New approach to the validity of the alcohol use disorders identification test: stratum-specific likelihood ratios analysis.
BACKGROUND
Previous validation studies of the Alcohol Use Disorders Identification Test (AUDIT) used either the fixed-threshold approach or receiver operating characteristic (ROC) analyses. This study was aimed to conduct a stratum-specific likelihood ratio (SSLR) analysis on the validity of the AUDIT for detecting alcohol use disorders.


METHODS
A two-phase validation study was conducted among nonpsychiatric inpatients at a general hospital, using the AUDIT for phase 1 screening and the Schedules for Clinical Assessment in Neuropsychiatry for the phase 2 interview. All of the patients with positive screening results and a subsample of the patients with negative screening results were interviewed in the second phase. The validity of the AUDIT for current alcohol use disorders was estimated using the ROC first, and an SSLR analysis was performed subsequently.


RESULTS
In 422 inpatients who completed the screening, 193 had a negative result with a zero score, 103 had a negative result with a nonzero score, and 126 had a positive result. Twenty screened patients with a negative result and a nonzero score and 107 patients with a positive result were interviewed in the second phase, in which 59 patients were found to have current alcohol use disorders according to DSM-IV criteria. The area under the ROC curve of the AUDIT for current alcohol use disorders was 0.98. The sensitivity and specificity of the AUDIT at the optimal cutoff of 8 were 0.97 and 0.90, respectively. Three strata of the AUDIT scores (0-7, 8-13, and > or = 14) were derived for alcohol use disorders, with the SSLRs being 0.04, 3.67, and 49.72, and the corresponding posttest probabilities being 0.01, 0.42, and 0.91, respectively.


CONCLUSIONS
The AUDIT is a valid screening tool for alcohol use disorders, and the three strata derived from the SSLR analysis are informative and readily applicable in clinical practice.