Outpatient insulin-related adverse events due to mix-up errors: Findings from two national surveillance systems, United States, 2012-2017.

PURPOSE We used data from two public health surveillance systems for national estimates and detailed descriptions of insulin mix-up errors resulting in emergency department (ED) visits and other serious adverse events to help inform prevention efforts. METHODS ED visits involving patients seeking care for insulin medication errors collected by the NEISS-CADES project in 2012-2017 and voluntary reports of serious insulin medication errors submitted to the US Food and Drug Administration (FDA) in 2016-2017 were analyzed. National estimates of insulin product prescriptions dispensed from retail pharmacies were obtained from IQVIA National Prescription Audit. RESULTS Between 2012 and 2017, based on 514 NEISS-CADES cases, there were an estimated 5636 (95% CI, 4143-7128) ED visits annually for insulin mix-up errors; overall, over three-quarters (77.5%; 95% CI, 71.6%-83.3%) involved taking rapid-acting instead of long-acting insulin. Between 2012 and 2017, the proportion of mix-up errors among all estimated ED visits for all insulin errors decreased by 60%; concurrently, the proportion of pens among all insulin package types dispensed increased by 50%. Among 58 voluntary reports submitted to FAERS, over one-half (56.9%) of cases involved taking rapid- instead of long-acting insulin. Among 27 cases with documented contributing factors, approximately one-half involved patients having difficulty differentiating products. CONCLUSIONS Among all ED visits for insulin errors collected by NEISS-CADES in 2012-2017, the proportion involving mix-up errors has declined. Continued reductions may require additional prevention strategies, including improving insulin distinctiveness, particularly for rapid- vs long-acting insulins. Ongoing national surveillance is important for identifying the impact of interventions.