Manual of Clinical Nutrition

Manual of Clinical Nutrition Management II- 10 Copyright © 2013 Compass Group, Inc.

ESTIMATION OF IDEAL BODY WEIGHT AND BODY MASS INDEX FOR

AMPUTEES

In the case where a patient had an amputation, ideal body weight (IBW) cannot be compared to the standards for
normal adults. Although body proportions vary from individual to individual, segmental weights can be used to
prove an approximation of IBW.

Percent Total Body Weight by Individual Body Parts (1)^

Source: Osterkamp, Linda. Current perspective on assessment of human body proportions of relevance to amputees. J Am Diet
Assoc. 1995:95;215-218.

Determining Adjusted Body Weight for the Amputee
Using the IBW of the patient before the amputation, subtract the percentage of the body limb or part that was
removed to obtain an adjusted IBW. For a method of determining IBW, see Section II: Determining Ideal Body
Weight (IBW) Based on Height and Weight: The Hamwi Method.

Example: Determine the adjusted IBW for a woman 5’5” with a below-knee amputation of the right leg.

IBW (female 5’5”) .......................................................................... 125 lb

Right below the knee (calf 4.4% + foot 1.5% = (-5.9%) 7.5 lb

Adjusted IBW .................................................................................... 117.5 lb

Formula for Body Mass Index (BMI) for Amputees (2)
Body mass index can be calculated for persons with amputees by using the following formula described by Himes
(2). Total body weight (TBW) or referred to as “WtE” is calculated by taking the “WtO” or observed body weight
which is the current measured body weight (after the amputation) and divide by one minus the total percentage
of limb(s) removed. The percentage of limbs missing can be derived from the Table above.

Formula for BMI in Amputees: WtE = WtO/(1-P)(2)

WtE is estimated total body weight (TBW); WtO is the observed body weight (measured weight after the
amputation); and P is the percentage of the missing limb segment (s) which can be estimated based on the Table
above.

Example: A below-the-knee amputation is 5.9% or 0.059 of TBW. Observed (measured) weight is 70 kg.
WtE = 70 kg /(1-0.059)
= 70 kg/(0.941)
= 74.4 kg
To obtain height for use in the BMI equation, use height prior to amputation, current height if it can be obtained,
or derived from the arm span (for formula see, Section II: Stature Determination). The WtE or adjusted Total