Because PEth detects alcohol use only in the 3 weeks prior to blood draw, we also conducted analysis in a subsample restricted to those with PEth blood draw within 21 days prior to or on the same day that AUDIT-C was measured, thus ensuring complete overlap of the 3 weeks covered by PEth measurement with the 1 year encompassed by AUDIT-C. This analysis yielded results consistent with our findings in the larger sample. It is important to emphasize that patients who self-reported abstinence are likely a heterogeneous group, which could include those with lifetime abstinence, those who are currently abstinent but previously consumed alcohol, and those who do not abstain but report non-drinking due to social desirability bias or other unknown factors. Taken together, these results underscore the need for further research evaluating health outcomes among patients who self-report abstinence. This will help to better understand the drivers of under-reporting alcohol exposure as well as to fully elucidate the mortality risk associated with this behavior, especially among HCV+ and HIV+/HCV+ co-infected individuals who are prone to greater risk of harm from unhealthy alcohol use.3–5
