PEth and the AUDIT questionnaire each found hazardous drinkers the other missed

Design

Retrospective cohort using linked primary care and registry data

Population

3,679 and 8,934 Swedish primary care patients with PEth and a self-report within 90 days

Primary outcome

Concordance between PEth and AUDIT score or weekly drinks

Effect

Hazardous use: AUDIT 26.5%, PEth 14.6% to 18.3%, weekly drinks 8.5%; moderate, non-linear correlation

This Swedish study linked regional primary care records to national registries to compare phosphatidylethanol (PEth), a blood marker of recent alcohol use, with two self-reported measures. One sample of 3,679 patients had both PEth and an AUDIT score within 90 days; another of 8,934 had PEth and a recorded weekly drink count.

The share classed as hazardous drinkers depended on the method: 26.5% by AUDIT (score 8 or more), 14.6% to 18.3% by PEth (above 210 ng/mL), and 8.5% by reported drinks (10 or more a week). Each method identified people the others did not. PEth correlated only moderately with both self-reports, and the relationship was not linear. At the same PEth level, men and people with higher education or income reported more weekly drinking, and younger patients scored higher on AUDIT.

For a family physician, PEth is useful but not a replacement for asking. It measures something different from a questionnaire, so a normal PEth does not cancel a high AUDIT, and a raised PEth with a low self-report is an opening for a conversation rather than an accusation.

• Use AUDIT or AUDIT-C as the first screen for hazardous drinking in consultations.
• Consider PEth when self-report seems unreliable or when monitoring change over weeks.
• Treat a raised PEth with low self-reported drinking as a reason to talk, not a verdict.
• Do not let a normal PEth override a high AUDIT score.

Why it matters

PEth is increasingly available to primary care, and this shows where it adds to the conversation and where it does not.

Don't overread it

Patients were tested for clinical reasons, not screened at random, so these proportions do not describe the general practice population.

The statistics, in plain English

A moderate correlation means PEth and questionnaires broadly move together but often disagree for an individual patient. The different prevalence figures partly reflect different thresholds measuring different things, so none is simply the right answer.

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