Nutritional Risk Index (NRI)

Buzby et al first reported the Nutritional Risk Index (NRI) which is used to identify malnourishment in elderly patients admitted to the hospital.

NOTE: There are several variations for the NRI.

Parameters:

(1) serum albumin in g/L

(2) present weight in kilograms

(3) usual weight in kilograms

NRI =

= ((factor 1) * (serum albumin in g/L)) + ((factor 2) * (present weight) / (usual weight))

Factor 1	Source	Comment
15.9	Buzby (1988)	probably should be 1.59; the results of the assay were probably reported in g/dL
1.519	Friedmann (1997)	gives Roubenoff as source
1.489	Naber (1997)	gives Buzby as source

Factor 2	Source	Comment
0.417	Buzby (1988)	ratio reported as percent from 0 to 100 (or more); obtained by multiplying by 100%
0.417 * 100	Friedmann (1997)	similar to Buzby; includes the 100 but refers to ratio as a percent
41.7	Naber (1997)	uses the ratio of weights without making a percent

Form used in implementation:

NRI =

= (1.519 * (serum albumin in g/L)) + (41.7 * (current weight in kg) / (usual weight in kg))

Interpretation:

• The higher the index the less likely the patient is malnourished.

Limitations:

• While the NRI would work for many elderly patients it seems to be intended to detect a protein malnutrition rather than vitamin deficiency.

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Purpose: To evaluate an elderly patient for malnutrition using the Nutritional Risk Index (NRI), originally reported by Buzby et al.