Under‐ and overdosing insulin in the hospital: A retrospective cohort study of dose deviation and patient outcomes
Hussein Zaitoon, Sher Matsri, Shira Nagler, Matteo M. Lalovich, Ralph A. DeFronzo, Eugene FeiginAbstract
Aims
Glycaemic abnormalities during hospitalization are common and linked to morbidity and mortality, yet little is known about how deviations from guideline‐recommended insulin dosing affect outcomes. The aim of this study is to examine whether deviation from an expected insulin dose in non‐critically ill hospitalized adults with type 2 diabetes, compared with guideline‐concordant dosing, is associated with mortality, length of stay or dysglycaemias.
Methods
This retrospective cohort study included adults with type 2 diabetes hospitalized at a tertiary academic medical centre (2010–2025) who received ≥ 24 h of subcutaneous insulin. The expected total daily insulin dose (TDID) was calculated based on guideline‐concordant dosing using the ADA‐recommended range (0.3–0.6 units/kg/day), and the observed TDID was derived from medication records. Patients were classified as undertreated (< 0.3 units/kg/day), guideline‐concordant (0.3–0.6 units/kg/day) or overtreated (> 0.6 units/kg/day). Outcomes included length of stay, and 30‐day mortality, hypoglycaemia and hyperglycaemia.
Results
Among 3430 hospitalized adults with type 2 diabetes receiving subcutaneous insulin, 37.6% received guideline‐concordant dosing, 43.7% were undertreated, and 18.7% were overtreated. Undertreatment was independently associated with increased 30‐day mortality (aHR 1.273, 95% CI 1.024–1.583; p = 0.03), while overtreatment was not. Undertreated patients had more hyperglycaemia and longer hospital stays ( p < 0.001), whereas hypoglycaemia rates were similar between groups.
Conclusion
Deviation from guideline‐based insulin dosing is common in hospitalized adults with type 2 diabetes. Undertreatment was associated with increased 30‐day mortality and prolonged hospitalization. Monitoring insulin dose deviation may help identify patients at risk for adverse outcomes.