Abstracts
Introduction
Metformin is a commonly used anti-diabetic drug due to its safety, low cost, and strong glucose-lowering effects. Recent research studies have identified novel molecular targets and pathways for metformin, thereby expanding its potential beyond the treatment of Type 2 diabetes.
Methodology
This systematic review provides the latest updates on the therapeutic applications of metformin in multiple diseases. This systematic review follows the PRISMA guidelines, focusing on experimental studies systematic reviews and meta-analyses from PubMed, Scopus, Web of Science and Google scholar, the search terms ("Metformin"[MeSH] OR "Metformin") AND ("Cancer" OR "Cardiovascular Disease" OR "Neurodegenerative Disease" OR "Aging") AND ("Therapeutic Use" OR "Non-diabetic"). A comprehensive search yielded numerous studies, from which relevant and up-to-date papers were carefully selected.
Results
The review highlights the multifaceted applications of metformin in various diseases. Evidence demonstrates its positive effects on cardiovascular diseases, obesity, different types of cancer, and liver and kidney disorders. These findings suggest that metformin acts through diverse molecular mechanisms, exerting benefits that extend beyond glycemic control.
Conclusion
Based on the current literature, metformin exhibits a broad spectrum of therapeutic benefits, extending beyond its primary use in diabetes management. Its role in treating multiple diseases has marked it as a multifaceted agent in modern medicine. Further research is warranted to fully explore its capabilities and optimize its use in different clinical settings.
Keywords: multiple therapeutic uses, metformin, cancer, obesity, cardiovascular diseases, anti-aging effect
INTRODUCTION
Metformin, an oral antidiabetic agent, functions by enhancing insulin sensitivity, reducing hepatic glucose production and limiting intestinal glucose absorption. Due to its efficacious glycemic control and established safety profile, metformin is frequently prescribed as the initial pharmacological intervention for patients diagnosed with Type 2 Diabetes Mellitus (T2DM).1
Beyond its role in managing blood sugar levels in T2DM, metformin also provides health benefits in various other areas. A growing number of studies suggest that metformin lowers the risk of cardiovascular diseases (CVD), breast and endometrial cancers, obesity, liver and kidney conditions, and may also offer anti-aging effects.2 Metformin exhibits a variety of biological effects, suggesting that it can influence different cellular processes. Studies have identified several cellular targets with which metformin interacts, resulting in its therapeutic effects. These interactions highlight the complex pathways by which metformin operates within the body, affecting not only blood sugar regulation but also other essential cellular functions that enhance its overall health benefits.3-5
Metformin suppresses high blood glucose levels mainly by two pathways: either through the AMPK (Adenosine Monophosphate-Activated Protein Kinase) dependent pathway6 or the AMPK independent pathway.7 In the case of the AMPK-dependent pathway, metformin works by blocking mitochondrial complex I in the liver, leading to the activation of AMPK. This activation enhances insulin sensitivity by modulating fat metabolism and reducing cAMP levels. The decreased cAMP levels have a negative/inhibitory effect on gluconeogenic enzymes involved in glucose synthesis in the liver. Recent studies suggest that metformin may also activate AMPK through a lysosomal pathway called the v-ATPase Regulator pathway.5 This review article sheds light on the off-label uses of metformin, extending beyond its well-established role in the management of diabetes. It explores the drug's multifaceted impacts on various biological processes and its potential applications in areas such as cardiovascular health, cancer prevention, anti-inflammatory activities, weight management, and aging. By highlighting the multi-faceted pharmacological profile, offering insights into its mechanisms of action, and paving the way for future research into its use in non-diabetic conditions.
METHODOLOGY
This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The PRISMA checklist is provided in Supplementary Table S1. Relevant studies were identified through a comprehensive search of PubMed, Scopus, Google Scholar and Web of Science databases. The search strategy included a combination of targeted keywords such as ("Metformin"[MeSH] OR "Metformin") AND ("Cancer" OR "Cardiovascular Disease" OR "Neurodegenerative Disease" OR "Aging") AND ("Therapeutic Use" OR "Non-diabetic"). The details of the MeSH terms searched across all databases are given in Supplementary Table S2. The inclusion criteria for the studies were: (1) studies investigated the effects of metformin beyond its primary use in diabetes management; (2) peer-reviewed articles published in English; and (3) studies providing details on metformin’s role in cancer treatment, cardiovascular protection, obesity management and other non-diabetic conditions. Studies were excluded if they: (1) focused exclusively on metformin’s role in glycemic control without addressing the additional therapeutic effects; (2) were conference abstracts, case reports, editorials or letters to the editor; or (3) lacked sufficient methodological details or relevance to the study objective. Eligible studies underwent a detailed data extraction process, focusing on key findings related to the multifaceted applications of metformin. The extracted data were then systematically analyzed and categorized to provide insights into the potential applications of the drug in cancer therapy, obesity management, cardiovascular protection and other non-diabetic conditions. The risk of bias was assessed using the Cochrane Tool for Randomized Controlled Trials (RCTs) and the Newcastle Ottawa Scale (NOS) for observational studies (Supplementary Table S1). The overall quality of evidence was moderate with heterogeneity in study designs. Findings were interpreted considering these limitations. Due to the significant heterogeneity in interventions (e.g., metformin dosages, combination therapies) and outcomes across studies, a meta-analysis was deemed inappropriate. A narrative synthesis was conducted to summarize key findings thematically.
Risk of bias assessment
Two reviewers (AU and AJ) independently assessed the risk of bias for each outcome measure using Cochrane RoB 2.0 (for RCTs) and NOS (for observational studies), with discrepancies resolved by a third reviewer (WAS). Rayan software aided the screening. Complete assessments are in Supplementary Table S1.
The PRISMA flowchart, shown in Figure 1, illustrates the detailed study selection process.
Figure 1.
PRISMA flowchart.
Metformin in obesity
A growing number of studies have reported the potential use of metformin in controlling obesity and associated comorbidities. Metformin has demonstrated modest yet significant effects on weight reduction in individuals without diabetes. In preclinical studies, metformin effectively mitigated obesity induced by high-fat diets. This effect is attributed to an increased expression of fibroblast growth factor 21 (FGF-21), a pivotal metabolic hormone that stimulates lipolysis in white adipose tissue, consequently reducing adipose accumulation.8 Additionally, metformin enhances the brown adipose tissue (BAT) metabolic activity that prevents obesity in mice. BAT contributes to energy dissipation through thermogenesis, a process facilitated by the uncoupling protein 1 (UCP1). Using PET/CT imaging, researchers found that metformin accumulates in BAT likely due to increased expression of organic cation transporters (OCT).9 Further studies have shown that metformin combats obesity effects by reducing fatty acid uptake, increasing mitochondrial biogenesis and stimulating thermogenesis.10,11 Animal studies indicate that metformin influences gut microbiota, reducing fat uptake and decreasing the development of fat-induced obesity.12 Table 1 illustrates an overview of different randomized clinical trials and other studies examining metformin as a treatment for obesity, including the study design, participant characteristics and interventions. The studies listed in Table 1 encompass a diverse range of study designs, including randomized, open-label and double-blind placebo-controlled trials. The study participants have met various diagnostic criteria, including the Rotterdam criteria for PCOS and the National Institutes of Health (NIH) 1990 criteria for obesity. The studies’ duration spans from 12 to 32 weeks, with sample sizes ranging from 28 to 176 participants. The age range of the participants is 18 to 45 years, and the baseline BMI values generally fall within the range of 24 and 39 kg/m². Regarding interventions, metformin was evaluated both as monotherapy and in combination with other pharmacological agents such as Liraglutide, Exenatide or combinations thereof. The metformin dosage ranged from 500 to 1000 mg daily (BID, TID, or QD). Table 2 presents the clinical outcomes of the investigations listed in Table 1, with a focus on anthropometric measurements, including BMI, body weight, waist circumference (WC) and fat mass. In the study by Jensterle et al., patients receiving metformin 1000 mg BID exhibited a notable decrease in BMI (37.4 ± 6.4 to 36.5 ± 6.3) and body weight (103.6 ± 19.7 kg to 101.3 ± 19.8 kg) following a 12-week intervention.13 Comparable results were observed by Ma et al. using metformin 500 mg TID, with reductions in BMI (30.8 ± 3.4 to 29.4 ± 3.3) and body weight (82.3 ± 11.4 kg to 78.6 ± 10.9 kg).14 Elkind-Hirsch et al., reported that liraglutide 3 mg substantially reduced BMI and WC, while the control group receiving a placebo showed minimal changes.15 Figure 2 depicts the comparative impact of metformin on body mass index (BMI) across different study groups. The data elucidate variations in BMI before and after metformin administration, demonstrating its potential for weight modulation. Error bars represent standard deviation.
Table 1.
Detailed description of included studies
| Author and publication year | Study type | Study duration | Study subjects | Age (years) | BMI (kg/m²) | Treatment groups |
|---|---|---|---|---|---|---|
| Jensterle et al. 201413 | RCT | 15 weeks | 32 | 27.6 ± 7.2 | 39.5 ± 6.2 | Metformin 1000 mg BD (n = 15), Liraglutide 1.2 mg OD (n = 17) |
| Feng et al. 201514 | RCT | 16 weeks | 50 | 18–40 | BMI ≥25 | Metformin 500 mg TID or combination therapy |
| Nylander et al. 201715 | RCT | 46 weeks | 92 | 18–45 | >30 | Liraglutide 3 mg, Placebo |
| Kesavan et al. 202316 | Open-label RCT |
22 weeks | 176 | 18–40 | >24 | Exenatide 10 μg BD, Metformin 1000 mg BD |
| Ling et al. 202517 | RCT | 36 weeks | 72 | 29.9 ± 6.1 | 25 | Liraglutide 1.8 mg OD, Placebo |
| Jensterle et al. 201618 | Prospective RCT | 10 weeks | 44 | 33.3 ± 4.4 | 37.2 ± 4.5 | Combination therapy (Metformin 1g BD + Liraglutide 1.2 mg OD), Liraglutide 1.2 mg OD) |
| Jensterle et al. 201719 | Open-label RCT | 26 weeks | 30 | 33.1 ± 6.1 | 38.3 ± 5.4 | Liraglutide 3 mg OD (n = 15), Combination therapy (Metformin 1000 mg BD + Liraglutide 1.2 mg OD, n = 15) |
| Salamun et al. 201820 | Open-label RCT | 14 weeks | 28 | 31.07 ± 4.75 | 36.7 ± 3.5 | Metformin 1000 mg BD, Combination therapy (Metformin 1000 mg BID + Liraglutide 1.2 mg) |
BMI: Body Mass Index; RCT: Randomized Controlled Trial; BD: twice daily; OD: once daily; TID: thrice daily
Table 2.
Clinical studies with anthropometrical outcomes
| Author and publication year | Group for intervention | Baseline for BMI after | Baseline for body weight after | Baseline for WC after | Baseline for body mass after | Baseline after |
|---|---|---|---|---|---|---|
| Jensterle et al. 201513 | Liraglutide (1.2 mg) | 41.6 ± 5.3 / 40.5 ± 5.1 | 113.7 ± 18.7 / 110.7 ± 18.1 | 128.5 ± 13.9 / 124.1 ± 11.7 | 42.5 ± 2.8 / 40.8 ± 3.2 | −3.0 / −2.3 |
| Metformin (1000 mg BID) | 38.4 ± 6.4 / 36.5 ± 6.3 | 103.6 ± 19.7 / 101.3 ± 19.8 | 121.6 ± 17.1 / 119 ± 18 | 43.3 ± 6.4 / 45.2 ± 4.2 | −6.2 ± 2.4 / −3.8 ± 3.5 | |
| Ma et al. 202114 | Metformin (500 mg TID) + Exenatide 2 mg | 30.8 ± 3.4 / 29.4 ± 3.3 | 82.3 ± 11.4 / 78.6 ± 10.9 | 97.3 ± 9.6 / 92.7 ± 8.7 | −3.8 ± 2.4 / −2.1 ± 3.0 | −5.7 ± 0.75 / −3.8 ± 3.5 |
| Metformin (500 mg TID) | 32.4 ± 3.2 / 29.6 ± 2.8 | 79.1 ± 10.8 / 77.0 ± 9.7 | 96.6 ± 9.1 / 95.0 ± 8.1 | (p < 0.01) / (p = 0.008) | −4.3 ± 1.3 / −2.3 ± 0.6 | |
| Elkind-Hirsch et al. 202215 | Liraglutide (3 mg) | 41.6 ± 1.1 / 39.1 ± 1.1 | 111 ± 2.8 / 104.7 ± 2.9 | 111 ± 2.2 / 101 ± 2.0 | 47.6 ± 0.8 / 46.0 ± 0.9 | −7.0 ± 6.0 / −7.5 ± 3.9 |
| Placebo | 43.9 ± 1.7 / 43.4 ± 1.8 | 119 ± 4.7 / 117.9 ± 5 | 116 ± 3.3 / 110 ± 3.3 | 48.2 ± 0.8 / 47.9 ± 0.9 | −7.0 ± 6.0 / −7.5 ± 3.9 | |
| Liu et al. 201716 | Exenatide (10 μg) | 29.1 ± 3.1 / 26.0 ± 3.5 | 72.9 ± 9.8 / 68.7 ± 9.7 | 92.9 ± 10.1 / 83.9 ± 9.7 | 44.1 ± 3.8 / 39.4 ± 3.7 | −7.0 ± 6.0 / −7.5 ± 3.9 |
| Metformin (1000 mg BID) | 27.3 ± 1.8 / 27.2 ± 1.8 | 70.4 ± 4.6 / 68.2 ± 4.6 | 89.4 ± 6.6 / 84.4 ± 5.3 | 41.3 ± 2.7 / 40.2 ± 2.9 | −7.0 ± 6.0 / −7.5 ± 3.9 | |
| Frøssing et al. 201817 | Liraglutide (1.8 mg) | 33.3 ± 5.1 / 33.3 ± 4.6 | 94.2 ± 15.4 / 91.3 ± 13.6 | 102.6 ± 10.8 / 102.6 ± 11.1 | 35.9 ± 8.5 / 35.7 ± 7.2 | NA |
| Placebo | 33.3 ± 4.6 / 33.3 ± 4.6 | 91.3 ± 13.6 / 91.3 ± 13.6 | 102.6 ± 11.1 / 102.6 ± 11.1 | 35.7 ± 7.2 / 35.7 ± 7.2 | NA | |
| Jensterle et al. 201718 | Metformin (1000 mg BID) + Liraglutide (1.2 mg) | 37.7 ± 4.0 / 35.5 ± 4.2 | 105.8 ± 15.8 / 99.6 ± 15.9 | 117.2 ± 14.5 / 105.2 ± 27.0 | 824.2 ± 254.7 / 735.3 ± 227.5 | −5.2 / 0.2 |
| Liraglutide (1.2 mg) | 36.7 ± 5.1 / 35.3 ± 5.1 | 102.6 ± 17.9 / 98.8 ± 17.6 | 113.0 ± 13.9 / 107.5 ± 15.4 | −6.2 ± 2.4 / −3.8 ± 3.5 | −6.3 ± 3.7 / 3.6 ± 2.5 | |
| Jensterle et al. 201519 | Liraglutide (3 mg) | 39.2 ± 5.5 / 37.0 ± 5.5 | 111.1 ± 14.8 / 104.7 ± 14.8 | 110.1 ± 12 / 105.9 ± 12.8 | −6.3 ± 3.7 / 3.6 ± 2.5 | NA |
| Liraglutide (1.2 mg) + Metformin (1000 mg BID) | 37.5 ± 5.3 / 36.2 ± 5.5 | 102.5 ± 9 / 98.9 ± 10.3 | 105.2 ± 10.7 / 103.0 ± 8.2 | −5.2 ± 2.5 / −4.4 ± 3.2 | NA | |
| Salamun et al. 201820 | Metformin (1000 mg BID) | 35.5 ± 4.9 / 33.0 ± 3.3 | 99.6 ± 17.8 / 92.6 ± 18 | 108.8 ± 14.5 / 97.5 ± 11 | 779.4 ± 247.3 / 698.1 ± 292.8 | NA |
| Metformin (1000 mg BID) + Liraglutide (1.2 mg) | NA | NA | NA | NA | NA |
BMI: Body Mass Index; BID: twice daily; TID: thrice daily; NA: Not Applicable WC: waist circumference
Figure 2.
Effect of metformin on Body Mass Index (BMI).
Metformin in cancer
An increasing number of scientific studies suggest that metformin shows therapeutic potential for various cancer types, including breast cancer,15 hematologic malignancies,17 bone cancer,18 colorectal cancer,19 endometrial cancer, and melanoma20 The anticancer effects of metformin stem from its capacity to directly and indirectly modulate cellular metabolism. It exerts its influence through two primary signaling pathways: the AMPK-dependent and the AMPK-independent. In the AMPK-dependent pathway, metformin triggers AMPK activation, which subsequently suppresses the mTOR (mammalian target of rapamycin) signaling pathway. This interference with mTOR activity impacts protein synthesis, consequently decelerating cell growth and division.21
Table 3 presents an overview of the studies examining metformin's role in cancer treatment, highlighting various treatment protocols, patient profiles and dosing strategies. The studies encompassed prospective cohort, randomized clinical, and retrospective designs with diverse sample sizes and treatment approaches, including MPA, MA and LNG-IUD in conjunction with metformin. Treatment efficacy, measured by complete response (CR) and partial response (PR), differed across studies, with the majority demonstrating favorable outcomes for the progestin-metformin combination. BMI and age information were also documented, revealing comparable baseline values among groups. Table 4 outlines the diagnostic and reproductive outcomes for patients in studies investigating metformin usage. These investigations compared progestin monotherapy to progestin-metformin combination therapy, assessing outcomes such as complete response (CR), partial response (PR), non-response (NR) and pregnancy rates. Reproductive outcomes varied, with some studies reporting pregnancy and live birth rates, while others omitted reproductive data. In general, the progestin-metformin combination showed promising results regarding response rates, although reproductive outcomes were not consistently reported across studies.
Table 3.
Overview of studies on metformin use in cancer treatment, including patient demographics, treatment methods and outcomes
| Author and publication year | Study Type | BMI (mean, baseline) | Number of patients (groups) | Treatment methods | Diagnosis groups | % | Age (mean, baseline) |
|---|---|---|---|---|---|---|---|
| Shao et al et al. 202322 | Prospective cohort study | PROG: 26.33 ± 4.30 / PROG + MET: 27.01 ± 4.43 | Total = 219, PROG = 138, CAH = 81 | MPA or MA + Metformin | CAH+PROG = 35.5, MET+PROG = 35.8 | PROG: 35.05 ± 5.14, PROG + MET: 32.00 ± 4.58 | PROG: 32.00 ± 4.58 |
| Janda et al. 202123 | 3 arm open-label RCT | 3-arm: 48.0 ± 9.7, 2-arm: 43.1 ± 9.6 | Total = 165, PROG = 118, Met = 47 | LNG-IUD + Metformin | EAC = 58%, EHA = 42% | 3-arm: 51.5 ± 14.1, 2-arm: 60.6 ± 13.8 | 3-arm: 51.5 ± 14.1, 2-arm: 60.6 ± 13.8 |
| Acosta-Torres et al. 202024 | Retrospective Study | PROG: 34.7 (26.9–45.3) / PROG + MET: 41.5 (32.7–53.1) | Total = 92, PROG = 58, PROG + MET = 34 | MPA or MA or Prometrium or LNG-IUD + Metformin | AH/EIN: 54 (59%), EC: 38 (41%) | PROG: 36.0 (30.0–38.5), PROG + MET: 32.0 (29.0–35.0) | PROG: 32.0 (29.0–35.0) |
| Mandelbaum et al. 202025 | Retrospective study | PROG: 38.3 (31.2–45.0), PROG + MET: 37.1 (32.7–46.3) | Total = 245, CAH = 176, Local progestin group = 69 | MPA or MA or norethindrone or depomedroxyprogesterone acetate (systemic); LNG-IUD (local) + Metformin | CAH: all patients | PROG: 32.9 (32.2–46.3), PROG + MET: 42.0 (38.0–60.5) | PROG: 42.0 (38.0–60.5) |
| Factor et al. 202426 | Randomized, single-center | PROG: 24.6 ± 4.1 / PROG + MET: 24.7 ± 5.2 | Total = 150, PROG = 74, PROG + MET = 76 | MA + Metformin | PROG: 62 (AEH) + 12 (EEC), PROG + MET: 61 (AEH) + 15 (EEC) | PROG: 34.4 ± 5.2, PROG + MET: 32.0 ± 4.5 | PROG: 32.0 ± 4.5 |
| Yuan et al. 202227 | No data | PROG: 33.37 ± 4.49, PROG + MET: 34.43 ± 4.24 | All = 120, EAC: all patients | MPA + Metformin | EEC: all patients | PROG: 36.12 ± 8.41, PROG + MET: 33.73 ± 7.47 | PROG: 33.73 ± 7.47 |
| Shan et al. 201428 | Controlled, single-blind | No data | All = 16, PROG = 8, PROG + MET = 8 | MA + Metformin | EAH: all patients | All patients: 35.2 ± 5.8, PROG: 34 ± 7.1, PROG + MET: 36.4 ± 4.2 | PROG + MET: 36.4 ± 4.2 |
| Shiwani et al. 202429 | Retrospective study | All patients: 26.7 (17.6–36.0) | All = 32, PROG = 23, PROG + MET = 32 | MPA or MA + Metformin | AH: 13/32 (40.6%), G1EC: 19/32 (59.4%) | All patients: 30.4 (20–40) | All patients: 30.4 (20–40) |
| Mitsuhashi et al. 201930 | Retrospective study | PROG: 23.3 (21.6–27.1), PROG + MET: 29.7 (27.3–32.0) | All = 63, PROG = 23, PROG + MET = 42 | MPA + Metformin | AEH/CAH: 21/63, EC: 42/63 | All patients: 35 (26–44) | All patients: 35 (26–44) |
BMI: Body mass index; EAC: endometrial adenocarcinoma; EIN: endometrial intraepithelial hyperplasia; M: oral metformin; WL: weight loss intervention; CR: complete response; PROG: progestin; MA: megestrol acetate; PROG+MET: Progestin+Metformin; CH: complex hyperplasia; AH: atypical hyperplasia; AEH: Atypical Endometrial Hyperplasia; CAH: Complex Atypical Hyperplasia
Table 4.
Reproductive and treatment outcomes comparing progestin + metformin versus progestin alone across different studies
| Author (year) | Diagnostic method | Patients (total) | Groups (PROG + MeT vs. PROG) | Intervention | Comparison | Treatment outcomes | Reproductive outcomes |
|---|---|---|---|---|---|---|---|
| Shao et al et al. 202322 | Hysteroscopic surgery | 219 | Group 1: 81, Group 2: 138 | MPA or MA + MET, MPA or MA | Group 1: MET + PROG, Group 2: PROG | CR: 93.8% (Group 1), 84.1% (Group 2); PR: 3.7% (Group 1), 3.6% (Group 2); NR: 2.5% (Group 1), 11.6% (Group 2) | Pregnancies: Group 1: 37%, Group 2: 36.8% Live births: Group 1: 22.2%, Group 2: 23.7% Abortions: Group 1: 40%, Group 2: 35.7% |
| Janda et al. 202123 | Endometrial biopsy or D&C | 165 | Group 1: 47, Group 2: 118 | LNG-IUD + MET, LNG-IUD | Group 1: PROG + MET, Group 2: PROG | CR: 61% (Group 1), 67% (Group 2); PR: 6% (Group 1), 12% (Group 2); NR: 24% (Group 1), 18% (Group 2) | No data on pregnancies, abortions, or live births |
| Acosta-Torres et al. 202024 | Endometrial biopsy or D&C | 92 | Group 1: 34, Group 2: 58 | MPA/MA/Prometrium/ LNG-IUD + MET | Group 1: PROG + MET, Group 2: PROG | CR: 68% (Group 1), 69% (Group 2); Relapse Rate: 4 cases on treatment, 10 off treatment | Pregnancies: Group 1: 6%, Group 2: 24% Live births: Group 1: 6%, Group 2: 24% |
| Mandelbaum et al. 202025 | Endometrial biopsy | 245 | Systemic Progestin Group: 176, Local Progestin Group: 69 | MPA or MA + MET | Systemic Progestin: Group 1 + MET, Group 2: PROG | CR: 34.1% (Systemic), 84.1% (Local); PR: 10.2% (Systemic), 1.4% (Local) | No data on pregnancies, abortions, or live births |
| Factor et al. 202426 | D&C +/− hysteroscopy | 150 | Group 1: 76, Group 2: 74 | MA + MET | Group 1: PROG + Metformin, Group 2: PROG | CR at 16 weeks: 34.3% (Group 1), 20.7% (Group 2) CR at 36 weeks: 74.3% (Group 1), 68.2% (Group 2) | Pregnancies: Group 1: 51.3%, Group 2: 48.4% Live births: Group 1: 21.6%, Group 2: 41.9% |
| Yuan et al. 202227 | Histopathological exam | 120 | Group 1: 60, Group 2: 60 | MPA + MET | Group 1: PROG + MET, Group 2: PROG | CR: 26.7% (Group 1), 20% (Group 2); PR: 45% (Group 1), 33.3% (Group 2) | Pregnancies: Group 1: 81.7%, Group 2: 61.7% ART: Group 1: 32.7%, Group 2: 37.8% |
| Adamyan et al. 202428 | D&C | 16 | Group 1: 8, Group 2: 8 | MA + MET | Group 1: PROG + MET, Group 2: PROG | CR: 75% (Group 1), 25% (Group 2); NR: 37.5% (Group 1), 67.7% (Group 2) | No data on pregnancies, abortions, or live births |
| Zhou et al. 201529 | Hysteroscopic biopsy or D&C | 32 | Group 1: 9, Group 2: 23 | MPA or MA + MET | Group 1: PROG + MET, Group 2: PROG | CR: 88.9% (Group 1), 84.4% (Group 2) | Pregnancies: Group 1: 55.6%; ART: Group 1: 88.9% |
| Mitsuhashi et al. 201930 | D&C | 63 | Group 1: 42, Group 2: 23 | MPA + MET | Group 1: PROG + MET, Group 2: PROG | CR: 97% (Group 1), 61% (Group 2); Relapse: 13.1% | Pregnancies: Group 1: 45%; ART: 83% of pregnancies occurred within 12 months |
PROG: Progesterone; MET: Metformin; MPA: Medroxyprogesterone Acetate; MA: Megestrol Acetate; D&C: Dilation and Curettage; CR: Complete Response; PR: Partial Response; NR: Non-Response; ART: Assisted Reproductive Technology
Metformin in cardiovascular diseases
Cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity worldwide. Multiple factors contribute to the development of CVDs, including lifestyle choices and medical conditions such as tobacco use, diabetes mellitus, obesity, hyperlipidemia and hypertension. Among these risk factors, diabetes mellitus demonstrates a strong association with CVDs (including coronary artery disease, atherosclerosis and heart failure) and frequently presents as a comorbid condition.31 Elevated blood glucose levels (hyperglycemia) induce oxidative stress, which can lead to endothelial dysfunction and a lipoprotein imbalance, thereby increasing the risk of CVDs. Metformin has demonstrated efficacy in reducing CVD incidence among individuals with diabetes. Metformin prevents deleterious modifications of apolipoprotein residues caused by alpha-dicarbonyl compounds through the activation of AMPK. This mechanism contributes to the restoration of high-density lipoprotein (HDL) function and mitigates alterations in low-density lipoprotein (LDL). Enhanced HDL function facilitates cholesterol transport and diminishes the risk of cardiovascular disorders. Furthermore, metformin attenuates oxidative stress in blood vessels and mitigates inflammation induced by hyperglycemia, further reducing the risk of CVDs. Type 2 diabetes mellitus (T2DM) elevates the risk of heart failure, with approximately one-third of heart failure cases reported in patients with diabetes. Metformin has been shown to enhance cardiac energy metabolism, which is necessary for normal heart function, by improving lipid and glucose metabolism through AMPK activation.32 Table 5 presents an overview of the study characteristics included in the review, evaluating incident heart failure outcomes in patients with preserved left ventricular ejection fraction (LVEF ≥50%). The table outlines the study design, demographic details of the populations and follow-up durations. Figure 3 illustrates a forest plot summarizing the effect of metformin treatment across four studies on HFpEF. Individual effect sizes ranged from 0.68 (95% CI: 0.51, 0.85) to 0.88 (95% CI: 0.83, 0.93), with a pooled random-effects model estimate of 0.82 (95% CI: 0.74, 0.90), demonstrating a statistically significant beneficial effect.
Table 5.
Study characteristics on the incident heart failure outcomes in patients with left ventricular ejection fraction ≥50%
| Study | Design | Sample size | Mean age (years) | % of Patients with LVEF ≥50% | Follow-up duration (years) |
|---|---|---|---|---|---|
| Lupon et al. 201833 | Retrospective study | 13,930 | 76 | 23% | 1.0 |
| Ziao et al. 202434 | Prospective study | 1,519 | 72 | 51% | 4.7 |
| Lee et al. 199335 | Retrospective study | 835 | 72 | 49% | 2.4 |
| Ohno et al. 202536 | Retrospective study | 6,185 | 68 | 45% | 2.2 |
LVEF: Left Ventricular Ejection Fraction
Figure 3.
Effect of metformin in patients with heart failure with preserved ejection fraction (HFpEF).
Metformin in neurodegenerative disorders
Neurodegenerative disorders, such as Parkinson’s disease (PD) and Alzheimer’s disease (AD), are characterized by progressive neuronal loss and cognitive or motor impairments. Parkinson’s disease primarily affects the dopaminergic neurons in the substantia nigra, resulting in tremors, bradykinesia, and rigidity. Genetic and environmental factors contribute to its pathogenesis.33,34 Metformin has been demonstrated to decelerate the progression of neurodegenerative disorders, mitigate age-related diseases, and extend lifespan.35-39 Table 6 summarizes the characteristics and quality of studies assessing the association between metformin use and the risk of neurodegenerative diseases, including dementia, Alzheimer’s disease (AD), and Parkinson’s disease (PD). It elucidates variations in study design, population demographics, outcome measurements, and quality scores. The findings demonstrate heterogeneous results, with some studies suggesting that metformin has protective effects, while others report an increased risk or no significant association.40
Table 6.
Characteristics and quality of included studies assessing the risk of neurodegenerative diseases with metformin use
| Study | Design | Study period | Outcome | Sample size (exposure vs control) | Adjusted OR (95% CI) | Quality score |
|---|---|---|---|---|---|---|
| Wang et al. 202441 | Cross-sectional | 2008–2012 | Cognitive dysfunction (FAB) | 2304 (318 vs 1986) | 1.29 (0.96 – 1.74) | 7 /11 (AHRQ) |
| Laurie-Anne et al. 202342 | Cohort | 2004–2009 | Dementia (ICD-9-CM) | 1829 (1033 vs 796) | 0.82 (0.52 – 1.28) | 7 /9 (NOS) |
| Fang et al. 202343 | Cohort | 1996–2007 | Parkinson’s Disease (ICD-9-CM or A-code) | 3758 (1879 vs 1879) | 1.30 (0.69 – 2.46) | 7 /9 (NOS) |
| Villani et al. 202244 | Cohort | 2000–2007 | Dementia (ICD-9-CM or A-code) | 12,383 (1864 vs 10,519) | 0.76 (0.58 – 0.98) | 7 /9 (NOS) |
| Garcia-Ptacek et al. 201645 | Cohort | 2000–2010 | Parkinson’s Disease (ICD-9-CM) | 9302 (4651 vs 4651) | 2.27 (1.68 – 3.07); Dementia: 1.66 (1.35 – 2.04) | 7 /9 (NOS) |
| Emre et al. 200346 | Cohort | 2003–2005 | Cognitive dysfunction (MMSE) | 365 | 0.49 (0.25 – 0.95) | 5 /9 (NOS) |
| Canet et al. 200347 | Case-control | 1998–2008 | Alzheimer’s Disease | 14,172 (7086 vs 7086) | 1.73 (1.11 – 2.68) | 7 /9 (NOS) |
| Armstrong et al. 201948 | Cohort | 2004–2010 | Dementia (ICD-10) | 5332 (1478 vs 3854) | 0.96 (0.89 – 1.03) | 7 /9 (NOS) |
| Gorelick et al. 201049 | Case-control | 2006 | Alzheimer’s or Cognitive Dysfunction | 126 (35 vs 91) | 1.75 (0.81 – 3.78) | 8 /9 (NOS) |
| Bamford et al. 202150 | Cohort | 2005–2014 | Parkinson’s Disease | 102,745 (94,349 vs 8396) | 1.39 (1.06 – 1.82) | 7 /9 (NOS) |
| Connor et al. 202051 | Cohort | 2001–2012 | Dementia (ICD-9) | 14,562 (10,437 vs 4125) | <75 yrs: 0.89 (0.79–0.99); ≥75 yrs: 0.96 (0.87 –1.05) | 8 /9 (NOS) |
| Ruan et al. 202552 | Cross-sectional | 2014 | Cognitive dysfunction (RCS) | 198 | 0.52 (0.24 –1.00) | 5 /11 (AHRQ) |
| Silvija et al. 202553 | Cross-sectional | 2012 | Cognitive dysfunction (MMSE) | 1323 | 0.59 (0.35 – 0.99) | 4 /11 (AHRQ) |
| Ordoobadi et al. 202454 | Cohort | 2004–2012 | Dementia (ICD-10) | 22,841 (NA) | 0.58 (0.39 – 0.88) | 8 /9 (NOS) |
| Negru et al. 202555 | Cohort | 1998–2011 | Alzheimer’s (NINCDS-ADRDA) | 5894 (2120 vs 3774) | 1.60 (0.87 – 2.93); Dementia: 1.42 (1.02 – 1.98) | 8 /9 (NOS) |
| Friedman et al. 201156 | Cohort | 2011–2014 | Cognitive dysfunction (MMSE) | 757 | 2.47 (1.10 – 5.57) | 6 /9 (NOS) |
| Riedel-Heller et al. 200157 | Case-control | 2013–2017 | Dementia (ICD-10) | 16,522 (8276 vs 8276) | 0.96 (0.88 – 1.04) | 8 /9 (NOS) |
| Du et al. 202358 | Cohort | 1997–2007 | Alzheimer’s (ICD-9) | 30,170 (4978 vs 25,192) | Mono: 0.69 (0.28 – 1.71); Combo: 0.57 (0.26–1.26) | 7 /9 (NOS) |
| Hsiao et al. 201559 | Cohort | 1999–2011 | Dementia (ICD-9) | 31,352 (15,676 vs 15,676) | 0.71 (0.63–0.79) | 7 /9 (NOS) |
SU: sulfonylurea; MET: Metformin; AD: Alzheimer’s disease; FAB: Frontal Assessment Battery; FBG: Fasting blood glucose; RCS: Rapid cognitive screen; RCS: Rapid cognitive screen; AHRQ: Agency for Healthcare Research and Quality; ICD-9-CM: International Classification of Diseases, 9th Revision, Clinical Modification; NOS: Newcastle–Ottawa Scale; MMSE: Mini-Mental State Examination; AHRQ: Agency for Healthcare Research and Quality; NA: Not Applicable; Mono: monotherapy; Combo; combination therapy
Metformin in liver diseases
Table 7 summarizes the characteristics of studies evaluating the effects of metformin on liver health, highlighting the diverse study designs, diagnostic methods and covariate adjustments employed. The varied metformin doses administered (ranging from 500 mg to 3000 mg) reflect individualized treatment approaches. Figure 4 illustrates the effects of metformin on key clinical and biochemical indicators in patients with Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD). Metformin significantly reduces Triglycerides (TG), Total Cholesterol (TC) and Insulin Resistance (IR), as indicated by the blue markers. Non-significant changes are observed for BMI, AST and ALT as indicated by gray markers with confidence intervals crossing the line of no effect.60-62 These findings elucidate the role of metformin in improving metabolic parameters in patients with MASLD.
Table 7.
Characteristics of studies evaluating the effects of metformin on liver health
| Study | Study Design | Case Count | Study Duration (Months) | Diagnostic Method | Metformin Dosage (Treatment Group) | NOS |
|---|---|---|---|---|---|---|
| Brackett et al. 201063 | RCT | 93 | 24 | Ultrasonography | 250 mg first week, 500 mg second week, and 1000 mg third week | 8 |
| Pinyopornpanish et al. 202164 | Prospective cohort | 50 | 6 | Ultrasonography | 1000 mg/day | 7 |
| Federica et al. 202465 | RCT | 42 | 6 | Ultrasound | 500 mg first week, 2000 mg second week | 8 |
| Idilman et al. 200866 | Cohort | 44 | 6 | Biopsy | 500 – 3000 mg/day | 7 |
| Ramanathan et al. 202267 | Prospective | 129 | 6 | Biochemical, radiological, and histological criteria | 850 mg/day | 9 |
| Nar et al. 200868 | Open label RCT | 28 | 12 | MRI, CT, imaging, and liver biopsy | 500 mg once daily (first week), 500 mg twice daily (second to third weeks), 1000 mg twice daily thereafter | 8 |
| Lee 202069 | Prospective cohort study | 34 | 6 | Ultrasonography | 850 – 1700 mg/day | 7 |
| Woo et al. 201470 | Prospective | 57 | 24 | Biopsy and ultrasonography | 1.5 g/day | 8 |
| García-Compeán et al. 202271 | RCT | 36 | 6 | Ultrasonography | 850 mg/day | 7 |
| Hesen et al. 201772 | Cohort | 63 | 4 | Ultrasonography | 850 – 1700 mg/day | 8 |
Figure 4.
Impact of metformin on clinical and biochemical indicators in MASLD patients.
The widespread use of metformin for non-diabetic purposes has gained significant attention in recent years. This shift in usage patterns reflects the drug's potential therapeutic benefits across various medical domains. Among these non-diabetic applications, liver disease stands out as the most prominent, accounting for 30% of the non-diabetes indications of metformin use. This suggests a growing recognition of metformin's hepatoprotective properties and its potential role in managing liver disorders. Following closely, cognitive dysfunction represents 15% of non-diabetes indications of metformin use, indicating an emerging interest in the drug's neuroprotective effects and its potential to mitigate cognitive decline. While cancer treatment and prevention still represent a significant area of research and clinical interest, they account for only 5%. The timeline plot presented in Figure 5 provides a chronological perspective on the evolution of metformin research across these different applications. This visual representation enables a comprehensive understanding of how scientific interest in metformin's non-diabetes indications has evolved over time. The timeline likely reveals key milestones, breakthrough studies, and shifting trends in research focus, offering valuable insights into the drug's expanding therapeutic potential. By examining this timeline, researchers and clinicians can better appreciate the progression of metformin's applications, from its traditional role in diabetes management to its current status as a multifaceted therapeutic agent with diverse clinical implications.
Figure 5.
Timeline of research on metformin by disease.
CONClUSION
The findings of this systematic review underscore the multifaceted therapeutic potential of metformin, extending well beyond its established role in managing type 2 diabetes. The analysis of recent literature reveals a growing body of evidence supporting metformin’s efficacy in various health conditions, including cardiovascular diseases,73 different types of cancers,74 neurodegenerative diseases, and obesity. This review aims to synthesize these findings, explore the implications for clinical practice, and highlight areas for future research. The positive effects of metformin on cardiovascular health are significant. Multiple studies have demonstrated that metformin not only improves glycemic control but also exerts beneficial effects on lipid profiles and blood pressure, thereby reducing cardio-vascular risk factors. The drug's ability to enhance insulin sensitivity and exert anti-inflammatory effects may contribute to these cardiovascular benefits. Given the high prevalence of CVD among diabetes patients, the integration of metformin into CVD management protocols could be a valuable therapeutic strategy. Metformin’s cardiovascular benefits extend beyond diabetes management, suggesting potential applications in non-diabetic populations for the prevention and treatment of heart disease. Long-term studies show reduced cardiovascular events and mortality in type 2 diabetes patients using metformin. The drug's diverse effects on metabolic pathways make it promising for further cardiovascular medicine research.
Evidence suggests that metformin inhibits cancer cell proliferation and induces apoptosis through various mechanisms, including activation of the AMP-activated protein kinase (AMPK) pathway. This review elucidates that metformin has demonstrated efficacy in treating several types of cancer, including breast, colorectal, and endometrial cancers. These findings indicate that metformin may be considered an adjunctive therapy in oncology, particularly for patients with insulin resistance or metabolic syndrome.
Emerging research suggests that metformin may play a potential role in reducing the risk of neurodegenerative diseases. The reviewed data suggest a potential association between metformin use and improved cognitive function, particularly in individuals with hyperglycemia. The neuroprotective effects of metformin can be attributed to its ability to mitigate oxidative stress and inflammation, which are critical factors in the pathogenesis of neurodegenerative disorders. However, additional longitudinal studies are necessary to establish causality and elucidate the underlying mechanisms involved.
Metformin's role in obesity management represents a further area of research interest. The medication has demonstrated efficacy in promoting weight reduction and enhancing metabolic parameters in overweight and obese individuals, particularly those exhibiting insulin resistance. Looking at the fact that obesity increases risk for diabetes and cardiovascular problems, the application of metformin in obesity for weight management could have significant public health implications.
In summary, metformin demonstrates a broad spectrum of therapeutic benefits that extend well beyond diabetes management. Its roles in treating cardiovascular diseases, various cancers, neurodegenerative diseases, and obesity position it as a multifaceted agent in modern medicine. As research continues to evolve, it is essential to optimize the use of metformin in clinical settings and explore its full potential in improving patient outcomes across a range of health conditions.
Acknowledgement
The authors express their sincere gratitude to Dr. Farhan Mukhtair for his guidance in the data search and for his valuable insights during the design of this review article.
Funding Statement
Funding Source None.
Statement of Authorship
All authors certified fulfillment of ICMJE authorship criteria.
CRediT Author Statement
AJ: Conceptualization, Methodology, Validation, Formal analysis, Data Curation, Writing – original draft preparation, Writing – review and editing; AU: Methodology, Writing – original draft preparation, Writing – review and editing; SSA: Methodology, Data Curation; RA: Formal analysis, Investigation.
Data Availability Statement
The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.
Author Disclosure
The authors declared no conflict of interest.
References
- 1.Abbasi M, Heath B, McGinness L. Advances in metformin-delivery systems for diabetes and obesity management. Diabetes Obes Metab. 2024;26(9):3512-29. PMID: 38984380 DOI: 10.1111/dom.15759 [DOI] [PubMed] [Google Scholar]
- 2.Adi S, Tjokroprawiro A. MetformIn: Effects Beyond Glycemic Control. In: Proceedings of Surabaya International Physiology Seminar (SIPS). Vol 1. Jawa Timur, Indonesia. 2017;1:349-55. DOI: 10.5220/0007339003490355 [DOI] [Google Scholar]
- 3.Hasanvand A. The role of AMPK-dependent pathways in cellular and molecular mechanisms of metformIn: A new perspective for treatment and prevention of diseases. Inflammopharmacology. 2022; 0(3):775-88. PMID: 35419709 PMCID: DOI: 10.1007/s10787-022-00980-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Ladeiras-Lopes R, Fontes-Carvalho R, Bettencourt N, Sampaio F, Gama V, Leite-Moreira A. Novel therapeutic targets of metformIn: Metabolic syndrome and cardiovascular disease. Expert Opin Ther Targets. 2015;19(7):869-77. PMID: 25762117 DOI: 10.1517/14728222.2015.1025051 [DOI] [PubMed] [Google Scholar]
- 5.Jin X, Qiu T, Li L, et al. Pathophysiology of obesity and its associated diseases. Acta Pharm Sin B. 2023;13(6):2403-24. PMID: 37425065 PMCID: DOI: 10.1016/j.apsb.2023.01.012 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Madiraju AK, Erion DM, Rahimi Y, et al. Metformin suppresses gluconeogenesis by inhibiting mitochondrial glycerophosphate dehydrogenase. Nature. 2014;510(7506):542-6. PMID: 24847880 PMCID: DOI: 10.1038/nature13270 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Agius L, Ford BE, Chachra SS. The metformin mechanism on gluconeogenesis and AMPK activation: The metabolite perspective. Int J Mol Sci. 2020;21(9):3240. PMID: 32375255 PMCID: DOI: 10.3390/ijms21093240 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Ziqubu K, Mazibuko-Mbeje SE, Mthembu SXH, et al. Anti-obesity effects of metformIn: A scoping review evaluating the feasibility of brown adipose tissue as a therapeutic target. 2023;24(3):2227. PMID: 36768561 PMCID: DOI: 10.3390/ijms24032227 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Karise I, Bargut TC, del Sol M, Aguila MB, Mandarim-de-Lacerda CA. Metformin enhances mitochondrial biogenesis and thermogenesis in brown adipocytes of mice. Biomed Pharmacother. 2019;111: 1156-65. PMID: 30841429 DOI: 10.1016/j.biopha.2019.01.021 [DOI] [PubMed] [Google Scholar]
- 10.Wei XL, Tao MH, Li RH, Ge SH, Xiao W. Metformin and adipose tissue: A multifaceted regulator in metabolism, inflammation, and regeneration. Endocrinol Metab (Seoul). 2025;40(4):523-38. PMID: 40775736 PMCID: DOI: 10.3803/EnM.2025.2371 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Niu X, Wang Y, Huang L, et al. Effect of oral metformin on gut microbiota characteristics and metabolite fractions in normal-weight type 2 diabetic mellitus patients. Front Endocrinol (Lausanne). 2024; 15:1397034. PMID: 39257903 PMCID: DOI: 10.3389/fendo.2024.1397034 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Johnson NP. Metformin use in women with polycystic ovary syndrome. Ann Transl Med. 2014;2(6):56. PMID: 25333031 PMCID: DOI: 10.3978/j.issn.2305-5839.2014.04.15 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Sever MJ, Kocjan T, Pfeifer M, Kravos NA, Janez A. Short-term combined treatment with liraglutide and metformin leads to significant weight loss in obese women with polycystic ovary syndrome and previous poor response to metformin. Eur J Endocrinol. 2014;170(3): 451-9. PMID: 24362411 PMCID: DOI: 10.1530/EJE-13-0797 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Feng P, Yu D, Chen L, et al. Liraglutide reduces the body weight and waist circumference in Chinese overweight and obese type 2 diabetic patients. Acta Pharmacol Sin. 2015;36(2):200-8. PMID: 25619391 PMCID: DOI: 10.1038/aps.2014.136 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Nylander M, Frøssing S, Kistorp C, Faber J, Skouby SO. Liraglutide in polycystic ovary syndrome: A randomized trial, investigating effects on thrombogenic potential. Endocr Connect. 2017;6(2):89-99. PMID: 28119323 PMCID: DOI: 10.1530/EC-16-0113 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Kesavan S, Chaudhry GS, Akim AM, Ranneh YK. The efficacy of metformin and exenatide in polycystic ovary syndrome (PCOS) patients. Ars Pharm (Online). 2023;64(2):100-22. DOI: 10.30827/ars.v64i2.27302 [DOI] [Google Scholar]
- 17.Ling J, Wang T, Huang W, et al. Combined liraglutide and metformin therapy in overweight or obese women with polycystic ovary syndrome: A systematic review and meta-analysis. Diabetes, Obes Metab. 2025;27(11):6139-53. PMID: 40855964 PMCID: DOI: 10.1111/dom.70028 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Jensterle M, Kravos NA, Goričar K, Janez A. Short-term effectiveness of low dose liraglutide in combination with metformin versus high dose liraglutide alone in treatment of obese PCOS: Randomized trial. BMC Endocr Disord. 2017;17(1):5. PMID: 28143456 PMCID: DOI: 10.1186/s12902-017-0155-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Jensterle M, Salamun V, Kocjan T, Vrtacnik Bokal E, Janez A. Short term monotherapy with GLP-1 receptor agonist liraglutide or PDE 4 inhibitor roflumilast is superior to metformin in weight loss in obese PCOS women: A pilot randomized study. J Ovarian Res. 2015;8:32. PMID: 26032655 PMCID: DOI: 10.1186/s13048-015-0161-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Salamun V, Jensterle M, Janez A, Bokal EV. Liraglutide increases IVF pregnancy rates in obese PCOS women with poor response to first-line reproductive treatments: A pilot randomized study. European Journal of Endocrinology. 2018;179(1):1-11. PMID: 29703793 DOI: 10.1530/EJE-18-0175 [DOI] [PubMed] [Google Scholar]
- 21.Chomanicova N, Gazova A, Adamickova A, Valaskova S, Kyselovic J. The role of AMPK/mTOR signaling pathway in anticancer activity of metformin. Physiol Res. 2021;70(4):501-8. PMID: 34062070 PMCID: DOI: 10.33549/physiolres.934618 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Shao F, Li Y, Zhao Y. Progestin plus metformin improves outcomes in patients with endometrial hyperplasia and early endometrial cancer more than progestin alone: A meta-analysis. Front Endocrinol (Lausanne). 2023;14:1139858. PMID: 37415671 PMCID: DOI: 10.3389/fendo.2023.1139858 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Janda M, Robledo KP, Gebski V, et al. Complete pathological response following levonorgestrel intrauterine device in clinically stage 1 endometrial adenocarcinoma: Results of a randomized clinical trial. Gynecol Oncoly. 2021;161(1):143-51. PMID: 33762086 DOI: 10.1016/j.ygyno.2021.01.029 [DOI] [PubMed] [Google Scholar]
- 24.Acosta-Torres S, Murdock T, Matsuno R, et al. The addition of metformin to progestin therapy in the fertility-sparing treatment of women with atypical hyperplasia/endometrial intraepithelial neoplasia or endometrial cancer: Little impact on response and low live-birth rates. Gynecologic Oncology. 2020;157(2):348-56. PMID: 32085863 DOI: 10.1016/j.ygyno.2020.02.008 [DOI] [PubMed] [Google Scholar]
- 25.Mandelbaum RS, Ciccone MA, Nusbaum DJ, et al. Progestin therapy for obese women with complex atypical hyperplasia: Levonorgestrel-releasing intrauterine device vs systemic therapy. American journal of obstetrics and gynecology. 2020;223(1):103.e1-13. PMID: 31978437 PMCID: DOI: 10.1016/j.ajog.2019.12.273 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Factor PAA, Pasamba KC. Metformin as an adjunct to progestin therapy in endometrial hyperplasia and early-stage endometrial cancer: A systematic review and meta-analysis of randomized controlled trials. Acta Medica Philipp. 2024;58(11)-62-71. PMID: 39006985 PMCID: DOI: 10.47895/amp.v58i11.8155 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Yuan F, Hu Y, Han X, Li Q. Metformin in combination with progesterone improves the pregnancy rate for patients with early endometrial cancer. 2022;2022:1961016. PMID: 35854762 PMCID: DOI: 10.1155/2022/1961016 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Adamyan L, Pivazyan L, Isaeva S, Shapovalenko R, Zakaryan A. Metformin and progestins in women with atypical hyperplasia or endometrial cancer: Systematic review and meta-analysis. Arch Gynecol Obst. 2024;309(6):2289-305. PMID: 38503850 DOI: 10.1007/s00404-024-07416-2 [DOI] [PubMed] [Google Scholar]
- 29.Shiwani H, Clement NS, Daniels JP, Atiomo W. Metformin for endometrial hyperplasia. Cochrane Database Sy Rev. 2024;2024(5): CD012214. PMID: 38695827 PMCID: DOI: 10.1002/14651858.CD012214.pub3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Mitsuhashi A, Habu Y, Kobayashi T, et al. Long-term outcomes of progestin plus metformin as a fertility-sparing treatment for atypical endometrial hyperplasia and endometrial cancer patients. J Gynecol Oncol. 2019;30(6):e90. PMID: 31576686 PMCID: DOI: 10.3802/jgo.2019.30.e90 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Bu Y, Peng M, Tang X, et al. Protective effects of metformin in various cardiovascular diseases: Clinical evidence and AMPK - dependent mechanisms. Journal of Cellular and Molecular Medicine. 2022;26(19):4886-903. PMID: 36052760 PMCID: DOI: 10.1111/jcmm.17519 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Smith GL, Masoudi FA, Vaccarino V, Radford MJ, Krumholz HM. Outcomes in heart failure patients with preserved ejection fraction. 2003;41(9):1510-8. PMID: 12742291 DOI: 10.1016/s0735-1097(03)00185-2 [DOI] [PubMed] [Google Scholar]
- 33.Lupón J, Bayes-Genis A. Left ventricular ejection fraction in heart failure. Eur Cardiol. 2018;13(2):91-2. PMID: 30697350 PMCID: DOI: 10.15420/ecr.2018.13.2.GE1 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Xiao J, Wu H, Gao Z, Wei H, Huang W. Association of left ventricular ejection fraction with risk of cardiovascular diseases: A prospective cohort study. Sci Rep. 2024;14(1):25233. PMID: 39448744 PMCID: DOI: 10.1038/s41598-024-76462-2 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Lee TH, Hamilton MA, Stevenson LW, et al. Impact of left ventricular cavity size on survival in advanced heart failure. Am J Cardiol. 1993;72(9):672-6. PMID: 8249843 DOI: 10.1016/0002-9149(93)90883-e [DOI] [PubMed] [Google Scholar]
- 36.Ohno M, Segawa T, Noda T, Yasuda Y, Yamamoto J. Retrospective comparison of left ventricular systolic dysfunction assessed by left ventricular global longitudinal strain in hemodialysis patients with preserved left ventricular ejection fraction and patients with hypertensive left ventricular hypertrophy. BMC Nephrol. 2025;26(1):425. PMID: 40745596 PMCID: DOI: 10.1186/s12882-025-04368-w [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Veldman BAJ, Wijn AM, Knoers N, Praamstra P, Horstink MWIM. Genetic and environmental risk factors in Parkinson’s disease. Clin Neurol Neurosurg. 1998;100(1):15-26. PMID: 9637199 DOI: 10.1016/s0303-8467(98)00009-2 [DOI] [PubMed] [Google Scholar]
- 38.Ball N, Teo WP, Chandra S, Chapman J. Parkinson’s Disease and the environment. Front Neurol. 2019;10(218). PMID: 30941085 PMCID: DOI: 10.3389/fneur.2019.00218 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39.Tahmi M, Luchsinger JA. Metformin in the prevention of Alzheimer’s disease and Alzheimer’s disease related dementias. J Prev Alzheimers Dis. 2023;10(4):706-17. PMID: 37874091 DOI: 10.14283/jpad.2023.113 [DOI] [PubMed] [Google Scholar]
- 40.Chen S, Gan D, Lin S, et al. Metformin in aging and aging-related diseases: Clinical applications and relevant mechanisms. Theranostics. 2022;12(6):2722-40. PMID: 35401820 PMCID: DOI: 10.7150/thno.71360 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 41.Wang L, Hu Z, Chen H, Zhou C, Hu X. Prevalence of mild cognitive impairment and its association with malnutrition in older Chinese adults in the community. Front Public Health. 2024;12:1407694. PMID: 39206002 PMCID: DOI: 10.3389/fpubh.2024.1407694 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 42.Laurie-Anne Boivin-Proulx, Brouillette J, Dorais M, Perreault S. Association between cardiovascular diseases and dementia among various age groups: A population-based cohort study in older adults. Sci Rep. 2023;13(1):14881. PMID: 37689801 PMCID: DOI: 10.1038/s41598-023-42071-8 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 43.Fang C, Lv L, Mao S, Dong H, Liu B. Cognition deficits in Parkinson’s disease: Mechanisms and treatment. Parkinson’s Dis. 2020; 2020:2076942. PMID: 32269747 PMCID: DOI: 10.1155/2020/2076942 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 44.Villani S, Ferraro OE, Poloni TE, Guaita A. Dementia and risk factors: Results from a prospective, population-based cohort study. Life (Basel). 2022;12(7):1055. PMID: 35888143 PMCID: DOI: 10.3390/life12071055 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 45.Garcia-Ptacek S, Kramberger MG. Parkinson disease and dementia. J Geriatr Psychiatry Neurol. 2016;29(5):261-70. PMID: 27502301 DOI: 10.1177/0891988716654985 [DOI] [PubMed] [Google Scholar]
- 46.Emre M. Dementia associated with Parkinson’s disease. Lancet Neurol. 2003;2(4):229-37. PMID: 12849211 DOI: 10.1016/s1474-4422(03)00351-x [DOI] [PubMed] [Google Scholar]
- 47.Canet J, Raeder J, Rasmussen LS, et al. ; ISPOCD2 investigators. Cognitive dysfunction after minor surgery in the elderly. Acta Anaesthesiol Scand. 2003;47(10):1204-10. PMID: 14616316 DOI: 10.1046/j.1399-6576.2003.00238.x [DOI] [PubMed] [Google Scholar]
- 48.Armstrong R. Risk factors for Alzheimer’s Disease. Folia Neuropathol. 2019;57(2):87-105. PMID: 31556570 DOI: 10.5114/fn.2019.85929 [DOI] [PubMed] [Google Scholar]
- 49.Gorelick PB. Role of inflammation in cognitive impairment: Results of observational epidemiological studies and clinical trials. Ann N Y Acad Sci. 2010;1207(1):155-62. PMID: 20955439 DOI: 10.1111/j.1749-6632.2010.05726.x [DOI] [PubMed] [Google Scholar]
- 50.Bamford A, Henderson EJ. Parkinson’s disease in older people. Medicine. 2021;49(1):56-61. DOI: 10.1016/j.mpmed.2020.10.008 [DOI] [Google Scholar]
- 51.Connor J. Diagnosis and management of dementia in older people. Medicine. 2020;49(1):22-5. DOI: 10.1016/j.mpmed.2020.10.005 [DOI] [Google Scholar]
- 52.Ruan X, Li H, Wang Z, et al. The influencing factors of cognitive impairment in elderly individuals in Chengdu city: A cross-sectional study based on AD8. BMC Geriatr. 2025;25(1):19. PMID: 39789427 PMCID: DOI: 10.1186/s12877-024-05661-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 53.Alšauskė SV, Grabauskytė I, Liseckienė I, Macijauskienė J. Assessment of cognitive functions in multimorbid patients in Lithuanian primary care settings: A cross-sectional study using MMSE and LT-GPCOG. Medicina (Kaunas). 2025;61(1):122. PMID: 39859104 PMCID: DOI: 10.3390/medicina61010122 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 54.Ordoobadi AJ, Dhanani H, Tulebaev SR, Salim A, Cooper Z, Jarman MP. Risk of dementia diagnosis after injurious falls in older adults. JAMA Netw Open. 2024;7(9):e2436606. PMID: 39348117 PMCID: DOI: 10.1001/jamanetworkopen.2024.36606 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 55.Negru DC, Tit DM, Negru PA, Bungau G, Marin RC. Predictors of cognitive decline in Alzheimer’s disease: A longitudinal Bayesian analysis. Medicina (Kaunas). 2025;61(5):877. PMID: 40428835 PMCID: DOI: 10.3390/medicina61050877 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 56.Friedman TW, Yelland GW, Robinson SR. Subtle cognitive impairment in elders with Mini-Mental State Examination scores within the “normal” range. Int J Geriatr Psychiatry. 2011;27(5):463-71. PMID: 21626569 DOI: 10.1002/gps.2736 [DOI] [PubMed] [Google Scholar]
- 57.Riedel-Heller SG, Busse A, Aurich C, Matschinger H, Angermeyer MC. Prevalence of dementia according to DSM–III–R and ICD–10. Br J Psychiatry. 2001;179(3):250-4. PMID: 11532803 DOI: 10.1192/bjp.179.3.250 [DOI] [PubMed] [Google Scholar]
- 58.Du XL, Song L. A large retrospective cohort study on the risk of Alzheimer’s disease and related dementias in association with vascular diseases and cancer therapy in men with prostate cancer. J Prev Alzheimers Dis. 2023;10(2):193-206. PMID: 36946446 PMCID: DOI: 10.14283/jpad.2023.8 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 59.Hsiao FY, Peng LN, Wen YW, Liang CK, Wang PN, Chen LK. Care needs and clinical outcomes of older people with dementia: A population-based propensity score-matched cohort study. PLoS One. 2015;10(5):e0124973. PMID: 25955163 PMCID: DOI: 10.1371/journal.pone.0124973 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 60.Li Y, Liu L, Wang B, Wang J, Chen D. Metformin in non-alcoholic fatty liver disease: A systematic review and meta-analysis. Biomed Rep. 2012;1(1):57-64. PMID: 24648894 PMCID: DOI: 10.3892/br.2012.18 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 61.Mazza AD, Fruci B, Garinis GA, Giuliano S, Malaguarnera R, Belfiore A. The role of metformin in the management of NAFLD. Exp Diabetes Res. 2012;2012:1-13. PMID: 22194737 PMCID: DOI: 10.1155/2012/716404 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 62.Huang Y, Wang X, Yan C, et al. Effect of metformin on nonalcoholic fatty liver based on meta-analysis and network pharmacology. Medicine (Baltimore). 2022;101(43):e31437. PMID: 36316840 PMCID: DOI: 10.1097/MD.0000000000031437 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 63.Brackett CC. Clarifying metformin’s role and risks in liver dysfunction. J Am Pharm Assoc (2003). 2010;50(3):407-10. PMID: 20452916 DOI: 10.1331/JAPhA.2010.08090 [DOI] [PubMed] [Google Scholar]
- 64.Pinyopornpanish K, Leerapun A, Pinyopornpanish K, Chattipakorn N. Effects of metformin on hepatic steatosis in adults with nonalcoholic fatty liver disease and diabetes: Insights from the cellular to patient levels. Gut Liver. 2021;15(6):827-40. PMID: 33820884 PMCID: DOI: 10.5009/gnl20367 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 65.Federica Perazza, Leoni L, Colosimo S, et al. Metformin and the liver: Unlocking the full therapeutic potential. Metabolites. 2024;14(4):186. PMID: 38668314 PMCID: DOI: 10.3390/metabo14040186 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 66.Idilman R, Mizrak D, Corapcioglu D, et al. Clinical trial: Insulin-sensitizing agents may reduce consequences of insulin resistance in individuals with non-alcoholic steatohepatitis. Aliment Pharmacol Ther. 2008;28(2):200-8. PMID: 18445142 DOI: 10.1111/j.1365-2036.2008.03723.x [DOI] [PubMed] [Google Scholar]
- 67.Ramanathan R, Ali AH, Ibdah JA. Mitochondrial dysfunction plays central role in nonalcoholic fatty liver disease. Int J Mol Sci. 2022;23(13):7280. PMID: 35806284 PMCID: DOI: 10.3390/ijms23137280 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 68.Nar A, Gedik O. The effect of metformin on leptin in obese patients with type 2 diabetes mellitus and nonalcoholic fatty liver disease. Acta Diabetol. 2008;46(2):113-8. PMID: 18839053 DOI: 10.1007/s00592-008-0067-2 [DOI] [PubMed] [Google Scholar]
- 69.Lee BW, Lee Y, Park CY, et al. Non-alcoholic fatty liver disease in patients with type 2 diabetes mellitus: A position statement of the fatty liver research group of the Korean Diabetes Association. Diabetes Metab J. 2020;44(3):382-401. PMID: 32431115 PMCID: DOI: 10.4093/dmj.2020.0010 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 70.Woo SL, Xu H, Li H, et al. Metformin ameliorates hepatic steatosis and inflammation without altering adipose phenotype in diet-induced obesity. PLoS One. 2014;9(3):e91111. PMID: 24638078 PMCID: DOI: 10.1371/journal.pone.0091111 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 71.García-Compeán D, Orsi E, Kumar R, et al. Clinical implications of diabetes in chronic liver disease: Diagnosis, outcomes and management, current and future perspectives. World J Gastroenterol. 2022;28(8):775-93. PMID: 35317103 PMCID: DOI: 10.3748/wjg.v28.i8.775 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 72.Hesen NA, Riksen NP, Aalders B, et al. A systematic review and meta-analysis of the protective effects of metformin in experimental myocardial infarction. 2017;12(8):e0183664. PMID: 28832637 PMCID: DOI: 10.1371/journal.pone.0183664 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 73.Mariam Ahmed Galal, Al-Rimawi M, Abdurrahman Hajeer, Dahman H, Samhar Alouch, Aljada A. MetformIn: A dual-role player in cancer treatment and prevention. Int J Mol Sci. 2024;25(7):4083. PMID: 38612893 PMCID: DOI: 10.3390/ijms25074083 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 74.Barnwal N, Dubey S, Tiwari P. Targeting metabolic dysregulation in Alzheimer’s disease: A potential therapeutic strategy. Curr Drug Metab. 2025. PMID: 40990282 DOI: 10.2174/0113892002408089250912080734 [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.






