What is the approach to managing new onset diabetes mellitus (DM)?

Approach to New-Onset Diabetes

The approach to new-onset diabetes depends critically on whether the patient presents with metabolic decompensation (ketoacidosis, severe hyperglycemia) versus stable disease, and whether this is Type 1 versus Type 2 diabetes, with immediate insulin therapy required for any patient with ketosis/ketoacidosis or severe hyperglycemia regardless of diabetes type. 1

Initial Assessment and Stabilization

Identify Metabolic Emergency

• Patients presenting with diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic nonketotic syndrome (HHNK), or ketosis require immediate IV insulin therapy until acidosis resolves, then transition to subcutaneous insulin. 1
• Check for severe hyperglycemia (blood glucose ≥600 mg/dL) which warrants assessment for HHNK. 1
• In youth with overweight/obesity where diabetes type is uncertain, initial therapy should address hyperglycemia regardless of ultimate diabetes type, as substantial percentages present with ketoacidosis. 1

Determine Diabetes Type

• For Type 1 Diabetes (T1DM): Initiate multiple-dose insulin injections (≥3 injections daily) or continuous subcutaneous insulin infusion immediately. 1
• The recommended starting dosage for T1DM is approximately one-third of total daily insulin requirements, with short-acting premeal insulin for the remainder. 2
• Use insulin analogues rather than regular insulin to reduce hypoglycemia risk. 1

Type 2 Diabetes Management Algorithm

Stratify by Presentation Severity

For A1C <8.5% without acidosis or ketosis (metabolically stable):

• Start metformin as first-line pharmacologic therapy (titrate up to 2,000 mg/day as tolerated). 1
• Metformin is preferred due to established efficacy, safety profile, low cost, and potential cardiovascular benefits. 1
• Initiate lifestyle modifications concurrently—never as isolated initial treatment. 1

For A1C ≥8.5% or blood glucose ≥250 mg/dL without acidosis:

• Start basal insulin (0.5 units/kg/day) while simultaneously initiating and titrating metformin. 1
• This applies to symptomatic patients with polyuria, polydipsia, nocturia, or weight loss. 1

For ketosis/ketoacidosis or severe metabolic decompensation:

• IV insulin until acidosis resolves, then subcutaneous insulin as for Type 1 diabetes. 1
• Start long-acting insulin at 0.5 units/kg/day, titrate every 2-3 days based on blood glucose monitoring. 1
• Once acidosis resolves, initiate metformin while continuing subcutaneous insulin. 1

Check Pancreatic Autoantibodies

• If autoantibodies are positive: Continue or initiate multiple daily injection insulin or pump therapy as for Type 1 diabetes; discontinue metformin. 1
• If autoantibodies are negative: Continue or start metformin; if on insulin and meeting glucose targets, taper insulin over 2-6 weeks by decreasing dose 10-30% every few days. 1

Intensification Strategy When Goals Not Met

Second-Line Therapy (after 3 months if A1C target not achieved)

• Continue metformin and add one of the following based on patient factors: 1
  • GLP-1 receptor agonist (liraglutide approved for youth ≥10 years; empagliflozin as SGLT2 inhibitor also approved for youth) 1
  • Basal insulin if not already initiated 1
  • For adults: sulfonylureas, thiazolidinediones, DPP-4 inhibitors, or SGLT2 inhibitors 1

Insulin Escalation

• Patients on basal insulin up to 1.5 units/kg/day not meeting targets should transition to multiple daily injections with basal and premeal bolus insulins. 1
• Total daily insulin dose may exceed 1 unit/kg/day in youth with Type 2 diabetes. 1

Essential Concurrent Interventions

Lifestyle Modifications (Non-Negotiable)

• Initiate diabetes self-management education and support at diagnosis—this is not optional. 1
• Medical nutrition therapy provided by registered dietitian for all patients. 1
• Physical activity: ≥150 minutes/week moderate-intensity aerobic activity plus resistance training ≥2 times/week for adults. 1
• Youth: ≥60 minutes daily moderate-to-vigorous physical activity with muscle/bone strengthening ≥3 days/week; limit screen time to <2 hours/day. 1

Monitoring Requirements

• Assess glycemic status (A1C) every 3 months. 1
• Blood glucose monitoring frequency depends on treatment regimen—more frequent for insulin users or those not meeting targets. 1
• Consider continuous glucose monitoring for patients on multiple daily injections or insulin pumps. 1

Glycemic Targets

• For youth with Type 2 diabetes: A1C <7% (<53 mmol/mol) is reasonable; more stringent <6.5% if achievable without significant hypoglycemia. 1
• Lower targets justified in youth with Type 2 diabetes due to lower hypoglycemia risk and higher complication risk compared to Type 1. 1

Critical Pitfalls to Avoid

Medication Errors

• Always verify insulin label before each injection to prevent accidental mix-ups between insulin products. 2
• Never share insulin pens, syringes, or needles between patients due to blood-borne pathogen transmission risk. 2

Hypoglycemia Risk

• When switching from other insulins to insulin glargine, reduce dose by 20% (use 80% of previous dose) to prevent hypoglycemia. 2
• Patients with renal or hepatic impairment require closer monitoring due to increased hypoglycemia risk. 2
• The long-acting effect of basal insulin may delay recovery from hypoglycemia. 2

Comorbidity Management

• Screen for and manage obesity, dyslipidemia, hypertension, and microvascular complications from diagnosis. 1
• Multidisciplinary team (physician, diabetes educator, dietitian, psychologist/social worker) is essential, not optional. 1

Special Considerations for Youth

• Family-centered approach is mandatory—individual-level interventions alone are insufficient given complex social/environmental factors. 1
• Only use FDA-approved medications for youth (insulin, metformin, GLP-1 receptor agonists, empagliflozin); avoid off-label use outside research trials. 1