Impact of Lowered Sliding-Scale Insulin Treatment Thresholds on Glycemic Control

Introduction: Stress-induced hyperglycemia is a common and significant complication in critically ill patients associated with increased morbidity and mortality. While current guidelines recommend insulin therapy for persistent hyperglycemia ≥180 mg/dL, the optimal threshold for administering correctional sliding scale insulin (SSI) to maintain blood glucose (BG) < 180 mg/dL, without increasing hypoglycemic risk, is undefined. The goal of this study was to evaluate the impact of decreasing the institutional threshold for SSI administration from a BG of >180 mg/dL to >160 mg/dL.


Methods: This retrospective, pre-post cohort study evaluated adult critically and non-critically ill patients requiring SSI admitted to the study institution. Patients were divided into two cohorts: a pre-protocol group (SSI administered for BG >180 mg/dL) and a post-protocol group (SSI administered for BG >160 mg/dL). The primary outcome was the percent of BG values falling within institutional goal range (70-180 mg/dL), above range (>180 mg/dL), and below range ( < 70 mg/dL). Secondary outcomes included the incidence of hypoglycemia (BG < 70 mg/dL), severe hypoglycemia (BG < 40 mg/dL), and mean total daily insulin requirement.


Results: Data from 100 patients (50 per group) were collected, with 1,091 checks analyzed in the pre-protocol group and 1,146 in the post-protocol group. Following the implementation of the reduced threshold SSI, hyperglycemic episodes decreased from 63% to 45% (p=0.0003), while BG checks within goal-range increased from 41% to 57% (p=0.0002). The percent of patients who experienced any hypoglycemic event increased slightly from 8% to 12.5% (p=0.505). However, patients who experienced severe hypoglycemia decreased from 6% to 4% (p= 0.646). A subgroup analysis of patients in intensive care units yielded similar results with percentage of BG checks within goal range increasing from 52% to 58% (p < 0.001) with no change in the rate of hypoglycemia.


Conclusions: Lowering the BG threshold for SSI administration was associated with improved glycemic control, reduced hyperglycemia, and increased goal-range checks. Although mild hypoglycemia was slightly more frequent, severe events declined. These findings support that initiating SSI at a reduced threshold of >160 mg/dL may improve time in goal glycemic range.