Future prospects for biomarkers of alcohol consumption and alcohol-induced disorders

Abstract

The lack of reliable measures of alcohol intake is a major obstacle to the diagnosis, treatment, and research of alcohol abuse and alcoholism. Successful development of a biomarker that allows for accurate assessment of alcohol intake and drinking patterns would not only be a major advance in clinical care but also a valuable research tool. A number of advances have been made in testing the validity of proposed biomarkers as well as in identifying potential new biomarkers through systems biology approaches. This commentary will examine the definition of a biomarker of heavy drinking, the types of potential biomarkers, the steps in biomarker development, the current state of biomarker development, and critical obstacles for the field. The challenges in developing biomarkers for alcohol treatment and research are similar to those found in other fields. However, the alcohol research field must reach a competitive level of rigor and organization. We recommend that NIAAA consider taking a leadership role in organizing investigators in the field and providing a common set of clinical specimens for biomarker validation studies.

Figure 1. Metrics for assessing biomarker performance

Unlike traditional statistics that examine differences between populations, diagnostics are intended to be informative of the individual patient. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy measures can be used to summarize a biomarker’s ability to correct classify subjects. In this example, the ability to classify heavy alcohol drinking and non-heavy alcohol drinking (abstainers or light drinkers) is portrayed. Sensitivity and specificity are the most commonly used measures, and, in this case, they respectively give the percentage of alcohol abusing and non-alcohol abusing subjects correctly identified.

Figure 2. Steps in developing biomarkers of alcohol-related disorders

As described in the text, development of a clinical biomarker requires multiple steps/stages of development. Successful completion of each of these steps results in a validated biomarker that is both sensitive and specific.

Figure 3. Biomarker development and use

Through the process of biomarker development steadily increasing numbers of samples are examined. With successful completion of each stage the confidence, the likelihood that a biomarker will be clinically useful, increases.