Diabetes - Management Flashcards
How many newly diagnosed diabetic patients can be adequately managed on diet alone?
Approximately 50% of new cases of diabetes can be controlled adequately by diet alone, 20-30% will need oral anti-diabetic medication, and 20-30% will require insulin.
The major problem in diabetes is the excess mortality and morbidity due to the long term complications of diabetes. The factors associated with these are:
- duration of diabetes
- early age at onset of disease
- high glycated Hb
- raised BP
- proteinuria, microalbuminuria
- dyslipidaemia
- obesity
How should diet composition be changed in patients with diabetes?
Dietary measures are required in the treatment of all people with diabetes. The aims are to improve glycaemic control, manage weight and avoid both acute and long term complications.
Carbohydrate:
People with type 1 diabetes can match the amount of carbohydrate in a meal with a dose of short acting insulin using methods such as DAFNE (dose adjustment for normal eating). This avoids pre and post prandial hypoglycaemia. For patients with type 2 diabetes, avoidance of refined carbohydrate and restriction of carbohydrate to 45-60% of total energy intake is recommended.
Glycaemic index (GI): Both the amount and source of carbohydrate determine post prandial glucose. Different foods can be ranked by their effect on post prandial glycaemia (GI). Consumption of foods with a low GI is encouraged because they produce a slow, gradual rise in blood glucose - e.g. pasta, rice, lentils. However, GI dose not address the total amount consumed.
Fat:
Intake of fat should be restricted to <35% of energy intake, with <10% as saturated fat, 10-20% monounsaturated fat and <10% from polyunsaturated fat. Omega 3 fatty acids have been shown to assist with secondary cardiovascular prevention.
In what groups of diabetic patients is weight management important?
A high percentage of people with type 2 diabetes are overweight or obese, and many anti-diabetic medications and insulin encourage weight gain. Abdominal obesity also predicts insulin resistance and cardiovascular risk. Weight loss is achieved through a reduction in energy intake and an increase in energy expenditure through physical activity. Overweight patients should be encouraged to reduce calorie intake and take regular exercise for approximately 30 mins daily as this improves insulin sensitivity and the lipid profile, and lowers BP.
Can patients with diabetes drink alcohol?
Alcohol can be consumed in moderation. As alcohol suppresses gluconeogenesis, it can precipitate or protract hypoglycaemia, particularly in patients taking insulin or sulphonylureas. Drinks containing alcohol can be a substantial source of calories and may have to be reduced to assist weight reduction.
Why are most oral anti-diabetic medications used in type 2 diabetes?
Most drugs used to treat type 2 diabetes depend upon a supply of endogenous insulin and therefore have no effect in patients with type 1 diabetes. The sulphonylureas and biguinides have been the mainstay of treatment in the past.
What is the mechanism of action of sulphonylureas?
Sulphonylureas stimulate the release of insulin from the pancreatic B cell. They are best used to treat non-obese people with type 2 diabetes who fail to respond to dietary measures, as treatment is often associated with weight gain.
Name some sulphonylureas used in clinical practice
Chlorpropamide is rarely used, has a long half life and is taken once daily, but may cause prolonged hypoglycaemia.
Gliclazide and glipizide cause few side effects, but glibenclamide is prone to induce hypoglycaemia and should be avoided in the elderly.
Newer long acting preparations such as glimepiride and modified release gliclazide have no apparent risk of hypoglycaemia.
Sulphonylureas are often used as an add on if metformin fails to produce adequate glycaemic control.
What is the term given to patients who fail to respond to initial treatment with sulphonylureas?
These patients are referred to as “primary treatment failures”. Patients with “secondary failure” (after a period of satisfactory glycaemic control) include patients with LADA, those with type 2 diabetes and advanced B cell failure, and most commonly, those who are not adhering to the recommended diet Secondary failure affects 3-10% of patients each year.
What is the main biguinide used in clinical practice? What is their mechanism of action?
The only biguinide currently used in clinical practice is metformin. Metformin reduces the myocardial infarctions in diabetic patients (UK Prospective Diabetes Study) and is widely used as 1st line treatment for patients with type 2 diabetes.
It improves insulin sensitivity and peripheral glucose uptake, and impairs both glucose absorption by the gut and hepatic gluconeogenesis. Endogenous insulin is required for its glucose lowering action, but it does not increase insulin secretion and seldom causes hypoglycaemia. Metformin does not increase body weight and is therefore suitable in obese patients.
What are the side effects of metformin and at what dose is it usually started?
Approximately 25% of patients develop mild gastrointestinal side effects (diarrhoea, abdominal cramps, bloating, and nausea), but only 5% are unable to tolerate it at low doses.
Metform acts synergistically with sulphonylureas so the two can be given together. It is usually given with food 2-3 times daily at an initial starting dose of 500mg BD.
Under what conditions is metformin contraindicated?
Alcohol excess
Impaired renal or hepatic function (due to the increased risk of lactic acidosis)
It should be discontinued temporarily if other medical conditions develop (e.g. shock or hypoxaemia).
What are the alpha glucosidase inhibitors?
These delay carbohydrate absorption in the gut by selectively inhibiting disaccharidases. Acarbose or miglitol is taken with each meal and lowers post prandial blood glucose. Side effects are flatulence, diarrhoea and bloating.
What is the mechanism of action of the thiazolidinediones?
These drugs (TZDs; glitazones) bind and activate peroxisome proliferator activated receptor gamma found in adipose tissue, and work by enhancing the actions of endogenous insulin. Plasma insulin concentrations are not increased and therefore hypoglycaemia is not usually a problem.
What are the side effects of the glitazones?
TZDs have been prescribed widely since the 1990s, but recently a number of adverse side effects have become apparent that has limited their use. Rosiglitazone was reported to increase the risk of myocardial infarction and was withdrawn in 2010. The other TZD in common use, pioglitazone, does not appear to increase the risk of MI but does exacerbate cardiac failure by causing fluid retention, and recent data show that it increases the risk of bone fracture and possible bladder cancer.
When are the glitazones used?
Pioglitazone can be effective in patients with insulin resistance and also has beneficial effect in reducing fatty liver and non alcohol steatohepatitis (NASH). Pioglitazone is usually added to metformin with or without suphonylurea therapy. It may be given with insulin, when it can be effective, but the combination of TZD and insulin markedly increases fluid retention and risk of cardiac failure, so should be used with caution.
