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Metformin COVID-19 studies. Most studies analyze existing use with diabetic patients. Many results are subject to confounding by indication — metformin is typically used early in the progression of type 2 diabetes. Recently added: Alamgir Ojeda-Fernández Pérez-Belmonte Lalau Li Oh Ghany. Submit updates/corrections.
Restrict:    All    Early    Prophylaxis
Jan 16
Early, Late, PrEP, PEP Covid Analysis (Preprint) (meta analysis)
Metformin for COVID-19: real-time meta analysis of 25 studies
Details   • Statistically significant improvements are seen for mortality and hospitalization. 16 studies from 16 independent teams in 6 different countries show statistically significant improvements in isolation (13 for the most serious outcome)...
Jan 10
PrEPPEP Ojeda-Fernández et al., Diabetes, Obesity and Metabolism, doi:10.1111/dom.14648 (Peer Reviewed)
death, ↓16.2%, p<0.0001
Metformin use is associated with a decrease in risk of hospitalization and mortality in COVID-19 diabetic patients: a population-based study in Lombardy
Details   Retrospective 31,966 COVID+ patients using anti-hyperglycemic drugs in Italy, showing lower mortality and ICU admission with metformin use.
Nov 19
In Vitro Parthasarathy et al., bioRxiv, doi:10.1101/2021.11.18.469078 (Preprint) (In Vitro)
In Vitro
Metformin Suppresses SARS-CoV-2 in Cell Culture
Details   In Vitro study showing metformin inhibits SARS-CoV-2 in Caco2 cells. Metformin reduced viral titers by nearly 99%, and by about 90% when cells were treated prior to infection.
Oct 30
PrEPPEP Ong et al., Journal of the ASEAN Federation of Endocrine Societies, doi:10.15605/jafes.036.02.20 (Peer Reviewed)
death, ↓46.8%, p=0.02
Association Between Metformin Use and Mortality Among Patients with Type 2 Diabetes Mellitus Hospitalized for COVID-19 Infection
Details   Retrospective 355 diabetic hospitalized COVID-19 patients in the Philippines, showing lower mortality with metformin use.
Oct 29
PrEPPEP Saygili et al., Irish Journal of Medical Science, doi:10.1007/s11845-021-02823-9 (Peer Reviewed)
death, ↓41.5%, p=0.02
Preadmission usage of metformin and mortality in COVID-19 patients including the post-discharge period
Details   Retrospective 586 diabetic hospitalized COVID-19 patients in Turkey, showing lower mortality with existing metformin use.
Oct 6
PrEPPEP Wander et al., Diabetes Care, doi:10.2337/dc21-1351 (Peer Reviewed)
death, ↓15.0%, p<0.0001
Prior Glucose-Lowering Medication Use and 30-Day Outcomes Among 64,892 Veterans With Diabetes and COVID-19
Details   Retrospective 64,892 veterans with diabetes in the USA, showing lower mortality with existing metformin use.
Sep 7
PrEPPEP Wang et al., BMJ Open Diabetes Research & Care, doi:10.1136/bmjdrc-2021-002299 (Peer Reviewed)
ICU, ↓12.0%, p=0.005
Evaluation and management of COVID-19-related severity in people with type 2 diabetes
Details   Retrospective 16,504 COVID-19 type 2 diabetes patients, showing lower risk of ICU admission with existing metformin use.
Aug 31
Early Reis et al., The Lancet Regional Health - Americas, doi:10.1016/j.lana.2021.100142 (preprint 8/31/21) (Peer Reviewed)
hosp., ↓5.6%, p=0.88
Effect of early treatment with metformin on risk of emergency care and hospitalization among patients with COVID-19: The TOGETHER randomized platform clinical trial
Details   RCT with 215 patients treated with metformin and 203 controls, showing no significant difference with treatment. The hospitalization risk for off-protocol patients was several times higher in both arms, resulting in Simpson's paradox whe..
Aug 20
PrEPPEP Cheng et al., Cell Metabolism, doi:10.1016/j.cmet.2020.08.013 (Peer Reviewed)
death, ↑65.0%, p=0.25
Metformin Is Associated with Higher Incidence of Acidosis, but Not Mortality, in Individuals with COVID-19 and Pre-existing Type 2 Diabetes
Details   Retrospective 1,213 hospitalized diabetic COVID-19 patients in China, showing no significant difference in mortality with pre-existing metformin use.
Jul 18
PrEPPEP Boye et al., Diabetes Therapy, doi:10.1007/s13300-021-01110-1 (Peer Reviewed)
hosp., ↓10.0%, p<0.0001
Risk Factors Associated with COVID-19 Hospitalization and Mortality: A Large Claims-Based Analysis Among People with Type 2 Diabetes Mellitus in the United States
Details   Retrospective 9531 COVID+ diabetes patients in the USA, showing lower risk of hospitalization with existing biguanides treatment (defined as mainly metformin in the abstract and entirely metformin in the text).
May 5
PrEPPEP Ravindra et al., medRxiv, doi:10.1101/2021.04.20.21255792 (Peer Reviewed)
death, ↓29.6%, p=0.42
Retrospective Assessment of Treatments of Hospitalized Covid-19 Patients
Details   Retrospective 1,035 hospitalized patients in India. Of 366 diabetic patients, there was lower mortality for the 53 that were on metformin.
Apr 6
PrEPPEP Alamgir et al., medRxiv, doi:10.1101/2021.03.22.21254110 (Preprint)
death, ↓27.0%, p<0.0001
Drug repositioning candidates identified using in-silico quasi-quantum molecular simulation demonstrate reduced COVID-19 mortality in 1.5M patient records
Details   In Silico study followed by PSM analysis of the National COVID Cohort Collaborative data in the USA, showing 27% lower mortality with metformin use. ABSTRACTBackgroundDr..
Mar 31
PrEPPEP Ghany et al., Diabetes & Metabolic Syndrome: Clinical Research & Reviews, doi:10.1016/j.dsx.2021.02.022 (Peer Reviewed)
death, ↓66.0%, p=0.0002
Metformin is associated with lower hospitalizations, mortality and severe coronavirus infection among elderly medicare minority patients in 8 states in USA
Details   Retrospective 1,139 elderly COVID+ patients in the USA, 392 with pre-existing metformin use, showing significantly lower mortality, hospitalization, and ARDS with treatment.
Mar 31
PrEPPEP Jiang et al., Diabetes Research and Clinical Practice, doi:10.1016/j.diabres.2020.108619 (Peer Reviewed)
death, ↓46.0%, p=0.40
Association of metformin with mortality or ARDS in patients with COVID-19 and type 2 diabetes: A retrospective cohort study
Details   Retrospective 328 COVID-19 patients with type 2 diabetes in China, showing significantly lower risk of ARDS with existing metformin use.
Mar 30
PrEPPEP Khunti et al., The Lacent Diabetes & Endocrinology, doi:10.1016/S2213-8587(21)00050-4 (Peer Reviewed)
death, ↓23.0%, p<0.0001
Prescription of glucose-lowering therapies and risk of COVID-19 mortality in people with type 2 diabetes: a nationwide observational study in England
Details   Retrospective 2,851,465 people with type 2 diabetes in the UK, showing lower mortality with existing metformin use. Results are subject to confounding by indication because metformin is typically used early in the progression of type 2 di..
Mar 30
PrEPPEP Holt et al., Thorax, doi:10.1136/thoraxjnl-2021-217487 (Peer Reviewed)
cases, ↑27.0%, p=0.42
Risk factors for developing COVID-19: a population-based longitudinal study (COVIDENCE UK)
Details   Prospective survey-based study with 15,227 people in the UK, showing lower risk of COVID-19 cases with vitamin A, vitamin D, zinc, selenium, probiotics, and inhaled corticosteroids; and higher risk with metformin and vitamin C. Statistica..
Feb 13
PrEPPEP Oh et al., Acta Diabetologica, doi:10.1007/s00592-020-01666-7 (Peer Reviewed)
death, ↑26.0%, p=0.30
Metformin use and risk of COVID-19 among patients with type II diabetes mellitus: an NHIS-COVID-19 database cohort study
Details   Retrospective 27,493 type II diabetes patients in the USA, 7,204 on metformin, showing significantly lower COVID-19 cases, but no significant difference in mortality.
Jan 31
PrEPPEP Lally et al., Journal of the American Medical Directors Association, doi:10.1016/j.jamda.2020.10.031 (Peer Reviewed)
death, ↓52.0%, p=0.009
Metformin is Associated with Decreased 30-Day Mortality Among Nursing Home Residents Infected with SARS-CoV2
Details   Retrospective 775 nursing home residents in the USA, showing lower mortality with existing metformin use.
Jan 13
PrEPPEP Crouse et al., Front. Endocrinol., doi:10.3389/fendo.2020.600439 (Peer Reviewed)
death, ↓60.8%, p=0.02
Metformin Use Is Associated With Reduced Mortality in a Diverse Population With COVID-19 and Diabetes
Details   Retrospective 219 COVID-19+ diabetes patients in the USA, showing lower mortality with existing metformin treatment.
Dec 19
PrEPPEP Huh et al., International Journal of Infectious Diseases, doi:10.1016/j.ijid.2020.12.041 (Peer Reviewed)
progression, ↑1.0%, p=0.11
Association of prescribed medications with the risk of COVID-19 infection and severity among adults in South Korea
Details   Retrospective database analysis showing no significant differences with pre-existing metformin use.
Dec 10
PrEPPEP Lalau et al., Diabetes & Metabolism, doi:10.1016/j.diabet.2020.101216 (Peer Reviewed)
death, ↓22.2%, p=0.16
Metformin use is associated with a reduced risk of mortality in patients with diabetes hospitalised for COVID-19
Details   Retrospective 2,449 hospitalized COVID-19 diabetes patients in France, 1,496 with existing metformin use, showing lower mortality with treatment. Statistical significance was reached in model 1 but not in models 2-4 which also adjust for ..
Dec 3
PrEPPEP Bramante et al., The Lancet Healthy Longevity, doi:10.1016/S2666-7568(20)30033-7 (Peer Reviewed)
death, ↓7.2%, p=0.15
Metformin and risk of mortality in patients hospitalised with COVID-19: a retrospective cohort analysis
Details   Retrospective 6,256 COVID-19+ diabetes patients in the USA, showing lower mortality with existing metformin treatment, statistically significant only for women.
Nov 16
PrEPPEP Pérez-Belmonte et al., BMC Medicine, doi:10.1186/s12916-020-01832-2 (Peer Reviewed)
death, ↑10.4%, p=0.48
Mortality and other adverse outcomes in patients with type 2 diabetes mellitus admitted for COVID-19 in association with glucose-lowering drugs: a nationwide cohort study
Details   Retrospective 2,666 type 2 diabetes COVID-19 patients in Spain, showing higher mortality with existing metformin use (not statistically significant).
Oct 1
PrEPPEP Li et al., Endocrine Practice, doi:10.4158/EP-2020-0466 (Peer Reviewed)
death, ↓77.7%, p=0.02
Metformin Use in Diabetes Prior to Hospitalization: Effects on Mortality in Covid-19
Details   Retrospective 131 type II diabetes patients with COVID pneumonia, showing lower mortality with existing metformin use. Acarbose (commonly used in China as an initial therapy for diabetes) did not have a similar association with mortality,..
Jul 31
PrEPPEP Chen et al., Diabetes Care, doi:10.2337/dc20-0660 (Peer Reviewed)
death, ↓33.0%, p=0.46
Clinical Characteristics and Outcomes of Patients With Diabetes and COVID-19 in Association With Glucose-Lowering Medication
Details   Retrospective 120 COVID-19 diabetes patients, showing non-statistically significantly lower mortality with existing metformin treatment.
Jul 14
PrEPPEP Wang et al., Journal of Hematology & Oncology, doi:10.1186/s13045-020-00934-x (Peer Reviewed)
death, ↓57.7%, p=0.43
A tertiary center experience of multiple myeloma patients with COVID-19: lessons learned and the path forward
Details   Retrospective 58 multiple myeloma COVID-19 patients in the USA, showing non-statistically significant lower mortality with metformin treatment.
May 21
PrEPPEP Luo et al., The American Journal of Tropical Medicine and Hygiene, doi:10.4269/ajtmh.20-0375 (Peer Reviewed)
death, ↓74.7%, p=0.02
Metformin Treatment Was Associated with Decreased Mortality in COVID-19 Patients with Diabetes in a Retrospective Analysis
Details   Retrospective 283 COVID-19+ diabetes patients in China, showing lower mortality with existing metformin treatment.
Please send us corrections, updates, or comments. Vaccines and treatments are both valuable and complementary. All practical, effective, and safe means should be used. Elimination of COVID-19 is a race against viral evolution. No treatment, vaccine, or intervention is 100% available and effective for all current and future variants. Denying the efficacy of any method increases mortality, morbidity, collateral damage, and the risk of endemic status. We do not provide medical advice. Before taking any medication, consult a qualified physician who can provide personalized advice and details of risks and benefits based on your medical history and situation. WCH and FLCCC provide treatment protocols.
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