What is the recommended management for type 2 diabetes mellitus?

Management of Type 2 Diabetes Mellitus

Start metformin immediately at diagnosis for all adults with type 2 diabetes who have an eGFR ≥30 mL/min/1.73 m², and add an SGLT2 inhibitor or GLP-1 receptor agonist if the patient has established cardiovascular disease, heart failure, chronic kidney disease, or is at high cardiovascular risk. 1, 2

Initial Assessment and Glycemic Targets

Set an HbA1c target of <7% for most adults to reduce microvascular complications 3, 1. However, individualize based on these specific criteria:

• Target 6.0-6.5% if: short disease duration (<5 years), long life expectancy (>15 years), no significant cardiovascular disease, and achievable without hypoglycemia 3, 1
• Target 7.5-8.0% (or higher) if: history of severe hypoglycemia, limited life expectancy (<10 years), advanced microvascular or macrovascular complications, extensive comorbidities, or difficulty achieving lower targets despite multiple medications 3, 1

Aim for fasting/premeal glucose <130 mg/dL and postprandial glucose <180 mg/dL 3, 1.

Lifestyle Interventions (Non-Negotiable Foundation)

Physical Activity

• Prescribe ≥150 minutes per week of moderate-intensity aerobic exercise (makes you breathe hard and sweat), spread over at least 3 days with no more than 2 consecutive rest days 1
• Add resistance training at least twice weekly to improve insulin sensitivity 1
• Break up every hour of sitting with 5 minutes of activity 1

Nutrition

• Refer immediately to a registered dietitian for medical nutrition therapy 1
• Emphasize vegetables, fruits, whole grains, legumes, plant-based proteins, unsaturated fats (olive oil, canola oil), and nuts 1, 4
• Limit sodium to <2 g/day 1
• Eliminate sugar-sweetened beverages including fruit juices 1
• For patients with chronic kidney disease (not on dialysis): restrict protein to 0.8 g/kg/day 1

Weight Management

• Target ≥5% weight loss in all overweight/obese patients—this meaningfully improves glycemic control 3, 1
• Achieving >10% weight loss early in disease course markedly increases chance of diabetes remission 1

Pharmacologic Algorithm

Step 1: First-Line Therapy (At Diagnosis)

Start metformin immediately unless eGFR <30 mL/min/1.73 m² or contraindicated 3, 1, 2. Metformin is inexpensive, reduces cardiovascular events and death, and can be continued down to eGFR 30-45 mL/min with dose reduction 3.

Step 2: Add Second Agent Based on Comorbidities

If patient has ANY of the following, add SGLT2 inhibitor immediately (even if HbA1c at goal):

• Established cardiovascular disease
• Heart failure
• Chronic kidney disease (eGFR ≥30 mL/min/1.73 m²)
• High cardiovascular risk 1, 2

SGLT2 inhibitors reduce cardiovascular events by 12-26%, heart failure hospitalizations by 18-25%, and kidney disease progression by 24-39% over 2-5 years 2. This is a strong recommendation based on multiple cardiovascular outcome trials 1.

If SGLT2 inhibitor cannot be used or additional glucose lowering needed, add a long-acting GLP-1 receptor agonist:

• High-potency GLP-1 RAs produce ≥5% weight loss in most patients, often exceeding 10% 1, 2
• GLP-1 RAs reduce cardiovascular events by 12-26% 2
• Do not use in patients with family history of medullary thyroid cancer 3

For enhanced weight loss (10-15% or more), consider dual GIP/GLP-1 receptor agonists (e.g., tirzepatide) 1, 5.

Step 3: If HbA1c Still Not at Goal After 3 Months

Add a third agent from different class:

• Sulfonylureas (risk: hypoglycemia, weight gain) 3
• Thiazolidinediones (risk: fluid retention, heart failure exacerbation) 3
• DPP-4 inhibitors (weight neutral, low hypoglycemia risk) 3

If HbA1c ≥9% at diagnosis, start dual therapy immediately (metformin + second agent) 3.

If HbA1c ≥10-12% or glucose ≥300-350 mg/dL with symptoms, start basal insulin immediately (with or without metformin) 3.

Step 4: Insulin Therapy

When maximum doses of 2-3 oral agents fail to achieve target:

• Start with basal insulin (glargine, detemir, degludec, or NPH) once daily at bedtime while continuing metformin ± other oral agents 3, 6
• Administer subcutaneously into abdomen, thigh, or deltoid at the same time daily 6
• Rotate injection sites to prevent lipodystrophy 6
• Do not dilute or mix insulin glargine with other insulins 6

If basal insulin alone insufficient, add prandial (mealtime) insulin:

• Use rapid-acting insulin before meals 3
• Total daily insulin dose may exceed 1 unit/kg/day 3

Critical Comorbidity Management

Hypertension with Albuminuria

Initiate ACE inhibitor or ARB and titrate to highest approved tolerated dose 1.

Tobacco Use

Advise all tobacco users to quit to reduce cardiovascular risk 1.

Heart Failure Risk with Thiazolidinediones

Monitor for fluid retention and heart failure symptoms; reduce dose or discontinue if heart failure develops 6.

Diabetes Self-Management Education (DSMES)

Initiate DSMES at diagnosis with trained diabetes educators—this is as important as medication selection 1. Provide:

• Annual DSMES updates 1
• Additional sessions when health status changes or during care transitions 1

Monitoring

• Measure HbA1c every 3 months until target achieved, then at least twice yearly 3
• For patients on intensive insulin: blood glucose monitoring ≥4 times daily (before meals and bedtime) 3
• Consider continuous glucose monitoring for patients requiring frequent monitoring 3

Common Pitfalls to Avoid

• Never share insulin pens or syringes between patients, even with needle changes 6
• Accidental mix-ups between insulin products occur—instruct patients to check labels before every injection 6
• Monitor potassium in patients at risk when starting insulin or SGLT2 inhibitors (hypokalemia can be life-threatening) 6
• Increase glucose monitoring frequency when changing insulin regimen, adjusting doses, or with changes in meal patterns or physical activity 6
• Do not delay SGLT2 inhibitor or GLP-1 RA in patients with cardiovascular/kidney disease just because HbA1c is at goal—these medications provide organ protection independent of glucose lowering 1, 2