- The Diabetes Control and Complications Trial and the UK Prospective Diabetes Study have confirmed the importance of normoglycaemia for the subsequent prevention of diabetic complications.
- Self-monitoring of blood glucose, hailed as one of the most important developments in diabetes care since the discovery of insulin, costs the NHS over £120 million each year (Diabet Med 2005; 22: 511).
- The role of self-monitoring for patients with type-2 diabetes who are not receiving insulin is still under debate.
WHAT IS THE EVIDENCE?
- Observational studies have shown that in patients treated by diet alone, an increased frequency of self-monitoring is associated with better outcomes, including HbA1c and mortality (Diabetes Care 2003; 26: 1,759, Diabetes Care 2002; 25: 245).
- These results may merely indicate that those who are highly motivated (as reflected in the uptake of the opportunity to self-monitor) are likely to do well in the long term (Diabet Med 2005; 22: 1).
- A qualitative study found that patients believed that blood testing was reserved for those whose diabetes was particularly severe (Diabet Med 2004: 21: 1,045).
- In a large study of non-insulin-treated patients with type-2 diabetes, the performance and frequency of SMBG did not predict better control over a three year period (Diabet Med 2005; 22: 900).
- A good-quality systematic review following Cochrane methodology identified six relevant randomised controlled trials that fulfilled their pre-determined quality standards (Diabetes Care 2005; 28; 1,510-51).
The overall effect was for self-monitoring to lower HBA1c by 0.39 per cent, which the authors felt was a clinically significant benefit.
- For people with diabetes controlled with diet and tablets, glycaemic control could be monitored more cost-effectively by using HbA1c alone, measured at three to four monthly intervals (BMJ 2004; 329: 754).
- NICE has supported the use of home blood glucose monitoring in type-2 diabetes, although it indicated that this should be part of integrated self care and 'if the purpose... is agreed with the patient'.
- A multidisciplinary group of healthcare professionals published consensus advice on home blood glucose monitoring (Diabetes Primary Care 2004; 6: 8).
The group agreed that monitoring was not required routinely in type-2 diabetes but suggested it was used in special circumstances (during intercurrent illnesses, when oral hypoglycaemic treatment is changed, if systemic glucocorticoids are prescribed and if post-prandial hyperglycaemia occurs).
- Role of blood glucose self-monitoring is still uncertain.
- Regular HbA1c testing may be as effective.
- Studies show conflicting results.
Dr Louise Newson is a GP in the West Midlands and author of 'Hot Topics for MRCGP and General Practitioners', Pas Test 2006.