SynthesisThe Indian journal of medical research2025

Metformin use & asthma outcomes in patients with concurrent diabetes & bronchial asthma: A systematic review & meta-analysis.

A B M Kamrul-Hasan, Joseph M Pappachan, Parth Jethwani, Shinjan Patra, Lakshmi Nagendra, Deep Dutta, Mohammad Delwar Jahan Khan, Saptarshi Bhattacharya

Abstract readSystematic ReviewMeta-Analysis
In one paragraph

Synthesis in The Indian journal of medical research, 2025. The graph read 5 numbers from its abstract, feeding 2 cells 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 HR 0.89 (0.83 to 0.97) for asthma exacerbation. Cited by 1 paper.

5numbers the graph read from it
0cells of the map it votes in
1citing 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

Use of rescue steroidsmetformin users (MU) vs non-metformin users (non-MU)an association or prognostic statement, not a treatment comparison · t2dfeeds one cell of the map
HR 0.950.87 to 1.03P=0.24
The two groups also had statistically identical risks of asthma-related hospitalisations (HR 0.76, 95% CI: 0.54, 1.07, P=0.12) and use of rescue steroids (HR 0.95, 95% CI: 0.87, 1.03, P=0.24).
Adverse events & safetycomparator not stated · t2dfeeds one cell of the map
HR 0.760.54 to 1.07P=0.12
The two groups also had statistically identical risks of asthma-related hospitalisations (HR 0.76, 95% CI: 0.54, 1.07, P=0.12) and use of rescue steroids (HR 0.95, 95% CI: 0.87, 1.03, P=0.24).
Asthma exacerbationmetformin users (MU) vs non-metformin users (non-MU), in after excluding a study from Taiwan (n=115486)an association or prognostic statement, not a treatment comparison · t2dfeeds one cell of the map
HR 0.890.83 to 0.97P=0.005
However, after excluding a study from Taiwan (n=115486), a significantly lower risk of asthma exacerbation (HR 0.89, 95% CI: 0.83-0.97, P=0.005) and asthma-related hospitalisations (HR 0.68, 95% CI: 0.49-0.93, P=0.02) was observed in MU.
Asthma-related emergency room visitsmetformin users (MU) vs non-metformin users (non-MU)an association or prognostic statement, not a treatment comparison · t2dfeeds one cell of the map
HR 0.630.39 to 1.01P=0.06
The risk of asthma-related emergency room visits appeared lower in MU than in non-MU, though the difference did not gain statistical significance (HR 0.63, 95% CI: 0.39, 1.01, P=0.06).
Asthma-related hospitalisationsmetformin users (MU) vs non-metformin users (non-MU), in after excluding a study from Taiwan (n=115486)an association or prognostic statement, not a treatment comparison · t2dfeeds one cell of the map
HR 0.680.49 to 0.93P=0.02
However, after excluding a study from Taiwan (n=115486), a significantly lower risk of asthma exacerbation (HR 0.89, 95% CI: 0.83-0.97, P=0.005) and asthma-related hospitalisations (HR 0.68, 95% CI: 0.49-0.93, P=0.02) was observed in MU.

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×adverse events & safety

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

22 readable studies in this cell: 9 favour the treatment, 8 find no difference, 5 favour the comparator.

Belief with this paper
0.27contested · 4 families support, 11 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 -8.90-13.3 to -4.50
NCT01126580807 enrolled · 2010
Δ -0.22-0.36 to -0.08
NCT01023581784 enrolled · 2009
Δ -0.67-0.96 to -0.37
NCT00386100688 enrolled · 2006
Δ 1.47-14.8 to 20.8
NCT01217073685 enrolled · 2010
Δ 1.00-9.80 to 13.1
NCT01890122647 enrolled · 2013
Δ -0.68-0.89 to -0.47
NCT00727857600 enrolled · 2007
Δ 0.860.51 to 1.22
NCT01958671461 enrolled · 2013
Δ -2.60-13.1 to 8.10
NCT00328172302 enrolled · 2006
Δ -0.85-1.10 to -0.59
NCT01485614200 enrolled · 2012
Δ 2.40-10.0 to 14.9

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

Metformin×costs & health-care use

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

1 readable study in this cell: 0 favour the treatment, 1 find no difference, 0 favour the comparator.

Belief with this paper
0.25no deciding trial · 0 families support, 0 contradict · against placebo
Without itNot a counted family in this claim, so removing it changes nothing.
← favours the treatmentfavours the comparator →
0 · no effect
NCT02980276535 enrolled · 2017
Δ -6.50-13.9 to 12.9

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

1 citing paper in PubMed.

  1. Review
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

8 authors.

A B M Kamrul-HasanDepartment of Endocrinology, Mymensingh Medical College, Mymensingh, Bangladesh.
Joseph M PappachanDepartment of Endocrinology, Countess of Chester Hospital NHS Trust, Chester, United Kingdom.
Parth JethwaniDepartment of Endocrinology, Kota Heart Hospital, Kota, Rajasthan, India.
Shinjan PatraDepartment of Endocrinology and Metabolism, All India Institute of Medical Sciences, Kalyani, West Bengal, India.
Lakshmi NagendraDepartment of Endocrinology, JSS Medical College, JSS Academy of Higher Education and Research, Mysuru, Karnataka, India.
Deep DuttaDepartment of Endocrinology, CEDAR Superspeciality Healthcare, New Delhi, India.
Mohammad Delwar Jahan KhanDepartment of Respiratory Medicine, Mymensingh Medical College, Mymensingh, Bangladesh.
Saptarshi BhattacharyaDepartment of Endocrinology, Indraprastha Apollo Hospitals, New Delhi, India.

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 & objectives Limited data exist on the effects of metformin on asthma outcomes in patients having type 2 diabetes (T2D) along with asthma. This meta-analysis seeks to determine whether metformin influences asthma outcomes in these patients. Methods Studies involving adults with T2D and asthma, using metformin in the intervention group and other glucose-lowering drugs in the control group, were systematically searched through databases. The primary outcome was the adjusted risk of asthma exacerbations in metformin users (MU) vs. non-metformin users (non-MU). Other outcomes included asthma-related emergency room visits, hospitalisations, and the need for rescue steroids. Meta-analysis was conducted using RevMan with random-effects models. Outcomes were reported as hazard ratios (HRs) with 95 per cent confidence intervals (95% CI). Results Six retrospective cohort studies with moderate overall risk of bias, involving 317,905 patients, were included. The risk of asthma exacerbation was comparable in MU and non-MU (HR 0.95, 95% CI: 0.86, 1.04, P=0.27). The risk of asthma-related emergency room visits appeared lower in MU than in non-MU, though the difference did not gain statistical significance (HR 0.63, 95% CI: 0.39, 1.01, P=0.06). The two groups also had statistically identical risks of asthma-related hospitalisations (HR 0.76, 95% CI: 0.54, 1.07, P=0.12) and use of rescue steroids (HR 0.95, 95% CI: 0.87, 1.03, P=0.24). However, after excluding a study from Taiwan (n=115486), a significantly lower risk of asthma exacerbation (HR 0.89, 95% CI: 0.83-0.97, P=0.005) and asthma-related hospitalisations (HR 0.68, 95% CI: 0.49-0.93, P=0.02) was observed in MU. Interpretation & conclusions Metformin therapy for T2D does not influence asthma outcomes; however, certain outcomes appear to improve when a Taiwanese study is excluded. Such results must be considered cautiously, as the included studies are observational and have a moderate risk of bias. Randomised controlled trials with diverse global representation are essential for clarifying the relationship between metformin use and asthma outcomes.

Indexed as

AsthmaDiabetes Mellitus, Type 2MetforminHospitalizationHumansHypoglycemic AgentsHypoglycemic AgentsMetforminAsthma exacerbationbronchial asthmameta-analysismetformintype 2 diabetes

Identifiers

PMID41100655
PMCPMC12624744

What Socratic holds

Texttitle and abstract
LicenceCC BY-NC-SA
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.