Marijuana use does not affect the outcomes of bariatric surgery

The decriminalization of marijuana and legalization of derived products requires investigation of their effect on healthcare-related outcomes. Unfortunately, little data are available on the impact of marijuana use on surgical outcomes. We aimed to determine the effect of marijuana use on 30-day complications and 1-year weight loss following laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG).

At a large academic center, 1176 consecutive patients undergoing primary bariatric surgery from 2012 to 2017 were identified and separated into cohorts according to marijuana use. The only exclusions were 19 patients lost to follow-up. Propensity score matching, using logistic regression according to preoperative age, gender, BMI, and comorbid conditions, yielded 73 patient pairs for the control and study arms. All patients were followed two years postoperatively.

Excess BMI lost did not differ between marijuana users and controls at 3 weeks (23.0% vs 18.9%, p = 0.095), 3 months (42.0% vs 38.1%, p = 0.416), 6 months (60.6% vs 63.1%, p = 0.631), 1 year (78.2% vs 77.3%, p = 0.789), or 2 years (89.1% vs 74.5%, p = 0.604). No differences in the rate of major 30-day postoperative complications, including readmission, infection, thromboembolic events, bleeding events and reoperation rates, were found between groups. Follow-up rate at two years was lower in marijuana users (12.3% vs 27.4%, p = 0.023).

This study suggests marijuana use has no impact on 30-day complications or weight loss following bariatric surgery, and should not be a contraindication to bariatric surgery.