METHODS: Nine databases were searched through November 2017. Randomized controlled trials that reported the smoking cessation effect of V. cinerea were included. Data were extracted by two independent researchers. Study quality was assessed using the Cochrane risk of bias and JADAD score. The estimates of pooled effects were calculated as relative risk (RR) with 95% CI using a random-effects model.
RESULTS: Five trials with 347 smokers were included. V. cinerea treatment group was significantly associated with cessation rate higher than that in the control group with no evidence of heterogeneity for both continuous abstinence rate (CAR) at week 8 with risk ratio (RR): 1.69, 95% CI [1.00, 2.86]; week 12 RR: 2.18, 95% CI [1.17, 4.04]) and 7-day point prevalence abstinence rate (PAR) (week 8 RR: 1.51, 95% CI [1.01, 2.27]; week 12 RR: 1.93, 95% CI [1.24, 2.99]) at week 8 and 12, respectively. There was no significant difference of all adverse events between the treatment and the control groups.
CONCLUSION: Our study demonstrates that V. cinerea has potential efficacy for smoking cessation. Further well-design RCTs of standardized V. cinerea compared with standard treatment should be conducted to strengthen this evidence.