Associations Between the Phosphatidylethanol Alcohol Biomarker and Self-Reported Alcohol Use in a Sample of HIV-Infected Outpatient Drinkers in Western Kenya

Background: To counteract the syndemics of HIV and alcohol in Sub-Saharan Africa, international collaborations have developed interventions to reduce alcohol consumption. Reliable and accurate methods are needed to estimate alcohol use outcomes. A direct alcohol biomarker called phosphatidylethanol (PEth) has been shown to validate heavy, daily drinking, but the literature indicates mixed results for moderate and nondaily drinkers, including among HIV-infected populations. This study examined the associations of the PEth biomarker with self-report alcohol use at 2 time points in 127 HIV-infected outpatient drinkers in western Kenya. Methods: Participants were consecutively enrolled in a randomized clinical trial to test the efficacy of a behavioral intervention to reduce alcohol use in Eldoret, Kenya. They endorsed current alcohol use, and a minimum score of 3 on the Alcohol Use Disorders Identification Test-Consumption or consuming ≥6 drinks per occasion at least monthly in the past year. Study interviews and blood draws were conducted at baseline and at 3 months post treatment from July 2012 through September 2013. Alcohol use was assessed using the Timeline Followback questionnaire. Blood samples were analyzed for the presence of the PEth biomarker and were compared to self-reported alcohol use. We also conducted semistructured interviews with 14 study completers in February through March 2014. Results: Baseline data indicated an average of moderate–heavy alcohol use: 50% drinking days and a median of 4.5 drinks per drinking day. At baseline, 46% of women (31 of 67) and 8% of men (5 of 60) tested negative for PEth (p < 0.001). At the 3-month follow-up, 93% of women (25 of 27) and 97% of men (30 of 31) who reported drinking tested positive, while 70% of women (28 of 40) and 35% of men (10 of 29) who denied drinking tested negative for PEth. Interviews were consistent with self-reported alcohol use among 13 individuals with negative baseline results. Conclusions: These results add to the growing literature showing lack of agreement between self-report and PEth results among unhealthy and nondaily drinkers, particularly women. More research is needed to determine at what level of consumption over what period of time PEth becomes a reliable and accurate indicator of alcohol use.