What is the prevalence of insulin overdoses among individuals with diabetes, particularly those with type 1 diabetes or advanced type 2 diabetes and a history of hypoglycemia?

Prevalence of Insulin Overdoses

Insulin overdoses resulting in severe hypoglycemia occur at rates of 0.7 to 12 per 100 person-years in randomized controlled trials of type 2 diabetes, with substantially higher rates in type 1 diabetes where severe hypoglycemia requiring assistance occurs in 2-3 events per patient per month. 1, 2

Epidemiological Data by Diabetes Type

Type 1 Diabetes

• Severe hypoglycemia (requiring assistance) occurs at rates of 2.18-3.06 events per patient per month in clinical trials, translating to approximately 26-37 events per patient-year 1
• In pediatric populations with type 1 diabetes, rates reach 2.68-3.20 major hypoglycemic events per patient per month 1
• Hyperglycemic crisis rates (DKA) reach 44.5-82.6 per 1,000 person-years, representing another form of insulin-related dosing error (underdosing) 3

Type 2 Diabetes

• Severe hypoglycemia requiring hospitalization or emergency department visits occurs at 0.2-2.0 per 100 person-years, with higher rates among insulin or sulfonylurea users 2
• In randomized trials, severe hypoglycemia rates range from 0.7 to 12 per 100 person-years 2
• Patient-reported hypoglycemia requiring any assistance occurs in 1-17% of patients over 6-12 months 2
• Among insulin-treated type 2 diabetes patients, 4-17% report needing assistance for hypoglycemia over 12 months, and 37-64% experience any hypoglycemic symptoms 2

Intentional Insulin Overdose/Omission

Disordered Eating Behaviors

• Insulin omission for weight loss is the most commonly reported disordered eating behavior in type 1 diabetes 3
• In type 2 diabetes patients treated with insulin, intentional omission is also frequently reported 3
• These behaviors are associated with high rates of comorbid psychiatric disorders including depression and anxiety 3

Psychiatric Comorbidities

• Lifetime prevalence of generalized anxiety disorder is 19.5% in people with either type 1 or type 2 diabetes, which can contribute to medication errors 3
• Fear of hypoglycemia is common and may lead to insulin underdosing, while depression and eating disorders increase risk of intentional overdose or omission 3

Medication Errors Leading to Overdose

Common Error Mechanisms

• Abbreviation errors (using "U" instead of "units") often result in 10-fold overdoses when the "U" is misread as a zero 4
• Use of tuberculin syringes instead of insulin syringes leads to overdose 4
• Confusion between different insulin products due to similar packaging causes dosing errors 4
• Electronic prescribing systems with numerous insulin products create confusion and wrong-dose errors 4

High-Risk Populations for Overdose

• Patients with chronic kidney disease (CKD stages 3-5) have 5-fold increased frequency of severe hypoglycemia due to decreased insulin clearance and impaired renal gluconeogenesis 3
• Older patients with multiple comorbidities, long diabetes duration, or prior hypoglycemia history are at highest risk 2
• Patients with cognitive dysfunction, hepatic dysfunction, or major limb amputation are more vulnerable 5

Clinical Consequences of Overdose

Immediate Effects

• Mild hypoglycemia can usually be treated with oral glucose, but more severe episodes may cause coma, seizures, or neurologic impairment requiring intramuscular/subcutaneous glucagon or intravenous glucose 1
• After apparent recovery, continued observation and additional carbohydrate intake are necessary to prevent recurrence 1

Long-term Morbidity

• Hypoglycemia can cause cardiovascular complications including arrhythmias and myocardial ischemia 6
• Recurrent severe hypoglycemia may cause permanent cognitive impairment or accelerate dementia onset in middle-aged and elderly patients 6
• Physical injuries from accidents during hypoglycemic episodes contribute to morbidity 6

Prevention Strategies

Monitoring and Assessment

• Annual hypoglycemia risk assessment is recommended for all patients with type 1 diabetes 7
• Patients should self-monitor blood glucose closely during the first 3-4 weeks after insulin initiation or dose adjustments 8
• Consider continuous glucose monitoring (CGM) for patients at high hypoglycemia risk 7, 8

Medication Management

• When initiating insulin therapy, reassess and reduce doses of sulfonylureas (by 50%) and total daily insulin (by approximately 20%) to minimize overdose risk 3, 8
• Monitor for overbasalization signs: basal dose exceeding 0.5 units/kg/day, hypoglycemia occurrences, or high glycemic variability 3, 9
• In CKD patients, avoid first-generation sulfonylureas and prefer glipizide or gliclazide which don't have active metabolites 3

Patient Education

• Structured education programs on hypoglycemia prevention and blood glucose awareness training are essential 7
• Patients should be educated about proper carbohydrate counting and matching prandial insulin to intake 7
• Glucagon should be prescribed for insulin-treated individuals with training provided to close contacts 7, 8