SynthesisFrontiers in endocrinology2026

Efficacy of Gegen Qinlian decoction plus metformin for type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials.

Hongyang He, Xiaocan Gai, Zhiheng Qiao, Guoliang Ji, Shumin Liu

Abstract readSystematic ReviewMeta-Analysis
In one paragraph

Synthesis in Frontiers in endocrinology, 2026. The graph read 3 numbers from its abstract, feeding 1 cell of the map, but none could be read as for or against, so it casts no vote. Not yet cited in PubMed.

3numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

Read, but not usablea number the graph found but could not read as for or against

FPGGQD plus metformin vs metformin alonecomparator not stated · t2dfeeds one cell of the map
Δ -1.08-1.71 to -0.440.0009
Statistically significant reductions were observed for FPG (MD = -1.08, 95% CI: -1.71 to -0.44, P = 0.0009) and 2hPG (MD = -1.73, 95% CI: -3.05 to -0.42, P = 0.010).

The authors add: However, substantial heterogeneity was present across analyses (I² = 85%-100%), and the certainty of evidence was rated as very low because of risk of bias, inconsistency, and imprecision.

HbA1cGQD plus metformin vs metformin alonecomparator not stated · t2dfeeds one cell of the map
Δ -1.92-4.43 to 0.59P = 0.13
In the primary change-score analysis, GQD plus metformin did not show a statistically significant reduction in HbA1c compared with metformin alone (mean difference [MD] = -1.92, 95% confidence interval [CI]: -4.43 to 0.59, P = 0.13).

The authors add: However, substantial heterogeneity was present across analyses (I² = 85%-100%), and the certainty of evidence was rated as very low because of risk of bias, inconsistency, and imprecision.

2hPGGQD plus metformin vs metformin alonecomparator not stated · t2dfeeds one cell of the map
Δ -1.73-3.05 to -0.420.010
Statistically significant reductions were observed for FPG (MD = -1.08, 95% CI: -1.71 to -0.44, P = 0.0009) and 2hPG (MD = -1.73, 95% CI: -3.05 to -0.42, P = 0.010).

The authors add: However, substantial heterogeneity was present across analyses (I² = 85%-100%), and the certainty of evidence was rated as very low because of risk of bias, inconsistency, and imprecision.

clause the extractor read what became the number

2 · Its place on the map

Where it lands on the map

Rows are treatments, columns are outcomes. The coloured squares are the cells this paper feeds, coloured by the vote it casts there. Click one to jump to what this paper adds to it.

supports the treatmentfavours the comparatorno clear differenceread, but no usable result
3 · What it changes

What it adds to each cell

For every cell the paper feeds: the belief in the claim with and without this paper, and this paper's estimate drawn against every other readable study in the cell. The ringed dot is this paper.

Metformin×glycemic control

No readable resultOpen on the map →What to test next →

40 readable studies in this cell: 41 favour the treatment, 13 find no difference, 7 favour the comparator.

Belief with this paper
0.84replicated · 32 families support, 6 contradict · against placebo
Without itNot a counted family in this claim, so removing it changes nothing.
← favours the treatmentfavours the comparator →
0 · no effect
NCT017190031,413 enrolled · 2012
Adjusted mean -0.72-0.95 to -0.48
NCT018093271,186 enrolled · 2013
Δ -0.40-0.59 to -0.21
NCT022730501,136 enrolled · 2014
Δ -0.89-1.08 to -0.69
NCT008598981,093 enrolled · 2009
Δ -0.53-0.74 to -0.32
Δ -0.85-43.8 to 26.7
NCT00643851994 enrolled · 2008
Δ -0.86-1.11 to -0.62
NCT01708902876 enrolled · 2012
Δ -1.00-1.23 to -0.78
NCT00676338820 enrolled · 2008
Δ -0.05-0.26 to 0.17
NCT01126580807 enrolled · 2010
Δ -0.22-0.36 to -0.08
NCT01023581784 enrolled · 2009
Δ -0.67-0.96 to -0.37
NCT01076088744 enrolled · 2010
Δ -0.84-1.15 to -0.52
NCT00386100688 enrolled · 2006
Δ -0.49-0.67 to -0.30

This paper's own estimate is on a different scale from the rest of the cell, so it is not drawn here.

4 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

5 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

6 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

7 · Who and what money

Authors and funding

5 authors.

Hongyang HeGraduate School, Heilongjiang University of Chinese Medicine, Harbin, China.
Xiaocan GaiGraduate School, Heilongjiang University of Chinese Medicine, Harbin, China.
Zhiheng QiaoGraduate School, Heilongjiang University of Chinese Medicine, Harbin, China.
Guoliang JiGraduate School, Heilongjiang University of Chinese Medicine, Harbin, China.
Shumin LiuSchool of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin, China.

Funding

No grant is acknowledged in the PubMed record.

8 · The paper itself

Abstract

The marked sentences are the ones the graph read a number from.

Background: Gegen Qinlian Decoction (GQD) is frequently used as an adjunctive therapy to metformin for type 2 diabetes mellitus (T2DM), but the certainty and consistency of the supporting clinical evidence remain unclear. Methods: We searched CNKI, Wanfang Data, PubMed, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials from database inception to January 31, 2026. Randomized controlled trials comparing GQD plus metformin with metformin alone in adults with T2DM were included. The primary outcome was glycated hemoglobin (HbA1c), and secondary outcomes were fasting plasma glucose (FPG) and 2-hour postprandial glucose (2hPG). Risk of bias was assessed using the Cochrane RoB 2 tool, and the certainty of evidence was evaluated using the GRADE framework. Random-effects meta-analyses were performed, with the primary analyses based on change-from-baseline values. Results: Eight randomized controlled trials involving 725 participants were included. In the primary change-score analysis, GQD plus metformin did not show a statistically significant reduction in HbA1c compared with metformin alone (mean difference [MD] = -1.92, 95% confidence interval [CI]: -4.43 to 0.59, P = 0.13). Statistically significant reductions were observed for FPG (MD = -1.08, 95% CI: -1.71 to -0.44, P = 0.0009) and 2hPG (MD = -1.73, 95% CI: -3.05 to -0.42, P = 0.010). However, substantial heterogeneity was present across analyses (I² = 85%-100%), and the certainty of evidence was rated as very low because of risk of bias, inconsistency, and imprecision. Post-treatment sensitivity analyses using all eight trials showed statistically significant reductions in HbA1c, FPG, and 2hPG, but these analyses were also affected by substantial heterogeneity and high risk of bias across the included trials. Conclusion: Current evidence is insufficient to confirm a reliable clinical benefit of GQD as an adjunct to metformin for T2DM. Although reductions in FPG and 2hPG were observed, these findings should be interpreted as exploratory because of substantial heterogeneity, methodological limitations, and very low certainty of evidence. Larger, prospectively registered, well-designed, and adequately blinded randomized trials are needed.

Indexed as

Diabetes Mellitus, Type 2Drugs, Chinese HerbalHypoglycemic AgentsMetforminBlood GlucoseDrug Therapy, CombinationGlycated HemoglobinHumansRandomized Controlled Trials as TopicTreatment OutcomeBlood GlucoseDrugs, Chinese HerbalGlycated HemoglobinHypoglycemic AgentsMetforminGegen Qinlian decoctionmeta-analysismetforminrandomized controlled trialstype 2 diabetes mellitus

Identifiers

PMID42539441
PMCPMC13423648

What Socratic holds

Texttitle and abstract
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.