Insulin Glargine Use in Dexamethasone-Induced Hyperglycemia: A Retrospective Cohort Analysis

Insulin is commonly used to manage steroid-induced hyperglycemia. However, optimal dosing strategies for long-acting steroids like dexamethasone remain unclear.

This study evaluated insulin glargine use for dexamethasone-induced hyperglycemia (DIH) and evaluated factors associated with achieving glucose targets (AGTs).

This retrospective, single-centered cohort study included adult, noncritically ill patients who received once-daily insulin glargine and dexamethasone for at least 3 consecutive days during admissions between July 1, 2021, and July 31, 2023. Patients were excluded if they had type 1 diabetes mellitus or received intravenous insulin within the first 3 days. The primary outcome was the percentage of patients AGT, defined as mean blood glucose 70 to 180 mg/dL on day 3 of combination therapy. Patients were then stratified into AGT and persistent hyperglycemia (PH) cohorts to evaluate secondary outcomes which included hypoglycemia incidence and patient or treatment characteristics associated with AGT.

Among 118 patients included, 28 (24%) were in the AGT cohort and 90 (76%) were in the PH cohort. The AGT cohort had a lower mean body mass index (29.1 vs 33.7 kg/m², P = .02) and fewer patients with preexisting type 2 diabetes mellitus (85.7% vs 97.8%, P = .03). Median insulin glargine units standardized by dexamethasone dose was similar between cohorts (2.25 [1.08-3.33] vs 2.00 [1.17-4.00] units/mg/day, P = .98). The PH cohort required significantly higher median daily bolus insulin doses (24 vs 6 units/day, P < .01). There was 1 patient, who was in the AGT cohort, who experienced hypoglycemia.

This study suggests that current practice underdoses insulin glargine initially for DIH management and relies on reactive bolus insulin with limited success. Earlier and more assertive insulin glargine dosing is warranted to improve early glycemic control without substantially increasing hypoglycemia risk. Limitations include the retrospective single-centered study design and limited sample size with imbalanced cohorts.