Diabetes Mellitus, Type 2



Diabetes mellitus (DM) type 2 is due to a progressive insulin secretory defect in the setting of insulin resistance.

Geriatric Considerations
Monitor for hypoglycemia; adjust doses for renal/hepatic dysfunction and cognitive function; less aggressive glucose targets than younger patients

Pediatric Considerations
Incidence is increasing and parallels obesity epidemic.

Pregnancy Considerations

  • Diet, metformin, glyburide, and insulin are all options for treatment of gestational diabetes.
  • In gestational diabetes, screen for diabetes/prediabetes with oral glucose tolerance test (OGTT) 6 to 12 weeks postpartum and every 3 years.


1.5 million new cases in the United States each year

Estimated 37.3 million Americans (11.3% of the population); 90–95% are likely type 2.

Etiology and Pathophysiology

  • Peripheral insulin resistance and defective insulin secretion with increased hepatic gluconeogenesis
  • Obesity and visceral adiposity
  • Associated with dyslipidemia, hypertension, and gut microbiome changes
  • Drug or chemical induced (e.g., glucocorticoids, antiretroviral therapy, atypical antipsychotics, organ transplant immunosuppressants)


  • Family history is strongly predictive of risk.
  • Polygenic; rarely monogenic (e.g., peroxisome proliferator–activated receptor [PPAR] γ and insulin gene mutations)

Risk Factors

  • Parental history of type 2 diabetes
  • Gestational diabetes or history of baby with birth weight ≥4 kg (9 lb)
  • Polycystic ovarian syndrome (PCOS)
  • Hypertriglyceridemia or low high-density lipoprotein (HDL)
  • Ethnicity: African American, Latino, Native American, Asian, and Pacific Islander
  • Sedentary lifestyle, visceral obesity

General Prevention

  • Maintenance of normal weight, or weight loss of 7% body weight, decrease intake of carbohydrates and overall calories; moderate-intensity exercise (150 min/week).
  • Metformin, α-glucosidase inhibitors, thiazolidinediones (TZDs), and glucagon-like peptide-1 receptor agonist (GLP-1 RA) in prediabetes

Commonly Associated Conditions

Hypertension, dyslipidemia, metabolic syndrome, fatty liver disease, PCOS, acanthosis nigricans, hemochromatosis

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