a serious long-term lung disease in which the airflow from the lungs is progressively reduced. By 2030, COPD will become the third cause of mortality and seventh cause of morbidity worldwide. With advances in technology and mobile communications, significant progress in the mobile health (mHealth) sector has been recently observed. Mobile phones with app capabilities (smartphones) are now considered as potential media for the self-management of certain types of diseases such as asthma, cancer, COPD, or cardiovascular diseases. While many mobile apps for patients with COPD are currently found on the market, there is little published material on the effectiveness of most of them, their features, and their adoption in health care settings.

Objectives

The aim of this study was to search the literature for current systems related to COPD and identify any missing links and studies that were carried out to evaluate the effectiveness of COPD mobile apps. In addition, we reviewed existing mHealth apps from different stores in order to identify features that can be considered in the initial design of a COPD support tool to improve health care services and patient outcomes.

Methods

In total, 206 articles related to COPD management systems were identified from different databases. Irrelevant materials and duplicates were excluded. Of those, 38 articles were reviewed to extract important features. We identified 214 apps from online stores. Following exclusion of irrelevant apps, 48 were selected and 20 of them were downloaded to review some of their common features.

Results

Our review found that out of the 20 apps downloaded, 13 (65%, 13/20) had an education section, 5 (25%, 5/20) consisted of medication and guidelines, 6 (30%, 6/20) included a calendar or diary and other features such as reminders or symptom tracking. There was little published material on the effectiveness of the identified COPD apps. Features such as (1) a social networking tool; (2) personalized education; (3) feedback; (4) e-coaching; and (5) psychological motivation to enhance behavioral change were found to be missing in many of the downloaded apps.

Conclusions

This paper summarizes the features of a COPD patient-support mobile app that can be taken into consideration for the initial design of an integrated care system to encourage the self-management of their condition at home.

COPD care delivery pathways in five European Union countries: mapping and health care professionals' perceptions

BACKGROUND

COPD is among the leading causes of chronic morbidity and mortality in the European Union with an estimated annual economic burden of €25.1 billion. Various care pathways for COPD exist across Europe leading to different responses to similar problems. Determining these differences and the similarities may improve health and the functioning of health services.

OBJECTIVE

The aim of this study was to compare COPD patients' care pathway in five European Union countries including England, Ireland, the Netherlands, Greece, and Germany and to explore health care professionals' (HCPs) perceptions about the current pathways.

METHODS

HCPs were interviewed in two stages using a qualitative, semistructured email interview and a face-to-face semistructured interview.

RESULTS

Lack of communication among different health care providers managing COPD and comorbidities was a common feature of the studied care pathways. General practitioners/family doctors are responsible for liaising between different teams/services, except in Greece where this is done through pulmonologists. Ireland and the UK are the only countries with services for patients at home to shorten unnecessary hospital stay. HCPs emphasized lack of communication, limited resources, and poor patient engagement as issues in the current pathways. Furthermore, no specified role exists for pharmacists and informal carers.

CONCLUSION

Service and professional integration between care settings using a unified system targeting COPD and comorbidities is a priority. Better communication between health care providers, establishing a clear role for informal carers, and enhancing patients' engagement could optimize current care pathways resulting in a better integrated system.

Qualitative investigation into a wearable system for chronic obstructive pulmonary disease: the stakeholders' perspective

OBJECTIVES

To ascertain the stakeholders' views and devise recommendations for further stages of the Wearable Sensing and Smart Cloud Computing for Integrated Care to Chronic Obstructive Pulmonary Disease (COPD) Patients with Co-morbidities (WELCOME) system development. This system aims to create a wearable vest to monitor physiological signals for patients concerned incorporating an inhaler adherence monitoring, weight, temperature, blood pressure and glucose metres, and a mobile health application for communication with healthcare professionals (HCPs).

DESIGN

A study of qualitative data derived from focus groups and semistructured interviews.

SETTING

4 participating clinical sites in Greece, the UK, Ireland and the Netherlands.

PARTICIPANTS

Purposive sampling was used to recruit 32 patients with COPD with heart failure, diabetes, anxiety or depression, 27 informal carers and 23 HCPs from 4 European Union (EU) countries for focus groups and interviews.

RESULTS

Most patients and HCPs described the WELCOME system as 'brilliant and creative' and felt it gave a sense of safety. Both users and HCPs agreed that the duration and frequency of vest wear should be individualised as should the mobile application functions. The parameters and frequency of monitoring should be personalised using a multidisciplinary approach. A 'traffic light' alert system was proposed by HCPs for abnormal results. Patients were happy to take actions in response.

CONCLUSIONS

WELCOME stakeholders provided valuable views on the development of the system, which should take into account patient's individual comorbidities, circumstances and concerns. This will enable the development of the individualised system in each member state concerned.

An official European Respiratory Society statement on physical activity in COPD

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

Metabolic load during strength training or NMES in individuals with COPD: results from the DICES trial

Background

Strength training and neuromuscular electrical stimulation (NMES) are effective training modalities for improving muscle function, exercise performance and health status in individuals with COPD. The aim of the present study was to analyze the metabolic load of these training modalities at baseline, half-way, and at the end of an eight-week interdisciplinary pulmonary rehabilitation program in a subgroup of individuals with COPD of the DICES trial.

Methods

Of 24 individuals with COPD (FEV₁: 34 ± 2% predicted, men: 58%, age: 66 (61–68) years), peak oxygen uptake (VO₂), peak minute ventilation (V_E), heart rate, oxygen saturation and symptom scores were assessed during HF-NMES (75 Hz), LF-NMES (15 Hz) and strength training at three moments during their pulmonary rehabilitation program.

Results

Intervention-related peak VO₂ did not change over time during HF-NMES, LF-NMES or strength training. Intervention-related peak V_E did not change over time during strength training or LF-NMES and increased slightly, but significantly over time during HF-NMES. Peak VO₂ and V_E were significantly higher during strength training compared to HF-NMES or LF-NMES. Oxygen saturation significantly decreased after the first measurements during HF-NMES and strength training group to baseline, while no significant changes in oxygen saturation were observed during the other measurements. Heart rate significantly increased compared to baseline in all groups at all moments and was significantly higher after strength training compared to HF-NMES or LF-NMES. Median end scores (points) for dyspnea, fatigue and muscle pain ranged from 1 to 3, from 0.5 to 2 and from 0 to 6 after HF-NMES, from 2 to 3, from 2 to 5 and from 0 to 9 after LF-NMES and from 2 to 5, from 1.5 to 4 and from 0 to 28 after strength training respectively.

Conclusions

To conclude, the metabolic load and symptom scores remain acceptable low over time with increasing training loads during HF-NMES, LF-NMES or strength training.

Trial registration

Trial registration:NTR2322