A more pragmatic approach to glycaemic control would have made a useful guideline even better, says Dr Rober Gadsby
A guideline for the management of blood glucose, the third in a series of guidelines for type 2 diabetes, has just been published under the auspices of NICE.
It contains sections on measurement, targets, self-monitoring, lifestyle interventions and patient education. It also has sections on the use of oral medications and insulin to lower blood glucose and on antiobesity drugs. It gives a treatment algorithm for glycaemic control and also contains a useful appendix entitled ‘A guide for adults with type 2 diabetes, and carers – managing blood glucose levels’.
In several of the sections most of the recommendations are graded at level D (based on evidence from expert committee reports or opinions and/or clinical experience of respected authorities) and so it is possible to quibble over them.
In the section on measurement it is recommended that HbA1c readings be taken every 6 months in individuals whose glycaemia is well controlled, and 2-6 monthly in others. Many would suggest that as the life of a red cell can be 10 weeks, HbA1c measurements should be performed at a minimum of 3-monthly intervals.
I look after a number of people with type 2 diabetes whose blood glucose has been very well controlled for between 3 and 5 years, and in this group a yearly check on HbA1c may be sufficient. The target for glycaemic control in the guideline is recommended as an HbA1c level of between 6.5% and 7.5%, which is an understandable target, if tough to meet.
The guideline does not mention the problem that such difficult targets can be demotivating for some individuals with diabetes. The point needs to be made that even if the target is unattainable, any reduction of HbA1c will reduce adverse outcomes. Thus to reduce HbA1c from 11% to 9.5% is worthwhile.
The guideline recommends that metformin should be the first therapy to be used if diet and exercise alone is insufficient to control glycaemia in the overweight (those with a BMI greater than 25). Metformin should also be considered for individuals who are not overweight. The guideline says that metformin is contraindicated in patients with renal impairment, and defines this as a creatinine level above 130µmol/l, whereas many authorities would use a figure of 150 or 160µmol/l.
The guideline uses the generic term ‘insulin secretagogues’ for the sulphonylureas and the newer short-acting agents repaglinide and nateglinide. It discusses in general terms the use of insulin secretagogues and thiazolidinediones in combination therapy. This could be seen as support for the more flexible use of combinations of agents to help in treating glycaemia to achieve the tough targets the guideline recommends.
The issue of concordance with oral agent therapy is an emerging problem, which is only briefly mentioned. It is my opinion that if an individual is not achieving glycaemic targets, concordance issues with present therapy should be explored in detail before any new agent is prescribed.
The section on using insulin in type 2 diabetes is very general.
My conclusion is that in general this new guideline gives helpful recommendations, although the lack of a clear evidence base in a number of areas gives rise to justifiable quibbles about some of the detail.
Copies of Clinical Guidelines for Type 2 Diabetes: Blood Glucose Management can be downloaded free of charge from the NICE website: www.nice.org.uk