The Effectiveness of Acupuncture in Management of Functional Constipation: A Systematic Review and Meta-Analysis

OBJECTIVE: The purpose of this study was to assess the effectiveness and safety of acupuncture for functional constipation (FC). METHODS: A rigorous literature search was performed in English (PubMed, Web of Science, the Cochrane Library, and EMBASE) and Chinese (China National Knowledge Infrastructure (CNKI), Chinese Biological Medical (CBM), Wanfang database, and China Science and Technology Journal (VIP)) electronic databases from their inception to October 2019. Included randomized controlled trials (RCTs) compared acupuncture therapy with sham acupuncture or pharmacological therapies. The outcome measures were evaluated, including the primary outcome of complete spontaneous bowel movement (CSBM) and secondary outcomes of Bristol Stool Form Scale (BSFS), constipation symptoms scores (CSS), responder rate, the Patient Assessment of Constipation Quality of Life (PAC-QOL) questionnaire, and safety evaluation. Meta-analysis was performed by using RevMan5.3. RESULTS: The merged data of 28 RCTs with 3525 participants indicated that acupuncture may be efficient for FC by increasing CSBMs (p < 0.00001; MD = 0.84 [95% CI, 0.65 to 1.03]; I(2) = 0%) and improving constipation symptoms (p=0.03; SMD = −0.4 [95% CI, −0.78 to −0.03]; I(2) = 74%), stool formation (p < 0.00001; MD = 0.24 [95% CI, 0.15 to 0.34]; I(2) = 0%), quality of life (p < 0.00001; N = 1, MD = −0.33 [95% CI, −0.45 to −0.21]), and responder rates (p=0.02; RR = 2.16; [95% CI, 1.1 to 4.24]; I(2) = 69%) compared with the effects of sham treatment. No increased risk of adverse events was observed (p=0.44; RR = 1.18; [95% CI, 0.77 to 1.81]; I(2) = 0%). With regard to medication comparisons, the pooled data indicated that acupuncture was more effective in increasing CSBMs (p=0.004; MD = 0.53 [95% CI, 0.17 to 0.88]; I(2) = 88%) and improving patients' quality of life (p < 0.00001; SMD = −0.73 [95% CI, −1.02 to −0.44]; I(2) = 64%), with high heterogeneity. However, there were no significant differences in responder rate (p=0.12; RR = 1.31; [95% CI, 0.94 to 1.82]; I(2) = 53%), BSFS (p=0.5; MD = 0.17 [95% CI, −0.33 to 0.68]; I(2) = 93%), or CSS (p=0.05; SMD = −0.62 [95% CI, −1.23 to −0.01]; I(2) = 89%). Regarding safety evaluation, acupuncture was safer than medications (p < 0.0001; RR = 0.3; [95% CI, 0.18 to 0.52]; I(2) = 30%). CONCLUSIONS: Current evidence suggests that acupuncture is an efficient and safe treatment for FC. Acupuncture increased stool frequency, improved stool formation, alleviated constipation symptoms, and improved quality of life. However, the evidence quality was relatively low and the relationship between acupuncture and drugs is not clear. More high-quality trials are recommended in the future. PROSPERO registration number: CRD42019143347.