Background
With the increasing legalization of medical and recreational cannabis, patients and providers have growing interest in the role of cannabinoids in treating inflammatory bowel disease. Prior meta-analysis has shown inconclusive evidence for efficacy of cannabinoids. We sought to produce an up-to-date meta-analysis that pools new data to evaluate the therapeutic effects of cannabinoids in both Crohn’s disease (CD) and ulcerative colitis (UC).

Methods
PubMed, Embase, CENTRAL and CINAHL were queried for randomized-controlled trials evaluating the impact cannabinoids in CD or UC. Random effects modeling was used to compute pooled estimates of risk difference. Heterogeneity was assessed using I2.

Results
Eight studies, including 4 studies of CD, 3 studies of UC, and 1 study of both diseases met inclusion criteria. Among 5 studies of CD, a statistically significant decrease in clinical disease activity following intervention was observed (risk ratios [RR],  −0.91; 95% CI, CI:1.54 to CI:0.28, I2 = 71.9%). Clinical disease activity in UC was not significantly lower in the pooled analysis (RR, −2.13; 95% CI, −4.80 to 0.55; I2 = 90.3%). Improvement in quality of life (QoL) was observed in both CD and UC combined (RR, 1.79; 95% CI, 0.92-0.2.66; I2 = 82.8%), as well as individually. No differences were observed in the analysis on endoscopic disease activity and inflammatory markers.

Conclusions
This meta-analysis of clinical trials suggests that cannabinoids are associated with improved quality of life in both CD and UC, as well as improved disease activity but not inflammation.