The effect of Astragalus as an adjuvant treatment in type 2 diabetes mellitus: A (preliminary) meta-analysis.
BACKGROUND
Astragalus is a traditional Chinese medicine that is widely used for tonifying Qi (Qi mainly means life energy) to treat diabetes mellitus and its complications.


OBJECTIVE
We performed a meta-analysis to evaluate the effect of Astragalus in adjuvant treatment of type 2 diabetes mellitus (T2DM), and to provide novel information to improve clinical decision-making.


METHODS
We conducted an exhaustive database search (PubMed, EMbase, Cochrane Library, China Knowledge Resource Integrated Database (CNKI), Wanfang data and SinoMed) of studies associated with "Astragalus" and "type 2 diabetes mellitus" until December 2015. Following quality assessment of study eligibility, the extracted data were statistically analyzed using STATA, ver. 12.0 (Stata Corp.).


RESULTS
A total of 13 studies with 1054 participants were included in this meta-analysis. Two subgroups were identified, based on Astragalus dosing regimens: control group vs. Astragalus injection (AI); control group vs. Astragalus aqueous decoction (AAD). The pooled results showed that, in comparison with control group, Astragalus administration significantly reduced fasting plasma glucose (FPG) in both the AI group (WMD=-0.28, 95% CI=-0.46 to -0.10, P=0.002, I(2)=18.5%) and the AAD group (WMD=-0.83, 95% CI=-1.07 to -0.58, P=0.000, I(2)=0.0%); postprandial plasma glucose (PPG) was also significantly reduced in the AI group (WMD=-0.47, 95% CI=-0.77 to -0.17, P=0.002, I(2)=46.8%) and the AAD group (WMD=-1.19, 95% CI=-1.63 to -0.75, P=0.000, I(2)=49.3%). Fasting insulin (Fins) was significantly reduced only in the AAD treatment group (SMD=-0.33, 95% CI=-0.55 to -0.10, P=0.005, I(2)=1.0%) as was the homeostasis model assessment insulin resistance index (HOMA-IRI) levels (SMD=-1.66, 95% CI=-3.24 to -0.09, P=0.038, I(2)=94.0%). Although AAD treatment significantly reduced levels of glycated hemoglobin A1c (HbA1c) (WMD=-1.77, 95% CI=-3.06 to -0.47, P=0.007, I(2)=90.8%), AI treatment failed to show significant efficacy (WMD=-0.28, 95% CI=-0.63 to 0.06, P=0.102, I(2)=83.8%). Sensitivity analysis failed to detect outliers in all studies while Egger's linear regression test revealed a lack of publication bias in this meta-analysis (P=0.771, 95%CI =-3.51 to 4.56).


CONCLUSIONS
Astragalus may be beneficial as an adjuvant therapy in the treatment of type 2 diabetes. However, due to the limited quality of existing studies, further high-quality studies are warranted before definitive conclusions may be reached.
Department of Pharmacy, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
Huiping
H
Tian
Clinical Research Center, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
Jun
J
Lu
Clinical Research Center, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
Hairong
H
He
Department of Pharmacy, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
Lu
L
Zhang
Department of Pharmacy, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China. Electronic address: dongyalin@mail.xjtu.edu.cn.
Yalin
Y
Dong
Department of Pharmacy, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
Hongping
H
Yao
Department of Pharmacy, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
Weiyi
W
Feng
Department of Pharmacy, the First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
Siwen
S
Wang
D027883:Astragalus Plant / Q000737:chemistry*; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects / Q000302:isolation & purification / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008517:Phytotherapy; D010936:Plant Extracts / Q000009:adverse effects / Q000302:isolation & purification / Q000627:therapeutic use*; D010946:Plants, Medicinal; D016896:Treatment Outcome
D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; D010936:Plant Extracts; C517652:hemoglobin A1c protein, human
Adjuvant treatment; Astragalus; Meta-analysis; Traditional chinese medicine; Type 2 diabetes mellitus