Lower Glucose Target Is Associated With Improved 30-Day Mortality in Cardiac and Cardiothoracic Patients

Practice guidelines recommend against intensive insulin therapy in patients who are critically ill based on trials that had high rates of severe hypoglycemia. Intermountain Healthcare uses a computerized IV insulin protocol that allows choice of blood glucose (BG) targets (80-110 vs 90-140 mg/dL) and has low rates of severe hypoglycemia. We sought to study the effects of BG target on mortality in adult patients in cardiac ICUs that have very low rates of severe hypoglycemia.

Critically ill patients receiving IV insulin were treated with either of two BG targets (80-110 vs 90-140 mg/dL). We created a propensity score for BG target using factors thought to have influenced clinicians' choice, and then we performed a propensity score-adjusted regression analysis for 30-day mortality.

There were 1,809 patients who met inclusion criteria. Baseline patient characteristics were similar. Median glucose was lower in the 80-110 mg/dL group (104 vs 122 mg/dL, P < .001). Severe hypoglycemia occurred at very low rates in both groups (1.16% vs 0.35%, P = .051). Unadjusted 30-day mortality was lower in the 80-110 mg/dL group (4.3% vs 9.2%, P < .001). This remained after propensity score-adjusted regression (OR, 0.65; 95% CI, 0.43-0.98; P = .04).

Tight glucose control can be achieved with low rates of severe hypoglycemia and is associated with decreased 30-day mortality in a cohort of largely patients in cardiac ICUs. Although such findings should not be used to guide clinical practice at present, the use of tight glucose control should be reexamined using a protocol that has low rates of severe hypoglycemia.