# Estimated Body Weight Loss Calculator

## Estimates body mass lost due to amputation

### Amputations ### Body Mass (optional)

 Gender Male Female Height in cm Weight kg lbs

## 0%EBWL

 Ideal weight Amputation ideal weight Percent Above Ideal Amputation adjusted weight

Estimated body weight loss (EBWL) describes the amount of body mass lost due to an amputation. EBWL is most commonly utilized for determining an amputee's ideal body weight, which is a function of patient height. An EBWL-adjusted ideal body weight is most commonly used for determining renal function with creatinine clearance.

#### Estimated Body Weight Loss (EBWL) Table

The following estimates are reasonable for determining a patient's amputation ideal body weight (or adjusted body weight for overweight patients).1,2

 Level of Amputation % EBWL Foot 1.5% Below-knee amputation (BKA) 3.5% Above-knee amputation (AKA) 11% Hip disarticulation 16% Hand 0.7% Forearm 1.5% Entire arm 4%

#### Ideal and Adjusted Amputation Body Weight

For patients without amputations, an ideal body weight equation (as described by Devine 1974) is calculated according to the equation below. For patients with amputations, the EBWL is used to calculate a percent of predicted ideal body weight:3

$$\\Ideal\;BW\;(men)\; = 50 + 2.3*(height\;over\;60\;inches) \\Ideal\;BW\;(women)\; = 45.5 + 2.3*(height\;over\;60\;inches) \\Amputation\;ideal\;BW = (1 - EBWL) * Ideal\;BW$$

In patients who are more than 30% of an amputation ideal weight, an "amputation adjusted weight" may be used. This adjusted body weight uses an adjustment factor of 0.4 (or 40%). Adjusted body weight is commonly used for calculations like creatinine clearance.

$$\\AdjustedBW\; = IdealBW + (0.4*(ActualBW - IdealBW))$$

1. Osterkamp LK. Current perspective on assessment of human body proportions of relevance to amputees. J Am Diet Assoc. 1995 Feb;95(2):215-8. PMID 7852688.
2. Im EE, Stewart IJ, Morrow BD, et al. Retrospective review of serum creatinine and creatinine-based measures of estimated glomerular filtration rate in an amputee population. Mil Med. 2012 Aug;177(8):952-6. PMID 22934376.
3. Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650–655.