Application of linear discriminant analysis to the biochemical and haematological differentiation of opiate addicts from healthy subjects: a case-control study

Objective : Biochemical and haematological parameters of nutritional interest were determined in the serum of opiate addicts in order to compare them with those obtained in healthy subjects. Linear discriminant analysis was applied for the differentiation of the opiate addicts. Subjects : Sera of 106 opiate addicts in detoxification treatment ( n =19) or in Methadone Maintenance Treatment Program (MMTP) ( n =87) were studied. Design : The determination of classical biochemical and haematological parameters in blood samples was carried out using standardized methods. Determination of retinol and α -tocopherol was carried out by high-performance liquid chromatography with diode-array detector. Folic acid and vitamin B 12 were determined using competitive binding techniques. Minerals were determined by flame emission spectrometry (Na and K) and atomic absorption spectrometry with air–acetylene flame (Ca, Mg, Fe, Cu and Zn) or with hydride generation (Se). Phosphorous was determined using a colorimetric method with ammonium molibdate. All statistical analyses were performed by means of the SPSS version 10.0 software for Windows. Results : Stepwise linear discriminant analysis simplified the system to the following variables: Na, K, Mg, number of leucocytes, triglycerides, GPT, glucose, albumin, retinol and folic acid; and 90.1% (86.4% after crossvalidation) of correct classification was obtained. Representing the first and second discriminant functions, the control groups were well separated from opiate addicts. Conclusions : Applying linear discriminant analysis on several biochemical and haematological parameters, the opiate addicts could clearly be differentiated from the control individuals, and a tendency to differentiate the opiate addicts in MMTP and in detoxification treatment was observed.