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Outcome benefit of intensive insulin therapy in the critically ill
Lead author’s name and email: Prof Greet Van den Berghe, Department of Intensive Care, University Hospital Gasthuisberg, University of Leuven. greta.vandenberghe@med.kuleuven.ac.be
Three-part Clinical Question: Among critically ill ICU patients, is it the normoglycaemia attained or the actual insulin dose infused that confers the beneficial effects of intensive insulin therapy?
Search Terms: 1. critical care 2. insulin 3. RCT filter
The Study: Single-blinded randomized controlled trial with intention-to-treat
The Study Patients: All patients requiring mechanical ventilation, admitted to a predominantly surgical ICU in Belgium. 62% had cardiac surgery. 13% had diabetes. Median APACHE II=9. Median TISS=43. Randomised at ICU admission. All patients fed continuously.
Control group: (N= 783; 783 analysed): Insulin infusion commenced if blood glucose >11.9 mmol/L and maintained between 10.0- 11.1 mmol/L. BM checked 1-4 hrly. Dose adjusted according to algorithm and advice of study physician not involved in patient care.
Experimental group: (N = 765; 765 analysed): Insulin infusion commenced if blood glucose >6.1 mmol/l and maintained between 4.4- 6.1 mmol/L. BM checked 1-4 hrly. Dose adjusted according to algorithm and advice of study physician not involved in patient care.
The Evidence: Multivariate regression analysis of impact of insulin dose vs. blood glucose on morbidity
AAn adjusted odds ratio of 1.240 for mean blood glucose level (per 1.1mmol increase) indicates that for every increase in blood glucose concentration the risk of critical illness polyneuropathy increases by 24%. The Evidence: Multivariate logistic analysis of determinates of ICU mortality
B An adjusted odds ratio of 1.300 for mean blood glucose level (per 1.1mmol increase) indicates that for every increase in blood glucose concentration the risk of death increases by 30%.
EBM Summary Questions: 1. Do the methods allow the adequate testing of the hypothesis? Yes, but raw data not available so the Cat software was unable to perform an analysis. Therefore results and statistical methodology must be taken at face value.
2. Do the statistical tests correctly test the results to allow differentiation of statistically significant results? Statistical methodology not clear.
3. Are the conclusions valid in light of results? Both insulin dose and blood glucose statistically significant risk factors for increased mortality, however blood glucose concentration independent risk factor for significant morbidity.
4. Did results get omitted, and why? Unable to tell, raw data not available.
5. Did they suggest areas of further research? No
6. Did they make recommendations based on results and were they appropriate? Yes- maintain tight glucose control 4.4-6.1mmol/l. Seems appropriate as: (a) There was gradual decrease in mortality with decreasing blood glucose levels, but with no identifiable threshold, and (b) the risks were significantly lower when blood glucose maintained <6.1mmol/l.
7. Is this study relevant to my clinical practice? Yes, significant decrease in mortality and morbidity in tight glucose control group. This is relatively easy and inexpensive to implement .
8. What level of evidence does this study represent? 1+
9. What grade of recommendation can I make on this result alone? A
10. What grade of recommendation can I make when this study is considered along with other available evidence? A
11. Should I change my practice because of these results? Yes- shows tight glucose control improves mortality compared to intermediate control.
12. Should I audit my current practice because of the results? Yes, again relatively simple audit to perform with a defined goal.
Appraised by: Dr Ryan Moffat. Intensive Care Unit, Royal Alexandria Hospital, Paisley.
Email: moffat_ryan@hotmail.com
Kill or Update By: End 2009
Citation: EBM Critical Appraisals. Scottish Intensive Care Society EBM Group. Moffat R .2005: Outcome benefit of intensive insulin therapy in the critically ill: Insulin dose versus glycemic control. Crit Care Med 2003; Vol 31(2): 359-366
Edited for the SICS EBMG by CC, KR. © SICS EBM Group 2005
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