Self-monitoring of blood glucose in diabetes: is it worth it?

Self-monitoring of blood glucose (SMBG) is advocated as a valuable aid in the management of diabetes. The volume and cost of monitoring continues to increase. SMBG has a number of theoretical advantages/disadvantages which might impact on treatment, outcome and wellbeing. Investigating and quantifying the effect of self-monitoring in a condition where self-management plays a central role poses major methodological difficulties because of the need to minimize confounding factors. Despite the absence of definitive evidence, some situations where monitoring is generally accepted to be beneficial include patients on insulin, during pregnancy, in patients with hypoglycaemia unawareness and while driving. An area of controversy is the role of monitoring in non-insulin-requiring type-2 diabetes where observational and controlled studies give conflicting results. The available evidence does not support the general use of monitoring by all patients with type-2 diabetes, although further research is needed to identify specific subgroups of patients or specific situations where monitoring might be useful. The best use of SMBG in patients with type-2 diabetes might be for those receiving insulin and those on sulphonylurea drugs. The impact of monitoring on patient wellbeing must also be considered, with some studies suggesting adverse psychological effects. Given the large increase in the prevalence of type-2 diabetes, it will be important to define the role of SMBG so that resources can be used appropriately. Presently, the widespread use of SMBG (particularly in type-2 diabetes patients) is a good example of self-monitoring that was adopted in advance of robust evidence of its clinical efficacy.