Manual of Clinical Nutrition Management II- 1 Copyright © 2013 Compass Group, Inc.
BODY WEIGHT EVALUATION and INDICATORS OF NUTRITION-RELATED
PROBLEMS
Overview
Weight evaluation is part of the nutrition assessment. Weight should also be routinely evaluated to determine
the outcome of nutrition interventions. If possible, a patient should be weighed on admission to any clinical
setting and monitored frequently throughout the length of stay. For the most reliable assessment, the patient
should be weighed on the same scale for each evaluation, preferably by using a beam scale with
nondetachable weights. In addition, the patient should be weighed while fasting, after voiding, and without
drainage bags and dressings. If drainage bags and dressings cannot be removed, weigh them separately and
deduct their weight.
Body Weight as an Indicator of Nutrition-Related Problems
Body weight and changes in body weight are two of the most reliable indicators of declining or improving
nutritional status. The three methods of evaluating body weight described by Blackburn are listed below (1-3).
The “percent usual weight”, “percent of recent weight change”, and the body mass index (BMI) are strongly
correlated with morbidity, mortality, and severity of illness in hospitalized patients and long-term care
residents (1,2). Unintended weight loss is a well-validated indicator of nutritional compromise and can be
used to diagnose nutrition-related problems, such as adult malnutrition (3). For the most complete evaluation
of weight status, the dietitian should use the three assessment parameters described below in addition to the
BMI level (3). For the evaluation of BMI height and weight should be measured rather than estimated (3). For
the dehydrated or edematous patient, the measured weight must be intuitively increased or decreased,
respectively, prior to evaluation (3).
The criteria listed in Tables II: 1-3 can be used in determining ICD- 9 - CM (International Classification of
Diseases, 9th Revision, Clinical Modification) diagnostic codes when clinically indicated. It is important to
clarify that existing ICD- 9 - CM codes may not be applicable to patients seen by acute and chronic care
clinicians in developed countries (3). The Academy advises that these codes will likely change some of the
definitions in the 10th revision cycle (3). In the interim, the Academy of Nutrition and Dietetics and A.S.P.E.N.
recently published guidelines for using weight in addition to five other nutrition related indicators for the
identification and documentation of adult malnutrition (undernutrition) (3). Because there is no single
parameter that is definitive of adult malnutrition, identification of at least two or more of the six
characteristics is recommended for diagnosis including, insufficient energy intake; weight loss; loss of muscle
mass; loss of subcutaneous fat; localized or generalized fluid accumulation; and diminished functional status
as measured by hand grip (3). Criteria specific to the evaluation of weight loss is outlined in Table II-3:
Evaluation of Weight Loss in Adult Malnutrition (3). For the complete list of characteristics of adult
malnutrition refer to Table II-3. In addition to these resources, the dietitian can refer to the Academy of
Nutrition and Dietetics International Dietetics & Nutrition Terminology (IDNT) Reference Manual (4). The
Academy cites BMI levels less than 18.5 kg/m^2 for adults and less than 23 kg/m^2 for older adults (>65 years
of age) as indicators of lower than recommended weight levels when determining a nutrition-related
diagnoses (4).
Percent ideal body weight (1) = Actual weight 100
Ideal weight
See Determining Ideal Body Weight Based on Height to Weight: The Hamwi Method (page II-6).
Percent usual body weight (1) = Actual weight (^) 100
Usual weight
Percent recent weight change (1) = (Usual weight – Actual weight) 100
Usual Weight
(^)
(^)