Insulin Therapy in Type 2 Diabetes with Severe Hyperglycemia
Insulin therapy should be strongly considered from the outset in type 2 diabetes patients presenting with blood glucose >300 mg/dL, HbA1c >10%, or ketonuria, with insulin being mandatory when ketonuria is present as it reflects profound insulin deficiency. 1
Indications for Immediate Insulin Initiation
- Insulin therapy is indicated when a patient presents with blood glucose levels ≥300 mg/dL (≥16.7 mmol/L), HbA1c ≥10% (≥86 mmol/mol), or if the patient has symptoms of hyperglycemia (polyuria, polydipsia) 1
- Insulin is mandatory when catabolic features (unexpected weight loss) or ketonuria are present, as ketonuria reflects profound insulin deficiency 1
- Patients with high baseline HbA1c (≥9.0%) have a low probability of achieving near-normal targets with oral monotherapy, justifying direct initiation with insulin 1
Approach to Insulin Initiation
- Begin with basal insulin added to existing pharmacological therapy (if any), while revisiting lifestyle modifications 1
- Discontinue sulfonylureas or other medications that can cause hypoglycemia once insulin is started 1
- For patients with marked hyperglycemia (blood glucose ≥250 mg/dL, A1C ≥8.5%) who are symptomatic, initiate basal insulin while metformin is started and titrated 1
- In patients with ketosis/ketoacidosis, treatment with subcutaneous or intravenous insulin should be initiated to rapidly correct hyperglycemia and metabolic derangement 1
Insulin Regimen Selection
- For initial insulin therapy in type 2 diabetes with severe hyperglycemia, basal insulin analogs are preferred over NPH insulin due to reduced risk of hypoglycemia 2
- If glycemic targets are not met with basal insulin, progress to multiple daily injections with basal and premeal bolus insulins 1
- Insulin regimens should be adjusted every three to four days until target self-monitored blood glucose levels are reached 3
Post-Stabilization Management
- Once symptoms are relieved and glucose toxicity resolves, it may be possible to taper insulin partially or entirely, transferring to non-insulin antihyperglycemic agents 1
- In patients initially treated with insulin and metformin who meet glucose targets based on home blood glucose monitoring, insulin can be tapered over 2–6 weeks by decreasing the insulin dose by 10–30% every few days 1
- Recent evidence suggests that combining SGLT2 inhibitors with insulin therapy may improve early glycemic control and reduce insulin requirements in hospitalized T2DM patients with severe hyperglycemia 4
Special Considerations
- Proper patient education regarding glucose monitoring, insulin injection technique, insulin storage, recognition/treatment of hypoglycemia, and "sick day" rules is essential 1
- When available, certified diabetes educators can be invaluable in guiding patients through insulin initiation 1
- In patients with severe hyperglycemia (blood glucose ≥600 mg/dL), consider assessment for hyperglycemic hyperosmolar nonketotic syndrome 1
Monitoring and Follow-up
- Monitor fasting and premeal blood glucose with a goal of 80-130 mg/dL and a two-hour postprandial goal of less than 180 mg/dL 3
- Glycemic status should be assessed every 3 months to determine if continued insulin therapy is necessary or if de-escalation to oral agents is possible 1
- Regular monitoring of ketone levels is important when initiating insulin therapy, especially if SGLT2 inhibitors are being used concurrently 4
Remember that insulin therapy in type 2 diabetes with severe hyperglycemia is often temporary and serves to reverse glucose toxicity. Once glycemic control is achieved, many patients can transition to oral agents, particularly if they do not have evidence of significant beta-cell failure 5.