What are the modalities of management of diabetes mellitus?

Management of Diabetes Mellitus

All patients with diabetes must begin with comprehensive lifestyle modifications and diabetes self-management education, followed by metformin as first-line pharmacologic therapy for type 2 diabetes or multiple-dose insulin for type 1 diabetes. 1, 2

Foundation: Universal Starting Point for All Patients

Every patient with diabetes requires these core interventions before or concurrent with pharmacologic therapy:

• Diabetes self-management education and support reduces A1C, mortality risk, and healthcare costs 1, 2
• Medical nutrition therapy delivered by a registered dietitian reduces A1C by 0.3-2% in type 2 diabetes and 1.0-1.9% in type 1 diabetes 1, 2
• Physical activity prescription: exactly 150 minutes of moderate-intensity aerobic activity weekly plus resistance training at least twice per week 3, 1, 2
• Weight loss of at least 5% for overweight/obese patients with type 2 diabetes through lifestyle modifications 3, 1, 2

Type 1 Diabetes: Insulin-Based Management

Start multiple-dose insulin injections (≥3 injections daily) or continuous subcutaneous insulin infusion immediately at diagnosis:

• Use insulin analogues (not regular insulin) to reduce hypoglycemia risk 3, 1, 2
• Match prandial insulin doses to carbohydrate intake, preprandial glucose levels, and anticipated activity 3, 2
• Implement continuous glucose monitoring to significantly reduce severe hypoglycemia risk 3, 1
• Insulin pump therapy with low glucose "suspend" feature reduces nocturnal hypoglycemia without increasing A1C 3

Type 2 Diabetes: Stepwise Pharmacologic Algorithm

Step 1: Initial Therapy at Diagnosis

Start metformin 500 mg twice daily with meals at or soon after diagnosis, increasing to 1000 mg twice daily over 2-4 weeks:

• Metformin is the mandatory first-line agent due to efficacy, safety, low cost, and cardiovascular mortality reduction 3, 1, 2
• Continue metformin even with declining renal function down to GFR 30-45 mL/min (reduce dose) 3
• Metformin rarely causes hypoglycemia alone but can when combined with inadequate food intake or alcohol 4

Critical exception: If the patient has established atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease, add an SGLT2 inhibitor or GLP-1 receptor agonist with proven cardiovascular benefit at diagnosis alongside metformin 3, 1

Step 2: Combination Therapy (If HbA1c Target Not Achieved in 3 Months)

Add a second agent immediately when monotherapy fails:

Choose from these six options based on patient-specific factors 3:

• Sulfonylureas: Low cost but hypoglycemia risk
• Thiazolidinediones: Avoid in heart failure
• DPP-4 inhibitors: Weight neutral, low hypoglycemia risk
• SGLT2 inhibitors: Cardiovascular and renal benefits, genitourinary infections
• GLP-1 receptor agonists: Weight loss, cardiovascular benefits, gastrointestinal side effects
• Basal insulin: Most effective for glucose lowering, requires injection

For HbA1c ≥9% at diagnosis: Start dual-regimen combination therapy immediately to achieve glycemic control faster 3

Step 3: Intensification (If Dual Therapy Insufficient)

Add a third agent or transition to basal insulin plus mealtime insulin:

• For blood glucose ≥300-350 mg/dL or HbA1c ≥10-12% with symptoms: start basal insulin plus mealtime insulin immediately 3
• GLP-1 receptor agonists are the preferred first injectable medication before insulin 3

Glycemic Targets and Monitoring

Target HbA1c <7% for most patients to reduce microvascular complications 2:

• Check HbA1c every 3 months until target achieved, then every 6 months 2
• Do not aggressively pursue near-normal HbA1c in patients with advanced disease, limited life expectancy, or hypoglycemia unawareness as this increases mortality 3, 2
• Severe or frequent hypoglycemia is an absolute indication to modify treatment regimens immediately 3, 1, 2

Hypoglycemia Management Protocol

Treat glucose <70 mg/dL with 15-20 grams of rapid-acting glucose (preferably pure glucose):

• Confirm reversal with blood glucose measurement after 15 minutes; repeat if hypoglycemia persists 2
• Prescribe glucagon to all patients at risk for severe hypoglycemia and train close contacts on administration 2
• Patients with hypoglycemia unawareness must increase glycemic targets for several weeks 1

Cardiovascular Risk Management (Mandatory for All Patients)

These interventions reduce mortality and must not be delayed:

• Blood pressure target <140/90 mmHg using ACE inhibitor or ARB as first-line therapy 2
• Initiate at least moderate-intensity statin for most patients aged ≥40 years 2
• Annual comprehensive dilated eye examination by ophthalmologist or optometrist starting at diagnosis 2

Critical Pitfalls to Avoid

• Never delay cardiovascular risk factor management while focusing solely on glycemic control—diabetes itself confers high cardiovascular risk 2
• Never aggressively lower blood pressure below 130/70 mmHg in older adults due to increased mortality risk 2
• Never continue aggressive glycemic targets in patients experiencing severe or frequent hypoglycemia 3, 1, 2
• Never mix or dilute insulin detemir (Levemir) with other insulin preparations as this alters the action profile 5
• Reassess medication regimens every 3-6 months and adjust based on A1C, side effects, and patient factors 1