Optimal use of the AUDIT in screening and brief intervention programs: a decision theoretic approach (part of Economics of SBI symposium)

摘要

BackgroundCurrent evidence suggests that screening and brief intervention(SBI) programs can be effective at reducing riskyalcohol consumption. While validity and reliability havebeen demonstrated for existing screening instruments, littleis known about how the diagnostic properties of an instrumentinfluence the cost-effectiveness of SBI. We develop adecision theoretic framework to model this issue, and tomeasure the potential improvement in cost-effectivenessthat could result from changes in screening instrumentproperties and other factors associated with SBI.Material and methodsTo make use of our decision theoretic model, we obtainestimates of the input parameters by conducting a comprehensivereview of the literature. In particular, wereview the literature on the sensitivity and specificity ofthe Alcohol Use Disorders Identification Test (AUDIT),and then synthesize this evidence using meta-analyticmethods. We also compile evidence on the cost of SBI,the QALY gains of SBI, and the prevalence of risky drinkingamong primary care patients. We assess uncertaintyvia Monte Carlo analysis. Finally, we conduct expectedvalue of perfect information (EVPI) analyses to investigatethe sources of decision uncertainty.ResultsWhen QALYs are valued at a conservative $1,000/QALYour decision theory indicates an optimal AUDIT thresholdscore of 5. Our model indicates that employing the recommendedthreshold score of 8 results in about $4.50 perpatient in foregone benefits. This suggests large aggregateforegone benefits with even modest sized patient populations.Gender-specific results are qualitatively similar, butreveal that the optimal SBI program is dramatically differentacross genders.ConclusionsDespite the relatively sound psychometric properties ofthe AUDIT, small differences in the sensitivity and specificitycan have large impacts on the cost-effectiveness ofSBI. Differences in the AUDIT’s performance across malesand females, as well as differences in the prevalence ofrisky drinking across genders, contribute heavily to thecost-effectiveness of SBI as well.