The Efficacy of Intensive versus Conventional Insulin Therapy in Reducing Mortality and Morbidity in Medical and Surgical Critically Ill Patients: A Randomized Controlled Study

Abstract

Context: Stress hyperglycemia in critically ill patients has been a matter of debate for years without any conclusive answer till date regarding glucose management and treatment thresholds.

Aims: We planned a study with an aim to compare the efficacy of intensive versus conventional insulin therapy in reducing the mortality and morbidity in critically ill patients. The primary objective was to compare mortality between the two groups. The secondary objective was to find out if intensive insulin therapy is better than conventional insulin therapy in terms of various outcomes such as infections and need for inotropes and transfusion requirements.

Settings and design: It was a prospective randomized controlled study. The study population included 100 patients who received mechanical ventilation and admitted to the intensive care department of a tertiary care institute.

Subjects and methods: Patients were randomly assigned to two groups: intensive insulin therapy (IIT) and conventional insulin therapy (CIT) to receive either intensive or conventional insulin therapy. Insulin infusion was started only when blood glucose levels exceeded 200 mg%. Blood glucose levels were maintained between 80 and 110 mg% in the IIG and between 180 and 200 mg% in the CIG.

Statistical analysis used: The data collected were analyzed separately for both the groups using Student's t-test and Chi-square test.

Results: The two groups were comparable in terms of baseline demographic data including age, sex, preadmission diabetic status, and HbA1c at the time of admission. The two groups were not comparable in terms of Acute Physiology and Chronic Health Evaluation-II scores, and the difference between them was statistically significant with higher scores in the conventional group. The primary outcome, that is, mortality, was higher in the CIG with 29 patients (58%) versus 3 (6%) in the IIG (P = 0.02). The secondary outcomes were the measures of morbidity including infections, need for inotropic support, and need for blood transfusions, and these were significantly higher in the conventional group (P < 0.05).

Conclusions: We conclude that tight glycemic control significantly lowers mortality and morbidity in critically ill patients, both surgical and medical. These benefits appear with the maintenance of tight blood glucose control of 80-110 mg.dL ^{- 1} and not due to administration of insulin.

Keywords: Conventional; conventional glycemic control; insulin infusion; insulin therapy; intensive care; mechanical ventilation; stress hyperglycemia.