What are the recommendations for managing diabetes mellitus (DM)?

Diabetes Mellitus Management for RITE Review

Initial Management Approach

All adults with newly diagnosed type 2 diabetes should start metformin immediately alongside lifestyle modifications unless contraindicated, as this combination reduces all-cause mortality by 29.5% and cardiovascular events by 30-35% compared to lifestyle changes alone. 1, 2

First-Line Therapy Algorithm

• Start metformin 500 mg daily, increase by 500 mg every 1-2 weeks to target dose of 2000 mg daily in divided doses 3
• Metformin can be taken without regard to meals 4
• Continue metformin unless contraindicated by renal insufficiency (eGFR considerations) or active liver disease with ALT >2.5x upper limit of normal 4
• Metformin monotherapy typically lowers HbA1c by approximately 1.5% 5

Special Initial Scenarios Requiring Insulin

For pediatric patients or specific presentations, initiate insulin immediately if: 3, 6

• Ketosis or diabetic ketoacidosis present
• Random blood glucose ≥250 mg/dL
• HbA1c >9% (>75 mmol/mol)
• Unclear distinction between type 1 and type 2 diabetes

Glycemic Targets

Target HbA1c of 7% (53 mmol/mol) or less for most nonpregnant adults with life expectancy >10 years to prevent microvascular complications. 1

• The American College of Physicians recommends HbA1c between 7-8% for most adults 7
• Deintensify therapy when HbA1c falls below 6.5% to avoid hypoglycemia risk 7
• Monitor HbA1c every 3 months 3, 6
• Greatest absolute risk reduction comes from improving poor glycemic control; modest reduction from near-normalization 1

Second-Line Therapy When Metformin Fails

When HbA1c remains above target after 3 months on metformin plus lifestyle modifications, add either an SGLT-2 inhibitor or GLP-1 receptor agonist—this combination reduces mortality and morbidity more effectively than other options. 7

Medication Selection Algorithm

Choose SGLT-2 inhibitor if: 7

• Heart failure present or high risk (reduces hospitalization for congestive heart failure)
• Chronic kidney disease present

Choose GLP-1 receptor agonist if: 7

• Increased stroke risk
• Weight loss desired (GLP-1 agonists promote weight loss) 3
• No family history of medullary thyroid cancer (contraindication) 3

Avoid DPP-4 inhibitors as second-line therapy—they lack mortality benefit compared to SGLT-2 inhibitors and GLP-1 agonists 7

Critical Safety Step When Adding SGLT-2i or GLP-1 RA

When adding SGLT-2 inhibitor or GLP-1 agonist achieves adequate glycemic control, reduce or discontinue sulfonylureas or long-acting insulin to prevent hypoglycemia. 7 This is a commonly missed step that leads to preventable hypoglycemic events.

Lifestyle Management (Foundational for All Patients)

Medical Nutrition Therapy

Refer all patients to a registered dietitian at diagnosis for individualized medical nutrition therapy. 1, 3, 6

Recommended eating patterns (choose based on patient preference): 1, 3

• Mediterranean diet (rich in monounsaturated fats, polyunsaturated fats, fatty fish, nuts, seeds)
• DASH diet
• Vegetarian/vegan patterns

Core nutritional principles: 1

• Emphasize nonstarchy vegetables, whole fruits, legumes, whole grains, nuts, seeds, low-fat dairy
• Minimize red meat, sugar-sweetened beverages, sweets, refined grains, processed foods
• Increase plant-based protein sources (nuts, seeds, legumes) to reduce cardiovascular risk
• Limit saturated fat intake (red meat, full-fat dairy, butter, coconut oil)

Carbohydrate management: 1

• For patients on fixed insulin doses: consistent carbohydrate intake at similar times daily
• For flexible insulin regimens: carbohydrate counting or qualitative meal size estimation
• Fiber intake: at least the amount recommended for general population 1

Physical Activity Requirements

Adults: At least 150 minutes per week of moderate-intensity OR 75 minutes of vigorous-intensity aerobic activity, plus resistance training at least twice weekly 1, 3, 6

Children/adolescents: At least 60 minutes daily of moderate-to-vigorous exercise combining aerobic, muscle-strengthening, and bone-strengthening activities 3

"Talk test" for intensity assessment: During moderate activity, can talk but not sing; during vigorous activity, cannot talk without pausing 3

Screen Time Limitations

• Limit non-academic screen time to <2 hours daily 3
• Remove video screens and televisions from bedrooms 3

Smoking Cessation (Non-Negotiable)

Include smoking cessation counseling as routine component of diabetes care—smoking increases CVD risk, premature death, and microvascular complications in diabetes. 1

• Brief counseling combined with pharmacologic therapy more effective than either alone 1
• Advise against e-cigarettes (insufficient evidence for safety or efficacy in smoking cessation) 1
• Smoking cessation improves metabolic parameters, reduces blood pressure and albuminuria at 1 year 1

Glucose Monitoring Strategy

Self-monitoring of blood glucose may be unnecessary in patients on metformin combined with SGLT-2 inhibitor or GLP-1 agonist (no hypoglycemia risk). 7

Finger-stick monitoring required for: 3

• Patients taking insulin or medications with hypoglycemia risk
• Initiating or changing treatment regimen
• Not meeting treatment goals
• Intercurrent illnesses

Continuous glucose monitoring (CGM): 1, 6

• Significantly reduces severe hypoglycemia risk in type 1 diabetes
• Improves time in range without increasing hypoglycemia
• Insufficient data to support routine use in type 2 diabetes or gestational diabetes

Exercise Precautions and Contraindications

Pre-exercise cardiac evaluation needed for: 1

• Diabetic autonomic neuropathy (independent risk factor for cardiovascular death and silent myocardial ischemia)
• High-risk patients should start with short periods of low-intensity exercise, slowly increasing as tolerated

Assess for conditions that contraindicate certain exercises: 1

• Uncontrolled hypertension
• Untreated proliferative retinopathy
• Autonomic neuropathy
• Peripheral neuropathy
• History of foot ulcers or Charcot foot

Diabetic kidney disease: No evidence that vigorous exercise increases progression rate; no specific restrictions needed 1

Hypoglycemia Management

Treat with 15-20g rapid-acting glucose (glucose tablets, fruit juice, sports drinks, regular soda, hard candy). 1, 6

• Recheck blood glucose after 15 minutes
• Repeat treatment if hypoglycemia persists
• When blood glucose ~50-60 mg/dL, 15g glucose raises levels ~50 mg/dL 1
• Severe or frequent hypoglycemia mandates treatment regimen modification 6

Insulin Therapy Specifics

Type 1 diabetes: Multiple-dose insulin injections or continuous subcutaneous insulin infusion with insulin analogues to reduce hypoglycemia risk 6

Type 2 diabetes on insulin: 4

• When adding pioglitazone to insulin, decrease insulin dose by 10-25% if hypoglycemia occurs or plasma glucose <100 mg/dL
• Insulin pump therapy with low glucose suspend features reduces nocturnal hypoglycemia without increasing HbA1c 6

Gestational Diabetes Management

Lifestyle behavior change (medical nutrition therapy, physical activity, weight management) is essential and may suffice for 70-85% of patients; add insulin if glycemic goals not met. 1

Glycemic targets for GDM: 1

• Fasting glucose <95 mg/dL (5.3 mmol/L) AND
• 1-hour postprandial <140 mg/dL (7.8 mmol/L) OR
• 2-hour postprandial <120 mg/dL (6.7 mmol/L)

Insulin is preferred medication; metformin and glyburide should not be used as first-line (lack long-term safety data) 1

Team-Based Care Structure

Utilize collaborative integrated team including: 6

• Physicians, nurse practitioners, physician assistants
• Certified Diabetes Care and Education Specialists (CDCES)
• Registered dietitian nutritionist
• Pharmacists (to reduce polypharmacy risks)
• Behavioral health specialists or social workers

Implement Chronic Care Model components: patient registries, decision support tools, community involvement—this approach reduces CVD risk by 56.6%, microvascular complications by 11.9%, and mortality by 66.1% 6

Common Pitfalls to Avoid

• Therapeutic inertia: Failing to intensify therapy within 3 months when HbA1c targets not met 6
• Forgetting to reduce sulfonylureas/insulin: When adding SGLT-2i or GLP-1 RA, must reduce or stop these to prevent hypoglycemia 7
• Sliding-scale insulin only in hospital: Strongly discouraged; use scheduled insulin regimens 6
• Aggressive targets in advanced disease: Avoid near-normal HbA1c targets in patients with hypoglycemia unawareness or where targets cannot be safely achieved 6
• Ignoring cost: No generic SGLT-2 inhibitors or GLP-1 agonists currently available—discuss cost implications 7