Detection of alcohol abuse in neurological patients: Variables of clinicalrelevance to the accuracy of the %CDT-TIA and CDTect methods

Objectives: Alcohol-related neurological diseases are encountered frequentl y. Early diagnosis is essential, because minimal intervention effectively r educes hazardous alcohol consumption and may prevent permanent neurological damage. Carbohydrate-deficient transferrin (CDT) is a valuable tool for th e identification of alcohol abuse, but for unselected patient populations, reduced test accuracy has been reported. Recently, factors other than alcoh ol use have been shown to influence CDT levels. Our aim was to identify cli nically relevant factors that might reduce test accuracy. Material and Methods: We included 397 neurological patients consecutively h ospitalized for seizures, ischemic stroke, or sciatica and 87 patients who attended routine outpatient controls for epilepsy. Blood samples were analy zed for CDT by using two commercially available tests, %CDT-TIA and CDTect. All patients underwent a semistructured clinical interview that included a record of the reported ethanol consumption during the last 8 days, and all completed the Alcohol Use Disorders Identification Test (AUDIT). Current m edication, medical history, and demographic information also were obtained. Results: Both tests were elevated in female antiepileptic drug users, compa red with others who reported no recent ethanol intake. A higher number of f alse-positive cases was seen for CDTect than for %CDT. Various combinations of CDT and gamma -glutamyltransferase improved sensitivity, but at the cos t of reduced specificity. Variables that predicted the variation of CDT inc luded antiepileptic drug use, sex, body mass index, and smoking. Total tran sferrin levels were reduced significantly in postmenopausal women, whereas a falling trend was seen for CDTect. Transferrin alterations caused a highe r number of false-positive results for CDTect than for %CDT. The area under the receiver operating characteristics curve for women was higher for CDTe ct than for %CDT, and for %CDT, the area under the receiver operating chara cteristics curve was higher for men than for women. Conclusion: The accuracy of CDT for detection of alcohol abuse in neurologi cal patients was generally low, particularly for women. Combination variabl es of CDT and gamma -glutamyltransferase did not increase test accuracy. Va riables that were associated with higher CDT levels included female sex, an tiepileptic drug use, transferrin alterations, and possibly low body mass i ndex. When factors known to cause poor accuracy in particular patient group s are appreciated, CDT may be a good adjunct to the clinical examination.