What are the steps for diagnosing and managing diabetes?

Diagnosis and Management of Diabetes

Diabetes should be diagnosed using specific glycemic criteria and managed through a structured approach including risk assessment, lifestyle modifications, and appropriate pharmacologic therapy based on diabetes type and individual factors. 1

Diagnostic Criteria for Diabetes

• Diabetes can be diagnosed using any of the following criteria (with confirmation by repeat testing on a subsequent day unless symptoms are present with random glucose ≥200 mg/dL): 1

  • Fasting plasma glucose (FPG) ≥126 mg/dL (after no caloric intake for at least 8 hours)
  • 2-hour plasma glucose ≥200 mg/dL during an oral glucose tolerance test (OGTT)
  • Hemoglobin A1c (HbA1c) ≥6.5%
  • Random plasma glucose ≥200 mg/dL in a patient with classic symptoms of hyperglycemia

• Prediabetes is diagnosed when: 1

  • FPG is 100-125 mg/dL (impaired fasting glucose)
  • 2-hour plasma glucose during OGTT is 140-199 mg/dL (impaired glucose tolerance)
  • HbA1c is 5.7-6.4%

Screening Recommendations

• Begin screening at age 35 for all people, regardless of risk factors 1

• Screen earlier in individuals with risk factors: 1, 2

  • Overweight or obesity
  • First-degree relative with diabetes
  • High-risk race/ethnicity (African American, Latino, Native American, Asian American, Pacific Islander)
  • History of gestational diabetes
  • History of cardiovascular disease
  • Hypertension
  • HDL cholesterol <35 mg/dL and/or triglycerides >250 mg/dL
  • Physical inactivity
  • Conditions associated with insulin resistance (e.g., polycystic ovary syndrome)

• For those at higher risk, consider using the ADA risk test to determine screening frequency 1

• Women with history of gestational diabetes should be screened every 3 years 1

Management of Type 1 Diabetes

• Most patients with type 1 diabetes should be treated with multiple-dose insulin injections (≥3 injections per day) or continuous subcutaneous insulin infusion 1
• Insulin analogs are preferred to reduce hypoglycemia risk 1
• Education on matching prandial insulin doses to carbohydrate intake, preprandial blood glucose levels, and anticipated activity level is essential 1
• Continuous glucose monitoring systems can significantly reduce severe hypoglycemia risk 1

Management of Type 2 Diabetes

Initial Approach

• Begin with lifestyle modifications for all patients, including: 1
  • Medical nutrition therapy (preferably by a registered dietitian)
  • Physical activity (at least 150 minutes of moderate-intensity aerobic activity weekly plus resistance training twice weekly)
  • Weight loss of at least 5% for overweight/obese patients
  • Diabetes self-management education and support

Pharmacologic Therapy

• If lifestyle efforts are insufficient to achieve glycemic goals, initiate metformin as first-line therapy (if not contraindicated) 1

• When monotherapy at maximum tolerated dose does not achieve HbA1c target over 3 months, add a second agent based on patient factors and comorbidities 1

• Consider combination of metformin with one of these options: 1

  • Sulfonylureas
  • Thiazolidinediones
  • Dipeptidyl peptidase-4 inhibitors
  • Sodium-glucose cotransporter 2 (SGLT2) inhibitors
  • Glucagon-like peptide-1 (GLP-1) receptor agonists
  • Basal insulin

• For patients with severe hyperglycemia (HbA1c ≥9%), consider starting with dual therapy 1

• For very severe hyperglycemia (blood glucose ≥300-350 mg/dL or HbA1c ≥10-12%) with symptoms, initiate insulin therapy immediately 1

Glycemic Targets and Monitoring

• Target HbA1c <7% for most nonpregnant adults 1
• Consider more stringent targets (HbA1c <6.5%) for selected patients with short disease duration, type 2 diabetes treated with lifestyle or metformin only, long life expectancy, or no cardiovascular disease 1
• Consider less stringent targets (HbA1c <8%) for patients with history of severe hypoglycemia, limited life expectancy, advanced complications, or extensive comorbidities 1
• Monitor HbA1c at least twice yearly in patients meeting treatment goals with stable glycemic control 1
• Monitor HbA1c quarterly in patients whose therapy has changed or who are not meeting glycemic goals 1

Self-Monitoring of Blood Glucose (SMBG)

• For patients on intensive insulin regimens (multiple daily injections or insulin pump): 1

  • Monitor before meals and snacks
  • Occasionally monitor postprandially
  • Monitor at bedtime
  • Monitor before exercise
  • Monitor when suspecting low blood glucose
  • Monitor before critical tasks like driving

• For patients not on intensive insulin regimens, SMBG frequency should be dictated by specific needs and goals 1

Prevention of Complications

• Regular screening for complications is essential: 1

  • Cardiovascular risk assessment annually
  • Retinopathy screening
  • Nephropathy screening (urine albumin-to-creatinine ratio)
  • Neuropathy screening
  • Foot examination

• Aggressive management of cardiovascular risk factors: 1

  • Blood pressure control
  • Lipid management
  • Antiplatelet therapy when indicated

Common Pitfalls to Avoid

• Delaying insulin therapy in patients not achieving glycemic goals 1
• Failing to adjust insulin doses based on SMBG results 1
• Not addressing hypoglycemia unawareness by temporarily raising glycemic targets 1
• Continuing with ineffective regimens despite poor control 3
• Not reducing basal insulin when adding prandial insulin 3
• Using sliding-scale insulin as the sole regimen in hospitalized patients 1
• Neglecting to screen for and address comorbidities and complications 1