I reviewed a wide range of studies on metformin and its impact on asthma. The overall consensus is strongly positive, especially in people with asthma who also have diabetes, obesity, or metabolic dysfunction.
- Most studies show reduced asthma exacerbations (fewer ER visits and hospitalizations) in people taking metformin.
- Benefits are likely due to anti-inflammatory effects via AMPK activation, not just blood sugar control.
- Animal studies support this too, showing reduced airway inflammation and remodelling.
- GLP-1 agonists may further enhance asthma control when added to metformin.
- SGLT2 inhibitors perform similarly to metformin, while DPP-4 inhibitors may be less helpful or even worsen asthma control.
- No studies in my review showed harm from metformin in asthma patients. Only one showed mixed results and called for more research.
As a side note: I went looking into this completely neutral to any particular outcome. I’ve not been that impressed with metformin for longevity from what I’ve read (compared to the hype), but I have to say this is very impressive and as someone who suffers from asthma I’m strongly considering bringing this information to my doctor to see if they’re willing to trial me on metformin.
Full details and study excerpts follow below:
FOR:
Association of Metformin Initiation and Risk of Asthma Exacerbation. A Claims-based Cohort Study
“In this cohort of adults with asthma and diabetes, initiation of metformin was associated with a lower hazard of asthma exacerbation. This result was driven by lower hazards of asthma-related emergency department visits and hospitalizations.”
Antidiabetic Medication and Asthma Attacks
“metformin was associated with a lowered risk of asthma attacks by approximately 30%, and adding glucagon-like peptide-1 receptor agonists were associated with an additional lowered risk of approximately 40%.”
https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2826086
Evidence Builds for a Role of Metformin in Asthma Management
“Wu and colleagues report on a beneficial effect of metformin in adults with asthma, particularly with regard to decreasing ED visits and hospitalizations.”
https://www.atsjournals.org/doi/10.1513/AnnalsATS.201909-713ED
P168 Association between metformin and asthma exacerbations: a self-controlled case series
“The incidence of asthma exacerbations significantly decreased after the initiation of metformin.”
Metformin use is associated with decreased asthma exacerbations in adolescents and young adults
“Asthma exacerbation rates decreased after metformin prescription, but a larger sample of patients who have experienced exacerbations and including patients with asthma who have not been prescribed metformin is needed to better know whether these decreases are driven by metformin use.”
https://onlinelibrary.wiley.com/doi/abs/10.1002/ppul.26704
Metformin use and respiratory outcomes in asthma-COPD overlap
“Metformin use was associated with fewer respiratory exacerbations and improved quality of life among individuals with ACO but not COPD alone.”
Metformin Ameliorates Inflammation and Airway Remodeling of Experimental Allergic Asthma in Mice by Restoring AMPKα Activity
“In conclusion, findings from our study suggest a potential benefit of metformin that targets both airway inflammation and remodeling in experimental allergic asthma through the restoration of AMPKα activity, which provides a potential therapeutic for asthma.”
Metformin Use and Risk of Asthma Exacerbation Among Asthma Patients with Glycemic Dysfunction
“Metformin use, independent of glycemic control and obesity, was associated with lower hazard of asthma-related ED visits and hospitalizations. Metformin may have benefit in patients with asthma and glycemic dysfunction.”
https://www.jaci-inpractice.org/article/S2213-2198(21)00794-7/abstract
Association of Novel Antihyperglycemic Drugs Versus Metformin With a Decrease in Asthma Exacerbations
“While DPP-4 Is and GLP-1 RAs were associated with poorer control of asthma compared with metformin, SGLT-2 Is offered asthma control comparable to that of metformin.”
https://www.sciencedirect.com/science/article/pii/S2213219824004677
Metformin Alleviates Airway Hyperresponsiveness in a Mouse Model of Diet-Induced Obesity
“Metformin reduced airway hyperresponsiveness in diet-induced obese mice. This finding suggests that metformin can be considered for adjuvant pharmacological therapy in obese asthma. Human studies are warranted to examine the translational significance of these findings.”
Utility of Hypoglycemic Agents to Treat Asthma with Comorbid Obesity
“By indirectly upregulating AMPK expression, metformin demonstrates highly efficacious and tolerable anti-inflammatory properties systemically and in lung tissue in murine models”
Association of Metformin Initiation and Risk of Asthma Exacerbation. A Claims-based Cohort Study
"In an administrative cohort of individuals with asthma and diabetes, metformin initiation was associated with a lower hazard of asthma-related emergency department visits and hospitalizations. These findings suggest a possible benefit of metformin in more severe asthma exacerbations."
https://www.atsjournals.org/doi/full/10.1513/AnnalsATS.201812-897OC
Metformin Use and Asthma Outcomes among Patients with Concurrent Asthma and Diabetes
“We evaluated the association between metformin use and asthma exacerbation among patients with concurrent asthma and diabetes, and found that the risk of exacerbation was lower among metformin users than non-users.”
NEUTRAL:
Association of metformin use with asthma development and adverse outcomes: A systematic review and meta-analysis
“In most outcome indicators, it cannot be assumed that the use of metformin can reduce asthma-related adverse events. However, the conclusion is not so certain, and longer observation and more evidence are still required. Metformin still shows some potential in the intervention of respiratory diseases.”
MIXED RESULTS:
Metformin and the Development of Asthma in Patients with Type 2 Diabetes
“Several studies suggest that metformin may reduce the occurrence and exacerbation of asthma. However, our research (after adjusting the patient’s health behavior) showed that metformin was associated with higher risks of asthma development and exacerbation. Randomized control studies are warranted to resolve this concern.”
AGAINST:
NA