Resting energy expenditure of morbidly obese patients using indirect calorimetry: a systematic review

Abstract

The increasing proportion of acutely ill hospital patient admissions presenting with a morbidly obese body mass index (BMI ≥ 40 kg m(-2) ) as a comorbidity is an emerging clinical concern. Suboptimal food intake and malnutrition is prevalent in the acute care hospital setting. The energy requirements necessary to prevent malnutrition in acutely ill patients with morbid obesity remains unclear. The aim of this systematic review was to identify studies in the literature that have used indirect calorimetry to measure the resting energy expenditure of patients with morbid obesity to establish their minimum energy requirements and the implications for optimal feeding practices in acutely ill hospitalized patients. A total of 20 studies from PubMed, Cochrane Library and Embase met the inclusion criteria and were reviewed. All articles were graded using the Australian National Health and Medical Research Council levels of evidence and given a quality rating using the American Dietetic Association recommendations. Studies were categorized according to the mean BMI of its subjects. The most commonly measured resting energy expenditures for morbidly obese patients are between 2,000 and 3,000 kcal d(-1) (8,400-12,600 kJ d(-1) ). Activity and injury factors of acutely ill morbidly obese patients could result in significantly greater energy requirements for this patient group and are unlikely to be met by standard hospital menus. Establishing the minimum energy requirements for this population group will help inform adequate and accurate energy provision in the acute setting. Outcomes of underfeeding and overfeeding in morbidly obese patients warrant further research.

Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient

“…Fifty‐seven percent of hospitalized patients with a BMI >25 show evidence of malnutrition. Patients with a BMI >30 have an OR of 1.5 for having malnutrition ( P = .02) 450 . The reasons for the surprisingly high rate of malnutrition in obese patients may stem in part from unintentional weight loss early after admission to the ICU and a lack of attention from clinicians who misinterpret the high BMI to represent additional nutrition reserves that protect the patient from insult.…”

Measuring energy expenditure in clinical populations: rewards and challenges

“…Recent analyses indicate that predictive equations estimated resting EE within 10% of measured rate in only 38–70% of non-hospitalized obese patients 29 and even in fewer patients when assessing hospitalized obese patients. 30,31 In general, predictive equations tend to overestimate the energy requirements in obese patients, while the Mifflin–St Jeor equation has been found to yield the closest prediction compared with measured resting EE. 29,31,32 Owing to an increasingly sedentary lifestyle as well as the vast availability of energy-dense foods, the patients of today, both inpatient and outpatient, are very different than those studied decades ago.…”

“…30,31 In general, predictive equations tend to overestimate the energy requirements in obese patients, while the Mifflin–St Jeor equation has been found to yield the closest prediction compared with measured resting EE. 29,31,32 Owing to an increasingly sedentary lifestyle as well as the vast availability of energy-dense foods, the patients of today, both inpatient and outpatient, are very different than those studied decades ago. Predictive equations include only weight as a variable and these analyses illustrate the limitations associated with using predictive equations in samples dissimilar to those from which they were derived.…”

Clinical Guide for the Use of Metabolic Carts

“…Energy requirements are difficult to define in these patients since their lean body mass, which determines the REE, may decrease, increase, or be normal, and fat may also contribute to variability in REE. In a review of the literature including 20 articles, Kee et al 32 found that the most common result for REE measured in morbidly obese but not acutely ill patients with a body mass index (BMI) between 40 and 80 kg/m 2 was between 1800 and 2600 kcal/d. These measurements are in great disparity with those derived from predictive equations 33 …”