Impact of Preoperative Toxicological Screening on Perioperative Anesthetic Management and Short-Term Outcomes Following Metabolic and Bariatric Surgery: A Prospective Observational Study

Figures

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  Fig. 1. Participant flowchart showing recruitment and follow-up

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  Fig. 2. Agreement between self-reported substance use and toxicology screening test (TST) results. Bar graph showing the percentage of self-reported substance use among TST-positive and TST-negative participants. All TST-negative participants reported no substance use, whereas 87.9% of TST-positive participants reported substance use. Agreement between TST results and self-reported data was assessed using Cohen’s kappa, demonstrating very high concordance (κ = 0.92; 95% CI: 0.89–0.96), with an overall agreement rate of 98.2%

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  Fig. 3. Distribution of detected substances among TST-positive patients and in the overall study cohort. Bar chart illustrating the prevalence of individual substances detected by toxicology screening among TST-positive patients, compared with their prevalence in the entire study population. Tramadol and cannabinoids were the most frequently detected substances among TST-positive cases. Opiates, benzodiazepines, and barbiturates were detected at lower frequencies

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  Fig. 4. Inverse propensity score–weighted postoperative visual analogue scale (VAS) pain scores over 24 h by TST group. Inverse propensity score–weighted (IPSW) mean Visual Analog Scale (VAS) pain scores with 95% confidence intervals at five postoperative time points (baseline, 1 h, 6 h, 12 h, and 24 h), stratified by TST-positive and TST-negative groups. Repeated measurements were analyzed using generalized estimating equations (GEE) to account for within-patient correlation. Across all time points, the TST-positive group reported higher pain scores. Asterisks (*) indicate statistically significant between-group differences (p < 0.05). Unadjusted results are presented in Supplementary Figure S4

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  Fig. 5. Inverse propensity score–weighted changes in body mass index (BMI), percent excess weight loss (%EWL), and percent total weight loss (%TWL) over one year by TST group. Inverse propensity score–weighted (IPSW) mean values with 95% confidence intervals for body mass index (BMI), percent excess weight loss (%EWL), and percent total weight loss (%TWL) measured at baseline, 6 months, and 1 year after bariatric surgery, stratified by TST group. BMI decreased over time in both groups without significant between-group differences. At 1 year, small differences in %EWL and %TWL were observed between groups. Asterisks (*) denote statistically significant between-group differences (p < 0.05). Unadjusted results are shown in Supplementary Figure S5