SynthesisAtencion primaria2005

[Metformin for type-2 diabetes mellitus. Systematic review and meta-analysis].

A Sáenz Calvo, I Fernández Esteban, A Mataix Sanjuán, M Ausejo Segura, M Roqué, D Moher

Open access · greenAbstract readComparative StudyMeta-AnalysisSystematic Review
In one paragraph

Synthesis in Atencion primaria, 2005. The graph read 5 numbers from its abstract, feeding 1 cell of the map, but none could be read as for or against, so it casts no vote. It also reports 2 associations that do not count as treatment evidence, such as RR 0.74 (0.60 to 0.90) for glycemic control. Cited by 5 papers.

5numbers the graph read from it
0cells of the map it votes in
5citing papers in PubMed
0.7field-weighted citation impact, top 29% of its field
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

Glycemic controlcomparator not stated · dyslipidemia, t2dfeeds one cell of the map
Δ -0.11-0.18 to -0.04
Metformin decreased glycosylated hemoglobin A1 (weighted mean difference, -1.21%; 95% CI, -1.48 to -0.94), low density lipoprotein cholesterol (weighted mean difference, -0.24; 95% CI, -0.40 to -0.09), and weight (standardized mean difference, -0.11; 95% CI, -0.18 to -0.04).
Glycemic controlcomparator not stated · dyslipidemia, t2dfeeds one cell of the map
Δ -1.21-1.48 to -0.94
Metformin decreased glycosylated hemoglobin A1 (weighted mean difference, -1.21%; 95% CI, -1.48 to -0.94), low density lipoprotein cholesterol (weighted mean difference, -0.24; 95% CI, -0.40 to -0.09), and weight (standardized mean difference, -0.11; 95% CI, -0.18 to -0.04).
Glycemic controlcomparator not stated · dyslipidemia, t2dfeeds one cell of the map
Δ -0.24-0.40 to -0.09
Metformin decreased glycosylated hemoglobin A1 (weighted mean difference, -1.21%; 95% CI, -1.48 to -0.94), low density lipoprotein cholesterol (weighted mean difference, -0.24; 95% CI, -0.40 to -0.09), and weight (standardized mean difference, -0.11; 95% CI, -0.18 to -0.04).
Glycemic controlan association or prognostic statement, not a treatment comparison · head-to-head · dyslipidemia, t2dfeeds one cell of the map
RR 0.740.60 to 0.90
Metformin was more beneficial than the sulphonylureas or insulin for any clinical event associated with diabetes (relative risk [RR]=0.78; 95% confidence interval [CI], 0.65-0.94) and than diet (RR=0.74; 95% CI, 0.60-0.90).
Glycemic controlan association or prognostic statement, not a treatment comparison · head-to-head · dyslipidemia, t2dfeeds one cell of the map
RR 0.780.65 to 0.94
Metformin was more beneficial than the sulphonylureas or insulin for any clinical event associated with diabetes (relative risk [RR]=0.78; 95% confidence interval [CI], 0.65-0.94) and than diet (RR=0.74; 95% CI, 0.60-0.90).

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

5 citing papers in PubMed, 17 citations in OpenAlex.

  1. Article
  2. Metformin for the Treatment of Type 2 Diabetes in Asian Adults: A Systematic Review.Diabetes, metabolic syndrome and obesity : targets and therapy · 2025
    Review
  3. SREBP-2, a new target of metformin?Drug design, development and therapy · 2018
    Article
  4. Article
  5. Review
6 · The record

Corrections and comments

7 · Who and what money

Authors and funding

6 authors at 4 institutions in 3 countries.

A Sáenz CalvoCentro de Salud Pozuelo 1, Area 6, Instituto Madrileño de la Salud, Pozuelo de Alarcón, Madrid, Spain. antoniosaenz@ya.com
I Fernández Esteban
A Mataix Sanjuán
M Ausejo Segura
M Roqué
D Moher
Instituto Nacional de la Salud · ESChildren's Hospital of Eastern Ontario · CAComunidad de Madrid · ESHospital de Sant Pau · ES

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.

objectiveTo evaluate the efficacy of metformin against placebo, diet, oral anti-diabetics, or insulin in type 2 diabetes mellitus.

designSystematic review. DATA SOURCES: MEDLINE (1966-2003), EMBASE (1974-2003), LILACS (1986-2003), Cochrane library (Issue 3, 2003). SELECTION OF STUDIES: 29 randomized clinical trials of metformin in monotherapy, with results on mortality, morbidity, and biochemistry. EXTRACTION OF DATA: RevMan 4 computer program. Two reviewers extracted the data and evaluated the quality. MAIN VARIABLES: any clinical event related to diabetes (mortality, coronary disease, stroke, arterial disease, and retinopathy). Secondary variables: weight and biochemistry.

results29 clinical studies with 37 comparisons of metformin were analyzed (13 with sulphonylureas, 12 with placebo, 3 with diet, 3 with thiazolidinediones, 2 with alpha-glucosidase inhibitors, 2 with insulin, and 2 with meglitinides). Metformin was more beneficial than the sulphonylureas or insulin for any clinical event associated with diabetes (relative risk [RR]=0.78; 95% confidence interval [CI], 0.65-0.94) and than diet (RR=0.74; 95% CI, 0.60-0.90). Metformin decreased glycosylated hemoglobin A1 (weighted mean difference, -1.21%; 95% CI, -1.48 to -0.94), low density lipoprotein cholesterol (weighted mean difference, -0.24; 95% CI, -0.40 to -0.09), and weight (standardized mean difference, -0.11; 95% CI, -0.18 to -0.04). Metformin was more beneficial than the placebo, diet or the thiazolidinediones on glycosylated hemoglobin A1, and than the sulphonylureas or insulin on weight.

conclusionsIn the long term metformin reduces the risks of clinical events associated with diabetes. There are no long term clinical trials which compare alpha-glucosidase inhibitors, meglitinides, and thiazolidinediones with metformin, in primary results. The different treatments compared with metformin did not obtain more benefit for the secondary results evaluated.

Indexed as

AdultAgedChi-Square DistributionCholesterol, LDLConfidence IntervalsDiabetes Mellitus, Type 2FemaleGlycated HemoglobinHumansHypoglycemic AgentsMaleMetforminMiddle AgedPlacebosRandomized Controlled Trials as TopicRiskCholesterol, LDLGlycated HemoglobinHypoglycemic AgentsMetforminPlacebos

Identifiers

PMID16153370
PMCPMC7684484
OpenAlexW2051969212

What Socratic holds

Texttitle and abstract
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.