National estimates of insulin-related hypoglycemia and errors leading to emergency department visits and hospitalizations.

IMPORTANCE: Detailed, nationally representative data describing high-risk populations and circumstances involved in insulin-related hypoglycemia and errors (IHEs) can inform approaches to individualizing glycemic targets.
OBJECTIVE: To describe the US burden, rates, and characteristics of emergency department (ED) visits and emergency hospitalizations for IHEs. DESIGN, SETTING, AND PARTICIPANTS: Nationally representative public health surveillance of adverse drug events among insulin-treated patients seeking ED care (National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project) and a national household survey of insulin use (the National Health Interview Survey) were used to obtain data from January 1, 2007, through December 31, 2011. MAIN OUTCOMES AND MEASURES: Estimated annual numbers and estimated annual rates of ED visits and hospitalizations for IHEs among insulin-treated patients with diabetes mellitus.
RESULTS: Based on 8100 National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance cases, an estimated 97,648 (95% CI, 64,410-130,887) ED visits for IHEs occurred annually; almost one-third (29.3%; 95% CI, 21.8%-36.8%) resulted in hospitalization. Severe neurologic sequelae were documented in an estimated 60.6% (95% CI, 51.3%-69.9%) of ED visits for IHEs, and blood glucose levels of 50 mg/dL (to convert to millimoles per liter, multiply by 0.0555) or less were recorded in more than half of cases (53.4%). Insulin-treated patients 80 years or older were more than twice as likely to visit the ED (rate ratio, 2.5; 95% CI, 1.5-4.3) and nearly 5 times as likely to be subsequently hospitalized (rate ratio, 4.9; 95% CI, 2.6-9.1) for IHEs than those 45 to 64 years. The most commonly identified IHE precipitants were reduced food intake and administration of the wrong insulin product. CONCLUSIONS AND RELEVANCE: Rates of ED visits and subsequent hospitalizations for IHEs were highest in patients 80 years or older; the risks of hypoglycemic sequelae in this age group should be considered in decisions to prescribe and intensify insulin. Meal-planning misadventures and insulin product mix-ups are important targets for hypoglycemia prevention efforts.