20 Oct 2010

WDF Strategies for improving diabetes care

Section A: DIABETES MELLITUS

Overview  of  Diabetes  Mellitus
The term diabetes m ellitus is used to denote a broad group of metabolic disorders characterized by long standing hyperglycaemia due to abnormalities of rotein, lipid and carbohydrate metabolism resulting from defective insulin secretion, insulin action, or both.  Most sufferers present with polyuria, excessive thirst and weight loss. Over time, diabetes mellitus may result in damage, dysfunction or failure of many body organs.
At  times,  diabetes  mellitus  with acute  metabolic  present complications such as diabetic ketoacidosis (DKA) or hyperosmolar hyperglycaemic state (HHS) which may lead to coma, stupor and even death. At other times, symptoms may not be severe or are even absent, hence hyperglycaemia sufficient to cause pathological and functional changes may be present for a long time before the diagnosis is made. The long term effects of diabetes mellitus include progressive development of specific complications including retinopathy which can lead to blindness, nephropathy, which may progress to renal failure, neuropathy with risk of foot ulcers and amputation. Others include Charcot joints and features of autonomic neuropathy which include erectile dysfunction. People with diabetes are also at increased risk of cardiovascular, peripheral vascular and cerebrovascular disease. Several pathogenetic processes are involved in the development of
diabetes. These include events which destroy the beta cells of the pancreas with consequent insulin deficiency, and others that result in resistance to insulin action. The abnormalities of carbohydrate, fat and protein metabolism are due to deficient action of insulin on target tissues resulting from insensitivity or lack of insulin.

Types  of  Diabetes
In Type 1 diabetes, the cause is an absolute deficiency of insulin production. Individuals at increased risk of developing this type of diabetes  can  often be  identified by  serological  evidence  of  an autoimmune pathologic process occurring in the pancreatic islets and by genetic markers including lack of c-peptides in blood. In type 2 diabetes, the cause is a combination of resistance to insulin action and an inadequate compensatory insulin secretory response. Type 2
diabetes however accounts for over 90% of all cases of diabetes worldwide. Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy.
The definition applies regardless of whether insulin or only diet modification is used for treatment during the pregnancy. The degree of hyperglycemia (if any) may change over time, depending on the extent of the underlying disease process. A disease process may be present  but  may  not  have  progressed  far  enough  to  cause hyperglycemia. The same disease process can cause impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) without fulfilling
the criteria for the diagnosis of diabetes i.e. blood glucose levels not up to the stipulated diagnostic requirements to make diagnosis of type 1 or type 2 diabetes. In some individuals with type 2 diabetes, adequate glycaemic control can be achieved with dietary therapy, regular exercise, weight reduction (if overweight or obese), and oral glucose lowering agents when necessary. Persons with type 2 diabetes may however later on require insulin for glycemic control. Persons with type 1 diabetes usually have extensive beta cell destruction and therefore little or no insulin secretion from the pancreas and so must have insulin for glycemic
control and for survival, in addition to dietary therapy and regular physical exercise. The severity of the metabolic abnormality in persons with diabetes can progress, regress, or remain the same.

Risk  Factors  for  Developing Diabetes  Mellitus
The risk factors for diabetes mellitus can be divided into genetic and environmental. For  type  1  diabetes  which occurs  mainly  in  children and adolescents, genes are the most important risk factor. Environmental factors which are implicated in type 1 diabetes include some viral infections and exposure to cow milk early in life.
The following are the risk factors implicated in type 2 diabetes:
• Age greater than 45 years
• Family history of diabetes mellitus
• Overweight and obesity (generalised and central obesity)
• Sedentary lifestyle
• Excessive caloric consumption
• History of gestational diabetes mellitus
• Hypertension or treatment for hypertension
• Delivery of a macrosomic baby (birth weight greater than 4.0 kg)
• Dyslipidemia (Elevated serum cholesterol, low HDL cholesterol
[<35mg/dl] and hypertriglyceridaemia [>250 mg/dl])
• Impaired glucose tolerance (IGT) or impaired fasting glucose
(IFG). In these conditions, the blood glucose level is higher
than normal, but not high enough for a diagnosis of diabetes to
be made (see topic on diagnosis of diabetes).
• Low birth weight individuals.
In those at risk of developing type 2 diabetes, addressing the modifiable risk factors especially obesity, sedentary lifestyle and inappropriate diet help to delay or prevent the development of the disease.

Diagnosis  of  Diabetes
The clinical diagnosis of diabetes is often prompted by the presence of its classical symptoms (such as increased urine volume and thirst, recurrent infections, unexplained weight loss) but it must be confirmed by determination of the blood glucose as shown below:
    A random blood glucose level of  >200 mg/dl (11.1 mmol/l)
or
    A fasting blood glucose level of  >126 mg/dl (7.0 mmol/l) after an overnight fast of 8 – 14 hours.
or
    A  two hour plasma glucose concentration > 200 mg/dl (11.1 mmol/l) after a 75g anhydrous glucose load following an overnight fast of 8-14 hours. This test is called the oral glucose tolerance test (OGTT) and should be performed as described by the World Health Organization (WHO).
The diagnosis of diabetes in an asymptomatic person should not  be  made  based on  a  single  abnormal  blood glucose  result.
The  abnormal  value  must  be  reconfirmed on  a  subsequent  day using any of the above methods. If such samples fail to confirm the  diagnosis  of  diabetes  mellitus,  it  is  advisable  to  maintain surveillance with periodic re-testing until the diagnostic situation becomes clear.
For clinical purposes, the diagnosis of diabetes should always be confirmed by repeating the test on another day unless there is unequivocal hyperglycemia with acute metabolic decompensation or obvious symptoms.
The OGTT is not recommended for routine clinical use. For clinical purposes, an OGTT to establish diagnostic status need only be considered if blood glucose values are equivocal (i.e. lies between the levels that establish or exclude diabetes), where repeat testing is inconclusive or in persons strongly suspected to have diabetes, even though the   fasting blood glucose levels are normal. It is also used for the diagnosis of gestational diabetes mellitus (GDM), in the absence of unequivocal hyperglycemia.

Table 1 :WHO diagnostic criteria for diabetes
Diabetes

Fasting Plasma glucose

2 hr plasma glucose *

> 126mg/dl (7.0mmol/l)
or
> 200mg/dl (11.1mmol/l)

Impaired Glucose Tolerance (IGT)
Fasting plasma glucose            < 126mg/dl (7.0mmol/l)
and

2-hr Plasma glucose*

>140 mg/dl and < 200 mg/dl

(> 7.8 mmol/l and < 11.1 mmol/l)

Impaired Fasting Glucose (IFG)

Fasting plasma glucose

2-hr Plasma glucose*

110 mg/dl to 125mg/dl (6.1
mmol/l to 6.9mmol/l) and (if
measured).
< 140 mg/dl (<7.8mmol/l).

*Venous plasma glucose 2 hrs after ingestion of 75gm oral glucose load
N.B. Corresponding values for capillary plasma glucose are:
Diabetes Mellitus: Fasting >126 mg/dl (7.0 mmol/l), 2 hours post glucose load >220mg/dl (12.2 mmol/l).
Impaired Glucose Tolerance: Fasting <126 mg/dl  (7.0 mmol/l) and two hours post glucose load > 160 mg/dl (8.9 mmol/l) and < 220 mg/dl (12.2 mmol/l).
Impaired Fasting Glucose: Fasting  >110 mg/dl (6.1 mmol/l)  and < 126 mg/dl
(7.0mmol/l) and if measured, two hour post glucose load < 160 mg/dl (8.9 mmol/l).

Treatment  Guidelines  for  Type  1  Diabetes
(i.) Diabetes education
Patient education provides a knowledge base which becomes a vehicle for optimal self management, which is essential for good diabetes care.
It should also be a continuous process.
It is vital to empower and motivate the patient with type 1 diabetes
to:
   understand diabetes;
   cope with the disease;
   take control of the disease; and
   develop survival skills.

(ii.) Nutrition
In order to achieve optimal care for the person with type 1 diabetes, initial and ongoing nutrition/dietary education should ideally be delivered by a dietitian where available, in the context of social, cultural and  psychological  influences.  Specific  nutritional  and  energy requirements for children and adolescents must be borne in mind with caloric intake and distribution reflecting the patient’s body weight, life- style, insulin regimen and local circumstances.
A healthy eating plan is required for all persons with type 1 diabetes, consisting of three regular meals and snacks.

(iii.) Physical activity
Regular physical activity is an essential component of a healthy lifestyle and is also beneficial in the management of children, adolescents and adults with type 1 diabetes.
However persons with type1 diabetes need to be educated on how self  blood glucose  monitoring needs  to  be  integrated into the exercise programme and the information used to adjust insulinintake and food intake with exercise. While exercise generally improves metabolic control, it may precipitate hypoglycemia during or after exercise, particularly after vigorous exercise. It may also exacerbate hyperglycemia in persons with poorly controlled type 1 diabetes.

(iv.) Insulin therapy
Insulin is the core treatment for persons with type 1 diabetes. Persons with type 1 diabetes lack functional -islets cells and require insulin for survival. Normal daily insulin secretion is continuous over 24 hours at a slow basal level that suppresses hepatic glucose output, with marked increases in response to meals, which lasts for 2-4 hours (bolus insulin). This ensures blood glucose levels are maintained within a normal range throughout the day.
Insulin replacement therapy should mimic physiological insulin secretion as closely as possible. Bolus insulin is provided as short (soluble/regular) or rapid acting insulin given before meals. It is meant to provide a quick insulin response to control blood glucose after meals and prevent post prandial hyperglycemia. The faster absorption of the rapid acting insulin analogues as compared with short acting (soluble) insulin allows better control of postprandial glucose and the
shorter duration of action reduces the risk of hypoglycaemia. Basal insulin can be maintained by injections of intermediate (NPH) acting insulin or long acting insulin given once or twice daily. The basal insulin provides slowly absorbed background insulin over a 24 hour period.
Health care providers involved in the care of persons with diabetes need to have adequate knowledge and good understanding of the various types of  insulins and their respective mode and duration of action.

 

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