Cited by 70Diabetes Treatment and ManagementMetabolism, Diabetes, and CancerDiabetes, Cardiovascular Risks, and Lipoproteins

Metformin for prevention or delay of type 2 diabetes mellitus and its associated complications in persons at increased risk for the development of type 2 diabetes mellitus

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Madsen, Kasper S, Chi, Yuan, Metzendorf, Maria-Inti, Richter, Bernd, Hemmingsen, Bianca·2019·Cochrane Database of Systematic Reviews

Abstract

BACKGROUND: The projected rise in the incidence of type 2 diabetes mellitus (T2DM) could develop into a substantial health problem worldwide. Whether metformin can prevent or delay T2DM and its complications in people with increased risk of developing T2DM is unknown. OBJECTIVES: To assess the effects of metformin for the prevention or delay of T2DM and its associated complications in persons at increased risk for the T2DM. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Scopus, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform and the reference lists of systematic reviews, articles and health technology assessment reports. We asked investigators of the included trials for information about additional trials. The date of the last search of all databases was March 2019. SELECTION CRITERIA: We included randomised controlled trials (RCTs) with a duration of one year or more comparing metformin with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or standard care in people with impaired glucose tolerance, impaired fasting glucose, moderately elevated glycosylated haemoglobin A1c (HbA1c) or combinations of these. DATA COLLECTION AND ANALYSIS: Two review authors read all abstracts and full-text articles and records, assessed risk of bias and extracted outcome data independently. We used a random-effects model to perform meta-analysis and calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the certainty of the evidence using GRADE. MAIN RESULTS: We included 20 RCTs randomising 6774 participants. One trial contributed 48% of all participants. The duration of intervention in the trials varied from one to five years. We judged none of the trials to be at low risk of bias in all 'Risk of bias' domains. Our main outcome measures were all-cause mortality, incidence of T2DM, serious adverse events (SAEs), cardiovascular mortality, non-fatal myocardial infarction or stroke, health-related quality of life and socioeconomic effects.The following comparisons mostly reported only a fraction of our main outcome set. Fifteen RCTs compared metformin with diet and exercise with or without placebo: all-cause mortality was 7/1353 versus 7/1480 (RR 1.11, 95% CI 0.41 to 3.01; P = 0.83; 2833 participants, 5 trials; very low-quality evidence); incidence of T2DM was 324/1751 versus 529/1881 participants (RR 0.50, 95% CI 0.38 to 0.65; P < 0.001; 3632 participants, 12 trials; moderate-quality evidence); the reporting of SAEs was insufficient and diverse and meta-analysis could not be performed (reported numbers were 4/118 versus 2/191; 309 participants; 4 trials; very low-quality evidence); cardiovascular mortality was 1/1073 versus 4/1082 (2416 participants; 2 trials; very low-quality evidence). One trial reported no clear difference in health-related quality of life after 3.2 years of follow-up (very low-quality evidence). Two trials estimated the direct medical costs (DMC) per participant for metformin varying from $220 to $1177 versus $61 to $184 in the comparator group (2416 participants; 2 trials; low-quality evidence). Eight RCTs compared metformin with intensive diet and exercise: all-cause mortality was 7/1278 versus 4/1272 (RR 1.61, 95% CI 0.50 to 5.23; P = 0.43; 2550 participants, 4 trials; very low-quality evidence); incidence of T2DM was 304/1455 versus 251/1505 (RR 0.80, 95% CI 0.47 to 1.37; P = 0.42; 2960 participants, 7 trials; moderate-quality evidence); the reporting of SAEs was sparse and meta-analysis could not be performed (one trial reported 1/44 in the metformin group versus 0/36 in the intensive exercise and diet group with SAEs). One trial reported that 1/1073 participants in the metformin group compared with 2/1079 participants in the comparator group died from cardiovascular causes. One trial reported that no participant died due to cardiovascular causes (very low-quality evidence). Two trials estimated the DMC per participant for metformin varying from $220 to $1177 versus $225 to $3628 in the comparator group (2400 participants; 2 trials; very low-quality evidence). Three RCTs compared metformin with acarbose: all-cause mortality was 1/44 versus 0/45 (89 participants; 1 trial; very low-quality evidence); incidence of T2DM was 12/147 versus 7/148 (RR 1.72, 95% CI 0.72 to 4.14; P = 0.22; 295 participants; 3 trials; low-quality evidence); SAEs were 1/51 versus 2/50 (101 participants; 1 trial; very low-quality evidence). Three RCTs compared metformin with thiazolidinediones: incidence of T2DM was 9/161 versus 9/159 (RR 0.99, 95% CI 0.41 to 2.40; P = 0.98; 320 participants; 3 trials; low-quality evidence). SAEs were 3/45 versus 0/41 (86 participants; 1 trial; very low-quality evidence). Three RCTs compared metformin plus intensive diet and exercise with id

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Crossref · 10.1002/14651858.cd008558.pub2

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Authors
Madsen, K. S., Chi, Y., Metzendorf, M.-I., Richter, B., & Hemmingsen, B.
Affiliations
  • University of Copenhagen (DK)
  • University of Zurich (CH)
  • Heinrich Heine University Düsseldorf (DE)
Venue
Cochrane Database of Systematic Reviews
Publisher
Wiley
Published
2019-12-03
Volume
2019
Issue
12
ISSN
  • 1361-6137 (ISSN-L)
  • 1465-1858
OpenAlex
W4211086992
Cited by
70
References
190
Citations by year
2026: 6 · 2025: 10 · 2024: 15 · 2023: 8 · 2022: 7 · 2021: 15 · 2020: 9
FWCI
1.19
Type
journal article
Language
en
Open access
Licence
other-oa
Locations
  • Cochrane Database of Systematic Reviews (publishedVersion)
  • Zurich Open Repository and Archive (University of Zurich) (acceptedVersion, other-oa)
  • Zurich Open Repository and Archive (University of Zurich)
Funders
Universitätsklinikum Jena
Topics
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes Treatment and Management
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes, Cardiovascular Risks, and Lipoproteins
Keywords
metformin, type 2 diabetes, diabetes prevention, impaired glucose tolerance, impaired fasting glucose, HbA1c, diabetes complications, all-cause mortality, cardiovascular mortality, serious adverse events, health-related quality of life, socio-economic impacts, diet and exercise, risk of bias, quality of evidence, risk of bias assessment

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