Perioperative cannabis use: a longitudinal study of associated clinical characteristics and surgical outcomes.

BACKGROUND: Despite increases in cannabis use generally and for pain management, data regarding cannabis use in patients undergoing surgery are lacking. This study examined the prevalence of cannabis use among patients undergoing elective surgery and explored differences in clinical characteristics and surgical outcomes between cannabis users and non-cannabis users.
METHODS: This prospective study included 1335 adults undergoing elective surgery. Participants completed self-report questionnaires preoperative and at 3-month and 6-month postsurgery to assess clinical characteristics and surgical outcomes.
RESULTS: Overall, 5.9% (n=79) of patients reported cannabis use (53.2% medical, 19.0% recreational and 25.3% medical and recreational). On the day of surgery, cannabis users reported worse pain, more centralized pain symptoms, greater functional impairment, higher fatigue, greater sleep disturbances and more symptoms of anxiety and depression versus non-cannabis users (all p<0.01). Additionally, a larger proportion of cannabis users reported opioid (27.9%) and benzodiazepine use (19.0%) compared with non-cannabis users (17.5% and 9.2%, respectively). At 3 and 6 months, cannabis users continued to report worse clinical symptoms; however, both groups showed improvement across most domains (p≤0.05). At 6 months, the groups did not differ on surgical outcomes, including surgical site pain (p=0.93) or treatment efficacy (p=0.88).
CONCLUSIONS: Cannabis use is relatively low in this surgical population, yet cannabis users have higher clinical pain, poorer scores on quality of life indicators, and higher opioid use before and after surgery. Cannabis users reported similar surgical outcomes, suggesting that cannabis use did not impede recovery. © American Society of Regional Anesthesia & Pain Medicine 2021. No commercial re-use. See rights and permissions. Published by BMJ.