Intensive care unit hypoglycemia predicts depression during early recovery from acute lung injury

Abstract

Objective: To evaluate the association between intensive care unit blood glucose levels and depression after acute lung injury.

Design: Prospective cohort study.

Setting: Twelve intensive care units in four hospitals in Baltimore, MD.

Patients: Consecutive acute lung injury survivors (n = 104) monitored during 1717 intensive care unit patient-days and screened for depression at 3 months after acute lung injury.

Interventions: None.

Measurements and main results: The prevalence of a positive screening test for depression (Hospital Anxiety and Depression subscale score > or = 8) at follow-up was 28%. After adjustment for confounders, patients with a mean daily minimum intensive care unit glucose level < 100 mg/dL had significant increases in mean depression score (2.1 points, 95% confidence interval 0.6-3.7) and in the likelihood of a positive depression screening test (relative risk 2.6, 95% confidence interval 1.2-4.2). Patients with documented hypoglycemia < 60 mg/dL during their intensive care unit stay also had greater symptoms of depression (2.0 points, 95% confidence interval 0.5-3.5; relative risk 3.6, 95% confidence interval 1.8-5.1). Other factors independently associated with a positive depression screening test included body mass index > 40 kg/m2 (relative risk 3.3, 95% confidence interval 1.2-4.2), baseline depression/anxiety (relative risk 3.9, 95% confidence interval 1.5-6.5), and mean daily intensive care unit benzodiazepine dose > 100 mg of midazolam-equivalent agent (relative risk 2.4, 95% confidence interval 1.1-3.8).

Conclusions: Hypoglycemia in the intensive care unit is associated with an increased risk of positive screening for depression during early recovery from acute lung injury. Baseline depressive symptoms, morbid obesity, and intensive care unit benzodiazepine dose were also associated with postacute lung injury depressive symptoms. These findings warrant increased glucose monitoring for intensive care unit patients at risk for hypoglycemia and further research on how patient and intensive care unit management factors may contribute to postintensive care unit depression.

Conflict of interest statement

The authors have not disclosed any potential conflicts of interest.

Figures

Figure 1. Study Flow Diagram

ALI, acute lung injury; ICU, intensive care unit

Figure 2. Depression during Early Recovery from Acute Lung Injury, by ICU Blood Glucose Levels

Bars show the proportion of patients with depressive symptoms by severity (gray, depression score ≥8; black, depression score ≥11). Lines show mean depression scores with 95% confidence intervals. Blood glucose (mg/dL) is depicted in tertiles according to mean ICU value (Figure 2A), mean daily minimum value (Figure 2B), and mean daily maximum value (Figure 2C) in the ICU. *, p

Figure 2. Depression during Early Recovery from Acute Lung Injury, by ICU Blood Glucose Levels

Bars show the proportion of patients with depressive symptoms by severity (gray, depression score ≥8; black, depression score ≥11). Lines show mean depression scores with 95% confidence intervals. Blood glucose (mg/dL) is depicted in tertiles according to mean ICU value (Figure 2A), mean daily minimum value (Figure 2B), and mean daily maximum value (Figure 2C) in the ICU. *, p

Figure 2. Depression during Early Recovery from Acute Lung Injury, by ICU Blood Glucose Levels

Bars show the proportion of patients with depressive symptoms by severity (gray, depression score ≥8; black, depression score ≥11). Lines show mean depression scores with 95% confidence intervals. Blood glucose (mg/dL) is depicted in tertiles according to mean ICU value (Figure 2A), mean daily minimum value (Figure 2B), and mean daily maximum value (Figure 2C) in the ICU. *, p

Figure 3. Effect of Documented Hypoglycemia and Mean Daily Minimum ICU Blood Glucose on Depression during Early Recovery from Acute Lung Injury

Bars show the proportion of patients with depressive symptoms, according to severity (gray, depression score ≥8; black, depression score ≥11). Lines show mean depression scores with 95% confidence intervals. Hypoglycemia is defined as a documented blood glucose