History and exam

Key diagnostic factors

It is very common for type 2 diabetes to be asymptomatic and detected on screening. Symptoms, when present, may indicate more overt hyperglycemia.

Usually in patients with fasting plasma glucose >300 mg/dL, HbA1c >11%.

Usually in patients with fasting plasma glucose >300 mg/dL, HbA1c >11%.

If marked hyperglycemia is present.

Usually in patients with fasting plasma glucose >300 mg/dL, HbA1c >11%.

Diabetic ketoacidosis and hyperosmolar hyperglycemic state may be the initial presentation of type 2 diabetes, particularly if there is an underlying infection.[3][46][47] Patients are symptomatic of hyperglycemia (polyuria, polydipsia, weakness) and significant volume depletion (dry mucous membranes, poor skin turgor, tachycardia, hypotension, and, in severe cases, shock). This is a life-threatening emergency and requires early diagnosis and management.[48] 

Other diagnostic factors

Increased fatigability may be an early warning sign of progressive cardiovascular disease; clinicians should have a low threshold for cardiac evaluation.

Due to elevated glucose.

Due to glucose-induced diuresis.

Most commonly vaginal, penile, or in skin folds.

Cellulitis or abscesses.

Cystitis or pyelonephritis.

May occur in the extremities as a result of neuropathy in those with prolonged undiagnosed diabetes.

A velvety, light brown-to-black marking, usually on the neck, under the arms, or in the groin. Can occur at any age. Most often associated with obesity. com.bmj.content.model.Caption@5c43d9fb[Figure caption and citation for the preceding image starts]: Acanthosis nigricans involving the axillaFrom the collection of Melvin Chiu, MD; used with permission [Citation ends].

Risk factors

Older patients are at increased risk, with the incidence of type 2 diabetes peaking between 70 and 79 years.[18] However, the incidence of type 2 diabetes in children and adolescents is increasing.[19] The American Diabetes Association recommends, in the absence of other risk factors, that screening should begin at age 45 years.[2]

Appears to be the precipitating factor leading to clinical expression of diabetes. The mean body mass index (BMI) at the time of diagnosis of diabetes in several studies is around 31 kg/m², and there is a graded increase in risk of diabetes with increasing BMI.[20] Clinical trials have shown that weight loss is associated with delayed or decreased onset of diabetes in high-risk adults.[21][22][23][24][25][26] Screening should be considered if the BMI is greater than or equal to 25 kg/m² (greater than or equal to 23 kg/m² for Asian-Americans).[2]

About 50% of women who have gestational diabetes mellitus will go on to develop overt diabetes mellitus within 10 years of delivery.[27] Women with gestational diabetes have a nearly 10-fold higher risk of developing type 2 diabetes than those with a normoglycemic pregnancy.[28] Screening for diabetes at least every 3 years is recommended in women with a history of gestational diabetes.[2]

Is defined by a single fasting plasma glucose of 100-125 mg/dL or a HbA1c of 5.7% to 6.4% in the absence of diabetes and is a major risk factor for onset of type 2 diabetes.[2] Progression from prediabetes to overt type 2 diabetes occurs at the rate of about 2% to 4% per year.[1] Annual screening is recommended for people with prediabetes.[2] 

Although the specific genetic profile that confers risk has yet to be fully elucidated, epidemiological observations leave little doubt of a substantial genetic component.[10]

Relative to white people, National Health and Nutrition Examination Survey (NHANES) and other data demonstrate higher risk of diabetes.[20][29]

While the impact on increased risk of diabetes is mediated in part through obesity/overweight, several interventions studies indicate that increased levels of physical activity delay or decrease onset of diabetes in high-risk adults.[22][23][24][30]

Elevated risk; testing for diabetes should be considered in overweight or obese women (BMI ≥25 kg/m² or ≥23 kg/m² in Asian Americans) with PCOS.[2]

Often associated with type 2 diabetes. Testing for diabetes should be considered in overweight or obese adults BMI (≥25 kg/m² or ≥23 kg/m² in Asian Americans) whose blood pressure is ≥140/90 mmHg or who are on therapy for hypertension.[2]

Especially with low high-density lipoprotein (<35 mg/dL) and/or high triglycerides (>250 mg/dL). Testing should be considered in overweight or obese adults (BMI ≥25 kg/m² or ≥23 kg/m² in Asian Americans) whose HDL cholesterol level is <35 mg/dL and/or who have a triglyceride level >250 mg/dL.[2]

Testing should be considered in overweight or obese adults (BMI ≥25 kg/m² or ≥23 kg/m² in Asian Americans) who have a history of cardiovascular disease.[2]

American College of Cardiology/American Heart Association statements identify a number of additional risk factors for atherosclerotic cardiovascular disease, which include: C-reactive protein ≥2 mg/L; coronary artery calcium score ≥100 Agatston units or ≥75% for age, sex, and ethnicity; and ankle-brachial index <0.9.[31]

Stress provokes release of hormones that elevate glucose, and there is some evidence that life stress may predispose to onset of type 2 diabetes.[32]

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