The Difficulties of Managing Pain in People Living with Frailty: The Potential for Digital Phenotyping.

Pain and frailty are closely linked. Chronic pain is a risk factor for frailty, and frailty is a risk factor for pain. People living with frailty also commonly have cognitive impairment, which can make assessment of pain and monitoring of pain management even more difficult. Pain may be sub-optimally treated in people living with frailty, people living with cognitive impairment and those with both these factors. Reasons for sub-optimal treatment in these groups are pharmacological (increased drug side effects, drug-drug interactions, polypharmacy), non-pharmacological (erroneous beliefs about pain, ageism, bidirectional communication challenges), logistical (difficulty in accessing primary care practitioners and unaffordable cost of drugs), and, particularly in cognitive impairment, related to communication difficulties. Thorough assessment and characterisation of pain, related sensations, and their functional, emotional, and behavioural consequences ("phenotyping") may help to enhance the assessment of pain, particularly in people with frailty and cognitive impairment, as this may help to identify who is most likely to respond to certain types of treatment. This paper discusses the potential role of "digital phenotyping" in the assessment and management of pain in people with frailty. Digital phenotyping is concerned with observable characteristics in digital form, such as those obtained from sensing-capable devices, and may provide novel and more informative data than existing clinical approaches regarding how pain manifests and how treatment strategies affect it. The processing of extensive digital and usual data may require powerful algorithms, but processing these data could lead to a better understanding of who is most likely to benefit from specific and targeted treatments.

Association between pain intensity and depressive symptoms in community-dwelling adults: longitudinal findings from the Survey of Health, Ageing and Retirement in Europe (SHARE).

PURPOSE: To investigate the longitudinal associations between pain and depressive symptoms in adults. METHODS: Prospective cohort study on data from 28,515 community-dwelling adults ≥ 50 years, free from depression at baseline (Wave 5), with follow-up in Wave 6 of the Survey of Health, Ageing and Retirement in Europe (SHARE). Significant depressive symptoms were defined by a EURO-D score ≥ 4. The longitudinal association between baseline pain intensity and significant depressive symptoms at follow-up was analysed using logistic regression models; odds ratios (ORs) and confidence intervals (CI) were calculated, adjusting for socio-demographic and clinical factors, physical inactivity, loneliness, mobility and functional impairments. RESULTS: Mean age was 65.4 years (standard deviation 9.0, range 50-99); 14,360 (50.4%) participants were women. Mean follow-up was 23.4 (standard deviation 3.4) months. At baseline, 2803 (9.8%) participants reported mild pain, 5253 (18.4%) moderate pain and 1431 (5.0%) severe pain. At follow-up, 3868 (13.6%) participants-1451 (10.3%) men and 2417 (16.8%) women-reported significant depressive symptoms. After adjustment, mild, moderate and severe baseline pain, versus no pain, were associated with an increased likelihood of significant depressive symptoms at follow-up: ORs (95% CI) were 1.20 (1.06-1.35), 1.32 (1.20-1.46) and 1.39 (1.19-1.63), respectively. These associations were more pronounced in men compared to women, and consistent in participants aged 50-64 years, those without mobility or functional impairment, and those without loneliness at baseline. CONCLUSION: Higher baseline pain intensity was longitudinally associated with a greater risk of significant depressive symptoms at 2-year follow-up, in community-dwelling adults without baseline depression.

Chronic pain in people living with dementia: challenges to recognising and managing pain, and personalising intervention by phenotype.

Pain is common in people with dementia, and pain can exacerbate the behavioural and psychological symptoms of dementia. Effective pain management is challenging, not least in people with dementia. Impairments of cognition, communication and abstract thought can make communicating pain unreliable or impossible. It is unclear which biopsychosocial interventions for pain management are effective in people with dementia, and which interventions for behavioural and psychological symptoms of dementia are effective in people with pain. The result is that drugs, physical therapies and psychological therapies might be either underused or overused. People with dementia and pain could be helped by assessment processes that characterise an individual's pain experience and dementia behaviours in a mechanistic manner, phenotyping. Chronic pain management has moved from a 'one size fits all' approach, towards personalised medicine, where interventions recommended for an individual depend upon the key mechanisms underlying their pain, and the relative values they place on benefits and adverse effects. Mechanistic phenotyping through careful personalised evaluation would define the mechanisms driving pain and dementia behaviours in an individual, enabling the formulation of a personalised intervention strategy. Central pain processing mechanisms are particularly likely to be important in people with pain and dementia, and interventions to accommodate and address these may be particularly helpful, not only to relieve pain but also the symptoms of dementia.

Association of pain and risk of falls in community-dwelling adults: a prospective study in the Survey of Health, Ageing and Retirement in Europe (SHARE).

PURPOSE: To investigate the longitudinal associations between pain and falls risks in adults. METHODS: Prospective cohort study on data from 40,636 community-dwelling adults ≥ 50 years assessed in Wave 5 and 6 in the Survey of Health, Ageing and Retirement in Europe (SHARE). Socio-demographic and clinical information was collected at baseline (Wave 5). At 2-year follow-up (Wave 6), falls in the previous 6 months were recorded. The longitudinal associations between pain intensity, number of pain sites and pain in specific anatomic sites, respectively, and falls risk were analysed by binary logistic regression models; odds ratios (95% confidence intervals) were calculated. All analyses were adjusted for socio-demographic and clinical factors and stratified by sex. RESULTS: Mean age was 65.8 years (standard deviation 9.3; range 50-103); 22,486 (55.3%) participants were women. At follow-up, 2805 (6.9%) participants reported fall(s) in the previous 6 months. After adjustment, participants with moderate and severe pain at baseline had an increased falls risk at follow-up of 1.35 (1.21-1.51) and 1.52 (1.31-1.75), respectively, compared to those without pain (both p < 0.001); mild pain was not associated with falls risk. Associations between pain intensity and falls risk were greater at younger age (p for interaction < 0.001). Among participants with pain, pain in ≥ 2 sites or all over (multisite pain) was associated with an increased falls risk of 1.29 (1.14-1.45) compared to pain in one site (p < 0.001). CONCLUSIONS: Moderate, severe and multisite pain were associated with an increased risk of subsequent falls in adults.

Comparison between first and second wave of COVID-19 outbreak in older people: the COPE multicentre European observational cohort study.

BACKGROUND: Effective shielding measures and virus mutations have progressively modified the disease between the waves, likewise healthcare systems have adapted to the outbreak. Our aim was to compare clinical outcomes for older people with COVID-19 in Wave 1 (W1) and Wave 2 (W2). METHODS: All data, including the Clinical Frailty Scale (CFS), were collected for COVID-19 consecutive patients, aged ≥65, from 13 hospitals, in W1 (February-June 2020) and W2 (October 2020-March 2021). The primary outcome was mortality (time to mortality and 28-day mortality). Data were analysed with multilevel Cox proportional hazards, linear and logistic regression models, adjusted for wave baseline demographic and clinical characteristics. RESULTS: Data from 611 people admitted in W2 were added to and compared with data collected during W1 (N = 1340). Patients admitted in W2 were of similar age, median (interquartile range), W2 = 79 (73-84); W1 = 80 (74-86); had a greater proportion of men (59.4% vs. 53.0%); had lower 28-day mortality (29.1% vs. 40.0%), compared to W1. For combined W1-W2 sample, W2 was independently associated with improved survival: time-to-mortality adjusted hazard ratio (aHR) = 0.78 [95% confidence interval (CI) 0.65-0.93], 28-day mortality adjusted odds ratio = 0.80 (95% CI 0.62-1.03). W2 was associated with increased length of hospital stay aHR = 0.69 (95% CI 0.59-0.81). Patients in W2 were less frail, CFS [adjusted mean difference (aMD) = -0.50, 95% CI -0.81, -0.18], as well as presented with lower C-reactive protein (aMD = -22.52, 95% CI -32.00, -13.04). CONCLUSIONS: COVID-19 older adults in W2 were less likely to die than during W1. Patients presented to hospital during W2 were less frail and with lower disease severity and less likely to have renal decline.

Feasibility of remote Memory Clinics using the plan, do, study, act (PDSA) cycle.

INTRODUCTION: A timely diagnosis of dementia is crucial for initiating and maintaining support for people living with dementia. The coronavirus disease (COVID) pandemic temporarily halted Memory Clinics, where this is organised, and rate of dementia diagnosis has fallen. Despite increasing use of alternatives to face-to-face (F2F) consultations in other departments, it is unclear whether this is feasible within the traditional Memory Clinic model. AIMS: The main aim of this service improvement project performed during the pandemic was to explore feasibility of telephone (TC) and videoconference (VC) Memory Clinic consultations. METHODS: Consecutive patients on the Memory Clinic waiting list were telephoned and offered an initial appointment by VC or TC. Data extracted included: age, internet-enabled device ownership, reason for and choice of Memory Clinic assessment. We noted Montreal Cognitive Assessment-Blind (TC) and Addenbrooke's Cognitive Examination-III (VC via Attend Anywhere) scores, and feasibility of consultation. RESULTS: Out of 100 patients, 12 had a home assessment, moved away, been hospitalised, or died. 45, 21 and 6 preferred F2F, VC and TC assessments respectively. 16 were not contactable and offered a F2F appointment. The main reason for preferring F2F was non-ownership, or inability to use an internet-enabled device (80%). VC and TC preference reasons were unwillingness to come to hospital (59%), and convenience (41%). Attendance rate was 100% for VC and TC, but 77% for F2F. Feasibility (successful consultations) was seen in 90% (VC) and 67% (TC) patients. CONCLUSION: For able and willing patients, remote Memory Consultations can be both feasible and beneficial. This has implications for future planning in dementia services.

The role of C-reactive protein as a prognostic marker in COVID-19.

BACKGROUND: C-reactive protein (CRP) is a non-specific acute phase reactant elevated in infection or inflammation. Higher levels indicate more severe infection and have been used as an indicator of COVID-19 disease severity. However, the evidence for CRP as a prognostic marker is yet to be determined. The aim of this study is to examine the CRP response in patients hospitalized with COVID-19 and to determine the utility of CRP on admission for predicting inpatient mortality. METHODS: Data were collected between 27 February and 10 June 2020, incorporating two cohorts: the COPE (COVID-19 in Older People) study of 1564 adult patients with a diagnosis of COVID-19 admitted to 11 hospital sites (test cohort) and a later validation cohort of 271 patients. Admission CRP was investigated, and finite mixture models were fit to assess the likely underlying distribution. Further, different prognostic thresholds of CRP were analysed in a time-to-mortality Cox regression to determine a cut-off. Bootstrapping was used to compare model performance [Harrell's C statistic and Akaike information criterion (AIC)]. RESULTS: The test and validation cohort distribution of CRP was not affected by age, and mixture models indicated a bimodal distribution. A threshold cut-off of CRP ≥40 mg/L performed well to predict mortality (and performed similarly to treating CRP as a linear variable). CONCLUSIONS: The distributional characteristics of CRP indicated an optimal cut-off of ≥40 mg/L was associated with mortality. This threshold may assist clinicians in using CRP as an early trigger for enhanced observation, treatment decisions and advanced care planning.

Routine use of immunosuppressants is associated with mortality in hospitalised patients with COVID-19.

BACKGROUND: Whilst there is literature on the impact of SARS viruses in the severely immunosuppressed, less is known about the link between routine immunosuppressant use and outcome in COVID-19. Consequently, guidelines on their use vary depending on specific patient populations. METHODS: The study population was drawn from the COPE Study (COVID-19 in Older People), a multicentre observational cohort study, across the UK and Italy. Data were collected between 27 February and 28 April 2020 by trained data-collectors and included all unselected consecutive admissions with COVID-19. Load (name/number of medications) and dosage of immunosuppressant were collected along with other covariate data. Primary outcome was time-to-mortality from the date of admission (or) date of diagnosis, if diagnosis was five or more days after admission. Secondary outcomes were Day-14 mortality and time-to-discharge. Data were analysed with mixed-effects, Cox proportional hazards and logistic regression models using non-users of immunosuppressants as the reference group. RESULTS: In total 1184 patients were eligible for inclusion. The median (IQR) age was 74 (62-83), 676 (57%) were male, and 299 (25.3%) died in hospital (total person follow-up 15,540 days). Most patients exhibited at least one comorbidity, and 113 (~10%) were on immunosuppressants. Any immunosuppressant use was associated with increased mortality: aHR 1.87, 95% CI: 1.30, 2.69 (time to mortality) and aOR 1.71, 95% CI: 1.01-2.88 (14-day mortality). There also appeared to be a dose-response relationship. CONCLUSION: Despite possible indication bias, until further evidence emerges we recommend adhering to public health measures, a low threshold to seek medical advice and close monitoring of symptoms in those who take immunosuppressants routinely regardless of their indication. However, it should be noted that the inability to control for the underlying condition requiring immunosuppressants is a major limitation, and hence caution should be exercised in interpretation of the results. PLAIN LANGUAGE SUMMARY: Regular Use of Immune Suppressing Drugs is Associated with Increased Risk of Death in Hospitalised Patients with COVID-19 Background: We do not have much information on how the COVID-19 virus affects patients who use immunosuppressants, drugs which inhibit or reduce the activity of the immune system. There are various conflicting views on whether immune-suppressing drugs are beneficial or detrimental in patients with the disease. Methods: This study collected data from 10 hospitals in the UK and one in Italy between February and April 2020 in order to identify any association between the regular use of immunosuppressant medicines and survival in patients who were admitted to hospital with COVID-19. Results: 1184 patients were included in the study, and 10% of them were using immunosuppressants. Any immunosuppressant use was associated with increased risk of death, and the risk appeared to increase if the dose of the medicine was higher. Conclusion: We therefore recommend that patients who take immunosuppressant medicines routinely should carefully adhere to social distancing measures, and seek medical attention early during the COVID-19 pandemic.

The influence of ACE inhibitors and ARBs on hospital length of stay and survival in people with COVID-19.

OBJECTIVE: During the COVID-19 pandemic the continuation or cessation of angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs) has been contentious. Mechanisms have been proposed for both beneficial and detrimental effects. Recent studies have focused on mortality with no literature having examined length of hospital stay. The aim of this study was to determine the influence of ACEi and ARBs on COVID-19 mortality and length of hospital stay. METHODS: COPE (COVID-19 in Older People) is a multicenter observational study including adults of all ages admitted with either laboratory or clinically confirmed COVID-19. Routinely generated hospital data were collected. Primary outcome: mortality; secondary outcomes: Day-7 mortality and length of hospital stay. A mixed-effects multivariable Cox's proportional baseline hazards model and logistic equivalent were used. RESULTS: 1371 patients were included from eleven centres between 27th February to 25th April 2020. Median age was 74 years [IQR 61-83]. 28.6% of patients were taking an ACEi or ARB. There was no effect of ACEi or ARB on inpatient mortality (aHR = 0.85, 95%CI 0.65-1.11). For those prescribed an ACEi or ARB, hospital stay was significantly reduced (aHR = 1.25, 95%CI 1.02-1.54, p = 0.03) and in those with hypertension the effect was stronger (aHR = 1.39, 95%CI 1.09-1.77, p = 0.007). CONCLUSIONS: Patients and clinicians can be reassured that prescription of an ACEi or ARB at the time of COVID-19 diagnosis is not harmful. The benefit of prescription of an ACEi or ARB in reducing hospital stay is a new finding.

The Clinical Frailty Scale: Estimating the Prevalence of Frailty in Older Patients Hospitalised with COVID-19. The COPE Study.

Frailty assessed using Clinical Frailty Scale (CFS) is a good predictor of adverse clinical events including mortality in older people. CFS is also an essential criterion for determining ceilings of care in people with COVID-19. Our aims were to assess the prevalence of frailty in older patients hospitalised with COVID-19, their sex and age distribution, and the completion rate of the CFS tool in evaluating frailty. Methods: Data were collected from thirteen sites. CFS was assessed routinely at the time of admission to hospital and ranged from 1 (very fit) to 9 (terminally ill). The completion rate of the CFS was assessed. The presence of major comorbidities such as diabetes and cardiovascular disease was noted. Results: A total of 1277 older patients with COVID-19, aged ≥ 65 (79.9 ± 8.1) years were included in the study, with 98.5% having fully completed CFS. The total prevalence of frailty (CFS ≥ 5) was 66.9%, being higher in women than men (75.2% vs. 59.4%, p < 0.001). Frailty was found in 161 (44%) patients aged 65-74 years, 352 (69%) in 75-84 years, and 341 (85%) in ≥85 years groups, and increased across the age groups (<0.0001, test for trend). Conclusion: Frailty was prevalent in our cohort of older people admitted to hospital with COVID-19. This indicates that older people who are also frail, who go on to contract COVID-19 may have disease severity significant enough to warrant hospitalization. These data may help inform health care planners and targeted interventions and appropriate management for the frail older person.

The effect of frailty on survival in patients with COVID-19 (COPE): a multicentre, European, observational cohort study.

BACKGROUND: The COVID-19 pandemic has placed unprecedented strain on health-care systems. Frailty is being used in clinical decision making for patients with COVID-19, yet the prevalence and effect of frailty in people with COVID-19 is not known. In the COVID-19 in Older PEople (COPE) study we aimed to establish the prevalence of frailty in patients with COVID-19 who were admitted to hospital and investigate its association with mortality and duration of hospital stay. METHODS: This was an observational cohort study conducted at ten hospitals in the UK and one in Italy. All adults (≥18 years) admitted to participating hospitals with COVID-19 were included. Patients with incomplete hospital records were excluded. The study analysed routinely generated hospital data for patients with COVID-19. Frailty was assessed by specialist COVID-19 teams using the clinical frailty scale (CFS) and patients were grouped according to their score (1-2=fit; 3-4=vulnerable, but not frail; 5-6=initial signs of frailty but with some degree of independence; and 7-9=severe or very severe frailty). The primary outcome was in-hospital mortality (time from hospital admission to mortality and day-7 mortality). FINDINGS: Between Feb 27, and April 28, 2020, we enrolled 1564 patients with COVID-19. The median age was 74 years (IQR 61-83); 903 (57·7%) were men and 661 (42·3%) were women; 425 (27·2%) had died at data cutoff (April 28, 2020). 772 (49·4%) were classed as frail (CFS 5-8) and 27 (1·7%) were classed as terminally ill (CFS 9). Compared with CFS 1-2, the adjusted hazard ratios for time from hospital admission to death were 1·55 (95% CI 1·00-2·41) for CFS 3-4, 1·83 (1·15-2·91) for CFS 5-6, and 2·39 (1·50-3·81) for CFS 7-9, and adjusted odds ratios for day-7 mortality were 1·22 (95% CI 0·63-2·38) for CFS 3-4, 1·62 (0·81-3·26) for CFS 5-6, and 3·12 (1·56-6·24) for CFS 7-9. INTERPRETATION: In a large population of patients admitted to hospital with COVID-19, disease outcomes were better predicted by frailty than either age or comorbidity. Our results support the use of CFS to inform decision making about medical care in adult patients admitted to hospital with COVID-19. FUNDING: None.

Performance status agreement assessed by the patient and clinician in a rapid access lung cancer service: Can either predict completion of treatment?

INTRODUCTION: Clinician-rated performance status (C-PS) is used routinely to predict whether patients are fit enough to undergo treatment for lung cancer. However, a good proportion of those with seemingly good C-PS do not go on to receive, let alone complete treatment. The value of C-PS in accurately predicting this is unclear, as is the merit of evaluating patient-rated PS (P-PS). OBJECTIVES: Our aim was to prospectively assess Eastern Cooperative Oncology Group (ECOG) and Karnofsky C-PS and P-PS in patients attending a rapid access lung cancer service (RALCS), the agreement between these scores, and whether any score could predict receipt and completion of multidisciplinary team (MDT)-planned treatment. RESULTS: ECOG and Karnofsky scores were highly correlated (Spearman's rho -0.79 for C-PS and -0.828 for P-PS, both p < 0.001). There was poor agreement between C-PS and P-PS scores (kappa statistics 0.275 for ECOG and 0.172 for Karnofsky); however, clinicians did not tend to consistently under- or overestimate patients' scores. ECOG P-PS showed an association with completion of MDT-planned treatment (p = 0.007), but C-PS did not. CONCLUSION: Clinician-rated PS was not associated with completion of MDT-planned treatment, but there may be a role for patient-rated PS. C-PS and P-PS were poorly correlated in a RALCS.

The value of physical performance measurements alongside assessment of sarcopenia in predicting receipt and completion of planned treatment in non-small cell lung cancer: an observational exploratory study.

INTRODUCTION: The presence of muscle mass depletion is associated with poor outcomes and survival in cancer. Alongside muscle mass, assessment of muscle strength or physical performance is essential for the diagnosis of sarcopenia. Non-small cell lung cancer (NSCLC) is a prevalent form of cancer with high mortality, and Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) is commonly used to assess patients' suitability for treatment. However, a significant proportion of patients with good PS are unable to complete multidisciplinary team (MDT)-planned treatment. Little is known about the ability of objective measurements of physical performance in predicting patients' ability to complete MDT-planned treatment and outcomes in NSCLC. OBJECTIVES: We sought to establish whether physical performance, utilising the short physical performance battery (SPPB), alongside muscle mass measurements, was able to predict receipt and completion of MDT-planned treatment, with a focus on chemotherapy in NSCLC. MATERIALS AND METHODS: Participants with NSCLC treated through a single lung cancer MDT and ECOG PS 0-2 were recruited and the following assessed: body composition [bioelectrical impedance (BIA) and whole body dual-energy X-ray absorptiometry (DXA) in a subset], physical performance (SPPB), PS and nutritional status. We recorded receipt and completion of chemotherapy, as well as any adverse effects, hospitalisations, and treatment delays. RESULTS: We included a total of 62 participants with NSCLC, and in 26 of these, the MDT-planned treatment was chemotherapy. Participants with earlier stage disease and weight loss of <10% were more likely to complete MDT-planned treatment (p < 0.001 and p < 0.05). Patients with a higher total SPPB score were more likely to complete more cycles of chemotherapy as well as the full course. Quicker gait speeds and sit-to-stand times were associated with completion of three or more cycles of chemotherapy (all p < 0.05). For every unit increase in SPPB score, there was a 28.2% decrease in adverse events, hospitalisations and delays of chemotherapy (incidence rate ratio 0.718, p = 0.001), whilst ECOG PS showed no correlation with these outcomes. CONCLUSION: Assessing physical performance by SPPB is quick and simple to do in clinical settings and may give better indication of likely chemotherapy treatment course completion than muscle mass alone and ECOG PS. In turn, this may identify specific targets for early functional intervention and impact on MDT decision-making and prudent use of resources.

Association of sarcopenia and observed physical performance with attainment of multidisciplinary team planned treatment in non-small cell lung cancer: an observational study protocol.

BACKGROUND: Non-small cell lung cancer (NSCLC) frequently presents in advanced stages. A significant proportion of those with reportedly good ECOG performance status (PS) fail to receive planned multidisciplinary team (MDT) treatment, often for functional reasons, but an objective decline in physical performance is not well described. Sarcopenia, or loss of muscle mass, is an integral part of cancer cachexia. However, changes in both muscle mass and physical performance may predate clinically overt cachexia, and may be present even with normal body mass index. Physical fitness for treatment is currently subjectively assessed by means of the PS score, which may be inadequate in predicting tolerance to treatment. This study aims to evaluate whether measuring physical performance and muscle mass at baseline in NSCLC patients, in addition to PS score, is able to predict commencement and successful completion of MDT-planned treatment. METHODS/DESIGN: This is a prospective, single-centre exploratory study of NSCLC patients attending a Rapid Access Lung Cancer clinic. Baseline data collected are (methods in brackets): physical performance (Short Physical Performance Battery), muscle mass (bioelectrical impedance ± dual energy x-ray absorptiometry), patient and physician-assessed PS (ECOG and Karnofsky), nutritional status and presence of cachexia. Longitudinal data consists of receipt and completion of MDT treatment plan. The primary outcome measure is commencement of MDT-planned treatment, and important secondary outcomes include successful completion of treatment, length of stay in surgical patients, and risk of chemotherapy- and radiotherapy-related side effects. DISCUSSION: A more comprehensive assessment of phenotype, particularly with regards to physical performance and muscle mass, will provide additional discriminatory information of patients' fitness for treatment. If positive, this study has the potential to identify targets for early intervention in those who are at risk of deterioration. This will subsequently enable optimisation of performance of patients with NSCLC, in anticipation of systemic treatment.

The assessment and impact of sarcopenia in lung cancer: a systematic literature review.

OBJECTIVES: There is growing awareness of the relationship between sarcopenia (loss of muscle mass and function), and outcomes in cancer, making it a potential target for future therapies. In order to inform future research and practice, we undertook a systematic review of factors associated with loss of muscle mass, and the relationship between muscle function and muscle mass in lung cancer, a common condition associated with poor outcomes. DESIGN: We conducted a computerised systematic literature search on five databases. Studies were included if they explored muscle mass as an outcome measure in patients with lung cancer, and were published in English. SETTING: Secondary care. PARTICIPANTS: Patients with lung cancer. PRIMARY OUTCOME: Factors associated with loss of muscle mass and muscle function, or sarcopenia, and the clinical impact thereof in patients with lung cancer. RESULTS: We reviewed 5726 citations, and 35 articles were selected for analysis. Sarcopenia, as defined by reduced muscle mass alone, was found to be very prevalent in patients with lung cancer, regardless of body mass index, and where present was associated with poorer functional status and overall survival. There were diverse studies exploring molecular and metabolic factors in the development of loss of muscle mass; however, the precise mechanisms that contribute to sarcopenia and cachexia remain uncertain. The effect of nutritional supplements and ATP infusions on muscle mass showed conflicting results. There are very limited data on the correlation between degree of sarcopenia and muscle function, which has a non-linear relationship in older non-cancer populations. CONCLUSIONS: Loss of muscle mass is a significant contributor to morbidity in patients with lung cancer. Loss of muscle mass and function may predate clinically overt cachexia, underlining the importance of evaluating sarcopenia, rather than weight loss alone. Understanding this relationship and its associated factors will provide opportunities for focused intervention to improve clinical outcomes.