Tuesday, 29 January 2008

UpDates in Diabetes Care with Potential Application To Japanese Medical Practise

The 2008 Guidelines for the Standards of Medical Care in Diabetes have been released by the American Diabetes Association.

I have endeavoured to summarize the important elements of the current ADA guidelines in addition to adding my opinion on their application to clinical practise in Japan plus any other recent evidence in support or contradicting these current guidelines to try and give an overall view of things.

Interestingly, the guidance refers to several interesting areas in particular which include:

1) HbA1c: aiming to get the HbA1c (DCCT-aligned value) as near to 7% is the goal with the aim to avoid hypoglycaemia. However, there is now the goal to get the HbA1c into the normal range if possible. The thought behind this is likely to maximise the advantage of avoiding the microscopic and macroscopic changes associated with diabetes. The HbA1c value that the ADA are advocating is to reduce it to less than 6%, if possible ,with the avoidance of hypoglycaemia.

This may of course be possible in proportionately more type 2 patients than type 1 patients as the severity of disease may be different and the former have relative insulin resistance rather than deficiency. The problem with attaining an HbA1c of <7%>

The downside to the application of such guidelines in Japan is the inability for type 2 patients taking oral hypoglycaemic agents to check their daily blood glucose levels because such monitoring therapy is not currently covered by the medical insurance system and therefore, patients are unable to know if their blood glucose levels are being well maintained on therapy or not. HbA1c measurement every 3 months is insufficient to really know if the patient is having good control. I say this because patients can have a seemingly good HbA1c result but still have frequent hypoglycaemic episodes and hyperglycaemic episodes alike.

Diabetes control can be imagined to be something like the climate and daily weather. The climate is the gradual change in temperature that beig like the HbA1c whereas the daily weather is the blood glucose level. We all know that one day there can be sun and the next there can be rain. The climate does not tell us what has happened on a day to day basis. Hence, measuring the HbA1c only tells us of an average of the glucose control over the last 2-3 months and particularly the last 1 month prior to testing.
Therefore, in Japan, the clinic doctors need to ask particularly about hypoglycaemic episodes and encourage at least urine testing for glucose. However, if patients can afford to buy their own glucose monitoring kits and to manage their diabetes through empowerment and better understanding, then in my opinion, they should be encouraged to do so.

2) Carbohydrate monitoring:
There is advice on carbohydrate counting and glycemic index which is of course part of the famous DAFNE thinking (Diabetes Adjustment for Normal Eating), which allows patients to adjust their insulin doses according to the amount of carbohydrate they consume. This is opposed to the traditional way of doing things where the person eats similar amounts of food every day and fixes their insulin doses. The latter can certainly work in those individuals who have a strict daily regimen, but is inflexible for young patients with hectic lives and who eat infrequently. I have seen such treatment used in the UK to good effect.

The usual regimen of insulin is the fast acting novorapid/humalog isulin for every time food is consumed and a long acting insulin at night to prevent hyperglycaemia e.g. detemir / glargine. However, such a carbohydrate monitoring regimen may not be possible in Japan because Lantus (glargine) was discontuned due to a problem of administration and as far as I am currently aware, detemir has yet to reach these shores. Hence, older regimens of longer acting insulins might be required instead e.g. insulatard, which have a shorter period of activity and can result in severe nocturnal hypoglycaemia.

Currently, some institutions are using mixed combinations of insulins e.g. novomix, three times a day with interesting results in HbA1c, in view of the lack of longer acting insulin availability, but this in my opinion, still does not provide the flexibility in insulin-food control that the DAFNE style of therapy can do. Moreover, I have yet to see any patient thus far being treated with combination of oral hypoglycaemic agent with insulin in Japan, which is standard practise in the USA and UK, with good results in HbA1c levels and reduced weight gain and lower amounts of insulin being required e.g. metformin with insulin.

3) Immunisation: The ADA guidelines suggests that all DM patients should be vaccinated for influenza on an annual basis of more than 6 months of age. Patients should also receive pneumococcal vaccination if more than 65 years of age. The pneumococcal vaccine is available in Japan and should be used in such high risk patients. I am aware though that stocks of the vaccine were previously low and hence, again, it may or may not be possible to administer such therapy depending on your local resources.

4) Lipid Management: Statin therapy should be added to lifestyle therapy (dieting and weight loss) REGARDLESS OF BASELINE LIPID LEVELS for diabetic patients:
i) with overt cardiovascular disease (CVD)

ii) without CVD who are over the age of 40 and have ONE or more CVD risk factors (e.g. hypertension, family history)

The above guidance is also in line with the International Diabetes Federation guidance (IDF) of 2005.

Statin therapy should be considered in patients with low risk if the LDL cholesterol remains > 100mg/dl or in those with multiple CVD risk factors.
Aim for LDL cholesterol in those patients with low risk is less than 100mg/dl.
In patients with overt CVD, a lower LDL cholesterol level of less than 70mg/dl, using high dose statin, is an option.
In the event that LDL-cholesterol levels do not reach these targets, a reduction of LDL-cholesterol of about 40% from baseline is an alternative therapeutic goal.

5) Antiplatelet Agents:Aspirin should be used in patients with a history of CVD as secondary prevention. Aspirin should also be used as Primary prevention in type 1 or type 2 patients at increased cardiovascular risk including all patients over 40 years of age or who have additional risk factors (family history of CVD, hypertension, smoking, dyslipidemia, or albuminuria).

Aspirin is not recommended under 30 years of age due to lack of evidence of benefit in this age group and certainly not to those aged less than 21 years because of the risk of Reye's Syndrome.

Combination with other anti-platelet agents e.g. clopidogrel (Plavix) should be used in patients with severe and progressive CVD.

6) Glucose Goals: There are also guidelines for use of tight control in patients with severe illness. There have been previous trials of use of insulin in critical care patients and the overall outcome has been a benefit in survival. However, a recent German study using insulin in such patients saw a detriment in using tight insulin control.
However, when one reads the methods of the study, they measured blood glucose levels every 1-4 hours. This is a major downfall with the study leaving a potential cause for the increased mortality. In fact, when tight control is required in such patients, hourly blood sugars should be done, and a four hour delay is dangerous, in my opinion. This study was published in a famous journal and the monitoring delay, which I see as a flaw in the study design, was not addressed in the conclusions by the Authors, which is disappointing. I would not advocate a change to the current advice of tight control in critically ill patients unless there are future studies with more rigorous designs showing similar adverse outcomes

There are many other areas of advice in the current ADA guidelines but are too much for today's blog. If you want to read more please go to Diabetes Care, Volume 31, Supplement 1, Jan 2008.

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