Editorial: Frailty, Comorbidity, and COPD

The role of TGF-β signaling in muscle atrophy, sarcopenia and cancer cachexia

Skeletal muscle, comprising a significant proportion (40 to 50 percent) of total body weight in humans, plays a critical role in maintaining normal physiological conditions. Muscle atrophy occurs when the rate of protein degradation exceeds protein synthesis. Sarcopenia refers to age-related muscle atrophy, while cachexia represents a more complex form of muscle wasting associated with various diseases such as cancer, heart failure, and AIDS. Recent research has highlighted the involvement of signaling pathways, including IGF1-Akt-mTOR, MuRF1-MAFbx, and FOXO, in regulating the delicate balance between muscle protein synthesis and breakdown. Myostatin, a member of the TGF-β superfamily, negatively regulates muscle growth and promotes muscle atrophy by activating Smad2 and Smad3. It also interacts with other signaling pathways in cachexia and sarcopenia. Inhibition of myostatin has emerged as a promising therapeutic approach for sarcopenia and cachexia. Additionally, other TGF-β family members, such as TGF-β1, activin A, and GDF11, have been implicated in the regulation of skeletal muscle mass. Furthermore, myostatin cooperates with these family members to impair muscle differentiation and contribute to muscle loss. This review provides an overview of the significance of myostatin and other TGF-β signaling pathway members in muscular dystrophy, sarcopenia, and cachexia. It also discusses potential novel therapeutic strategies targeting myostatin and TGF-β signaling for the treatment of muscle atrophy.

Systematic review and meta-analysis of prevalence, trajectories, and clinical outcomes for frailty in COPD

This systematic review synthesised measurement and prevalence of frailty in COPD and associations between frailty and adverse health outcomes. We searched Medline, Embase and Web of Science (1 January 2001-8 September 2021) for observational studies in adults with COPD assessing frailty prevalence, trajectories, or association with health-related outcomes. We performed narrative synthesis and random-effects meta-analyses. We found 53 eligible studies using 11 different frailty measures. Most common were frailty phenotype (n = 32), frailty index (n = 5) and Kihon checklist (n = 4). Prevalence estimates varied by frailty definitions, setting, and age (2.6-80.9%). Frailty was associated with mortality (5/7 studies), COPD exacerbation (7/11), hospitalisation (3/4), airflow obstruction (11/14), dyspnoea (15/16), COPD severity (10/12), poorer quality of life (3/4) and disability (1/1). In conclusion, frailty is a common among people with COPD and associated with increased risk of adverse outcomes. Proactive identification of frailty may aid risk stratification and identify candidates for targeted intervention.

Tailored or adapted interventions for adults with chronic obstructive pulmonary disease and at least one other long-term condition: a mixed methods review

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory condition characterised by shortness of breath, cough and recurrent exacerbations. People with COPD often live with one or more co-existing long-term health conditions (comorbidities). People with more severe COPD often have a higher number of comorbidities, putting them at greater risk of morbidity and mortality.

OBJECTIVES

To assess the effectiveness of any single intervention for COPD adapted or tailored to their comorbidity(s) compared to any other intervention for people with COPD and one or more common comorbidities (quantitative data, RCTs) in terms of the following outcomes: Quality of life, exacerbations, functional status, all-cause and respiratory-related hospital admissions, mortality, pain, and depression and anxiety. To assess the effectiveness of an adapted or tailored single COPD intervention (simple or complex) that is aimed at changing the management of people with COPD and one or more common comorbidities (quantitative data, RCTs) compared to usual care in terms of the following outcomes: Quality of life, exacerbations, functional status, all-cause and respiratory-related hospital admissions, mortality, pain, and depression and anxiety. To identify emerging themes that describe the views and experiences of patients, carers and healthcare professionals when receiving or providing care to manage multimorbidities (qualitative data).

SEARCH METHODS

We searched multiple databases including the Cochrane Airways Trials Register, CENTRAL, MEDLINE, Embase, and CINAHL, to identify relevant randomised and qualitative studies. We also searched trial registries and conducted citation searches. The latest search was conducted in January 2021.

SELECTION CRITERIA

Eligible randomised controlled trials (RCTs) compared a) any single intervention for COPD adapted or tailored to their comorbidity(s) compared to any other intervention, or b) any adapted or tailored single COPD intervention (simple or complex) that is aimed at changing the management of people with COPD and one or more comorbidities, compared to usual care. We included qualitative studies or mixed-methods studies to identify themes.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for analysis of the RCTs. We used Cochrane's risk of bias tool for the RCTs and the CASP checklist for the qualitative studies. We planned to use the Mixed Methods Appraisal tool (MMAT) to assess the risk of bias in mixed-methods studies, but we found none. We used GRADE and CERQual to assess the quality of the quantitative and qualitative evidence respectively. The primary outcome measures for this review were quality of life and exacerbations.

MAIN RESULTS

Quantitative studies We included seven studies (1197 participants) in the quantitative analyses, with interventions including telemonitoring, pulmonary rehabilitation, treatment optimisation, water-based exercise training and case management. Interventions were either compared with usual care or with an active comparator (such as land-based exercise training). Duration of trials ranged from 4 to 52 weeks. Mean age of participants ranged from 64 to 72 years and COPD severity ranged from mild to very severe. Trials included either people with COPD and a specific comorbidity (including cardiovascular disease, metabolic syndrome, lung cancer, head or neck cancer, and musculoskeletal conditions), or with one or more comorbidities of any type. Overall, we judged the evidence presented to be of moderate to very low certainty (GRADE), mainly due to the methodological quality of included trials and imprecision of effect estimates. Intervention versus usual care Quality of life as measured by the St George's Respiratory Questionnaire (SGRQ) total score may improve with tailored pulmonary rehabilitation compared to usual care at 52 weeks (mean difference (MD) -10.85, 95% confidence interval (CI) -12.66 to -9.04; 1 study, 70 participants; low-certainty evidence). Tailored pulmonary rehabilitation is likely to improve COPD assessment test (CAT) scores compared with usual care at 52 weeks (MD -8.02, 95% CI -9.44 to -6.60; 1 study, 70 participants, moderate-certainty evidence) and with a multicomponent telehealth intervention at 52 weeks (MD -6.90, 95% CI -9.56 to -4.24; moderate-certainty evidence). Evidence is uncertain about effects of pharmacotherapy optimisation or telemonitoring interventions on CAT improvement compared with usual care. There may be little to no difference in the number of people experiencing exacerbations, or mean exacerbations with case management compared with usual care (OR 1.09, 95% CI 0.75 to 1.57; 1 study, 470 participants; very low-certainty evidence). For secondary outcomes, six-minute walk distance (6MWD) may improve with pulmonary rehabilitation, water-based exercise or multicomponent interventions at 38 to 52 weeks (low-certainty evidence). A multicomponent intervention may result in fewer people being admitted to hospital at 17 weeks, although there may be little to no difference in a telemonitoring intervention. There may be little to no difference between intervention and usual care for mortality. Intervention versus active comparator We included one study comparing water-based and land-based exercise (30 participants). We found no evidence for quality of life or exacerbations. There may be little to no difference between water- and land-based exercise for 6MWD (MD 5 metres, 95% CI -22 to 32; 38 participants; very low-certainty evidence). Qualitative studies One nested qualitative study (21 participants) explored perceptions and experiences of people with COPD and long-term conditions, and of researchers and health professionals who were involved in an RCT of telemonitoring equipment. Several themes were identified, including health status, beliefs and concerns, reliability of equipment, self-efficacy, perceived ease of use, factors affecting usefulness and perceived usefulness, attitudes and intention, self-management and changes in healthcare use. We judged the qualitative evidence presented as of very low certainty overall.

AUTHORS' CONCLUSIONS

Owing to a paucity of eligible trials, as well as diversity in the intervention type, comorbidities and the outcome measures reported, we were unable to provide a robust synthesis of data. Pulmonary rehabilitation or multicomponent interventions may improve quality of life and functional status (6MWD), but the evidence is too limited to draw a robust conclusion. The key take-home message from this review is the lack of data from RCTs on treatments for people living with COPD and comorbidities. Given the variation in number and type of comorbidity(s) an individual may have, and severity of COPD, larger studies reporting individual patient data are required to determine these effects.

Supportive and palliative care for people with chronic respiratory disease and frailty

PURPOSE OF REVIEW

Frailty is a multidimensional syndrome associated with increased risk of poor outcomes. It is estimated that at least one in five people with chronic respiratory disease is also living with frailty. In this review, we consider recent advances in how frailty can be recognized, and its associated impact on people with chronic respiratory disease. We then discuss advances in supportive and palliative care for those with both chronic respiratory disease and frailty.

RECENT FINDINGS

The interconnectedness of chronic respiratory disease and frailty is being better understood. An increasing number of factors associated with frailty in respiratory disease have been identified, from increased symptom burden (e.g. breathlessness, fatigue) to increased exacerbations and higher mortality. These contribute to accumulating multidimensional losses in reserve, and unpredictable health. Recent advances in respiratory research, while not always with people with frailty, may inform supportive and palliative care to address frailty in chronic respiratory disease. These include rehabilitation interventions to strengthen reserves, advance care planning interventions to help manage unpredictable trajectories, and integrated models of care (e.g. incorporating respiratory, geriatric, and palliative care) to address multidimensional needs.

SUMMARY

Recent evidence supporting the role of rehabilitation, advance care planning, and early palliative care, may be of benefit to people living with chronic respiratory disease and frailty. Models showing integration across multiple specialities and professionals may have the most potential to meet the multidimensional needs of this group. Future research should develop and test models of care that address frailty and/or explore the role of frailty in triggering integrated multidisciplinary input.

Daily living activities, exercise capacity, cognition, and balance in COPD patients with and without frailty

BACKGROUND

Information on the interaction between frailty and chronic obstructive pulmonary disease (COPD) is limited.

AIMS

This study aimed to compare activities of daily living (ADL), exercise capacity, balance, and cognition in COPD patients with and without frailty.

METHODS

Twenty frail and 28 non-frail COPD patients aged 55 years and over were included. Frailty was determined according to Fried et al. Dyspnea was evaluated using the modified Medical Research Council (mMRC) dyspnea scale. Respiratory and peripheral muscle strength were measured. Functional capacity was assessed using a 6-min walk test (6MWT); ADL performance was evaluated using the Glittre ADL test. The balance was evaluated using the functional reach test (FRT). Cognitive function was assessed using the Montreal Cognitive Evaluation (MoCA) Test. Quality of life was measured using the COPD Assessment Test (CAT).

RESULTS

The mMRC and CAT scores were higher in the frail patients as compared with the non-frail patients (p < 0.05). The maximal inspiratory pressure, handgrip strength, 6MWT distance, and FRT score were lower in the frail patients as compared with the non-frail patients (p < 0.05). The duration for the Glittre ADL test was longer in the frail patients than the non-frail patients (p < 0.05). There was no significant difference between MoCA scores between groups (p > 0.05).

CONCLUSIONS

Frail COPD patients have increased dyspnea perception, impaired muscle strength, and functional capacity, ADL performance, balance, and quality of life. Whether pulmonary rehabilitation programs for patients with frail COPD need to be adapted with new rehabilitation strategies, including components of frailty, needs further investigation.

Improving Exercise-Based Interventions for People Living with Both COPD and Frailty: A Realist Review

Background

People living with both chronic obstructive pulmonary disease (COPD) and frailty have high potential to benefit from exercise-based interventions, including pulmonary rehabilitation, but face challenges completing them. Research to understand ways to optimise exercise-based interventions in this group is lacking. We aimed to understand how exercise-based interventions might improve outcomes for people living with both COPD and frailty.

Methods

This realist review used database searches and handsearching until October 2019 to identify articles of relevance to exercise-based interventions for people living with COPD and frailty. A scoping search explored what is important about the context of living with COPD and frailty, and what mechanisms might be important in how exercise-based interventions result in their intended outcomes. Through discussion with stakeholders, the review scope was refined to areas deemed pertinent to improving care. We retained articles within this refined scope and identified additional articles through targeted handsearching. Data were extracted and synthesised in a narrative, prioritised by relevance and rigour.

Results

Of 344 records identified, 35 were included in the review and 20 informed the final synthesis. Important contextual factors to consider included: negative beliefs about themselves and exercise-based interventions; heterogenous presentation and comorbidities; decreased reserves and multidimensional loss; and experiencing unpredictable health and disruptions. In these circumstances, mechanisms that may help maximise outcomes from exercise-based interventions included: trusting relationships; creating a shared understanding of needs; having the capacity to address multidimensional concerns; being able to individualise approaches to needs and priorities; and flexible approaches to intervention delivery. Mixed-methods research and explicit theorising were often absent.

Conclusion

Building trusting relationships, understanding priorities, using individualised and multidisciplinary approaches, and flexible service delivery can improve the value of exercise-based interventions for people living with both COPD and frailty. Development and evaluation of new and adapted interventions should consider these principles.

Is it possible to reverse frailty in patients with chronic obstructive pulmonary disease?

In recent years, frailty has attracted increasing attention from clinicians and health care workers. The influence of frailty on the elderly, especially those with chronic diseases of the respiratory system, is highly significant. Frailty is particularly more common in patients with chronic obstructive pulmonary disease (COPD). Frailty and COPD share many risk factors and pathophysiological mechanisms. As a comprehensive interventional method for chronic respiratory diseases, pulmonary rehabilitation is an important basic measure for the management of patients with COPD. Frailty in these patients can be reversed using pulmonary rehabilitation by targeting five components of the frailty phenotype at the entry point. The present review discusses the benefits of pulmonary rehabilitation in patients with COPD complicated by frailty and provides a theoretical basis for pulmonary rehabilitation treatment in this population. In addition, the timing of pulmonary rehabilitation is also addressed, with the prefrail stage being the "golden" period. The implementation of pulmonary rehabilitation must vary among individuals, and individualized treatment strategies will help maximize benefits.

Frailty in medically complex individuals with chronic HIV

OBJECTIVES

Multimorbidity and frailty are consequences of aging with HIV, yet not everyone with medical disease is frail. Our objective was to identify factors associated with frailty in a multimorbid HIV-infected cohort.

DESIGN

Analysis of a prospective, observational, longitudinal cohort.

METHODS

Three hundred and thirty-two participants in the medically advanced National NeuroAIDS Tissue Consortium (NNTC) study were categorized as frail, prefrail, or robust with the Fried Frailty Index. A series of logistic regression analyses (first univariate, then multivariable) were conducted to determine whether medical comorbidities, immunologic and virologic parameters, and/or neuropsychiatric variables predicted increased odds of frailty.

RESULTS

The mean number of medical comorbidities per participant was 2.7, mean CD4 T-cell count was 530 cells/μl, and 77% had undetectable HIV RNA in blood. Twenty-two percent were frail, 55% prefrail, and 23% robust. Significant predictors of frailty in multivariable analysis were cognitive diagnosis rendered by Frascati criteria, depressive symptoms, diabetes mellitus, chronic obstructive pulmonary disease (COPD), and sex. Men were less likely to be frail than women. Higher odds of frailty were seen with: symptomatic, but not asymptomatic, cognitive impairment (compared with cognitive normals); more depressive symptoms; diabetes mellitus; and COPD.

CONCLUSION

Neuropsychiatric illness increased odds of being frail on a predominantly physical/motoric measure, but only when symptomatic. Lack of association with asymptomatic impairment may reflect the importance of functional limitation to frailty, or possibly a unique resilience phenotype. Understanding why sex and symptomatic neuropsychiatric illness are associated with frailty will be important in managing HIV-associated morbidity in aging populations.