FACTORS AFFECTING THE DISCRIMINANT FUNCTION-ANALYSIS OF BLOOD-CHEMISTRY PROFILES

The discriminant function analysis (DFA) of a battery of blood chemist ry tests is generally more sensitive and specific than single biochemi cal test in detecting alcoholism or hazardous drinking. This study exa mined factors affecting the DFA of blood chemistry profiles (BCP) from alcoholics (ALC) in treatment, primary care outpatients (PC), and the general population (GP). Our data indicate that of the 32 variables i n the BCP, 14 are not correlated with alcohol intake or consequences a nd can be deleted from the set considered for use in the DFA. Confound ing medical conditions in the data set used in the DFA did not adverse ly affect the correct classification of ALC or heavy drinkers. It was not necessary to use only extreme groups (e.g., alcoholics vs. light d rinkers/abstainers) to develop the discriminant function. Transformati on of some blood variables greatly improved the selection of key varia bles in the DFA. Another finding was that there was little benefit fro m fitting the DFA to the demographics of subjects. When the BCP was co mbined with the results of a brief questionnaire, the TWEAK, it only i mproved slightly the classification power of the DFA based only on the TWEAK questions. (C) 1997 Elsevier Science Inc.