What medications can be prescribed to adults to prevent type 2 diabetes?

The U.S. Food and Drug Administration has not approved any drugs for diabetes prevention.

Metformin has the strongest evidence base for diabetes prevention.

Who should be considered for metformin therapy to prevent type 2 diabetes?

Adults aged 25–59 years with a BMI ≥35 kg/m2  Those with higher A1C (e.g., ≥6.0% [≥42 mmol/mol]) 
Individuals with higher FPG (e.g., ≥110 mg/dL [≥6 mmol/L])  Individuals with a history of GDM 
Adults aged 25–59 years with a BMI ≥35 kg/m2  Those with higher A1C (e.g., ≥6.0% [≥42 mmol/mol]) 
Individuals with higher FPG (e.g., ≥110 mg/dL [≥6 mmol/L])  Individuals with a history of GDM 
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What parameters should be monitored in people on metformin therapy?

Vitamin B12 should be measured periodically, especially in those with anemia or peripheral neuropathy.

Does statin therapy increase the risk of developing type 2 diabetes?

  • Statin therapy may elevate type 2 diabetes risk in high-risk individuals.

  • In primary and secondary prevention of cardiovascular disease, statin benefits outweigh diabetes risk.

  • Discontinuing statins based on concerns about increased diabetes risk is not advised.

Does pioglitazone have a role in secondary cardiovascular prevention in people at risk for type 2 diabetes?

Pioglitazone could reduce stroke and myocardial infarction risks in people with a history of stroke and evidence of insulin resistance or prediabetes. However, the benefit must be weighed against potential weight gain, edema, and increased fracture risk. Lower doses may lessen these adverse effects.

Stage 1Stage 2Stage 3
Characteristics 

  • Autoimmunity

  • Normoglycemia

  • Presymptomatic

 

  • Autoimmunity

  • Dysglycemia

  • Presymptomatic

 

  • Autoimmunity

  • Overt hyperglycemia

  • Symptomatic

 
Diagnostic criteria 

  • Multiple islet autoantibodies

  • No IGT or IFG, normal A1C

 

  • Islet autoantibodies (usually multiple)

  • Dysglycemia:

    • ⁃ IFG: FPG 100–125 mg/dL (5.6–6.9 mmol/L) or

    • ⁃ IGT: 2-h PG 140–199 mg/dL (7.8–11.0 mmol/L) or

    • ⁃ A1C 5.7–6.4% (39–47 mmol/mol) or ≥10% increase in A1C

 

  • Autoantibodies may become absent

  • Diabetes by standard criteria

 
Stage 1Stage 2Stage 3
Characteristics 

  • Autoimmunity

  • Normoglycemia

  • Presymptomatic

 

  • Autoimmunity

  • Dysglycemia

  • Presymptomatic

 

  • Autoimmunity

  • Overt hyperglycemia

  • Symptomatic

 
Diagnostic criteria 

  • Multiple islet autoantibodies

  • No IGT or IFG, normal A1C

 

  • Islet autoantibodies (usually multiple)

  • Dysglycemia:

    • ⁃ IFG: FPG 100–125 mg/dL (5.6–6.9 mmol/L) or

    • ⁃ IGT: 2-h PG 140–199 mg/dL (7.8–11.0 mmol/L) or

    • ⁃ A1C 5.7–6.4% (39–47 mmol/mol) or ≥10% increase in A1C

 

  • Autoantibodies may become absent

  • Diabetes by standard criteria

 

Adapted from Skyler JS, Bakris GL, Bonifacio E, et al. Differentiation of diabetes by pathophysiology, natural history, and prognosis. Diabetes 2017;66:241–255. IFG, impaired fasting glucose; IGT, impaired glucose tolerance; 2-h PG, 2-h plasma glucose. Alternative additional stage 2 diagnostic criteria of 30-, 60-, or 90-min plasma glucose on oral glucose tolerance test ≥200 mg/dL (≥11.1 mmol/L) and confirmatory testing in those aged ≥18 years have been used in clinical trials (Herold KC, Bundy BN, Long SA, et al.; Type 1 Diabetes TrialNet Study Group. An anti-CD3 antibody, teplizumab, in relatives at risk for type 1 diabetes. N Engl JMed 2019;381:603–613).

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© 2025 by the American Diabetes Association
2025
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