Background: Approximately 65 amputations can be expected for 100,000 inhabitants per year in Hungary, 57 of them are lower limb amputation. The representation of peripheral vascular disease reached 80–90% of the causes of amputation in Hungary and in the developed countries at the end of the last century.
Aims: To determine the total body weight and the body mass index (BMI) of amputees, methodology that can be used in practice.
Methods: Calculation of total body weight from measured or estimated body weight and body height, determination of BMI that is needed to (nutritional) rehabilitation.
Subjects: adult lower limb amputees. Calculation of BMI from measured body weight and body height without correction is often an incorrectly applied method in the practice. Authors represent the distorting results of this incorrect practice in 49 (31 males and 18 females) unilateral amputees and in 10 (8 male and 2 female) both legs (femur) amputees. In the absence of both lower limbs estimation of the body height from the length of the ulna is a reliable method.
Results: according to the BMI values calculated from the “original” data only one third of these patients belonged to the optimal category and one third have BMI≥30.0. Considering the weight of the missing limb, 45 patients belonged to other category.
Conclusions: Authors are aware of the limited usability of BMI (especially regarding people older than 65 years), however, intend to draw attention to the incorrect classifi cation that results form false—
routine—use and the opportunities for practical use.
Background
Lower limb arterial obstruction is a potential disease. According to international surveys 30% of the population over 50 is at risk, so in Hungary nearly one million people can be affected. The stenosis and the obstruction of the arteries are serious health and social burden due to the estimated 7,000 limb amputations per year.1
Amputation is the removal of body parts and organs with all types of tissues.2 Peripheral vascular disease, commonly known as atherosclerosis, is the manifestation of general atherosclerosis. In this disease, stenosis mostly occurs in the arteries of the lower limb, late diagnosis of it can lead to amputation. Data characterizes the national situation; in 2005, more amputations were performed than surgeries for lower limb artery reconstructions.3
6,733 lower limb amputations were performed in Hungarian vascular surgery departments in 2004. According to the database of “Gyógyinfok”, approximately 65
I Faculty of Health Sciences, University of Pécs, Pécs, Hungary
II „Kaposi Mór” Teaching Hospital, Kaposvár, Hungary
1 KOLLÁR – SZEGEDI 2007. 2249.
2 KULLMANN 1999. 99.
3 BORNEMISZA 2010. 51.
amputations can be expected for 100,000 inhabitants per year in Hungary, 57 of them are lower limb amputation. Just over one third of the lower limb amputations done below the level of the knee (from these 1/3 is performed on the lower leg and at the level of the ankle). Comparative data with the Western European and Northern American States:
25–30 lower limb amputations per 100,000 inhabitants per year, in more than 50% knee is kept (in some countries is about 60%), only 5–10% of these amputations are at the level of the ankle or the lower leg.4
Diseases that lead to lower limb amputation in the order of prevalence: vascular disease and diabetes (>80%), trauma (14%), cancer (<3%), infl ammatory disease, limb malformation and other causes together (<4%).5
The possibility of amputation increases by aging. Most frequently performed in 50–70 years old people. More than 70% of the amputees are males. 50–70% of all non-traumatic amputations performed in patients with diabetes in the United States that means 20–30,000 amputations in every year. Also approximately 20,000 lower limb amputations are performed in people with diabetes in Germany per year.6
Aim of the study
The aim of the study was to determine the whole body weight and body mass index (BMI) of lower limb amputees, to apply a methodology that can be used in practice.
In this way, we calculated BMI from the measured or estimated body weight and body height and compare the BMI and the corrected BMI. We also aimed to support the rehabilitation of these patients with this method.
Methods
Determination of corrected BMI that is required in (nutritional) rehabilitation. The whole body weight was determined from measured or estimated body weight and body height.
There are different ways to estimate body height. We can calculate it form the length of the ulna. Measure the length between the processus olecranon and the processus styloideus, if it is possible on the left side. Estimate height according to sex and age with the help of a table. In this way, we can include people in the screening who were dropped out earlier or “produced” false results.
Another way to estimate body height is the application of a formula. While the arm is at the height of the shoulder measure the distance between the middle of the collarbone and the mid-fi nger (demi-span). From the result of it, we can calculate the body height.
There are two different formulas, one for females and one for males.
Females: Height in cm = (1.35 × demispan in cm) + 60.1 Males: Height in cm = (1.40 × demispan in cm) + 57.87
Calculation of BMI from measured body weight and body height without correction is often an incorrectly applied method in the practice. This method results in differences compared to the corrected BMI. According to BMI, without correction we can state
4 ANGIOLÓGIAI ÚTMUTATÓ 2009
5 KULLMANN – BELICZA – LÁSZLÓ 1997. 2327.
6 WINKLER 2000. 189.
7 A GUIDE TO COMPLETING THE MINI NUTRITIONAL ASSESSMENT MNA
that, if the basis of the nutritional rehabilitation is false, the rehabilitation cannot be successful.
Estimated BMI
First, we have to estimate the body weight of the patient including the missing limb.
The entire leg is 16% of the whole body.
There is in example for the calculation:
A man whose height is 172cm and his weight is 58kg, one of his entire leg has been amputated.
Corrected BMI:
Estimated body weight = actual body weight ÷ (1 – the percentage of the missing limb)
Example: 58 (kg) ÷ (1–0.16) = 58 (kg) ÷ 0.84 = 69.1 (kg) Calculation of BMI = estimated body weight ÷ body height (m)2 Example: 69.1 ÷ (1.72×1.72) = 23.4
Calculation of BMI without correction = 58 ÷ (1.72×1.72) = 19.6 In this example, the differences can be well recognized.
Subjects
Adult lower limb amputees took part in the survey, 49 (31 males and 18 females) unilateral amputees and 10 (8 males and 2 females) both legs (femur) amputees.
Their body weight and body height was measured or estimated, than the BMI was calculated.
Results
Calculation of BMI from measured body weight and body height without correction is often an incorrectly applied method in the practice. Authors represent the distorting results of this incorrect calculation.
According to the BMI values calculated from the “original” data, only one third of these patients belonged to the optimal category and one third have BMI≥30.0.
Considering the weight of the missing limb, 45 (76.3%) patients belonged to other category from the 59 patients.
We compared the BMI values with and without correction (Figure 1). According to the results 100% of the males in the overweight category, 91.7% in the optimal category and 66.7% in the undernourished category were classifi ed wrong. Only in the extreme obese category were all the patients in the good category.
If we calculate without correction, the body weight of these people is less than calculating with the weight of the missing leg. To get correct results, we have to calculate with the weight of the leg. Many times it is also a fault in the practice that the medical stuff says to the patients after the surgery that weight loss happened because of the surgery and the patient have to gain these kilograms back.
100% of the females with optimal BMI, 66.7% of the overweight, 50% of the obese and 50% of the undernourished were in the wrong group according to the comparison of BMI and the corrected BMI values (Figure 2).
Only in the extreme obese category were 100% of the patients (both males and females) in the good category comparing the BMI values with and without correction.
It is obvious, because if someone is extremely obese without the weight of the missing leg, the patient also belongs to the extreme obese category with the weight of the leg.
There are no differences in the category in his case, but the correct BMI value is very important in the rehabilitation, because there are differences in the nutritional/feeding plan and rehabilitation, for example between a patient with BMI = 46 [kg/m2] and a patient with a BMI = 63 [kg/m2].
33.3%
100.0%
66.7%
91.7%
100.0%
25.0%
8.3%
75.0%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
BMI < 18.5 18.5 ≤ BMI < 25.0 25.0 ≤ BMI < 30.0 30.0 ≤ BMI < 40.0 40.0 ≤ BMI
Males, correct categorization Males, false categorization
50.0%
100.0%
50.0%
100.0%
66.7%
50.0%
33.3%
50.0%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
BMI < 18.5 18.5 ≤ BMI < 25.0 25.0 ≤ BMI < 30.0 30.0 ≤ BMI < 40.0 40.0 ≤ BMI
Females, correct categorization Females, false categorization
Figure 1. Correct and false BMI categories of unilateral male amputees
Figure 2. Correct and false BMI categories of unilateral female amputees
Figure 3. Correct and false BMI categories of bilateral amputees
The results of both legs amputees are differing from the group of unilateral amputees.
Both legs missing, in this way there are major differences between the results of BMI calculation with and without correction. All patients were in a wrong category except for patients from the extremely obese group. If we consider the fi ve BMI categories, we can see that 80% is the possibility of categorizing patients in a wrong group (Figure 3).
Figure 4. Correct and false BMI categories of all patients
The biggest problem is in the optimal and overweight group. Almost every patient is in the wrong category (Figure 4).
100.0%
100.0%
100.0%
100.0%
100.0%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
BMI < 18.5 18.5 ≤ BMI < 25.0 25.0 ≤ BMI < 30.0 30.0 ≤ BMI < 40.0 40.0 ≤ BMI
Both legs amputees, correct categorization Both legs amputees, false categorization
100.0%
66.7%
95.0%
93.8%
50.0%
6.3%
5.0%
50.0%
33.3%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
BMI < 18.5 18.5 ≤ BMI < 25.0 25.0 ≤ BMI < 30.0 30.0 ≤ BMI < 40.0 40.0 ≤ BMI
All, correct categorization All, false categorization
A 82 years old male with bilateral amputations had the highest BMI, without correction it was 46.4 [kg/m2]; with correction it was 67.5 [kg/m2]. A 67 years old male had the lowest BMI, without correction it was 13.8 [kg/m2], with correction it was 20.1 [kg/m2]. We can see the huge differences between the BMI values. There are differences in the nutritional therapy of a male with a BMI 46.4 [kg/m2] and with 67.5 [kg/m2]. A male whose BMI is 13.8 [kg/m2] needs therapy because he is malnourished and also the degree of malnutrition is serious, so he needs nutritional therapy, the BMI 20.1 [kg/m2] is optimal, so it is a fault if we start to feed him to gain weight because he will gain overweight.
Uncorrected BMI formula underestimates body fat in unilateral amputees and overestimates body fat in subjects with bilateral amputations.8 In bilateral amputees, if we use the corrected body height and the uncorrected body weight it also underestimates the BMI, as we can see in the results.
Conclusions
Authors are aware of the limited usability of BMI (especially regarding people older 65), however, intend to draw attention to the incorrect classifi cation that results form false—routine—use and the opportunities for practical use.
The nutritional status of lower limb amputees is a very important factor in many aspects: after the surgery—in wound heeling, later because of the prosthesis—make a prosthesis that is right in size and also to achieve optimal nutritional status and keep it.
Steps for successful (nutritional) rehabilitation:
1. Correct determination of nutritional status 2. To make a nutritional/ feeding plan
3. Regular control, modify the plan if it is necessary
These steps are required to help and to make the prosthesis and in the use of it.
All these steps make it possible for the patients to move more, and in this way the rehabilitation will be successful.
Literature
A GUIDE TO COMPLETING THE MINI NUTRITIONAL ASSESSMENT MNA = A guide to completing the Mini Nutritional Assessment MNA, Nestlé Nutrition Institute. [s. a.]
ANGIOLÓGIAI ÚTMUTATÓ 2009 = Magyar Angiológiai és Érsebészeti Társaság: A végtag-amputáció szakmai irányelve. Angiológiai Útmutató. 2009/09. http://www.iranyelvek.hu/iranyelvek/
old/all/Angiologia/A%20vegtag-amputacio%20szakmai%20iranyelv.pdf (2012. 02. 21.) BOROMISZA 2010 = BOROMISZA Piroska: Ereink védelmében. Országos program a tünetmentes
érszűkület felkutatásáért. IME 2010/3. 51–52.
KOLLÁR – SZEGEDI 2007 = KOLLÁR Lajos – SZEGEDI János: Lappangó betegség – súlyos követ-kezmények – folyamatosan küzdő szakma. Orvosi Hetilap 2007/47. 2249.
KULLMANN 1999 = KULLMANN Lajos: Ortopédiai betegek rehabilitációja. In: Katona Ferenc – Siegler János (szerk.): Rehabilitáció. Budapest: Medicina 1999. 99.
KULLMANN – BELICZA – LÁSZLÓ 1997 = KULLMANN Lajos – BELICZA Éva – LÁSZLÓ Gergely:
Az alsó végtag amputáció kétéves eredményei Magyarországon, országos adatbázis lapján.
Orvosi Hetilap 1997/37: 2327–2332.
8 TZAMALOUKAS – PATRON – MALHOTRA 1994. 355.
TZAMALOUKAS – PATRON – MALHOTRA 1994 = TZAMALOUKAS, Antonios H. – PATRON, Annette – MALHOTRA, Deepak: Body mass index in amputees. JPEN Journal of Parenteral and Enteral Nutrition, 1994/4. 355–358.
WINKLER 2000 = WINKLER Gábor: A diabeteses láb-szindróma: az ellátás interdiszciplináris vonatkozásai. In: Baranyai Éva – Winkler Gábor (szerk.): Válogatott fejezetek a klinikai diabetológiából. Budapest: Medicina, 2000. 189–200.