Measurement of Ethanol Use in a Chronic Pain Population Using the Biomarker Phosphatidylethanol

Background: Measurement of ethanol (EtOH) use in chronic pain patients has always been a challenge. Current biomarkers are easily confounded, giving unreliable results. Self-reporting is unreliable. Phosphatidylethanol (PEth) is a recent EtOH biomarker that shows promise as an alternative measure of EtOH. Methods: Twenty patients were included in this study. All were 21 years of age or older and had chronic pain for greater than 3 months. Patients took the Alcohol Use Disorders Identification Test (AUDIT) questionnaire. Blood was collected for PEth testing. Correlation between Audit score (0 - 40) and PEth level (ng/mL) was done with the Pearson Product-moment correlation coefficient (SPSS). Values are means ± S.E.M. Significance at p ≤ 0.05. Opioid use with EtOH use was also examined. Results: Twenty patients were enrolled, 17 (85%) males and 3 (15%) females. AUDIT scores were 8.1 ± 1.4. PEth levels were 178.3 ± 43.5. Eighty-five percent of patients had Audit scores indicating mild to moderate use of EtOH while 15% had severe use. PEth levels indicated 70% mild to moderate EtOH use and 30% heavy use. The correlation coefficient between the Audit score and PEth was 0.219 (p = 0.353) and not significant. Twenty-five percent of patients in the study were on opioids. The average PEth level in these patients was 273 ± 101.7. Conclusions: There is a poor correlation between self-reporting of EtOH use per AUDIT and PEth levels. Twenty-five percent of patients in the study were also on opioids, with PEth levels indicating high levels of EtOH consumption in this group. This suggests that self-reporting of EtOH use is inadequate in the chronic pain setting to detect actual EtOH use.