Impact of admission hyperglycemia on hospital mortality in various intensive care unit populations

Abstract

Objective: Hyperglycemia in intensive care unit patients has been associated with an increased mortality rate, and institutions have already begun tight glucose control programs based on a limited number of clinical trials in restricted populations. This study aimed to assess the generalizability of the association between hyperglycemia and in-hospital mortality in different intensive care unit types adjusting for illness severity and diabetic history.

Design: Retrospective cohort study.

Setting: The medical, cardiothoracic surgery, cardiac, general surgical, and neurosurgical intensive care units of the University of Maryland Medical Center.

Patients: Patients admitted between July 1996 and January 1998 with length of stay > or = 24 hrs (n = 2713).

Interventions: On intensive care unit admission, blood glucose and other physiologic variables were evaluated. Regular measurements were taken for calculation of Acute Physiology and Chronic Health Evaluation III scoring. Patients were followed through hospital discharge. Admission blood glucose was used to classify patients as hyperglycemic (> 200 mg/dL) or normoglycemic (60-200 mg/dL). The contribution of hyperglycemia to in-hospital mortality stratified by intensive care unit type and diabetes history while controlling for illness severity was estimated by logistic regression.

Measurements and main results: The adjusted odds ratios for death comparing all patients with hyperglycemia to those without were 0.81 (95% confidence interval, 0.37, 1.77) and 1.76 (95% confidence interval, 1.23, 2.53) for those with and without diabetic history, respectively. Higher mortality was seen in hyperglycemic patients without diabetic history in the cardiothoracic, (adjusted odds ratio, 2.84 [1.21, 6.63]), cardiac (adjusted odds ratio, 2.64 [1.14, 6.10]), and neurosurgical units (adjusted odds ratio, 2.96 [1.51, 5.77]) but not the medical or surgical intensive care units or in patients with diabetic history.

Conclusions: The association between hyperglycemia on intensive care unit admission and in-hospital mortality was not uniform in the study population; hyperglycemia was an independent risk factor only in patients without diabetic history in the cardiac, cardiothoracic, and neurosurgical intensive care units.