Effects of probiotics supplement in patients with type 2 diabetes mellitus: A meta-analysis of randomized trials.

BACKGROUND AND OBJECTIVE: To objectively evaluate the effects of probiotics supplement on glycemic control and lipid metabolism in patients with type 2 diabetes mellitus (T2DM).

MATERIAL AND METHODS: The randomized controlled trials (RCTs) with regard to the probiotics or synbiotics for the treatment of T2DM were collected through retrieving 5 databases from their establishment to March 2016. After study selection, quality assessment and data extraction were performed by 2 authors independently; and STATA software was used for statistical analysis. The level of evidence was evaluated by applying the GRADE system.

RESULTS: Twelve RCTs involving 770 participants were enrolled. The results of the meta-analysis showed that probiotics could significantly reduce fasting blood glucose by -11.27mg/dL (95% CI -21.76 to -0.79; P<.001) and serum insulin concentration by -2.36μU/mL (95% CI -4.01 to -0.72; P=.005), but with no significant reduction on HbA1c (-0.19%; 95% CI -0.49 to 0.12; P=.23). Probiotics could significantly reduce HOMA-IR of T2DM patients (-1.05; 95% CI -1.52 to -0.59; P<.001). Nevertheless, the effect on QUICKI was negligible (0.00; 95% CI -0.00 to 0.01; P=.27). Results also confirmed the significant lowering effect of probiotics on total cholesterol (-8.49mg/dL; 95% CI -15.24 to -1.73; P=.014) and triglycerides (TG; -23.66mg/dL; 95% CI -40.26 to -7.05; P<.001), as well as the elevating effect on HDL-c (3.92mg/dL; 95% CI 2.14 to5.7; P<.01). However, there was no significant change on LDL-c (-0.84mg/dL; 95% CI -5.84 to 4.17; P=.75). Subgroup analysis was conducted for 2 outcomes, that is, serum insulin concentration and TG, whose heterogeneity was too high. The results showed multiple species of probiotics had stronger reduction effect on serum insulin concentration (-3.32μU/mL; 95% CI -5.89 to-0.75; P=.001) and TG (-25.94mg/dL; 95% CI -65.33 to 13.44; P<.001). In addition, it also suggested that only the duration of treatment for≥8 weeks could significantly reduce TG by -24.47mg/dL (95% CI -40.15 to -8.78; P=.001). The duration of treatment for<8 weeks didn't result in significant reduction on TG (-4.31mg/dL; 95% CI -37.69 to 29.06; P=.8). Finally, all the evidences were at moderate and low levels according to the GRADE system.

CONCLUSION: As a kind of the potential biotherapeutics in the management of T2DM, probiotics can improve glucose control and lipid metabolism.