Effect and Safety of Acupuncture for Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of 21 Randomised Controlled Trials

Objective To evaluate the effects of acupuncture on hypoglycaemic outcomes in type 2 diabetes mellitus (T2DM). Methods PubMed, Embase, Cochrane Library, and ClinicalTrials.gov were searched from inception up to July 2020, to identify randomised controlled trials (RCTs) that enrolled patients with T2DM and compared acupuncture combined with antidiabetic drugs to antidiabetic drugs alone. The primary outcomes were haemoglobin A1c (HbA1c) and fasting blood glucose (FBG). The secondary outcomes included 2-h blood glucose (2hBG), fasting insulin (FINS), homeostatic model assessment for insulin resistance (HOMA-IR), and acupuncture-related adverse events. Mean difference (MD) and 95% confidence interval (CI) were used as the effect measure in the meta-analysis. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation tool. Results Twenty-one RCTs (n=1,188) were included. The meta-analytic results showed that the acupuncture group had greater reductions in FBG (MD -6.46 mg/dL, 95% CI -11.95 to -0.98; moderate-quality evidence) and HOMA-IR (MD -1.23, 95% CI -2.16 to -0.31; low-quality evidence), but comparable changes in HbA1c (MD -0.39%, 95% CI -0.84 to 1.61; very-low-quality evidence), 2hBG (MD -4.99 mg/dL, 95% CI -20.74 to 10.76; low-quality evidence), and FINS (MD -1.32 µIU/mL, 95% CI -3.76 to 1.12; low-quality evidence). No data on the incidence of diabetic complications were found. All acupuncture-related adverse events reported were mild. Conclusions The current evidence suggests that acupuncture, as a complementary therapy to antidiabetic drugs, has a small but statistically significant effect on decreasing FBG and improving insulin resistance. The effects of acupuncture on HbA1c, 2hBG, and FINS remain uncertain. Acupuncture is generally safe in patients with mild diabetes. More evidence for the long-term effects of acupuncture on T2DM is needed. (Trial registration No. CRD42018115639).