80

Part II Nutrition Assessment, Consequences, and Implications

seriously ill hospitalized patients reported that a low BMI (equal to the 15th percentile) was associated with an increased risk of mortality within six months of admission, after factors such as serum albumin and weight loss were controlled (39).

The following are three formulas for calculating BMI:

BMI = Wt (kg)/Ht (m)2 BMI = HF × Wt (lb) BMI = [Wt (lb)/Ht (in)2] × 705

Table 6.2 shows height factors (HFs) for given heights. HFs can be used to determine BMI. Tables to deter- mine BMI and BMI calculators can be found online:

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Body Mass Index Table 1 (www.nhlbi.nih.gov/ health/educational/lose_wt/BMI/bmi_tbl.htm)

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Body Mass Index Table 2 (www.nhlbi.nih.gov/ health/educational/lose_wt/BMI/bmi_tbl2.htm)

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Calculate Your Body Mass Index (calculator) (www.nhlbi.nih.gov/health/educational/lose_wt/ BMI/bmicalc.htm)

TABLE 6.2 Body Mass Index Height Factors

Height HF Height HF Height HF 4'7" 4'8" 4'9"

4'10" 4'11" 5'0" 5'1" 5'2"

0.232 0.224 0.216 0.209 0.202 0.195 0.189 0.183

5'3" 5'4" 5'5" 5'6" 5'7" 5'8" 5'9"

5'10" Abbreviation: HF, height factor

0.177 0.172 0.166 0.161 0.157 0.152 0.148 0.143

5'11" 6'0" 6'1" 6'2" 6'3" 6'4" 6'5" 6'6"

0.139 0.136 0.132 0.128 0.125 0.122 0.119 0.116

Source: Reprinted from Osterkamp LK. Current perspective on assessment of human body proportions of relevance to amputees. J Am Diet Assoc. 1995;95:215-218, with permission from the Academy of Nutrition and Dietetics.

Example:

Previous target weight range: 131 to 161 lb Adjusted weight range with above-the-knee ampu-

tation (AKA)

Calf and foot (5.9% of total body weight [TBW]) + ½ thigh (5.05% of TBW) = 10.95% of TBW

131 lb × 0.1095 (10.95%) = 14.3 lb 161 lb × 0.1095 (10.95%) = 17.62 lb

Adjusted body weight: 117 lb to 144 lb

Amputation and Anthropometric Assessment

Adjusted Weight The percentages shown in Figure 6.4 (40) can be used as a guide when calculating an adjusted weight for an amputation.

Formula for Body Mass Index in Amputees Using the percentages shown in Figure 6.4, Himes has provided a formula for estimating TBW, including missing limb segments, for amputees who can be weighed. The TBW estimate can then be used to calcu- late the individual’s BMI (41):

WtE = WtO/(1 – P)

Figure 6.4 Percentage of Total Body Weight Contributed by Individual Body Parts