Comorbidity and the risk of complications often complicate the management of type 2 diabetes. GPSI Dr Roger Gadsby tackles five common problems
1 Does aspirin have a role in primary prevention of cardiovascular disease?
The role of aspirin in someone with type 2 diabetes who does not have cardiovascular disease is changing.
The 2008 NICE guideline on type 2 diabetes1 still recommends aspirin for primary prevention for those over 50 who do not have uncontrolled hypertension.
However, the new SIGN guideline on type 2 diabetes2 specifically states that low-dose aspirin is not recommended for primary prevention in patients with diabetes.
This change has come about because of new research showing no statistically significant reduction in the risk of major cardiovascular events or all-cause mortality when aspirin was used in primary prevention in people with type 2 diabetes.
There are several current research studies that should give further information about the risk-benefit ratio of aspirin in primary prevention. The findings of these studies are due to be published in the next few years, but at present the recommendation is not to use it.
Note that low-dose aspirin (75mg daily) is still an appropriate treatment for a patient with diabetes and established cardiovascular disease.
2 Should anyone anyone with diabetes be given a statin?
The dilemma is also about which statin should be used and what the most appropriate cholesterol target is.
NICE recommends that in a person who is 40 years old or over, simvastatin 40mg per day should be given unless the cardiovascular risk from non-hyperglycaemic related factors is low – in which case, the risk should be established using a risk engine generated by the UK Prospective Diabetes Study, available at www.dtu.ox.ac.uk/riskengine. If the calculated 10-year cardiovascular risk exceeds 20%, give simvastatin 40mg.
NICE also recommends considering intensifying cholesterol-lowering therapy with a more effective statin if there is existing or newly diagnosed cardiovascular disease or if there is microalbuminuria, to achieve a total cholesterol level below 4mmol/l and a low density lipoprotein cholesterol level below 2mmol/l.
The SIGN guideline recommends that:
• lipid-lowering drug therapy with simvastatin 40mg daily or atorvastatin 10mg is recommended for primary prevention in patients with type 2 diabetes aged over 40 years regardless of baseline cholesterol
• people under 40 with diabetes and other important risk factors (such as microalbuminuria) should be considered for simvastatin 40mg daily.
SIGN does not recommend any target cholesterol values in primary prevention.
The QOF type 2 diabetes cholesterol target is 5mmol/l or less. If this is not achieved with simvastatin 40mg daily, change to a more effective statin and titrate upwards if necessary.
3 Are current HbA1c targets too low for some patients?
Earlier this year UK research suggested the lowest risk of mortality was in patients with an HbA1c of around 7.5%. The study of 50,000 patients from the UK general practice research database suggested the mortality risk then started to rise at levels lower than this.3
The NICE guideline target for HbA1c is 6.5% for those newly diagnosed and those on one or two oral therapies. For those on maximum tolerated doses of two oral therapies, the recommended HbA1c target for adding a third glucose-lowering therapy is 7.5%.
SIGN states that an HbA1c target of 7% among people with type 2 diabetes is reasonable to reduce the risk of microvascular and macrovascular disease.
A target of 6.5% may be appropriate at diagnosis. Targets should be set for individuals in order to balance benefits with harms, particularly weight gain and hypoglycaemia.
In order to get maximum QOF points:
• 50% of people need to have an HbA1c at or below 7%
• 70% – HbA1c needs to be at or below 8%
• 90% – HbA1c needs to be at or below 9%.
If a practice is struggling to meet the 50% below HbA1c of 7% target there might be a temptation to add a third agent. In my opinion this should be avoided as the risks are likely to outweigh the small benefit of reducing blood glucose.
4 What’s the optimum blood-pressure target in type 2 diabetes?
NICE recommends a target blood pressure of below 140/80mmHg, but 130/80mmHg in those with kidney, eye or cardiovascular damage. SIGN recommends a target blood pressure at or below 80 diastolic and below 130 for systolic, in all people with type 2 diabetes.
NICE recommends that initial therapy should be started with an ACE inhibitor (or ARB if the ACE is not tolerated).
If this doesn’t reduce the blood pressure to target, a thiazide diuretic or calcium channel blocker should be added as second line.
If two agents together do not reduce the blood pressure to target, the other agent not used second line should be added.
If three agents do not control the blood pressure to target, further agents such as a-blockers, ß-blockers or other agents will need to be added.
The SIGN guideline agrees with this treatment algorithm.
5 What’s the best way to manage microalbuminuria?
NICE recommends an annual check for microalbuminuria and if present the patient needs to be started on an ACE inhibitor – or an ARB if intolerant. These recommendations are in line with the QOF clinical indicators 13 and 15.
Microalbuminuria can occur in healthy people after they have been standing for a while, which is why tests are done after a period of lying down, usually after sleep. It can occur also after exercise or during a febrile illness.
Microalbuminuria can be detected in a urine sample sent to a laboratory for measurement of the albumin:creatinine ratio. A ratio greater than 2.5mg/mmol for men and 3.5mg/mmol for women indicates microalbuminuria.
• If the ACR is normal, the patient can be left for a repeat check in one year.
• If the ACR is abnormal, NICE recommends that it needs to be repeated within one month.
If this repeat measurement is positive, a diagnosis of microalbuminuria can be recorded. If it is negative, a third sample needs to be sent to the laboratory. If this result is positive, microalbuminuria can be recorded. If negative, microalbuminuria has not been confirmed and the test will need to be repeated annually.
NICE recommends a target blood pressure of below 130/80mmHg if microalbuminuria is present.
The SIGN guideline recommends that blood pressure should be reduced to the lowest achievable level to slow the rate of decline in renal function and to reduce protein loss.
It is important to remember that microalbuminuria is also an independent risk factor for cardiovascular disease.
Dr Roger Gadsby is a GP and associate clinical professor, Warwick Medical School, University of Warwick
Competing interests: none declared
Practical box BP in type 2 diabetes