The American Diabetes Association and Surviving Sepsis Campaign recommend tight glucose control in critically ill patients based largely on 1 trial that shows decreased mortality in a surgical intensive care unit. Because similar studies report conflicting results and tight glucose control can cause dangerous hypoglycemia, the data underlying this recommendation should be critically evaluated.
To evaluate benefits and risks of tight glucose control vs usual care in critically ill adult patients.
MEDLINE (1950-2008), the Cochrane Library, clinical trial registries, reference lists, and abstracts from conferences from both the American Thoracic Society (2001-2008) and the Society of Critical Care Medicine (2004-2008).
We searched for studies in any language in which adult intensive care patients were randomly assigned to tight vs usual glucose control. Of 1358 identified studies, 34 randomized trials (23 full publications, 9 abstracts, 2 unpublished studies) met inclusion criteria.
Two reviewers independently extracted information using a prespecified protocol and evaluated methodological quality with a standardized scale. Study investigators were contacted for missing details. We used both random- and fixed-effects models to estimate relative risks (RRs).
Twenty-nine randomized controlled trials totaling 8432 patients contributed data for this meta-analysis. Hospital mortality did not differ between tight glucose control and usual care overall (21.6% vs 23.3%; RR, 0.93; 95% confidence interval [CI], 0.85-1.03). There was also no significant difference in mortality when stratified by glucose goal ( very tight: < or = 110 mg/dL; 23% vs 25.2%; RR, 0.90; 95% CI, 0.77-1.04; or  moderately tight: < 150 mg/dL; 17.3% vs 18.0%; RR, 0.99; 95% CI, 0.83-1.18) or intensive care unit setting ( surgical: 8.8% vs 10.8%; RR, 0.88; 95% CI, 0.63-1.22;  medical: 26.9% vs 29.7%; RR, 0.92; 95% CI, 0.82-1.04; or  medical-surgical: 26.1% vs 27.0%; RR, 0.95; 95% CI, 0.80-1.13). Tight glucose control was not associated with significantly decreased risk for new need for dialysis (11.2% vs 12.1%; RR, 0.96; 95% CI, 0.76-1.20), but was associated with significantly decreased risk of septicemia (10.9% vs 13.4%; RR, 0.76; 95% CI, 0.59-0.97), and significantly increased risk of hypoglycemia (glucose < or= 40 mg/dL; 13.7% vs 2.5%; RR, 5.13; 95% CI, 4.09-6.43).
In critically ill adult patients, tight glucose control is not associated with significantly reduced hospital mortality but is associated with an increased risk of hypoglycemia.