Zao Ren An Shen for insomnia: a systematic review with meta-analysis

To assess the effectiveness and safety of Zao Ren An Shen (ZRAS), a Chinese herbal medicine formula, for the treatment of insomnia.

Seven databases (ie, EMBASE, PubMed, the Cochrane library, and PsycINFO, Chinese National Knowledge Infrastructure, Wanfang and Chongqing VIP) were searched from their inception to 6 November 2018. Controlled trials comparing the effectiveness or safety of ZRAS to conventional treatments, a placebo or no-treatment in an insomnia population were selected. Primary outcomes were: sleep quality (assessed with the Pittsburgh Sleep Quality Index, PSQI), and the number of adverse events at post-treatment. The risk of bias was assessed with the Cochrane Collaboration's tool and meta-analyses were performed using RevMan 5.3.

A total of 19 studies (1780 participants) were included. The effect of ZRAS on sleep quality (mean difference) was found to be superior compared to placebo in the sole placebo-controlled study located [-0.90 (-1.56, -0.24; 95% CI), p = 0.007] and similar to Benzodiazepine Receptor Agonists (BzRAs) [0.17 (-0.29, 0.64); 95% CI, p = 0.46]. The number of adverse events (relative risk) was lower for ZRAS than BzRAs [0.16 (0.12, 0.23; 95% CI), p < 0.001]. An overall high risk of bias was found in the selected studies.

The results favor ZRAS against BzRAs and placebo for the treatment of insomnia. However, the poor methodology of the studies prevents strong recommendations for ZRAS. Clinical trials with higher quality designs are required.