Marijuana use was not associated with worse 30-day surgical outcomes or 1-year weight loss after bariatric surgery and should not be a barrier to the procedure.
Bariatric surgeons, obesity medicine specialists, and surgical program administrators.
No worse outcomesfor marijuana users on 30-day surgical complications or 1-year weight loss after bariatric surgery
What the researchers found
Marijuana use was not associated with worse 30-day outcomes or 1-year weight loss. However, marijuana users were more likely to be current smokers (14% vs. 8%), use other substances, and report depression.
Why it matters
Many bariatric surgery programs exclude marijuana users due to assumed risks. This large study suggests that policy should be reconsidered, while providing additional mental health support.
The numbers in context
6,879 patients, 574 baseline marijuana users, 139 persistent users at 1 year. No differences in 30-day complications. No differences in 1-year weight loss. Users: 14% vs. 8% smokers (p-value significant). Higher depression and substance use rates.
How the study worked
Multicenter statewide study using Michigan Bariatric Surgery Collaborative registry data (June 2019-June 2020). Regression analysis comparing 30-day and 1-year outcomes between marijuana users and non-users.
Who was studied
6,879 bariatric surgery patients from over 40 hospitals across Michigan (2019-2020).
What this study cannot tell us
Self-reported marijuana use may be underreported. One-year follow-up may miss longer-term effects. Michigan-specific data. Cannot assess dose-response relationship.
How to read the evidence
Large multicenter registry study with appropriate regression analysis; strong evidence for surgical outcomes.
When this study was published
Data from June 2019 to June 2020 across Michigan.
The bigger picture
This is one of the largest studies addressing whether marijuana use should disqualify patients from bariatric surgery, and the results suggest it should not, though co-occurring mental health and substance use issues deserve attention.
Replication
Large multicenter study; longer follow-up would strengthen conclusions.
Funding
Not specified in abstract
Conflicts of interest
Not specified in abstract
Questions still open
- Should bariatric surgery programs update their marijuana use policies?
- Do marijuana users need different post-surgical mental health support?
Read the original research
The effect of marijuana use on short-term outcomes with bariatric surgery.
Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery, 19(9), 964-970
Citation
Janes, Lindsay A; Hammond, John W; Bonham, Aaron J; Carlin, Arthur M; Ghaferi, Amir A; Varban, Oliver A; Ehlers, Anne P; Finks, Jonathan F. (2023). The effect of marijuana use on short-term outcomes with bariatric surgery.. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery, 19(9), 964-970. https://doi.org/10.1016/j.soard.2023.02.025