Cannabis Use Did Not Worsen Major Complications After Liver and Pancreas Surgery | Research

The takeaway

Among 191,315 patients undergoing hepatobiliary and pancreatic surgery, cannabis users had similar complication rates and a lower risk of pneumonia compared to non-users.

surgeons, anesthesiologists, perioperative medicine specialists, cannabis-using surgical patients

What the researchers found

Cannabis users (0.89% of 191,315 patients) had no significant differences in in-hospital mortality, acute kidney injury, blood transfusion, mechanical ventilation, venous thromboembolism, surgical site infection, or other major complications compared to non-users. Cannabis users had significantly lower odds of pneumonia (OR 0.54, 95% CI 0.29-0.99). No differences in length of stay or hospitalization costs.

Why it matters

Surgeons and anesthesiologists need to know whether cannabis use affects surgical outcomes. This national database analysis provides reassurance that cannabis use does not appear to worsen major perioperative complications after complex abdominal surgery.

The numbers in context

191,315 patients total. 1,705 cannabis users (0.89%). Pneumonia: OR 0.54 (CI 0.29-0.99). No significant difference in mortality (OR 0.64, CI 0.31-1.30). No difference in LOS (10.99 vs 9.69 days, p=0.348) or costs ($49,444 vs $43,661, p=0.109).

How the study worked

Retrospective analysis of the Nationwide Inpatient Sample (2016-2020). 191,315 HPB surgery patients identified, 1,705 (0.89%) with cannabis use. Multivariate analysis adjusted for demographics and comorbidities compared complications, length of stay, and costs.

What this study cannot tell us

Administrative database with ICD coding limitations. Cannabis use likely underreported. Cannot determine dose, frequency, or recency of use. Healthy user bias possible. Cannot distinguish between active and former users. Observational design.

How to read the evidence

Large national database with multivariate adjustment, but administrative data limitations and likely underreporting of cannabis use limit to moderate.

When this study was published

NIS data from 2016-2020.

The bigger picture

While reassuring for surgical planning, the lower pneumonia rate in cannabis users is unexpected and warrants cautious interpretation. It may reflect healthy user bias or demographic differences rather than a protective effect of cannabis.

Questions still open

Why did cannabis users have lower pneumonia risk?
Should cannabis use change perioperative management for HPB surgery?

Common questions

Should I stop cannabis before liver or pancreas surgery?

This study found no increased complication risk for cannabis users, but it cannot provide specific clinical recommendations. Anesthetic interactions and other factors should still be discussed with your surgical team.

Did cannabis users actually do better in surgery?

Cannabis users had a lower rate of pneumonia, but this may reflect demographic differences (younger, potentially healthier baseline) rather than a protective effect of cannabis itself.

Read the original research

Impact of cannabis consumption on perioperative outcomes in patients undergoing hepatobiliary and pancreatic surgery: a nationwide analysis.

HPB : the official journal of the International Hepato Pancreato Biliary Association, 27(7), 981-987

View on PubMed ↗Publisher’s paper ↗

Citation

Sohail, Amir H; Quazi, Mohammed A; Sheikh, Abu B; Greenbaum, Alissa; Nir, Itzhak; Hernandez, Matthew C. (2025). Impact of cannabis consumption on perioperative outcomes in patients undergoing hepatobiliary and pancreatic surgery: a nationwide analysis.. HPB : the official journal of the International Hepato Pancreato Biliary Association, 27(7), 981-987. https://doi.org/10.1016/j.hpb.2025.04.006