Wearables, Physical Activity, and Exercise Testing in Liver Disease

Unsupervised Exercise Intervention vs. Adherence to a Mediterranean Diet Alone: The Role of Bioelectrical Impedance Vector Analysis and Cardiovascular Performance in Liver-Transplanted Recipients

(1) Background: Cardiovascular disease is one of the leading causes of mortality after liver transplantation. Body composition and cardiovascular performance assessment represent a potential approach for modulating lifestyle correction and proper follow-up in chronic disease patients. This study aimed to verify the additional role of an unsupervised physical activity program in a sample of male liver transplant recipients who follow the Mediterranean diet. (2) Methods: Thirty-three male liver transplant recipients were enrolled. Sixteen subjects followed a moderate-intensity home exercise program in addition to nutritional support, and seventeen received advice on the Mediterranean diet. After six months, bioelectrical vector impedance analysis (BIVA) and cardiopulmonary exercise testing (CPET) were performed. (3) Results: No differences in CPET (VO2 peak: exercise 21.4 ± 4.1 vs. diet 23.5 ± 6.5 mL/kg/min; p = 0.283) and BIVA (Z/H: exercise 288.3 ± 33.9 vs. diet 310.5 ± 34.2 Ω/m; p = 0.071) were found. Furthermore, the BIVA values of resistance correlate with the submaximal performance of the Ve/VCO2 slope (R = 0.509; p < 0.05) and phase angle with the maximal effort of the VO2 peak (R = 0.557; p < 0.05). (4) Conclusions: Unsupervised physical exercise alone for six months does not substantially modify liver transplant recipients' cardiovascular performance and hydration status, despite their adherence to a Mediterranean diet. The body composition analysis is useful to stratify the risk profile, and it is potentially associated with better outcomes in transplanted subjects.

Digital Therapeutics: Emerging New Therapy for Nonalcoholic Fatty Liver Disease

The increased prevalence of nonalcoholic fatty liver disease (NAFLD) worldwide is particularly worrisome, as no medication has been approved to treat the disease. Lifestyle modifications aimed at promoting weight loss and weight maintenance remain the current first-line treatment for NAFLD. However, due to the lack of standard and scientific guidance and out-of-hospital supervision, long-term outcomes of lifestyle interventions for patients with NAFLD are often unsatisfactory. In addition, the COVID-19 pandemic aggravated this dilemma. At the same time, digital therapeutics (DTx) are expected to be a new method for the convenient management and treatment of patients with NAFLD and are attracting a great deal of attention. DTx, which provide evidence-based medicine through software programs for remote intervention in preventing, treating, or managing diseases, overcome the drawbacks of traditional treatment. The efficacy of the approach has already been demonstrated for some chronic diseases, but DTx have not been fully developed for NAFLD. This study reviews the concepts, clinical value, and practical applications related to DTx, with an emphasis on recommendations based on unmet needs for NAFLD. A better understanding of the current state will help clinicians and researchers develop high-quality, standardized, and efficient DTx products, with the aim of optimizing the prognosis of patients with NAFLD.

Digital interventions in the management of advanced liver disease: Prescription and monitoring of healthy living in homes

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Smart Consumer Wearables as Digital Diagnostic Tools: A Review

The increasing usage of smart wearable devices has made an impact not only on the lifestyle of the users, but also on biological research and personalized healthcare services. These devices, which carry different types of sensors, have emerged as personalized digital diagnostic tools. Data from such devices have enabled the prediction and detection of various physiological as well as psychological conditions and diseases. In this review, we have focused on the diagnostic applications of wrist-worn wearables to detect multiple diseases such as cardiovascular diseases, neurological disorders, fatty liver diseases, and metabolic disorders, including diabetes, sleep quality, and psychological illnesses. The fruitful usage of wearables requires fast and insightful data analysis, which is feasible through machine learning. In this review, we have also discussed various machine-learning applications and outcomes for wearable data analyses. Finally, we have discussed the current challenges with wearable usage and data, and the future perspectives of wearable devices as diagnostic tools for research and personalized healthcare domains.

Mastering Core Recommendations during HEPAtology ROUNDS in Patients with Advanced Chronic Liver Disease

Efficient and thorough care of hospitalized patients with advanced chronic liver disease is of utter importance to improve outcomes and optimize quality of life. This requires understanding current evidence and best practices. To facilitate focus on up-to-date knowledge and a practical approach, we have created the HEPA-ROUNDS mnemonic while outlining a practical review of the literature with critical appraisal for the busy clinician. The HEPA-ROUNDS mnemonic provides a structured approach that incorporates critical concepts in terms of prevention, management, and prognostication of the most common complications frequently encountered in patients with advanced chronic liver disease. In addition, implementing the HEPA-ROUNDS mnemonic can facilitate education for trainees and staff caring for patients with advanced chronic liver disease.

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.

A Telemedicine Alternative to the 6-Minute Walk Test Using Personal Activity Trackers in Liver Transplant Candidates

The COVID-19 pandemic has limited liver transplant (LT) candidates access to clinics. Telehealth methods to assess frailty are needed. We developed a method to estimate the step length of LT candidates, which would permit remotely obtaining the 6-min walk test (6MWT) distance with a personal activity tracker (PAT).

Methods

6MWT was performed while candidates wore a PAT. On first 21 subjects (stride cohort), the step length was measured and compared with calculated one (6MWT-distance/6MWT steps). On a second cohort (PAT-6MWT; n = 116), we collected the 6MWT step count and used multivariable models to generate formulas estimating step length. We multiplied the estimated step length times 6MWT steps to estimate the distance and compared it to the measured distance. The liver frailty index (LFI) and 6MWT were used as frailty metrics.

Results

Measured/calculated step length were highly correlated (ρ = 0.85; P < 0.001) in the stride cohort. In the PAT-6MWT cohort, LFI was the strongest variable associated with step length, along with height, albumin, and large-volume paracentesis (R ² = 0.58). On a second model without LFI, age, height, albumin, hemoglobin, and large-volume paracentesis were strongly associated with step length (R ² = 0.45). There was a robust correlation between observed 6MWT and PAT-6MWT utilizing step length equations with (ρ = 0.80; P < 0.001) or without LFI (ρ = 0.75; P < 0.001). Frailty by 6MWT <250 m did not change significantly using the observed (16%) or the with/without LFI-estimated (14%/12%) methods.

Conclusions

We created a method to obtain 6MWT distance remotely with the use of a PAT. This novel approach opens the possibility of performing telemedicine PAT-6MWT to monitor LT candidates' frailty status.

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.