Identification of symptom clusters and change trajectories in patients with acute exacerbation of chronic obstructive pulmonary disease

Aim and objectives

This study aimed to identify symptom cluster (SC) patterns and change trajectories in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), the correlation of the SCs with laboratory and imaging indicators, and the intrinsic association of the SCs with prognostic outcomes and disease burden.

Method

Symptom information was collected using a digital evaluation scoring system at the time of admission, on the third day after admission, and upon discharge. Laboratory and imaging examination data were compiled simultaneously. Exploratory factor analysis was used to identify the AECOPD SCs. The number of factors (clusters) was determined by examining factors with eigenvalues ≥1.0, using 0.50 for factor loadings as the minimum cut-off value. Spearman's correlation analysis was used to explore the link between the SCs and laboratory and imaging indicators, as well as the relationship between the severity of the symptoms in different clusters, prognostic outcomes, and disease burden.

Results

This study included 148 patients. Three SCs were identified: activity-nutrition SC, breath-sleep SC and respiratory SC. Correlation analysis indicated a connection between the activity-nutrition SC and the white blood cell count, and serum sodium and potassium levels, whereas the breath-sleep SC was correlated with white blood cells and eosinophil counts, serum potassium level, and pleural effusion. Additionally, the respiratory SC was associated with serum calcium and magnesium levels, the partial pressure of carbon dioxide, and C-reactive protein (CRP) level. There was a positive correlation between the activity-nutrition SC and hospitalization cost, as well as between the breath-sleep SC and both the hospitalization length and cost.

Conclusion

Patients with AECOPD presented three SCs that affected the length and cost of hospitalization. Concurrently, the severity of the symptoms in the clusters was related to white blood cell and eosinophil counts; serum sodium, potassium, calcium, and magnesium levels; CRP level; the partial pressure of carbon dioxide; and pleural effusion, indicating that the symptoms in each clusters may share related physiological mechanisms. An in-depth exploration of the pathogenesis and intervention paths of health problems is of great significance for promoting precision nursing.

Symptom clusters, associated factors and health-related quality of life in patients with chronic obstructive pulmonary disease: A structural equation modelling analysis

AIMS AND OBJECTIVES

To identify symptom clusters and develop a symptom cluster model among people living with chronic obstructive pulmonary disease (COPD).

BACKGROUND

The examination of symptom clusters in COPD patients is an emerging field of scientific inquiry directed towards symptom management. However, no studies have modelled the relationships among symptom clusters, associated factors and health-related quality of life.

DESIGN

A cross-sectional design with convenience sampling following STROBE guidelines.

METHODS

Data were collected from 450 COPD participants in three university teaching hospitals. Participants were invited to complete a structured questionnaire comprised of a socio-demographic/clinical questionnaire, Integrated Palliative Care Outcome Scale and Clinical Respiratory Questionnaire. Exploratory factor analysis and confirmatory factor analysis were used to identify symptom clusters. Structural equation modelling was used to examine the proposed model.

RESULTS

The respiratory related symptom cluster, psychological symptom cluster and cough-insomnia related symptom cluster were identified. The final model demonstrated a good fit with the data. Gender, stage of disease and monthly income were significant factors associated with symptom clusters. Respiratory related and cough-insomnia related symptom clusters had a direct negative impact on health-related quality of life, while the psychological symptom cluster was found to have a direct and indirect negative effect on health-related quality of life.

CONCLUSIONS

Final COPD symptom cluster model should serve as a framework to guide intervention research targeting symptom clusters to improve health-related quality of life of people living with COPD.

RELEVANCE TO CLINICAL PRACTICE

Nurses should be especially attuned to identify those at most risk of facing a higher symptom burden in this case those who are female, have advanced stage COPD and/or lower income. During the clinical symptom assessment, nurses should pay attention to the close relationships among symptoms within a cluster to identify any 'trigger' symptom that could cause the development or exacerbation of other symptoms.

Prevalence of fatigue and associated factors among clinically stable patients with chronic obstructive pulmonary disease in Guizhou, China: A cross-sectional study

INTRODUCTION

Fatigue is important, but ignored symptom among COPD patients. At present, there is very limited data are available for the prevalence of fatigue and its risk factors among COPD patients in China.

OBJECTIVE

The purpose of this study is to determine the prevalence of fatigue and to investigate the factors associated with fatigue among clinically stable patients with COPD in China.

METHODS

This is a cross-sectional study using a questionnaire to collect data on sociodemographic, related to COPD disease, and exercise habits. Multidimensional fatigue inventory (MFI-20) was used to assess the prevalence of fatigue. Independent samples t test, bivariate correlation, one-way ANOVA test, and test for several independent samples were used to compare the sociodemographic factors with MFI-20 scores of COPD patients. Multiple stepwise linear regression was performed to estimate influencing factors related to the MFI-20 of COPD patients.

RESULTS

Among the participants, the prevalence of fatigue was 88.62%. Negative correlations were found between FEV_1% and multidimensional fatigue (r = -0.40, p < 0.01), general fatigue (r = -0.20, p < 0.05), reduced activity (r = -0.20, p < 0.01), and physical fatigue (r = -0.10, p < 0.01). A multiple linear regression models revealed that age (p < 0.05), BMI (p < 0.05), FEV₁ % (p < 0.01), exercise times (p < 0.01), and the times of hospitalization in the past 12 months (p < 0.05) were associated with multidimensional fatigue scores.

CONCLUSIONS

The prevalence of fatigue is high among clinically stable patients with COPD. Keeping exercise, prevention obesity, and exacerbation should be an effective intervention strategy to reduce COPD-related fatigue.

The fatigue and quality of life in patients with chronic pulmonary diseases

BACKGROUND

Patients with pulmonary diseases often experience fatigue. Severe fatigue is associated with a worse health status and worse physical and social functioning. The study aimed to evaluate the relationship between fatigue and quality of life in patients with nonmalignant pulmonary diseases.

METHODS

The St George's Respiratory Questionnaire (SGRQ) was used to assess health status and the Fatigue Impact Scale (MFIS) to measure the level of fatigue. The Shapiro-Wilk test was used to test for normal distribution. Correlations were described as Spearman's rank correlation coefficient.

RESULTS

The study included 200 consecutive patients (mean age, 57.7) with the following diagnoses: COPD (26%), asthma (36%), obstructive sleep apnoea (19%), pneumonia or bronchitis of various aetiologies (8.5%), bronchiectasis (2.5%), interstitial lung disease (3%). The mean score in the SGRQ was 44.62 ± 24.94. The mean score in the MFIS was 28.64 ± 15.8. The strongest correlations appeared between quality-of-life scales and fatigue as measured by physical functioning (symptoms r = 0.622; activity r = 0.632; impact r = 0.692; p < 0.001 for all subscales); however, all the correlations between SGRQ and MFIS were significant.

CONCLUSIONS

Patients with chronic pulmonary diseases were revealed to have a reduced level of quality of life and an increased level of fatigue. The negative influence of fatigue on quality of life highlights the need for careful and routine assessment of this symptom in pulmonary patients. Treating fatigue may improve quality of life and increase the ability of patients with chronic pulmonary diseases to perform activities in daily life.

Physical Frailty in COPD Patients with Chronic Respiratory Failure

Background

The prevalence of physical frailty and its clinical characteristics in advanced chronic obstructive pulmonary disease (COPD) is unknown, as well as the usefulness of functional capacity tests to screen for physical frailty. The aim of the study was to evaluate the proportion and clinical portrait of COPD patients with chronic respiratory failure exhibiting physical frailty at the time of referral to home-based pulmonary rehabilitation. We also evaluate the usefulness of the short physical performance battery (SPPB) and timed-up and go (TUG) as potential screening tools for physical frailty. Finally, we evaluated the specific contribution of gait speed to the frailty Fried total score.

Methods

This was a prospective observational study in which physical frailty was defined using Fried criteria (body mass loss, exhaustion, low physical activity, slower walking and weakness). Clinical portrait was documented from daily physical activity, exercise tolerance, functional capacity, anxiety and depressive symptoms, health-related quality of life, and fatigue scores. The ability of the SPPB and TUG to predict physical frailty was investigated using receiver operating characteristic curves. Contribution of each Fried criteria was evaluated with a principal component analysis (PCA).

Results

Amongst the 44 included participants (FEV₁, 33 ± 13% of predicted), 19 were physically frail. Frail individuals had lower daily steps number, exercise tolerance and functional capacity, and higher fatigue, anxiety, and depressive symptom scores (p<0.05) compared to non-frail individuals. SPPB and TUG did not have an acceptable detection accuracy for screening physical frailty. PCA indicated that gait speed was the main contributor to the Fried total score of physical frailty.

Conclusion

Physical frailty affects a large proportion of COPD patients with chronic respiratory failure starting a home-based intervention and was associated with worse clinical status. Although the present results need to be confirmed by adequately powered studies, gait speed seems to have the potential to become a simple screening tool for physical frailty in this population.

The prevalence and related factors of fatigue in patients with COPD: a systematic review

BACKGROUND

Fatigue is a distressing symptom in patients with COPD. Little is known about the factors that contribute to fatigue in COPD. This review summarises existing knowledge on the prevalence of fatigue, factors related to fatigue and the instruments most commonly used to assess fatigue in COPD.

METHODS

Pubmed, PsycINFO, EMBASE, Cochrane and CINAHL databases were searched for studies from inception up to 7 January 2020 using the medical subject headings "COPD" and "Fatigue". Studies were reviewed in accordance with PRISMA guidelines.

RESULTS

196 studies were evaluated. The prevalence of fatigue ranged from 17-95%. Age (r=-0.23 to r=0.27), sex (r=0.11), marital status (r=-0.096), dyspnoea (r=0.13 to r=0.78), forced expiatory volume in 1 s % predicted (r=-0.55 to r=-0.076), number of exacerbations (r=0.27 to r=0.38), number of comorbidities (r=0.10), number of medications (r=0.35), anxiety (r=0.36 to r=0.61), depression (r=0.41 to r=0.66), muscle strength (r=-0.78 to r=-0.45), functional capacity (r=-0.77 to r=-0.14) and quality of life (r=0.48 to r=0.77) showed significant associations with fatigue.

CONCLUSIONS

Fatigue is a prevalent symptom in patients with COPD. Multiple physical and psychological factors seem to be associated with fatigue. Future studies are needed to evaluate these underlying factors in integral analyses in samples of patients with COPD.

Chronic Obstructive Pulmonary Disease Symptom Cluster Composition, Associated Factors, and Methodologies: A Systematic Review

This systematic review details symptom clusters, their compositions, and associated factors and appraises the methodologies of studies that reported symptom clusters in patients with chronic obstructive pulmonary disease (COPD). Ten studies were eligible for inclusion in this study. Four common symptom clusters were identified. Two theoretical frameworks, four statistical methods, and various symptom assessment tools were used to identify symptom clusters. Factors associated with symptom clusters included demographic, clinical, and biological factors. No studies examined the subjective experiences of symptom clusters. Overall, inconsistencies were identified in the composition of symptom clusters across studies. This may be due to variations in study design, assessment tools, and statistical methods. Future studies should attempt to arrive at a common definition, especially that is theoretically derived, for symptom clusters, standardize the criteria for symptoms for inclusion in the clusters, and focus on patients' subjective experience to inform which clusters are clinically relevant.

Energy management education and occupation-related outcomes in adults with chronic diseases: A scoping review

Introduction

Fatigue is a pervasive symptom of chronic disease that often interferes with occupational performance. Our objective was to describe what is known about energy management education and occupation-related outcomes in adults with chronic diseases.

Methods

Seven electronic databases were searched for relevant literature published before August 2019. Eligible articles were full-text, available in English, and studied energy management education in adults with a chronic disease. The first author assessed article eligibility with validation from a second reviewer, extracted characteristics of included studies, and described them using descriptive statistics. A narrative synthesis of findings was conducted for each chronic disease population.

Results

Forty-four studies addressed eight different chronic disease populations. The most common program delivery format was face-to-face in a group setting (42%), 39% of programs were informed by a learning theory, and their median cumulative length was 8 hours. Positive outcomes were associated with a specific, group-based energy management program in people with multiple sclerosis. The evidence on other energy management programs and in other chronic disease populations was more limited and inconclusive.

Conclusions

Further research is needed to understand the impact of energy management education in chronic disease populations beyond multiple sclerosis, and its impact on occupational performance.

The responsiveness of the Manchester Chronic Obstructive Pulmonary Disease Fatigue Scale to pulmonary rehabilitation

Background:

We examined the responsiveness of the Manchester Chronic Obstructive Pulmonary Disease (COPD) Fatigue Scale (MCFS) in patients with COPD following 8 weeks of pulmonary rehabilitation (PR).

Methods:

Patients (n = 273) with clinically stable COPD completed 8 weeks of outpatient multidisciplinary PR, comprising 2 h (1 h exercise and 1 h education) weekly. Anxiety, exercise capacity, quality of life, dyspnea, fatigue were measured pre- and post-PR, utilizing the Anxiety Inventory for Respiratory Disease (AIR), Incremental Shuttle Walk Test (ISWT), St. George’s Respiratory Questionnaire (SGRQ), and modified Medical Research Council (mMRC) scale and MCFS, respectively.

Results:

The mean (SD) age of participants was 72 (8) years, and 50% were women. Total MCFS score fell after PR mean (95% confidence interval) −4.89 (–7.90 to −3.79) as did domain scores: physical −1.89 (–2.33 to −1.46), cognition −1.37 (–1.65 to −1.09), and psychosocial −1.62 (–2.00 to −1.62). Total MCFS effect size (ES) was 0.55; and for domains, physical was 0.52, cognition was 0.59, and psychosocial was 0.51. The ES for AIR was 0.30, mMRC was 0.38, SGRQ was 0.66, and ISWT was 1.19. MCFS changes correlated with changes in both SGRQ (p < 0.002) and AIR (p < 0.004), but not ISWT (p = 0.30) or mMRC (p = 0.18). The AIR, SGRQ, mMRC, and ISWT all improved after PR (all, p < 0.001).

Conclusion:

The MCFS scale is a valid and responsive scale to measure fatigue in patients with COPD after pulmonary rehabilitation.

Pulmonary Rehabilitation Reduces Subjective Fatigue in COPD: A Responder Analysis

To date, it remains unknown which patients report a clinically-relevant improvement in fatigue following pulmonary rehabilitation (PR). The purpose of this study was to identify and characterize these responders. Demographics, lung function, anxiety (anxiety subscale of the 90-item symptom checklist (SCL-90-A)), depression (Beck depression inventory for primary care (BDI-PC)), exercise tolerance (six-minute walking distance test (6MWD)), and health status (Nijmegen clinical screening instrument (NCSI)) were assessed before and after a 12-week PR programme. Fatigue was assessed using the checklist individual strength (CIS)-Fatigue. Patients with a decline ≥ 10 points (minimally clinically important difference, MCID) on the CIS-Fatigue were defined as responders. Chronic obstructive pulmonary disease (COPD) patients (n = 446, 61 ± 9 years, 53% male, forced expiratory volume in 1 s (FEV1) 43% ± 18% predicted, 75% severe fatigue) were included. Mean change in fatigue after PR was 10 ± 12 points (p < 0.01) and exceeded the MCID. In total, 56% were identified as fatigue responders. Baseline CIS-Fatigue (45 ± 7 vs. 38 ± 9 points, respectively, p < 0.001) and health-related quality-of-life (HRQoL; p < 0.001) were different between responders and non-responders. No differences were found in demographics, baseline anxiety, depression, lung function, 6MWD, and dyspnoea (p-values > 0.01). Responders on fatigue reported a greater improvement in anxiety, depression, 6MWD, dyspnoea (all p-values < 0.001), and most health status parameters. PR reduces fatigue in COPD. Responders on fatigue have worse fatigue and HRQoL scores at baseline, and are also likely to be responders on other outcomes of PR.

A Systematic Review of Biological Mechanisms of Fatigue in Chronic Illness

Fatigue, a commonly reported symptom, is defined as an overwhelming, debilitating, and sustained sense of exhaustion that decreases the ability to function and carry out daily activities. To date, cancer researchers have been in the forefront in investigating the possible biological mechanisms of fatigue, identifying inflammation, dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, and activation of the autonomic nervous system. The purpose of this systematic review is to describe fatigue and what is known about the biological mechanisms described in cancer in five chronic, noninfectious illnesses: heart failure, multiple sclerosis, chronic kidney disease, rheumatoid arthritis, and chronic obstructive pulmonary disease. We searched PubMed and EMBASE using fatigue as a major Medical subject headings (MeSH) heading with each individual disease added as a search term followed by each biological mechanism. We included only primary research articles published in English between 1996 and 2016 describing studies conducted in adult humans. We identified 26 relevant articles. While there is some evidence that the biological mechanisms causing fatigue in cancer are also associated with fatigue in other chronic illnesses, more research is needed to explore inflammation, the HPA axis, and the autonomic nervous system, and other mechanisms in relation to fatigue in a variety of chronic illnesses.

A Comparison of Pain, Fatigue, Dyspnea and their Impact on Quality of Life in Pulmonary Rehabilitation Participants with Chronic Obstructive Pulmonary Disease

In addition to dyspnea and fatigue, pain is a prevalent symptom in chronic obstructive pulmonary disease (COPD). Understanding the relative prevalence, magnitude, and interference with aspects of daily living of these symptoms can improve COPD management. Therefore, the purposes of this study were to: (1) compare the prevalence and magnitude of dyspnea, fatigue, and pain and how each limits aspects of daily living; (2) determine the association between pain and the other two symptoms; and (3) assess the impact of these symptoms on quality of life in COPD. Participants were recruited from pulmonary rehabilitation programs. Pain, dyspnea, and fatigue were measured using the Brief Pain Inventory (BPI), Brief Fatigue Inventory (BFI), and Dyspnea Inventory (DI), respectively. Quality of life was measured using the Clinical COPD Questionnaire (CCQ). The prevalence of dyspnea, fatigue, and pain were 93%, 77%, and 74%, respectively. Individuals with COPD reported similar severity scores of the three symptoms. Dyspnea interfered with general activity more than pain (F_1.7,79.9 = 3.1, p < 0.05), whilst pain interfered with mood (F_{1.8, 82.7} = 3.6, p < 0.05) and sleep (F_1,46 = 7.4, p < 0.01) more than dyspnea and fatigue. These three symptoms were moderately-to-highly correlated with each other (ρ = 0.49-0.78, p < 0.01) and all individually impacted quality of life. In summary, pain is a common symptom in addition to dyspnea and fatigue in COPD; all three interfere similarly among aspects of daily living with some exceptions. Accordingly, management of COPD should include a multifaceted approach that addresses pain as well as dyspnea and fatigue.

Palliative care and management of troublesome symptoms for people with chronic obstructive pulmonary disease

People with advanced chronic obstructive pulmonary disease (COPD) have distressing physical and psychological symptoms, often have limited understanding of their disease, and infrequently discuss end-of-life issues in routine clinical care. These are strong indicators for expert multidisciplinary palliative care, which incorporates assessment and management of symptoms and concerns, patient and caregiver education, and sensitive communication to elicit preferences for care towards the end of life. The unpredictable course of COPD and the difficulty of predicting survival are barriers to timely referral and receipt of palliative care. Early integration of palliative care with respiratory, primary care, and rehabilitation services, with referral on the basis of the complexity of symptoms and concerns, rather than prognosis, can improve patient and caregiver outcomes. Models of integrated working in COPD could include: services triggered by troublesome symptoms such as refractory breathlessness; short-term palliative care; and, in settings with limited access to palliative care, consultation only in specific circumstances or for the most complex patients.

The Breathing, Thinking, Functioning clinical model: a proposal to facilitate evidence-based breathlessness management in chronic respiratory disease

Refractory breathlessness is a highly prevalent and distressing symptom in advanced chronic respiratory disease. Its intensity is not reliably predicted by the severity of lung pathology, with unhelpful emotions and behaviours inadvertently exacerbating and perpetuating the problem. Improved symptom management is possible if clinicians choose appropriate non-pharmacological approaches, but these require engagement and commitment from both patients and clinicians. The Breathing Thinking Functioning clinical model is a proposal, developed from current evidence, that has the potential to facilitate effective symptom control, by providing a rationale and focus for treatment.

The Frailty Phenotype and Palliative Care Needs of Older Survivors of Critical Illness

OBJECTIVES

To assess symptoms in older intensive care unit (ICU) survivors and determine whether post-ICU frailty identifies those with the greatest palliative care needs.

DESIGN

A prospective cohort study.

SETTING

Urban tertiary care hospital and community hospital.

PARTICIPANTS

Medical ICU survivors of mechanical ventilation aged 65 and older (N = 125).

MEASUREMENTS

Baseline measurements of the Edmonton Symptom Assessment Scale (ESAS), categorized as mild (0-3), moderate (4-6), and severe (7-10), and the frailty phenotype were made during the week before hospital discharge. Functional recovery was defined as a return to a Katz activity of daily living dependency count less than or equal to the prehospitalization dependency count within 3 months. In the last 29 participants recruited, we made additional assessments of fatigue and ESAS both at baseline and 1 month after discharge.

RESULTS

Fatigue was the most-prevalent moderate to severe symptom (74%), followed by dyspnea (53%), drowsiness (50%), poor appetite (47%), pain (45%), depression (42%), anxiety (36%), and nausea (17%). At 1-month follow-up, there were no significant differences in the proportions of participants with moderate to severe symptoms. Each increase in baseline ESAS fatigue severity category was associated with 55% lower odds of functional recovery (odds ratio = 0.45, 95% confidence interval = 0.24-0.84), independent of age, sex, comorbidities, and critical illness severity. Frail participants had a higher median baseline total ESAS symptom distress score (34, interquartile range (IQR) 23-44) than nonfrail participants (13, IQR 9-22) (P < .001).

CONCLUSION

Older ICU survivors have a high burden of palliative care needs that persist 1 month after discharge. Fatigue is the most-prevalent symptom and may interfere with recovery. Post-ICU frailty may be a useful trigger for palliative care consultation and a treatment target.

The Effect of Fatigue and Fatigue Intensity on Exercise Tolerance in Moderate COPD

INTRODUCTION

Fatigue is one of the most disabling symptoms in COPD, but little is known about the impact of fatigue on functional disability. We explored the impact of fatigue and fatigue intensity on exercise tolerance after adjusting for other factors using multivariate analysis and compared it to that of dyspnoea.

METHODS

A total of 119 patients with mainly moderate-severe stable COPD (38 % women, mean age 66 years) were enrolled. We used the Medical Research Council dyspnoea scores (MRC), Manchester COPD fatigue scale (MCFS) and its three dimensions, Borg scales for fatigue and dyspnoea, six-minute walk distance (6MWD), St George's Respiratory Questionnaire, the BODE index, and the Centre for Epidemiological Study on Depression scale (CES-D), and we measured spirometry, blood gases, systemic inflammatory markers and fat-free mass index (FFMI).

RESULTS

Fatigue measured using the MCFS was associated with 6MWD and explained 22 % of the variability in 6MWD (p < 0.001). Fatigue remained associated with 6MWD after adjusting for MRC dyspnoea, FFMI and FEV1, FVC, PaO2, PaCO2, CES-D, TNF-alpha, smoking status, age and gender. We found that 33, 50 and 23 % of patients reported an increase by 2 scores on Borg scales for fatigue, dyspnoea or both at the end of the 6MWT. Fatigue scores (both before and after the 6MWT) were negatively correlated with 6MWD after adjusting for FEV1, FFMI, CES-D score and age (p = 0.007 and 0.001, respectively).

CONCLUSION

In moderate stable COPD, fatigue may be a central driver of functional disability, to the same extent as dyspnoea.

Factors associated with experience of fatigue, and functional limitations due to fatigue in patients with stable COPD

BACKGROUND

The aim of this study was to determine the influence of selected physiological, psychological and situational factors on experience of fatigue, and functional limitations due to fatigue in patients with stable chronic obstructive pulmonary disease (COPD).

METHODS

In total 101 patients with COPD and 34 control patients were assessed for experience of fatigue, functional limitation due to fatigue (Fatigue Impact Scale), physiological [lung function, 6-minute walk distance (6MWD), body mass index (BMI), dyspnoea, interleukin (IL)-6, IL-8, high sensitivity C-reactive protein (hs-CRP), surfactant protein D], psychological (anxiety, depression, insomnia), situational variables (age, sex, smoking, living alone, education), and quality of life.

RESULTS

Fatigue was more common in patients with COPD than in control patients (72% versus 56%, p < 0.001). Patients with COPD and fatigue had lower lung function, shorter 6MWD, more dyspnoea, anxiety and depressive symptoms, and worse health status compared with patients without fatigue (all p < 0.01). No differences were found for markers of systemic inflammation. In logistic regression, experience of fatigue was associated with depression [odds ratio (OR) 1.69, 95% confidence interval (CI) 1.28-2.25) and insomnia (OR 1.75, 95% CI 1.19-2.54). In linear regression models, depression, surfactant protein D and dyspnoea explained 35% (R(2)) of the variation in physical impact of fatigue. Current smoking and depression explained 33% (R(2)) of the cognitive impact of fatigue. Depression and surfactant protein D explained 48% (R(2)) of the psychosocial impact of fatigue.

CONCLUSIONS

Experiences of fatigue and functional limitation due to fatigue seem to be related mainly to psychological but also to physiological influencing factors, with depressive symptoms, insomnia problems and dyspnoea as the most prominent factors. Systemic inflammation was not associated with perception of fatigue but surfactant protein D was connected to some dimensions of the impact of fatigue.

The Assessment of Burden of COPD (ABC) Scale: A Reliable and Valid Questionnaire

The newly developed Assessment of Burden of COPD (ABC) scale is a 14-item self-administered questionnaire which measures the physical, psychological, emotional and/or social burden as experienced by patients with chronic obstructive pulmonary disease (COPD). The ABC scale is part of the ABC tool that visualises the outcomes of the questionnaire. The aim of this study was to assess the reliability and construct validity of the ABC scale. This multi-centre survey study was conducted in the practices of 19 general practitioners and 9 pulmonologists throughout the Netherlands. Next to the ABC scale, patients with COPD completed the Saint George Respiratory Questionnaire (SGRQ). Reliability analyses were performed with data from 162 cases. Cronbach's alpha was 0.91 for the total scale. Test-retest reliability, measured at a two week interval (n = 137), had an intra-class correlation coefficient of 0.92. Analyses for convergent validity were performed with data from 133 cases. Discriminant and known-groups validity was analysed with data from 162 cases. The ABC scale total score had a strong correlation with the total score of the SGRQ (r = 0.72, p < 0.001) but a weak correlation with the forced expired volume in 1 second predicted (r = -0.28, p < 0.001). Subgroups with more severe disease, defined by GOLD-stage, frequency of exacerbations, activity level and depression scored statistically significantly (p < 0.05) worse on almost all domains of the ABC scale than the less severe subgroups. The ABC scale seems a valid and reliable tool with good discriminative properties.

Physical activity and fatigue in chronic obstructive pulmonary disease - A population based study

BACKGROUND

In subjects with chronic obstructive pulmonary disease (COPD), symptoms of fatigue, concomitant heart disease and low physical activity levels are more frequently described than in subjects without COPD. However, there are no population-based studies addressing the relationship between physical activity, fatigue and heart disease in COPD. The aim was to compare physical activity levels among subjects with and without COPD in a population based study, and to evaluate if concomitant heart disease and fatigue was associated to physical activity.

METHODS

In this, 470 subjects with COPD and 659 subjects without COPD (non-COPD) participated in examinations including structured interview and spirometry. A ratio of the forced expiratory volume in one second (FEV1)/best of forced vital capacity (FVC) and vital capacity (VC) < 0.7 was used to define COPD. Physical activity was assessed with the International Physical Activity Questionnaire (IPAQ), and fatigue with the Functional Assessment of Chronic Illness Therapy - Fatigue scale (FACIT-F).

RESULTS

The prevalence of low physical activity was higher among subjects with FEV1 < 80% predicted compared to non-COPD subjects (22.4% vs. 14.6%, p = 0.041). The factors most strongly associated with low physical activity in subjects with COPD were older age, OR 1.52, (95% CI 1.12-2.06), a history of heart disease, OR 2.11 (1.10-4.08), and clinically significant fatigue, OR 2.33 (1.31-4.13); while obesity was the only significant factor among non-COPD subjects, OR 2.26 (1.17-4.35).

CONCLUSION

Physical activity levels are reduced when lung function is decreased below 80% of predicted, and the factors associated with low physical activity are different among subject with and without COPD. We propose that the presence of fatigue and heart disease are useful to evaluate when identifying subjects for pulmonary rehabilitation.

Measuring fatigue as a symptom in COPD: From descriptors and questionnaires to the importance of the problem

Fatigue is a symptom commonly diagnosed in cancers and in many other chronic debilitating diseases and is one of the main therapeutic targets for various pharmacologic and non-pharmacologic interventions. However, in chronic obstructive pulmonary disease (COPD), this symptom, which can be considered as the main extrapulmonary clinical feature of the disease, can impact significantly on the health-related quality of life of the patients. The aims of this review are to discuss the issues related to fatigue assessment in COPD and to highlight the importance of this symptom in this setting based on the data retrieved from articles published between 1987 through August 2014 available on MEDLINE database. Fatigue can be measured by various scales or questionnaires that are designed for generic purposes or for COPD-related purposes but is still underdiagnosed and undertreated. This is due to the fact that its clinical and prognostic relevance are not appropriately acknowledged. The early identification of fatigue clinical descriptors from patients' reports could help with better management of this symptom.

Effect of home-based nursing pulmonary rehabilitation on patients with chronic obstructive pulmonary disease: a randomised clinical trial

Fatigue is a common symptom of patients with chronic obstructive pulmonary disease (COPD), and results in a reduction of daily activity and quality of life in patients with the disease. The authors aimed to identify the effect of home-based nursing pulmonary rehabilitation on fatigue, activities of daily living (ADL) and quality of life (QOL) in patients with COPD. A block randomisation method was used to randomise participants into case and control groups. Fatigue, ADL and QOL were assessed before and after the intervention in both groups. Independent and paired t-tests, chi-squared tests and covariance analysis were used to analysing data. Findings showed the significant decrease in the mean scores of fatigue (p<0.001) and significant improvement in mean scores of ADL (p<0.001) and QOL (p<0.001) after home-based nursing pulmonary rehabilitation in the case group. Home-based nursing pulmonary rehabilitation can be an effective, inexpensive and accessible programme for decreasing fatigue and improving ADL and QOL for patients with COPD.

Functional and psychological variables both affect daily physical activity in COPD: a structural equations model

BACKGROUND

Daily physical activity (DPA) level is reduced in patients with COPD. The aim of this study was to investigate the association of DPA with functional and psychological variables in these patients.

METHODS

155 COPD patients (102 males, median (IQR) age 62 years (54-69 years), predicted FEV1 60% (40-75%) were included. We assessed DPA (DigiWalker SW-200), functional capacity and psychological factors.

RESULTS

DPA level was significantly associated with all functional capacity variables and two psychological variables (Perceived Physical Ability Subscale, depression subscale of the Hospital Anxiety and Depression Scale). The six-minute walking distance and St. George Respiratory Questionnaire activity score explained 37% of the variance of DPA in a regression analysis. A structural equations model revealed that psychological variables indirectly explained DPA through functional capacity variables. DPA was stronger associated with functional capacity variables and weaker with psychological variables in patients with lower functional status than in patients with higher functional status.

CONCLUSIONS

Higher levels of DPA are associated with better functional capacity, but interestingly, DPA is also affected by psychological factors, though only indirectly, via functional capacity. The effect of specific treatment addressing psychological factors on DPA level and exercise tolerance needs further investigation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT00614796.

Determinação do limiar anaeróbio pela variabilidade da frequência cardíaca de pacientes com DPOC durante exercício em cicloergômetro

INTRODUÇÃO: A Doença Pulmonar Obstrutiva Crônica (DPOC) é caracterizada por alterações estruturais do parênquima pulmonar, acarretando manifestações sistêmicas. Além disso, esses pacientes podem apresentar marcada alteração do controle autonômico cardíaco. Nesse contexto, estudos investigando a variabilidade da frequência cardíaca (VFC) em pacientes com DPOC durante a realização de exercício físico em cicloergometro têm sido pouco explorados. OBJETIVO: Determinar o limiar anaeróbio por meio da VFC com o propósito de estabelecer parâmetros de avaliação e prescrição da intensidade de exercício desses pacientes em cicloergômetro. MATERIAIS E MÉTODOS: Foram avaliados oito pacientes do sexo masculino com diagnóstico de DPOC com idade média de 69,5 ± 7,6 anos. A frequência cardíaca foi analisada no repouso e em diferentes intensidades do exercício. O teste foi realizado em um cicloergômetro e consistiu em um período de aquecimento de quatro minutos em uma potência mínima. Foram, também, realizados degraus com potência inicial de 4W, com acréscimos de 5 em 5W, até que o paciente atingisse o limiar anaeróbio. RESULTADOS: Os pacientes que apresentaram maiores valores de VEF1 apresentaram maiores potências no cicloergômetro. Houve redução significativa da VFC durante o exercício físico se comparado ao repouso sentado p < 0,05. CONCLUSÃO: Os pacientes estudados apresentaram um severo descondicionamento físico reafirmado pela impossibilidade determinada pelo LA de 50% da amostra.

Examining fatigue in COPD: development, validity and reliability of a modified version of FACIT-F scale

Introduction

Fatigue is a disruptive symptom that inhibits normal functional performance of COPD patients in daily activities. The availability of a short, simple, reliable and valid scale would improve assessment of the characteristics and influence of fatigue in COPD.

Methods

At baseline, 2107 COPD patients from the ECLIPSE cohort completed the Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) scale. We used well-structured classic method, the principal components analysis (PCA) and Rasch analysis for structurally examining the 13-item FACIT-F.

Results

Four items were less able to capture fatigue characteristics in COPD and were deleted. PCA was applied to the remaining 9 items of the modified FACIT-F and resulted in three interpretable dimensions: i) general (5 items); ii) functional ability (2 items); and iii) psychosocial fatigue (2 items). The modified FACIT-F had high internal consistency (Cronbach's α = 0.91) and it did not fit a uni-dimensional Rasch model, confirming the prior output from the PCA. The correlations between total score and each dimension were ≥ 0.64 and within dimensions ≥0.43 (p < 0.001 for all).

The original and modified FACIT-F had significant convergent validity; its scores were associated with SGRQ total score (0.69 and 0.7) and mMRC dyspnoea scores (0.48 and 0.47), (p = <0.001 for all). The scale had meaningful discriminating ability in identifying patients with poor exercise performance and more depressive symptoms.

Conclusion

The original and modified FACIT-F are valid and reliable scales in COPD. The modified version is shorter and measures not only total fatigue but also its sub-components in COPD.

Long-term nose-only cigarette smoke exposure induces emphysema and mild skeletal muscle dysfunction in mice

Mouse models of chronic obstructive pulmonary disease (COPD) focus on airway inflammation and lung histology, but their use has been hampered by the lack of pulmonary function data in their assessment. Systemic effects such as muscle dysfunction are also poorly modeled in emphysematous mice. We aimed to develop a cigarette-smoke-induced emphysema mouse model in which serial lung function and muscular dysfunction could be assessed, allowing the disease to be monitored more appropriately. C57Bl6 mice were nose-only exposed to cigarette smoke or filtered air for 3–6 months. Lung function tests were repeated in the same mice after 3 and 6 months of cigarette smoke or air exposure and compared with lung histological changes. Contractile properties of skeletal muscles and muscle histology were also determined at similar time points in separate groups of mice. Serial lung function measurements documented hyperinflation after 3 and 6 months of cigarette smoke exposure, with a significant 31–37% increase in total lung capacity (TLC) and a significant 26–35% increase in compliance (Cchord) when compared with animals exposed to filtered air only (P<0.001 after 3 and after 6 months). These functional changes preceded the changes in mean linear intercept, which became only significant after 6 months of cigarette smoke exposure and which correlated very well with TLC (r=0.74, P=0.004) and Cchord (r=0.79, P=0.001). After 6 months of cigarette smoke exposure, a significant fiber-type shift from IIa to IIx/b was also observed in the soleus muscle (P<0.05), whereas a 20% reduction of force was present at high stimulation frequencies (80 Hz; P=0.09). The extensor digitorum longus (EDL) muscle was not affected by cigarette smoke exposure. These serial pulmonary function variables are sensitive outcomes to detect emphysema progression in a nose-only cigarette-smoke-exposed animal model of COPD. In this model, muscular changes became apparent only after 6 months, particularly in muscles with a mixed fiber-type composition.