Prealbumin in nutrition evaluation

Abstract

We compressed 16 test-pattern classes of albumin (ALB), cholesterol (CHOL), and total protein (TPR) in 545 chemistry profiles to 4 classes by converting decision values to a number code to separate malnourished (1 or 2) from nonmalnourished (NM) (0) patients, using as cutoff values for nonmalnourished (0), mild (1), and moderate (2): ALB 35, 27 g/L; TPR 63, 53 g/L; CHOL 3.9, 2.8 mmol/L; and BUN 9.3, 3.6 mmol/L. The BUN was found to have too low an S-value to make a contribution to the compressed classification. The cutoff values for classifying the data were assigned prior to statistical analysis, after examining information in the structured data. The data was obtained by a natural experiment in which the test profiles routinely done by the laboratory were randomly extracted. The analysis identifies the values for the variables used that best classify the data and are not dependent on distributional assumptions. The data were converted to 0, 1, or 2 as outcomes, to create a ternary truth table (each row is nnnn, the n value is 0 to 2). This allows for 3 4 (81) possible patterns, without the inclusion of prealbumin (PAB). The emerging system has much fewer patterns in the information-rich truth table formed (a purposeful, far from random, event). We added PAB, coded, and examined the data for 129 patients. The classes are a compressed truth table of n-coded patterns with outcomes of 0, 1, or 2 with protein-energy malnutrition (PEM) increasing from an all-0 to all-2 pattern. Pattern class (F = 154), PAB (F = 35), ALB (F = 56), and CHOL (F = 18) were different across PEM class and predicted PEM class (R 2 = 0.7864, F = 119, p < E −5). Kruskal-Wallis analysis of class by ranks was significant for pattern class (1E −18), PAB (6.1E −15), ALB (1E −16), CHOL (9E −10), and TPR (5.3E −13). The medians and standard error (SEM) for PAB, ALB, and CHOL of all four PABCLASSES (NM, mild, moderate, severe) are: PAB = 209, 8.7; 159, 9.3; 137, 10.4; 72, 11.1 mg/L, ALB = 36, 0.7; 30.5, 0.8; 25.0, 0.8; 24.5, 0.8 g/L; CHOL = 4.43, 0.17; 4.04, 0.20; 3.11, 0.21; 2.54, 0.22 mmol/L. PAB and CHOL values show the effect of nutrition support on PAB and CHOL in PEM. Moderately malnourished patients receiving nutrition support have PAB values in the normal range at 137 mg/L and at 159 mg/L when the ALB is at 25 g/L or at 30.5 g/L.