Screening properties of questionnaires and laboratory tests for the detection of alcohol abuse or dependence in a general practice population

Background: Early identification of alcohol abuse or dependence is importan t in general practice because many diseases are influenced by alcohol. Gene ral practitioners, however, fail to recognise most patients with alcohol pr oblems. Aim: To assess the diagnostic performance of the CAGE and AUDIT questionnai res, their derivatives, and laboratory tests in screening for alcohol abuse or dependence in a primary care population (male and female patients), att ending their general practitioner (GP). Design of study: A diagnostic cross-sectional study. Setting: A random sample of patients who were over 18 years of age (n = 199 2) attending 69 general practices situated in the same region in Belgium. Method: Alcohol questionnaires (CIDI 1.1, section 1, CAGE, AUDIT AUDIT-C, F ive-Shot, and AUDIT Piccinelli) were completed, demographic information was recorded, and patients underwent conventional blood tests, including mean corpuscular volume, liver function tests, the gamma-glutamyl transferase te st, and carbohydrate-deficient transferrin (CDT, estimated using %CDT). Cal culations of sensitivity, specificity, positive predictive value, negative predictive value, odds ratios with their 95% CIs, and receiver operating ch aracteristic (ROC) curves for different scores of the questionnaires and la boratory tests using DSM-III-R as the reference standard. Results: The past-year prevalence of alcohol abuse or dependence in this po pulation was 8.9% (178/1992) of which there were 132 male and 45 female pat ients attending a general practice. The GPs identified 33.5% of patients wi th alcohol abuse or dependence. Among male patients all questionnaires had reasonable sensitivities between 68% and 93% and hence at lower cut-points than recommended. Only the sensitivity of the CAGE, even at its lowest cut- point of greater than or equal to1 was lower (62%). In female patients the sensitivities were lower; however, odds ratios were higher for different qu estionnaires. The receiver operating characteristic (ROC) curves did not di ffer between the questionnaires. The laboratory tests had low diagnostic ac curacy with areas under the ROC curves (AUCs) between 0.60 and 0.67 for fem ale patients and 0.57 and 0.65 for male patients. Conclusions: This is one of the largest known studies on alcohol abuse or d ependence among family care practices. We confirm earlier results that the AUDIT questionnaire seems equally appropriate for malts and females; howeve r, screening properties among male patients are higher Nevertheless, the Fi ve-Shot questionnaire is shorter and easier to use in a general practice se tting and has nearly the same diagnostic properties in male and female gene ral practice patient populations. We confirm that conventional laboratory r ests are of no use for detecting alcohol abuse or dependence in a primary c are setting. Also, the %CDT cannot been used as a screening instrument in t his general practice population.