Evaluation of an inpatient automatic dose reduction protocol for concentrated insulin glargine upon therapeutic interchange to insulin detemir on hypoglycemia rates.

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Purpose: A previous study at Ascension Seton Hospital Network (ASHN) found a 1:1 dose conversion to insulin detemir 100 units/mL (iDet100) from insulin glargine 300 units/mL (iGlar300) increased the incidence of hypoglycemia as compared to a 1:1 conversion from insulin glargine 100 units/mL. No studies have evaluated an automatic 20% dose reduction for this specific therapeutic interchange. The purpose of this study was to compare hypoglycemia rates following implementation of a protocol specifying a minimum 20% dose reduction when converting from iGlar300 to inpatient iDet100.

Methods: This multicenter, retrospective chart review-based study was a before/after study evaluating the impact of an ASHN protocol implemented in April 2021 requiring a minimum 20% reduction when converting from home iGlar300 to inpatient iDet100. Previously, a 1:1 interchange was standard. Patients admitted between May 2019 and December 2022 were included if at least 1 dose of iDet100 was received following interchange from iGlar300. The primary endpoint was hypoglycemia incidence before and after protocol implementation. Secondary endpoints included time to first hypoglycemia and number of doses given before hypoglycemia. Logistic regression was performed to analyze the relationship between percent interchange from home dose and hypoglycemia rate.

Results: A total of 284 patients were included: 128 in the preprotocol arm and 156 in the postprotocol arm. The incidence of hypoglycemia was significantly lower in the postprotocol arm than in the preprotocol arm (11.9% vs 24.7%; P = 0.018). The median time to first hypoglycemia was longer in the postprotocol versus the preprotocol arm, though the difference was not statistically significant (13 vs 18.5 hours, P = 0.082). For each percent reduction from iGlar300 to iDet100, the likelihood of hypoglycemia was reduced by 5.3%.

Conclusion: A protocol requiring a minimum 20% dose reduction from iGlar300 to inpatient iDet100 reduced the incidence of hypoglycemia. Health systems should consider adopting a similar approach to reduce the occurrence of hypoglycemia upon interchange.