What are the guidelines for managing a typical adult patient with type 2 (T2) diabetes?

Type 2 Diabetes Management Guidelines

For adults with type 2 diabetes, start metformin immediately at diagnosis combined with lifestyle modifications, then add either an SGLT-2 inhibitor or GLP-1 receptor agonist after 3 months if HbA1c remains above 7%. 1, 2

Initial Pharmacologic Management

• Metformin is mandatory first-line therapy at diagnosis unless contraindicated, continued long-term as the foundation of treatment. 3, 2, 4
• Start metformin at low doses with gradual titration to minimize gastrointestinal side effects; take with food or 15 minutes after meals if symptoms persist. 5
• Monitor for vitamin B12 deficiency during long-term metformin use, especially if anemia or peripheral neuropathy develops. 1, 2, 5

Lifestyle Modifications (Class I, Level A Evidence)

Nutrition:

• Implement a tailored nutrition plan focusing on heart-healthy dietary patterns to improve glycemic control and achieve weight loss if needed. 3
• Restrict calorie intake to 1500 kcal/day. 1, 2
• Limit dietary fat to 30-35% of total energy intake (20-30% per ACC/AHA). 3, 1
• Carbohydrates should account for 50-65% of total calorie intake. 3
• Protein intake should be approximately 0.8 g/kg/day (15-20% of total calories) in patients with normal renal function. 3

Physical Activity:

• Perform at least 150 minutes per week of moderate-intensity aerobic physical activity (50-70% maximum heart rate) or 75 minutes of vigorous-intensity activity, spread over at least 3 days with no more than 2 consecutive days without exercise. 3
• Add resistance training at least twice per week involving all major muscle groups on nonconsecutive days. 3, 1, 2
• Reduce sedentary behavior throughout the day—taking breaks from sitting improves glycemic management even without structured exercise. 3

Glycemic Targets and Monitoring

• Target HbA1c between 7-8% for most adults with type 2 diabetes. 1, 2, 5
• If HbA1c falls below 6.5%, deintensify treatment immediately to avoid hypoglycemia and overtreatment. 1, 2
• Test HbA1c every 3 months to evaluate treatment response. 5
• Reassess the medication plan every 3-6 months and adjust based on glycemic control, weight goals, presence of metabolic comorbidities, and hypoglycemia risk. 2, 5

Second-Line Therapy Algorithm (After 3 Months if HbA1c >7%)

When metformin plus lifestyle modifications fail to achieve target HbA1c after 3 months, add either an SGLT-2 inhibitor or GLP-1 receptor agonist based on the following decision tree: 2, 5

Choose SGLT-2 Inhibitor when:

• Patient has congestive heart failure (to prevent heart failure hospitalizations). 2, 5
• Patient has chronic kidney disease with eGFR 20-60 mL/min/1.73 m² and/or albuminuria (to minimize CKD progression). 2, 5
• Cardiovascular mortality reduction is the primary goal. 2

Choose GLP-1 Receptor Agonist when:

• Patient has increased stroke risk. 2
• Patient needs substantial weight loss (GLP-1 agonists, particularly tirzepatide, produce superior weight loss). 1, 2
• Patient has advanced CKD with eGFR <30 mL/min/1.73 m² (lower hypoglycemia risk). 2, 5
• All-cause mortality reduction is the primary goal. 2

For patients with BMI >25 specifically, tirzepatide is the preferred GLP-1 receptor agonist as it produces mean weight loss of 8.47 kg with up to 67% of patients achieving ≥10% weight reduction and demonstrates superior glycemic control compared to other GLP-1 receptor agonists. 1

Cardiovascular Risk Management

Statin Therapy:

• In adults 40-75 years of age with diabetes, regardless of estimated 10-year ASCVD risk, moderate-intensity statin therapy is indicated (Class I, Level A). 3
• In adults with diabetes who have multiple ASCVD risk factors, prescribe high-intensity statin therapy with the aim to reduce LDL-C levels by 50% or more. 3

Blood Pressure Management:

• Measure waist circumference to identify those at higher cardiometabolic risk (≥40 inches in men, ≥35 inches in women). 3
• Calculate BMI annually or more frequently to identify adults with overweight and obesity for weight loss considerations. 3

Cost-Constrained Situations

When newer agents (SGLT-2 inhibitors, GLP-1 agonists) are unaffordable:

• Maximize glipizide dose. 1, 2
• If HbA1c remains >8% after maximizing glipizide, add basal insulin. 1, 2
• Immediately reduce glipizide dose by 50% when adding insulin to prevent severe hypoglycemia. 1, 2

Complication Screening

• Perform initial retinopathy examination within 3-5 years of type 1 diabetes diagnosis and shortly after type 2 diabetes diagnosis, then annually by an ophthalmologist or optometrist experienced in diabetic retinopathy. 5
• Assess eGFR and albuminuria every 3-6 months with medication adjustments as needed. 5

Critical Pitfalls to Avoid

• Do not delay treatment intensification when patients fail to meet glycemic targets after 3 months—therapeutic inertia worsens long-term outcomes. 1, 2
• Do not continue sulfonylureas once SGLT-2 inhibitors or GLP-1 agonists achieve glycemic control—they increase hypoglycemia risk without mortality benefit. 1, 2
• Do not use DPP-4 inhibitors as they lack mortality benefit. 2
• Do not combine tirzepatide with DPP-4 inhibitors as this provides no additional glucose lowering beyond tirzepatide alone. 1
• Do not target HbA1c below 6.5%—this requires deintensification. 1, 2
• Avoid vigorous aerobic or resistance exercise in patients with proliferative diabetic retinopathy or severe non-proliferative diabetic retinopathy due to risk of vitreous hemorrhage or retinal detachment. 3

Smoking Cessation

• Every diabetic smoker should be advised to stop smoking or using tobacco products and reduce second-hand smoke exposure. 3
• Assess smoking status and extent of nicotine dependence; provide brief consultations, hotlines, and prescribe medications if necessary to help patients quit. 3

Special Populations

Older Adults with Advanced Disease:

• Continue previous regimen focusing on hypoglycemia prevention. 5
• Keep glucose levels below renal threshold with minimal role for aggressive HbA1c lowering. 5

Patients with Organ Failure:

• Hypoglycemia prevention is paramount. 5
• Reduce insulin secretagogue doses as oral intake decreases. 5
• Allow glucose values in the upper level of the target range. 5