Clinical Guidelines for the Hospitalized Adult Patient with Obesity 1 Definition of obesity: Obesity is characterized by an excess storage of adipose tissue that is related to an imbalance between energy intake and energy expenditure. Obesity can also be defined as a body mass index >30 kg/m 2 or as a body status of 20% above the ideal body weight of an individual. 1, 2 Global prevalence of obesity: The proportion of adult men who were classified as obese in the world increased by 682% between 1975 and 2014 (34 million to 266 million) and the proportion of adult women who were classified as obese in the world increased by 428%. Furthermore, English speaking countries having the highest proportion of the world severely obese population. 3 Etiology of obesity: Obesity originates from an interaction between genetic, environmental, and psychosocial factors that contribute to positive energy balance. 2 Mortality and morbidities: Obesity increases an individual s risk of developing co-morbidities. 1,4 Common obesity-associated co-morbidities: o Type 2 diabetes mellitus, cancer, dyslipidemia, hypertension, cardiovascular disease, gallbladder disease, stroke, obstructive sleep apnea, osteoarthritis, fatty liver, etc. Body mass index (BMI): BMI should be used to classify overweight and obesity and be used as the first-degree anthropometric screen for adiposity, to estimate nutrition risk for disease, co-morbidity risk, and to evaluate treatment options. 6,7 BMI = Actual weight (kg) (Height in meters) 2 Table 1. International BMI classifications for adults 20 years and older. 8 Classification BMI (kg/m 2 ) Underweight <18.5 Severe <16.0 Moderate 16.0 16.9 Mild 17.0 18.4 Normal 18.5 24.9 Overweight > 25.0 Pre-obese 25.0 29.9 Obese > 30.0 Obese class I 30.0 34.9 Obese class II 35.0 39.9 Obese class III (morbid obesity) > 40.0
Considerations when assessing BMI classifications of obese patients: Gender, age, ethnicity, co-morbities, edema, amputations, physical activity level, muscle mass, fat mass, fatfree mass, visible signs of malnutrition, dietary habits, overall lifestyle, socio economic factors, etc. 7 BMI may overestimate body fat in athletes, individuals with a large muscular build, or those with fluid overload. 7 BMI may underestimate body fat in older adults and individuals who are experiencing loss of muscle mass, including individuals who have sarcopenic obesity or cachexia. 7 Resting energy expenditure in the obese patient: A major determinant of Resting Energy Expenditure (REE) is body composition, specifically highly metabolically active organs such as the brain, heart, liver, kidneys, and gastrointestinal tract, which are all considered fat free mass (FFM). 2 Using indirect calorimetry (IC), Resting Energy Expenditure (REE), and Basal Energy Expenditure (BEE) is positively correlated with higher body weight, even after adjusting for FFM. Studies have shown a 240 to 540 caloric difference between REE per day in obese individuals and their non-obese counterparts. 2 Many factors can increase or decrease a patient s energy, protein, or fluid needs, including mechanical ventilation, certain illnesses, surgery, etc. It is important for the Registered Dietitian Nutritionist to provide ongoing monitoring and evaluation of individual patients and to apply critical thinking when interpreting evidence-based guidelines for determining nutrient needs based on the patient s overall health and nutrition 9, 10 status. The less metabolically active FFM (e.g. skeletal muscle and bones) increases as body fat increases in order to support excess body weight. This may account for why it has been shown that obese individuals have higher REE or BEE compared to non-obese individuals. However, residual FFM (the metabolically active organs) does not increase as body fat increases. Therefore, the ratio between REE and FFM (kcals/kg) is lower in obese individuals to account for this. 2 Since the REE:FFM ratio is lower in obese patients compared to non-obese individuals, the caloric Predictive equations: recommendations for obese patients in the clinical inpatient setting is less. 2 Estimating the nutritional needs of obese patients is challenging because body composition does not change in a linear fashion with increasing body weight. Gained body fat is metabolically inactive and is indistinguishable from an increase in overall weight. 1 IC is the gold standard for measuring resting metabolic rate in patients who are healthy, acutely ill, or 2, 5, 9, 11 critically ill. Nutrition assessment: Primary focus should be on actual, usual, and ideal body weight. Adjusted body weight is not recommended due to lack of validation studies. Many of the RMR predicative equations were developed using actual body 5, 12, 13 weight. Adjusted body weight can underestimate the energy needs of an obese individual. BMI should be calculated, obesity class identified, and weight circumference measured, when possible. 7 2
Biomarkers of metabolic syndrome should be evaluated, including serum glucose, triglycerides, cholesterol concentrations, level of inflammation, and blood pressure. 5 Clinical awareness of co-morbities helps the Registered Dietitian Nutritionist adjust the nutrition regimen if complications arise. Monitoring nutrition therapy is important to avoid worsening hyperlipidemia, hyperglycemia, fluid overload, hepatic fat accumulation, altered serum electrolytes, triglycerides, blood urea nitrogen, ammonia build up, malabsorption, and overall diet/nutrition support tolerance. 5 Nutrition recommendations for the obese non-critically ill acute care patient: If IC cannot be used to estimate RMR, the Mifflin-St Jeor equation using actual body weight is the most 7, 11, 14, 15 accurate predictive equation for estimating energy needs. Mifflin-St. Jeor equation: Men: RMR = (9.99 X weight) + (6.25 X height) (4.92 X age) + 5 Women: RMR = (9.99 X weight) + (6.25 X height) (4.92 X age) 161 (Note: Equations use actual weight in kilograms and height in centimeters) Nutrition recommendations for the obese critically ill acute care patient: Providing 60-70% of caloric needs promotes steady weight loss in obese patients and can help improve insulin sensitivity and reduce risk of co-morbities. Higher protein recommendations helps to preserve nitrogen 5, 11 balance and allow for sufficient wound healing. 3 Table 2. Estimated energy/protein requirements for the critically ill non-mechanically ventilated patient. 5 BMI classification Caloric needs Protein needs (kg/m 2 ) 30.0 40.0 11 14 kcals/kg actual body ~2.0 grams/kg ideal body 40.1 50.0 >50 11 14 kcals/kg actual body 22 25 kcals/kg ideal body 2.0 2.5 grams/kg ideal body
11, 15 Table 3. Predicative equations for the obese critically ill mechanically ventilated patient. BMI Age Name Predictive equation > 30 kg/m2 > 60 years old Modified Penn State University 2010 (PSU 2010) < 30 kg/m2 Any age Penn State University 2003b (PSU 2003b) > 30 kg/m2 < 60 years old Penn State Note: University 2003b (PSU 2003b) RMR = Mifflin(0.71) + V E (64) + T max (85) 3085 RMR = Mifflin(0.96) + V E (31) + T max (167) 6212 RMR = Mifflin(0.96) + V E (31) + T max (167) 6212 * The Modified PSU 2010 equation is predicts the Resting Metabolic Rate (RMR) with 74% accuracy. * The PSU 2003b equation predicts the Resting Metabolic Rate (RMR) with 70% accuracy. * All other predictive equations have tested with lower accuracy rates. 4 Enteral nutrition support (EN): Initiation of EN within 24 48 hours of admission to ICU if patient is unable to maintain adequate PO intake. 5 High protein hypocaloric tube feed formula should be implemented instead of high protein eucaloric formulas Ideal Body Weight: in order to preserve lean body mass, mobilize adipose stores, and minimize the metabolic complications of over feeding. The use of high protein hypocaloric formulas have been correlated with shorter hospital stays, 5, 11 decreased duration of antibiotics, and fewer days of mechanical ventilation. According to the Academy of Nutrition and Dietetics Nutrition Care Manual, there is no evidence suggesting that adjusted or ideal body weight results in improved accuracy of estimating nutritional needs. 12 However, the A.S.P.E.N. guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient specifies to use ideal body weight for critically ill patients with a BMI >50 kg/m 2 in order to prevent overestimating the caloric needs of these patients. 5 Hamwi equation: 6 o Five feet or over: Female = 100 pounds first 5 feet + 5 pounds each additional inch Male = 106 pounds first 5 feet + 6 pounds each additional inch o Under five feet: Female = 100 pounds 3 pounds each additional inch under five feet Female = 106 pounds 3 pounds each additional inch under five feet
5 Protein: There are no definitive protein recommendations for the non-critically ill obese patient. Protein recommendations should be based off of the RDA, the patient s co-morbities, and the individual s physical conditions (e.g. presence of pressure ulcers, wounds, malnutrition, or any other hypermetabolic conditions). 7 References: 1. Alves EG, da Rocha EE, Gonzalez MC, da Fonseca RB, Silva MH, Chiesa CA. Assessment of resting energy expenditure of obese patients: comparison of indirect calorimetry with formulae. Clin Nutr. 2009:28(3):299-304. 2. Carneiro IP, Elliot SA, Siervo M, et al. Is obesity associated with altered energy expenditure? Adv Nutr. 2016: 7:476-487. 3. NCD Risk Factor Collaboration (NCD-RisC). Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19.2 million participants. Lancet. 2016; 387:1377-1396. 4. Guh DP, Zhang W, Bansback N, Amarsi Z, Birmingham L, Anis AH. The incidence o co-morbities related to obesity and overweight: a sysmtemic review and meta-analysis. BMC Public Health. 2009:9(88): 1-20. 5. McClave SA, Taylor BE, Martindale RG, et al. Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.). JPEN J Parenter Enteral Nutr. 2016; 40(2):159-211. 6. Peterson CM, Thomas DM, Blackburn GL, Heymsfield SB. Universal equation for estimating ideal body weight and body weight at any BMI. Am J Clin Nutr. 2016; 103:1197-1203. 7. Academy of Nutrition and Dietetics. Evidence Analysis Library. Adult Weight Management. Available from: http://www.andeal.org/topic.cfm?menu=5276. Accessed May 18 2016. 8. World Health Organization. BMI Classification. http://apps.who.int/bmi/index.jsp?intropage=intro_3.html. Updated May 2016. Accessed May 10, 2016. 9. Kohn JB. Adjusted or Ideal Body Weight for Nutrition Assessment? J Acad Nutr Diet. 2015; 115(4):680. 10. Charney P, Peterson SJ.Practice paper of the Academy of Nutrition and Dietetics: Critical thinking skills in nutrition assessment and diagnosis. J Acad Nutr Diet. 2013; 113(11):1545. 11. Choban P, Dickerson R, Malone A, Worthington P, Compher C. American Society for Parenteral and Enteral Nutrition. A.S.P.E.N. clinical guidelines: nutrition support of hospitalized adult patients with obesity. JPEN J Parenter Enteral Nutr. 2013;37(6):714-714. 12. Academy of Nutrition and Dietetics. Nutrition Care Manual. Nutrition Care Manual Calculators. Available from: http://www.nutritioncaremanual.org/calculators.cfm?ncm_category_id=10&ncm_heading=. Accessed May 18, 2016. 13. Academy of Nutrition and Dietetics. Nutrition Care Manual. Energy Expenditure in Acute Care and Critical Care. Available from: http://www.nutritioncaremanual.org/topic.cfm?ncm_category_id=11&lv1=255519&lv2=255689&ncm_toc_id=255689ncm_ heading=&. Accessed May 15, 2016. 14. Academy of Nutrition and Dietetics. Evidence Analysis Library. Critical Illness. Available from: https://www.andeal.org/topic.cfm?menu=5302&cat=4800. Accessed May 10, 2016. 15. Academy of Nutrition and Dietetics. Nutrition Care Manual. Equations. Available from: https://www.nutritioncaremanual.org/topic.cfm?ncm_toc_id=255519. Accessed May 18, 2016.