A103-21 A Comparison of Validated Survey and Biomarker Measures to Detect Alcohol Misuse in Critically Ill Patients

Rationale

Alcohol misuse increases risk for harmful health consequences and is a common pre-existing condition in hospitalized patients, particularly those who require critical care. One validated survey to screen for alcohol misuse is the Alcohol Use Disorders Identification Test-C (AUDIT-C), a three-question instrument; however, obtaining survey data from critically ill patients is challenging, limiting its utility. Therefore, objective strategies to identify alcohol misuse in the critical care setting are necessary. We sought to determine how the direct alcohol biomarker red blood cell (RBC) phosphatidylethanol (PEth) compared with concomitantly collected AUDIT-C information in a cohort of acutely ill, hospitalized patients.

Methods

We included 474 patients consecutively enrolled in the NIH-supported ARDS, Pneumonia, and Sepsis (APS) consortium, a multicenter prospective cohort of critically ill patients with shock and/or respiratory failure. Trained research coordinators performed AUDIT-C assessments to determine risk of alcohol misuse in the past year. RBCs collected concurrently were subjected to liquid chromatography-tandem mass spectrometry for PEth to establish recent (2-4 week) alcohol consumption. Spearman’s correlation quantified the association between AUDIT-C and PEth values with agreement between accepted classifications reported as counts and percentages. ROC curve analysis identified the optimal PEth cutoff to classify risk for alcohol misuse by AUDIT-C.

Results

Among the 344 of 474 patients with available AUDIT-C, 10% displayed increased risk of alcohol misuse; however, PEth assessments in all 474 patients indicated that 20% had significant recent alcohol consumption (PEth ≥ 20 ng/mL). Moderate correlations between AUDIT-C and PEth were present in patients with concomitantly available measures (n = 344, rho=0.38 [0.26, 49], p < 0.001). PEth assessment corroborated AUDIT-C classification in 86% (265/309) and 66% (23/35) of patients classified as low risk and elevated risk for alcohol misuse, respectively (Table 1). Discrepancies in classification occurred in 34% of patients with AUDIT-C suggesting alcohol misuse who had low PEth, and in 14% who had AUDIT-C suggesting no misuse who had elevated PEth. ROC curves indicated that a PEth threshold of 36 ng/mL had a sensitivity of 63% and specificity of 93% to identify increased risk of alcohol misuse (PPV=49%, NPV=96%, AUC=0.77 [0.67,0.86]).

Conclusions

PEth assessments in the APS cohort suggest that risk of alcohol misuse may be higher than that detected by AUDIT-C screening. Limited concurrent classification was evident between AUDIT-C and PEth, yet significant associations existed. PEth thresholds to identify alcohol misuse were comparable to previous reports, but additional investigation will be necessary to account for covariates in critically ill patients.

This abstract is funded by: U01HL168145, R24AA019661