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Logo of bmjThis ArticleThe BMJ
BMJ. 2007 August 11; 335(7614): 271.
PMCID: PMC1941853
Self Monitoring in Diabetes

Useful in which patients?

Andrew Moore, editor, Bandolier, Sheena Derry, senior research associate, and Grace McGeogh, medical student

The conclusion of the randomised trial reported by Farmer et al1 is in line with a recent systematic review of randomised trials (1000 patients, three trials) and observational studies (60 000 patients, 13 studies),2 which shows that only when the average starting HbA1c is above 8% do studies consistently show benefit of self monitoring.

The inference that self monitoring may be beneficial where control is poor is just common sense. That it is difficult to show benefit when control is already pretty good is also common sense—there is no sensitivity to show a difference even if there were one.

A different way of reporting results of trials like this would be interesting. Our interest is not in the average patient, since few patients are average: what we require is to know the number of patients who showed improvement (however defined, or perhaps at several levels of HbA1c) versus the number showing no change or an increase in HbA1c, as has been done before.3

Generalised policy decisions should not be based on data like these. Extrapolating averages from trials into health economic models does disservice to patients and professionals in several ways. A more useful approach would be some operational and other research to identify the patients who would benefit most from self monitoring and the best way to engage them in actively helping themselves. This would build on professional skill and responsibility.

Where doctors make their own decisions, the results have been terrific, especially in clinical outcomes with major consequence. They did it by deciding which patients with type 2 diabetes would benefit from self monitoring, and prescribing self monitoring in those patients.4


Competing interests: The authors have written a recently published systematic review on this topic.


1. Farmer A, Wade A, Goyder E, Yudkin P, French D, Craven A, et al, on behalf of the Diabetes Glycaemic Education and Monitoring Trial Group. Impact of self monitoring of blood glucose in the management of patients with non-insulin treated diabetes: open parallel group randomised trial. BMJ 2007;335:132-6. (21 July.) [PMC free article] [PubMed]
2. McGeoch G, Derry S, Moore RA. Self-monitoring of blood glucose in type-2 diabetes: what is the evidence? Diabetes Metab Res Rev 2007; [Epub ahead of print].
3. Guerci B, Drouin P, Grange V, Bougneres P, Fontaine P, Kerlan V, et al. Self-monitoring of blood glucose significantly improves metabolic control in patients with type 2 diabetes mellitus: the Auto-Surveillance Intervention Active (ASIA) study. Diabetes Metab 2003;29:587-94. [PubMed]
4. Martin S, Schneider B, Heinemann L, Lodwig V, Kurth H-J, Kolb H, et al. Self-monitoring of blood glucose in type 2 diabetes and long-term outcome: an epidemiological cohort study. Diabetologia 2006;49:271-8. [PubMed]

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