What are the initial management and treatment recommendations for diabetes mellitus?

Initial Management and Treatment of Diabetes Mellitus

The initial management of diabetes mellitus should begin with lifestyle modifications including dietary changes, physical activity, and weight loss, followed by metformin as first-line pharmacologic therapy for type 2 diabetes if lifestyle interventions are insufficient to achieve glycemic targets. 1, 2

Foundations of Care for All Diabetes Patients

• All patients with diabetes should participate in comprehensive diabetes self-management education and support to improve outcomes 1
• An individualized medical nutrition therapy program, preferably provided by a registered dietitian, is recommended for all persons with diabetes 1
• Physical activity plan should include at least 150 minutes of moderate-intensity aerobic activity per week, reduced sedentary time, and resistance training at least twice per week 1, 2
• For overweight or obese patients, counseling to lose at least 5% of body weight is recommended to improve glycemic control, blood pressure, and lipid levels 1, 2

Type 1 Diabetes Management

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

Type 2 Diabetes Management

Initial Therapy

• For newly diagnosed patients who are overweight or obese, begin with lifestyle modifications including physical activity and weight loss counseling 1, 3
• If lifestyle efforts are not sufficient to achieve glycemic goals, metformin should be added at or soon after diagnosis if not contraindicated 1, 3
• Metformin is the preferred initial pharmacologic agent (A rating) due to its efficacy, safety, low cost, and potential cardiovascular benefits 1, 2
• Start metformin at a low dose (500 mg daily) and increase gradually to minimize gastrointestinal side effects, with an ideal maximum dose of 2000 mg daily in divided doses 2, 3, 4
• Metformin can be continued in patients with declining renal function down to a GFR of 30-45 mL/min, though the dose should be reduced 1

Special Circumstances Requiring Insulin First

• Insulin therapy should be initiated instead of metformin as first-line treatment in patients with:
  • Ketosis or diabetic ketoacidosis
  • Random blood glucose ≥250 mg/dL
  • HbA1c >8.5%
  • Symptomatic hyperglycemia with polyuria, polydipsia, and weight loss 2, 3

Combination Therapy

• When monotherapy with metformin at maximum tolerated dose does not achieve or maintain the HbA1c target over 3 months, a second agent should be added 1
• Consider adding one of these six options to metformin:
  • Sulfonylureas
  • Thiazolidinediones (e.g., pioglitazone)
  • DPP-4 inhibitors
  • SGLT-2 inhibitors
  • GLP-1 receptor agonists
  • Basal insulin 1
• Initial dual-regimen combination therapy should be considered when the HbA1c level is ≥9% to achieve glycemic control more quickly 1
• Choice of second agent should be based on patient factors, disease characteristics, drug properties, and patient preferences 1

Glycemic Targets and Monitoring

• A reasonable HbA1c goal for most adults with diabetes is <7% 2
• More stringent targets (such as <6.5%) may be appropriate for selected individuals if achievable without significant hypoglycemia 2
• HbA1c should be monitored every 3 months until target is reached, then at least twice yearly 2
• Treatment goals should be individualized based on patient factors including age, comorbidities, and risk of hypoglycemia 2

Cardiovascular Risk Management

• Blood pressure control is essential for reducing cardiovascular risk in diabetes patients 1
• For patients with confirmed blood pressure ≥140/90 mmHg, prompt initiation of pharmacologic therapy is recommended in addition to lifestyle therapy 1
• For blood pressure ≥160/100 mmHg, initiate and titrate two drugs or a single-pill combination 1
• Preferred antihypertensive medications include ACE inhibitors, angiotensin receptor blockers, thiazide-like diuretics, or dihydropyridine calcium channel blockers 1

Common Pitfalls and Caveats

• Delaying treatment intensification when glycemic targets are not met can lead to poor outcomes 3
• Failing to adjust medications during periods of acute illness can lead to complications 3
• Metformin rarely causes hypoglycemia by itself, but hypoglycemia can occur if patients don't eat enough, consume alcohol, or take other glucose-lowering medications 4
• Patients with hypoglycemia unawareness should temporarily increase their glycemic targets to reduce future risk 2
• Avoid aggressively targeting near-normal HbA1c levels in patients with advanced disease where such targets cannot be safely achieved 2