Are Predictive Energy Expenditure Equations Accurate in Cirrhosis?

Redefining Nutritional Requirements in End-Stage Liver Disease: Towards a Personalized Approach

Malnutrition is ubiquitous in cirrhotic patients presenting for liver transplant (LT). Providing an appropriate energy prescription is fundamental to effective nutrition therapy. We aimed to compare measured energy expenditure (mEE) with predicted energy expenditure (pEE) in patients awaiting LT and determine clinical factors associated with mEE. In this prospective observational study, energy expenditure was measured by indirect calorimetry in 110 adult patients referred for LT and predicted by commonly utilized equations (Harris-Benedict, Schofield, and EASL guidelines). Nutritional status, anthropometry, muscle function, biochemical and clinical data were also collected. The median model for end-stage liver disease (MELD) was 19 (IQR 13, 25), and the majority were Child-Pugh B (51%) or C (37%). Malnutrition was evident in 85%. Median mEE by calorimetry was 1756 (1531, 2104) kcal/d and significantly higher than pEE as per Harris-Benedict 1480 (1322, 1722) kcal/d and Schofield 1474 (1349, 1723) kcal/d (both p < 0.001), but lower than EASL guidelines (35 kcal/kg) when an activity factor was applied to mEE; 2283 (1990, 2735) kcal/d versus 2590 (2178, 3010) kcal/d (p < 0.001). Hypermetabolism (mEE:pEE > 1.2) was evident in 48% of the cohort. Multivariate analysis found MELD, Child-Pugh class, diuretic use, and severe malnutrition to be independent predictors of hypermetabolism. A new liver-specific predictive model has been developed, showing superior agreement with mEE than common predictive equations. In conclusion, there is a poor correlation between mEE and pEE in patients awaiting LTs, and hypermetabolism is common. Relying on historical predictive equations in this patient population may result in significant under or over-feeding. A tailored energy prescription based on indirect calorimetry or a liver-specific predictive model is recommended for LT candidates.

Predicted estimates of resting energy expenditure have limited clinical utility in patients with cirrhosis

BACKGROUND & AIMS

Malnutrition is associated with adverse clinical outcomes in patients with cirrhosis. Accurate assessment of energy requirements is needed to optimize dietary intake. Resting energy expenditure (REE), the major component of total energy expenditure, can be measured using indirect calorimetry (mREE) or estimated using prediction equations (pREE). This study assessed the usefulness of predicted estimates of REE in this patient population.

METHODS

Individual mREE data were available for 900 patients with cirrhosis (mean [±1 SD] age 55.7±11.6 years-old; 70% men; 52% south-east Asian) and 282 healthy controls (mean age 36.0±12.8 years-old; 52% men; 18% south-east Asian). Metabolic status was classified using thresholds based on the mean ± 1 SD of the mREE in the healthy controls. Comparisons were made between mREE and pREE estimates obtained using the Harris-Benedict, Mifflin, Schofield and Henry equations. Stepwise regression was used to build 3 new prediction models which included sex, ethnicity, body composition measures, and model for end-stage liver disease scores.

RESULTS

The mean mREE was significantly higher in patients than controls when referenced to dry body weight (22.4±3.8 cf. 20.8±2.6 kcal/kg/24 hr; p <0.001); there were no significant sex differences. The mean mREE was significantly higher in Caucasian than Asian patients (23.1±4.4 cf. 21.7±2.9 kcal/kg/24 hr; p <0.001). Overall, 37.1% of Caucasian and 25.3% of Asian patients were classified as hypermetabolic. The differences between mREE and pREE were both statistically and clinically relevant; in the total patient population, pREE estimates ranged from 501 kcal/24 hr less to 548 kcal/24 hr more than the mREE. Newly derived prediction equations provided better estimates of mREE but still had limited clinical utility.

CONCLUSIONS

Prediction equations do not provide useful estimates of REE in patients with cirrhosis. REE should be directly measured.

LAY SUMMARY

People with cirrhosis are often malnourished and this has a detrimental effect on outcome. Provision of an adequate diet is very important and is best achieved by measuring daily energy requirements and adjusting dietary intake accordingly. Prediction equations, which use information on age, sex, weight, and height can be used to estimate energy requirements; however, the results they provide are not accurate enough for clinical use, particularly as they vary according to sex and ethnicity.

Assessment of resting energy expenditure in patients with cirrhosis

BACKGROUND

Malnutrition affects 20% to 50% of patients with cirrhosis. It may be associated with serious complications and has a direct impact on prognosis. Resting energy expenditure (REE) is an important parameter to guide the optimization of therapy and recovery of nutritional status in patients with cirrhosis. However, the REE of patients with cirrhosis is still unclear, casting doubt upon the optimal nutritional management approach.

AIM

To identify the best method that predicts the REE of cirrhotic patients, using indirect calorimetry (IC) as the gold standard.

METHODS

An observational study was performed on 90 patients with cirrhosis. REE was assessed by IC, bioelectrical impedance analysis (BIA), and predictive formulas, which were compared using Bland-Altman plots and the Student’s t-test.

RESULTS

REE values measured by IC (1607.72 ± 257.4 kcal) differed significantly from those determined by all other methods (BIA: 1790.48 ± 352.1 kcal; Harris & Benedict equation: 2373.54 ± 254.9 kcal; IOM equation: 1648.95 ± 185.6 kcal; Cunningham equation: 1764.29 ± 246.2 kcal), except the Food and Agriculture Organization of the United Nations, World Health Organization, and United Nations University (FAO/WHO/UNU) (1616.07 ± 214.6 kcal) and McArdle (1611.30 ± 241.8 kcal) equations. We found no significant association when comparing IC and 24-h dietary recall among different Child-Pugh classes of cirrhosis.

CONCLUSION

The IOM and FAO/WHO/UNU equations have the best agreement with the CI. These results indicate a possibility of different tools for the clinical practice on cirrhotic patients.

Sarcopenia and frailty in decompensated cirrhosis

In patients with decompensated cirrhosis, sarcopenia and frailty are prevalent. Although several definitions exist for these terms, in the field of hepatology, sarcopenia has commonly been defined as loss of muscle mass, and frailty has been broadly defined as the phenotypic manifestation of the loss of muscle function. Prompt recognition and accurate assessment of these conditions are critical as they are both strongly associated with morbidity, mortality, poor quality of life and worse post-liver transplant outcomes in patients with cirrhosis. In this review, we describe the complex pathophysiology that underlies the clinical phenotypes of sarcopenia and frailty, their association with decompensation, and provide an overview of tools to assess these conditions in patients with cirrhosis. When available, we highlight data focusing on patients with acutely decompensated cirrhosis, such as inpatients, as this is an area of unmet clinical need. Finally, we discuss management strategies to reverse and/or prevent the development of sarcopenia and frailty, which include adequate nutritional intake of calories and protein, as well as regular exercise of at least moderate intensity, with a mix of aerobic and resistance training. Key knowledge gaps in our understanding of sarcopenia and frailty in decompensated cirrhosis remain, including best methods to measure muscle mass and function in the inpatient setting, racial/ethnic variation in the development and presentation of sarcopenia and frailty, and optimal clinical metrics to assess response to therapeutic interventions that translate into a reduction in adverse outcomes associated with these conditions.

The centenary of the Harris-Benedict equations: How to assess energy requirements best? Recommendations from the ESPEN expert group

BACKGROUND & AIMS

The year 2019 marked the centenary of the publication of the Harris and Benedict equations for estimation of energy expenditure. In October 2019 a Scientific Symposium was organized by the European Society for Clinical Nutrition and Metabolism (ESPEN) in Vienna, Austria, to celebrate this historical landmark, looking at what is currently known about the estimation and measurement of energy expenditure.

METHODS

Current evidence was discussed during the symposium, including the scientific basis and clinical knowledge, and is summarized here to assist with the estimation and measurement of energy requirements that later translate into energy prescription.

RESULTS

In most clinical settings, the majority of predictive equations have low to moderate performance, with the best generally reaching an accuracy of no more than 70%, and often lead to large errors in estimating the true needs of patients. Generally speaking, the addition of body composition measurements did not add to the accuracy of predictive equations. Indirect calorimetry is the most reliable method to measure energy expenditure and guide energy prescription, but carries inherent limitations, greatly restricting its use in real life clinical practice.

CONCLUSIONS

While the limitations of predictive equations are clear, their use is still the mainstay in clinical practice. It is imperative to recognize specific patient populations for whom a specific equation should be preferred. When available, the use of indirect calorimetry is advised in a variety of clinical settings, aiming to avoid under-as well as overfeeding.

Prevalence and Nonpharmacological Interventions for Sarcopenia among Cirrhotic Patients

Sarcopenia is the most common feature of hepatic cirrhosis characterized by progressive loss of muscle mass and function and increases permanently the mortality and morbidity rates among those patients. The incidence of sarcopenia in cirrhotic patients ranged 40-70% associating with impaired quality of life and augmented rates of infection. Based on these issues, this review is aimed at determining the prevalence and main causes of sarcopenia among cirrhotic patients and recognizing the recent diagnostic and physical treatment modalities that prevent risk factors for sarcopenia in those patients. No ideal modality is currently demonstrated for diagnosing sarcopenia in hepatic diseases, particularly cirrhosis; however, recent studies reported different diagnostic modalities for muscle function in different individuals including handgrip strength, skeletal muscle index, six-min walk test, liver frailty index, short physical performance battery, and radiological assessments for quadriceps and psoas muscles. Exercise training and therapeutic nutrition are strongly recommended for controlling sarcopenia in cirrhotic patients. The exercise program is designed and carried out on a frequent basis within an extensive scheduled time aimed at improving functional performance, aerobic capacity, and healthy conditions. Finally, a combination of exercise training and therapeutic nutrition is powerfully recommended to control sarcopenia in cirrhosis.

Molecular Mechanisms and Treatment of Sarcopenia in Liver Disease: A Review of Current Knowledge

Sarcopenia is characterized by progressive and generalized loss of skeletal muscle mass and strength that occurs with aging or in association with various diseases. The condition is prevalent worldwide and occurs more frequently in patients with chronic diseases owing to the intrinsic relationship of muscles with glucose, lipid, and protein metabolism. Liver cirrhosis is characterized by the progression of necro-inflammatory liver diseases, which leads to fibrosis, portal hypertension, and a catabolic state, which causes loss of muscle tissue. Sarcopenia is of significant concern in the state of liver cirrhosis because sarcopenia has been associated with higher mortality, increased hospital admissions, worse post-liver transplant outcomes, decreased quality of life, and increased risk for other complications associated with cirrhosis. Therefore, sarcopenia is also an important feature of liver cirrhosis, representing a negative prognostic factor and influencing mortality. An increased understanding of sarcopenia could lead to the development of novel therapeutic approaches that could help improve the cognitive impairment of cirrhotic patients; therefore, we present a review of the mechanisms and diagnosis of sarcopenia in liver disease and existing therapeutic approaches.

Resting energy expenditure in cirrhotic patients with and without hepatocellular carcinoma

BACKGROUND

The diagnosis of malnutrition in patients with independent hepatocellular carcinoma (HCC) varies from 20% to 50%, is related to important complications and has a direct impact on the prognosis. Determination of the resting energy expenditure (REE) has become an important parameter in this population, as it allows therapeutic adjustments to recover their nutritional status. The REE in cirrhosis, with and without HCC, is not clearly defined, and requires the identification and definition of the best nutritional approach.

AIM

To evaluate the REE of patients with cirrhosis, with and without HCC.

METHODS

This is a prospective observational study evaluating the REE of 118 patients, 33 with cirrhosis and hepatocellular carcinoma and a control group of 85 patients with cirrhosis without HCC, using indirect calorimetry (IC), bioimpedance, and predictive formulas.

RESULTS

The REE determined by IC in cirrhotic patients with HCC was 1643 ± 364 and in those without HCC was 1526 ± 277 (P = 0.064). The REE value as assessed by bioimpedance was 1529 ± 501 for those with HCC and 1660 ± 385 for those without HCC (P = 0.136). When comparing the values of REE determined by IC and predictive formulas in cirrhotics with HCC, it was observed that only the formulas of the Food and Agriculture Organization (FAO)/World Health Organization (WHO) (1985) and Cunningham (1980) presented values similar to those determined by IC. When comparing the REE values determined by IC and predictive formulas in cirrhotics without HCC, it was observed that the formulas of Schofield (1985), FAO/WHO (1985), WHO (2000), Institute of Medicine (IOM) (2005) and Katch and McArdie (1996) presented values similar to those determined by IC.

CONCLUSION

The FAO/WHO formula (1985) could be used for cirrhotic patients with or without HCC; as it is the one with the values closest to those obtained by IC in these cirrhotic patients.

Nutrition in Chronic Liver Disease: Consensus Statement of the Indian National Association for Study of the Liver

Malnutrition and sarcopenia are common in patients with chronic liver disease and are associated with increased risk of decompensation, infections, wait-list mortality and poorer outcomes after liver transplantation. Assessment of nutritional status and management of malnutrition are therefore essential to improve outcomes in patients with chronic liver disease. This consensus statement of the Indian National Association for Study of the Liver provides a comprehensive review of nutrition in chronic liver disease and gives recommendations for nutritional screening and treatment in specific clinical scenarios of malnutrition in cirrhosis in adults as well as children with chronic liver disease and metabolic disorders.

Accuracy of resting metabolic rate prediction equations among healthy adults in Trinidad and Tobago

BACKGROUND

Over 50% of adults in Latin America and the Caribbean have a body mass index (BMI) ≥ 25 suggesting excess energy intakes relative to energy expenditure. Accurate estimation of resting metabolic rate (RMR), the largest component of total energy requirements, is crucial to strategies aimed at reducing the prevalence and incidence of overweight and obesity.

AIM

We evaluated the accuracies of established and locally developed RMR prediction equations (RMR_P) among adults.

METHODS

Four hundred adult volunteers ages 20 to 65 years had RMR measured (RMR_M) with a MedGem® indirect calorimeter according to recommended procedures. RMR_P were compared to RMR_M with values ± 10% of RMR_M deemed accurate. Anthropometry was measured using standard procedure. Linear regression with bootstrap analyses was used to develop local RMR_P equations based on anthropometric and demographic variables. The University of the West Indies Ethics Committee approved the study.

RESULTS

Males had higher mean absolute RMR (p < 0.001) but similar mean age-adjusted measured RMR per kg of body (20.9 vs. 21.5 kcals/day; p = 0.1) to females. The top performing established anthropometry-based RMR_P among participants by sex, physical activity (PA) level and BMI status subgroups were Mifflin-St Jeor, Owen, Korth, Harris-Benedict, and Livingston, while Johnstone, Cunningham, Müller (body composition (BC)), Katch and McArdle, Mifflin-St Jeor (BC) were the most accurate BC-based RMR_P. Locally developed RMR_P had accuracies comparable to their top-ranked established RMR_P counterparts.

CONCLUSIONS

Accuracies of established RMR_P depended on habitual PA level, BMI status, BC and sex. Furthermore, locally developed RMR_P provide useful alternatives to established RMR_P.

Serum Zinc Level and non-Protein Respiratory Quotient in Patients with Chronic Liver Diseases

We sought to clarify the correlation between non-protein respiratory quotient (npRQ) in indirect calorimetry and serum zinc (Zn) level in chronic liver diseases (CLDs, n = 586, 309 liver cirrhosis (LC) patients, median age = 63 years). Clinical parameters potentially linked to npRQ <0.85 (best cutoff point for the prognosis in LC patients) were also examined in receiver operating characteristic curve (ROC) analyses. The median npRQ was 0.86. The median serum Zn level was 64 μg/dL. The median npRQ in patients with non-LC, Child–Pugh A, Child–Pugh B and Child–Pugh C were 0.89, 0.85, 0.83 and 0.82 (overall p < 0.0001)). The median serum Zn level in patients with npRQ <0.85 (58 μg/dL) was significantly lower than that in patients with npRQ ≥ 0.85 (68 μg/dL) (p < 0.0001). The correlation coefficient (r) between npRQ level and serum Zn level for all cases was 0.40 (p < 0.0001). Similar tendencies were observed in all subgroup analyses. The highest correlation coefficient between serum Zn level and npRQ was found in patients with Child–Pugh C (n = 22, r = 0.69). In ROC analyses for npRQ <0.85, serum Zn level had the highest area under the ROC (AUC) among baseline laboratory parameters (AUC = 0.69). In conclusion, serum Zn level can be helpful for npRQ in patients with CLDs.

Assessment of Malnutrition, Sarcopenia and Frailty in Patients with Cirrhosis: Which Tools Should We Use in Clinical Practice?

Malnutrition is a common comorbidity in patients with cirrhosis. Its prognostic value is indisputable as it greatly affects the evolution of liver diseases. It has a major impact on both morbi-mortality before and after liver transplantation. Being now integrated in the definition of malnutrition and recognized as a new entity in the international classification of diseases, physicians have taken great interest in sarcopenia. Its negative consequences on the fate of patients with cirrhosis are well-demonstrated. The concept of frailty has recently been enlarged to chronic liver diseases as symptoms of impaired global physical functioning. In this article, we will discuss the definitions of malnutrition and emphasize its links with sarcopenia and frailty. We will show the relevance of frailty and sarcopenia in the course of liver diseases. The emerging role of muscle depletion on the cardiorespiratory system will also be highlighted. The importance of body composition will be demonstrated and the main tools reviewed. Finally, we adapted the definition of malnutrition to patients with cirrhosis based on the assessment of sarcopenia together with reduced food intakes.

Controversies in Diagnosing Sarcopenia in Cirrhosis-Moving from Research to Clinical Practice

Sarcopenia, defined as loss of muscle mass and function, is increasingly recognized as a common consequence of advanced cirrhosis that is associated with adverse clinical outcomes. Despite the recent proliferation in publications pertaining to sarcopenia in end-stage liver disease, there remains no single 'best method' for its diagnosis. The inability to identify a gold standard is common to other specialties, including geriatrics from which many diagnostic tools are derived. Controversies in diagnosis have implications for the accuracy and reproducibility of cohort studies in the field, largely prohibit the introduction of sarcopenia measurement into routine patient care and impede the development of clinical trials to identify appropriate therapies. Difficulties in diagnosis are partly driven by our ongoing limited understanding of the pathophysiology of sarcopenia in cirrhosis, the mechanisms by which it impacts on patient outcomes, the heterogeneity of patient populations, and the accuracy, availability and cost of assessments of muscle mass and function. This review discusses the currently studied diagnostic methods for sarcopenia in cirrhosis, and outlines why reaching a consensus on sarcopenia diagnosis is important and suggests potential ways to improve diagnostic criteria to allow us to translate sarcopenia research into improvements in clinical care.

Indirect Calorimetry in Clinical Practice

Indirect calorimetry (IC) is considered as the gold standard to determine energy expenditure, by measuring pulmonary gas exchanges. It is a non-invasive technique that allows clinicians to personalize the prescription of nutrition support to the metabolic needs and promote a better clinical outcome. Recent technical developments allow accurate and easy IC measurements in spontaneously breathing patients as well as in those on mechanical ventilation. The implementation of IC in clinical routine should be promoted in order to optimize the cost–benefit balance of nutrition therapy. This review aims at summarizing the latest innovations of IC as well as the clinical indications, benefits, and limitations.