Patient and Caregiver Attitudes and Practices of Exercise in Candidates Listed for Liver Transplantation

Frailty in liver transplantation: Exploring prescribing exercise as medicine to improve patient outcomes

Liver transplantation (LT) represents a curative avenue for individuals with advanced chronic liver disease. Given the inherent illness severity of LT candidates, identifying patients at greater risk for adverse outcomes before and after transplantation is paramount. Approximately 50% of cirrhotic patients are frail and have considerable functional impairment. Various measures have been used to assess frailty, including performance-based tests and functional status evaluations. Frailty carries significant prognostic implications and predicts both mortality and pre- and post-LT complications. Contributing factors to frailty in this population include sarcopenia, malnutrition, inflammation, and psychosocial factors. Recognizing the prevalence of frailty among LT candidates, exercise interventions have been developed to improve physical frailty and offer potential to improve patient outcomes. While many interventions have demonstrated efficacy without notable adverse events, the absence of a universally accepted standard for exercise prescription underscores the variability in intervention elements and patient adherence. Given the safety profile of exercise interventions, there remains a critical need for standardized protocols and guidelines to optimize exercise regimens for LT candidates. This review delves into the landscape of frailty among LT candidates, elucidating its etiological underpinnings, impact on outcomes, utilization of exercise interventions, and the efficacy of exercise programs in reducing the burden frailty in those awaiting LT.

A randomized, controlled, prehabilitation intervention to maximize early recovery (PRIMER) in liver transplantation

Frailty and impaired functional status are associated with adverse outcomes on the liver transplant (LT) waitlist and after transplantation. Prehabilitation prior to LT has rarely been tested. We conducted a 2-arm patient-randomized pilot trial to evaluate the feasibility and efficacy of a 14-week behavioral intervention to promote physical activity prior to LT. Thirty patients were randomized 2:1 to intervention (n = 20) versus control (n = 10). The intervention arm received financial incentives and text-based reminders linked to wearable fitness trackers. Daily step goals were increased by 15% in 2-week intervals. Weekly check-ins with study staff assessed barriers to physical activity. The primary outcomes were feasibility and acceptability. Secondary outcomes included mean end-of-study step counts, short physical performance battery, grip strength, and body composition by phase angle. We fit regression models for secondary outcomes with the arm as the exposure adjusting for baseline performance. The mean age was 61, 47% were female, and the median Model for End-stage Liver Disease sodium (MELD-Na) was 13. One-third were frail or prefrail by the liver frailty index, 40% had impaired mobility by short physical performance battery, nearly 40% had sarcopenia by bioimpedance phase angle, 23% had prior falls, and 53% had diabetes. Study retention was 27/30 (90%; 2 unenrolled from intervention, 1 lost to follow-up in control arm). Self-reported adherence to exercise during weekly check-ins was about 50%; the most common barriers were fatigue, weather, and liver-related symptoms. End-of-study step counts were nearly 1000 steps higher for intervention versus control: adjusted difference 997, 95% CI, 147-1847; p = 0.02. On average, the intervention group achieved daily step targets 51% of the time. A home-based intervention with financial incentives and text-based nudges was feasible, highly accepted, and increased daily steps in LT candidates with functional impairment and malnutrition.

Effects of Early Resistance Training After Liver Transplantation Procedures: A Randomized Controlled Pilot Trial

BACKGROUND

Exercise interventions improve muscle performance and functionality when applied more than 6 months after liver trans- plantation, but no studies have reported on earlier exercise interventions. Hence, we assessed the effects of early resistance training on functional outcomes in adult liver recipients.

METHODS

The study included 30 liver transplantation patients (53.2 ± 12.4 years) randomly assigned to a training group (n = 15) or a control group (n = 15). Data collected preoperatively and 4 and 8 weeks post-surgery were analyzed, including peripheral and respiratory muscle strength, exercise capacity, physical performance, and fatigue. An 8-week physiotherapy program was applied (training group: standard physiotherapy + resistance training; control group: standard physiotherapy) for 2 sessions/day, 5 days/week.

RESULTS

Baseline data showed a homogeneous distribution in the between-group comparisons. In the within-group analysis; EG showed higher improvements in physical performance (TG: P = .001, CG: P = .05) and fatigue perception (TG: P = .001; CG: P = .006), than the CG. The TG showed eight-week improvements in exercise capacity, peripheral muscle strength, and maximal inspiratory pressure (P = .001), and maximal expiratory pressure (P = .047), while CG remained unchanged (P > .05). In the between-group analysis; the improvements indicated significant differences in deltoid strength and fatigue perception, in favor of the TG (P < .05). A change of 0.9 kg in peripheral muscle strength and >37.8 m in 6-min walk distance (6MWD) was determined, representing clinically significant improvement in liver recipients.

CONCLUSION

Early resistance training may improve muscle strength, exercise capacity, physical performance, and fatigue perception in liver recipients, when added to standard physiotherapy. The estimated minimal clinically important differences are meaningful to clini- cians in setting liver transplanted patient-specific goals.

Low Daily Step Count Is Associated With a High Risk of Hospital Admission and Death in Community-Dwelling Patients With Cirrhosis

BACKGROUND & AIMS

Daily step count measures cardiorespiratory fitness and has been associated with clinical outcomes. However, its utility in patients with cirrhosis remains largely unexplored. We aimed to investigate the association between step count, frailty metrics, and clinical outcomes in cirrhosis.

METHODS

All participants underwent frailty evaluation with the liver frailty index, 6-minute walk test, and gait speed test. To monitor step count, participants were given a personal activity tracker (PAT). A subset also was invited to use Exercise and Liver FITness (EL-FIT). Daily step counts from the first week of PAT use and frailty metrics were investigated as predictors of hospital admission and mortality.

RESULTS

There were 116 patients included (age, 56 ± 11 y; male, 55%; body mass index, 31 ± 7; model for end-stage liver disease-sodium, 15 ± 7). The main etiologies of cirrhosis were alcohol-related (33%) and nonalcoholic steatohepatitis (30%). Monitoring for the week was accomplished in 80% of participants given both PAT+EL-FIT vs 62% in those with PAT only (P = .04). During follow-up evaluation, hospital admission was observed in 55% and death in 15%. Kaplan-Meir curves showed increased readmission and deaths among patients performing in the lowest quartile (ie, <1200 steps/d). When adjusted by model for end-stage liver disease-sodium and EL-FIT use, the lowest quartile was associated with hospital admission and death (hazard ratio, HR [95% confidence interval], 1.90 [1.09-3.30] and 3.46 [1.23-9.68], respectively), along with the 6-minute walk test (HR, 0.63 [0.47-0.83] and 0.66 [0.44-0.99] per 100 m, respectively) and gait speed test (HR, 0.29 [0.11-0.72] and 0.21 [0.05-0.84], respectively).

CONCLUSIONS

Daily step count predicted hospital admission and mortality rates in patients with cirrhosis, similar to the current standard frailty metrics. Incorporation of a physical training-dedicated smartphone application was associated with increased PAT use and step reporting.

Prehabilitation-Driven Changes in Frailty Metrics Predict Mortality in Patients With Advanced Liver Disease

INTRODUCTION

Frailty is a predictor of morbidity and mortality in cirrhosis. Although evidence for prehabilitation is promising, the data for liver transplant (LT) candidates are limited. The primary aim of this study was to evaluate the effect of a novel prehabilitation strategy on changes in frailty metrics and survival in LT candidates. The secondary aim was to determine liver-related and extrahepatic conditions associated with frailty.

METHODS

In this ambispective cohort study, all patients underwent frailty assessment using the liver frailty index (LFI), 6-minute walk test, and gait speed test performed by a dedicated physical therapist. Home-based exercise prescription was individualized to each patient's baseline physical fitness.

RESULTS

We included 517 patients (59% men, median age 61 years, and a model for end-stage liver disease score of 12) evaluated during 936 PT visits. Frailty metrics were affected by age, sex, and liver-related parameters, but not by model for end-stage liver disease. Patients with nonalcoholic fatty liver disease and alcohol-related cirrhosis had worse frailty metrics by all tools. We demonstrated the feasibility of prehabilitation in improving both LFI and 6-minute walk test, particularly in adherent patients. A median LFI improvement of 0.3 in frail patients was associated with improved survival in univariate analysis. Compliance with physical therapist visits (hazards ratio = 0.35 [0.18-0.67] for 2 visits and hazards ratio = 0.54 [0.31-0.94] for ≥3 visits) was independently associated with increased survival.

DISCUSSION

Prehabilitation improves frailty metrics in LT candidates and is associated with a survival advantage. Our findings provide a framework for the standardized prehabilitation program in LT candidates while prioritizing compliance, adherence, and on-training LFI goal accomplishment.

Wearables, Physical Activity, and Exercise Testing in Liver Disease

Physical inactivity is a major cause of deterioration in all forms of advanced liver disease. It is especially important as a driver of the components of the metabolic syndrome, with nonalcoholic fatty liver disease rapidly becoming the dominant cause of liver-related death worldwide. Growing realization of the health benefits of moderate-to-vigorous physical activity has captured the interest of persons who desire to improve their health, including those at risk for chronic liver injury. They are increasingly adopting wearable activity trackers to measure the activity that they seek to improve. Improved physical activity is the key lifestyle behavior that can improve cardiorespiratory fitness, which is most accurately measured with cardiopulmonary exercise testing (CPET). CPET is showing promise to identify risk and predict outcomes in transplant hepatology. Team effort among engaged patients, social support networks, and clinicians supported by web-based connectivity is needed to fully exploit the benefits of physical activity tracking.

A Multicenter Pilot Randomized Clinical Trial of a Home-Based Exercise Program for Patients With Cirrhosis: The Strength Training Intervention (STRIVE)

INTRODUCTION

We developed the strength training intervention (STRIVE), a home-based exercise program targeting physical function in patients with cirrhosis. In this pilot study, we aimed to evaluate the safety and efficacy of STRIVE.

METHODS

Eligible were adult patients with cirrhosis at 3 sites. Patients were randomized 2:1-12 weeks of STRIVE, a 30-minute strength training video plus a health coach or standard of care (SOC). Physical function and quality of life were assessed using the Liver Frailty Index (LFI) and Chronic Liver Disease Questionnaire (CLDQ), respectively.

RESULTS

Fifty-eight and 25 were randomized to STRIVE and SOC arms, respectively: 43% women, median age was 61 years, MELDNa, Model for End-Stage Liver Disease Sodium was 14, and 54% were Child-Pugh B/C. Baseline characteristics were similar in the STRIVE vs SOC arms except for rates of hepatic encephalopathy (19 vs 36%). LFI @ 12 weeks was available in 43 STRIVE and 20 SOC participants. After 12 weeks, the median LFI improved from 3.8 to 3.6 (ΔLFI -0.1) in the STRIVE arm and 3.7 to 3.6 (ΔLFI -0.1) in the SOC arm (P = 0.65 for ΔLFI difference). CLDQ scores improved from 4.6 to 5.2 in STRIVE participants (ΔCLDQ 0.38) and did not change in SOC participants (4.2-4.2; ΔCLDQ -0.03) (P = 0.09 for ΔCLDQ difference). One patient died (SOC arm) of bleeding. Only 14% of STRIVE participants adhered to the strength training video for 10-12 weeks. No adverse events were reported by STRIVE participants.

DISCUSSION

STRIVE, a home-based structured exercise program for patients with cirrhosis, was safely administered at 3 sites, but adherence was low. Although all participants showed minimal improvement in the LFI, STRIVE was associated with a substantial improvement in quality of life.

Exercise and physical activity in cirrhosis: opportunities or perils

Reduced exercise capacity and impaired physical performance are observed in nearly all patients with liver cirrhosis. Physical activity and exercise are physiological anabolic stimuli that can reverse dysregulated protein homeostasis or proteostasis and potentially increase muscle mass and contractile function in healthy subjects. Cirrhosis is a state of anabolic resistance, and unlike the beneficial responses to exercise reported in physiological states, there are few systematic studies evaluating the response to exercise in cirrhosis. Hyperammonemia is a mediator of the liver-muscle axis with net skeletal muscle ammonia uptake in cirrhosis causing signaling perturbations, mitochondrial dysfunction with decreased ATP content, modifications of contractile proteins, and impaired ribosomal function, all of which contribute to anabolic resistance in cirrhosis and have the potential to impair the beneficial responses to exercise. English language-publications in peer-reviewed journals that specifically evaluated the impact of exercise in cirrhosis were reviewed. Most studies evaluated responses to endurance exercise, and readouts included peak or maximum oxygen utilization, grip strength, and functional capacity. Endurance exercise for up to 12 wk is clinically tolerated in well-compensated cirrhosis. Data on the safety of resistance exercise are conflicting. Nutritional supplements enhance the benefits of exercise in healthy subjects but have not been evaluated in cirrhosis. Whether the beneficial physiological responses with endurance exercise and increase in muscle mass with resistance exercise that occur in healthy subjects also occur in cirrhotics is not known. Specific organ-system responses, changes in body composition, or improved long-term clinical outcomes with exercise in cirrhosis need evaluation.