The dose-effect relationship of acupuncture in the treatment of functional gastrointestinal disorders: A meta-regression of randomized controlled trials

Introduction: The efficacy of acupuncture in treating functional gastrointestinal disorders (FGIDs) has been widely acknowledged. However, the dose-response relationship between acupuncture frequency and FGIDs remains uncertain. This review aimed to explore the relationship between the number of acupuncture sessions and the efficacy of acupuncture for FGIDs. Methods: Seven major databases were searched from their inception to April 25, 2023. Literature screening, risk of bias assessment, and data extraction were performed by two reviewers independently. The quality of included randomized controlled trials (RCTs) was assessed using the Cochrane bias risk tool and Jadad score. The doseeffect relationship between acupuncture sessions and the clinical response rate in patients with FGIDs was investigated by using the cubic spline limited nonlinear meta-regression method in statal5.1. Before the review, we conducted the PROSPERO registration (CRD42022344699). Results: Our analysis included 100 studies on acupuncture treatment of FGIDs, encompassing 8,589 participants. The meta-analysis of the dose-response relationship indicated that acupuncture could improve clinical symptoms and clinical response in patients with FGIDs to some extent. The clinical response rate increased with the number of acupuncture sessions in the range of ten to twenty sessions, with the odds ratio (OR) value rising from 1.05 (95 % CI: 0.89, 1.21) to 1.38 (95 % CI: 1.22,1.53). The peak of clinical response rate was observed at 24 acupuncture sessions (OR = 1.40; 95 % CI: 1.25, 1.55), representing a 40 % increase in OR. Compared with 24 sessions, the clinical response rate decreased after 56 sessions (OR = 1.22; 95 % CI: 0.64, 1.81). Conclusion: There is a dose-response relationship between the number of acupuncture sessions and the clinical response in individuals with FGIDs. Twenty-four acupuncture treatments correlate with the optimal clinical response.