Archive for the ‘meta-analysis’ Tag

Dopexamine & Meta-analysis

Meta-analyses of the effects of dopexamine in major surgery: do all roads lead to Rome? J. J. Pandit. Anaesthesia. 64;6:585-8. (Editorial)

Meta-analyses of the effect of dopexamine on hospital mortality. Gopal et al. Anaesthesia. 64;6:589-94.

Effect of dopexamine infusion on mortality following major surgery: individual patient data multi-regression analysis of published clinical trials. Crit Care Med. 2008 Apr;36(4):1323-9

Two recent meta-analysis have been published in answer to the question “does dopexamine reduce mortality in high risk general surgical patients”, with conflicting results. Pearse’s group found no difference in mortality using the entire data set, but a 50% mortality reduction with low-dose infusions. Gopal’s group found no difference using essentially the same data set, but a different statistical methodology. Panjit’s accompanying editorial does an excellent job of dissecting out why such apparent large differences might arise from the same data, and is recommended.

The take home message for me is that the results of combining heterogeneous studies together into meta-analysis tell us more about the statistical method than they do about the clinical question. Does dopexamine have a role? Is it the dopamine renal failure story all over again? I’m afraid we’ll need more data…..



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Tight Glucose Control – A Meta-analysis

Benefits & Risks of Tight Glucose Control in Critically Ill Adults; A Meta-Analysis. Weiner et al. JAMA. 2008;300(8):933-944.

This meta-analysis of 28 studies of “tight glucose control” on AICU inevitably includes papers studying different protocols on different patients and hence is limited in its applicability. I’m not sure that meta-analysis serves any purpose not bettered by a brief reading of the key studies of this concept, as there is significant heterogenity within the studies and the vast majority of the numbers come from a few well known trials. The failure of any study to replicate Van de Berge’s original 30% mortality reduction now begins to suggest that the benefit of tight glucose control is at best marginal and perhaps non-existent. There is of course a potential harm from the well documented increased risk of hypoglyceamia. The meta-analysis generates an RR of 0.93 (0.85-1.03) for tight glycaemic control. They could identify no stratified group that showed a consistent mortality benefit, including medical ICU patients (as in the original study).

The accompanying editorial is more useful and summarises the problems with investigating glucose control. Namely…

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