# Alcohol and Other Substance Screening in Bariatric Surgery Candidates: Utility of Self-Report and Toxicology Tests, Including Ethyl-Glucoronide

## TL;DR

This study examines alcohol and substance use in bariatric surgery candidates, finding that self-reports and toxicology tests help identify risky drinking behaviors.

## Contribution

The study introduces the use of ethyl-glucuronide in urine tests alongside self-reports to better assess alcohol misuse risks in bariatric surgery candidates.

## Key findings

- 15% of bariatric surgery candidates had ethyl-glucuronide levels indicating recent alcohol use.
- Men were more likely to be risky drinkers compared to women and the general population.
- Combining self-reports and objective toxicology tests improves the accuracy of substance use assessment.

## Abstract

Following bariatric surgery (BS) patients have an increased risk of alcohol misuse.

This 1-year cross-sectional study in potential BS candidates had several objectives: (a) assess the prevalence of risky drinking, alcohol use disorder (AUD), and other substance use/disorder; (b) compare the prevalence of these behaviors to that of the general Spanish population; (c) determine the proportion of patients with positive results in toxicology tests; and (d) study the predictive factors of risky drinking. Setting: tertiary university hospital.

Alcohol and other substance use were evaluated with the AUDIT-C and ASSIST questionnaires. Urine tests analyzed several markers (ethyl-glucoronide [EtG] ≥ 500 ng/ml, amphetamine, benzodiazepine, cannabinoid, cocaine, and opioid). The Mini-International-Neuropsychiatric-Interview (5.0.0) was employed to assess psychiatric diagnoses.

Among 308 candidates for BS, 196 were accepted to participate (69% women; mean age 46.7 ± 10.9 years; mean body mass index 45.6 ± 5.9). AUDIT-C and ASSIST identified 7% and 5% of risky drinkers, respectively. Men were more frequently risky drinkers compared to women (18% vs. 2%) and compared to the general population (18% vs. 8%). Six percent of individuals had AUD, being men the most affected, and 2% met criteria for other substance disorder. Fifteen percent of the sample presented risky tobacco use. Cannabis was self-reported only by males (3%). EtG ≥ 500 ng/ml was present in 15% of the sample, being a risk factor for risky drinking together with the male sex.

Identification of candidates at risk for risky drinking can help to prevent any alcohol misuse after BS. The combination of subjective and objective measures improves the validity of the assessment of substance use.

The online version contains supplementary material available at 10.1007/s11695-025-07774-z.