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Managing Clinical Problems in Diabetes, Case Study #14: Diagnosis and Classification

Edited by Trisha Dunning AM, RN, MEd, PhD, CDE, FRCNA and Glenn Ward MBBS, BSc, DPhil (Oxon), FRACP, FRCPath

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Mr.  BE was referred by a nurse working in acute care. Mr. BE is a 78-year-old male who had lithotripsy yesterday. He had an incidental random glucose 12.8 BGLs on ward range between 7 and 13. He is not a known diabetic but his GP told him he has borderline diabetes. Both his sisters developed diabetes later in life. His fasting glucose is 8.5 mmol/L and his fasting lipids are slightly elevated. He is having an HbA1c tomorrow. Please advise….

General practitioner

Mr. BE has diabetes (see Figure 2.1). I would check that this fasting glucose performed was a laboratory result to ensure it was accurate. Blood glucose meters have an error of up to 10% or more if they are not calibrated or outdated strips are used. It is important for people with ‘borderline diabetes’ to have a glucose tolerance test (GTT) because some people with a fasting glucose between 5.5 and 7.0 mmol/L have diabetes. Mr. BE should then have at least a fasting glucose or repeat GTT annually.

 

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It is important to diagnose diabetes early so that you can institute appropriate treatment and prevent complications. Five percent of people with diabetes have complications at diagnosis, which indicates that many people have had diabetes long before they were initially diagnosed. The Australian diabetes, obesity and lifestyle study (AusDiab) (Dunstan et al. 2000) demonstrated that for each person with known diabetes there is another one undiagnosed. 

The use of terms such as ‘borderline diabetes’ or ‘mild diabetes’ is unhelpful and can often lead to people being reassured inappropriately. Diabetes is a serious illness with significant morbidity and mortality. Early diagnosis and management is essential to prevent or appropriately manage long-term complications. People with diabetes have a risk of heart disease equivalent to people in the general population who have already had a myocardial infarct. This risk extends to patients with ‘pre-diabetes;’ that is those with impaired fasting glucose or impaired glucose tolerance. 

It is likely that Mr. BE has type 2 diabetes with such a strong family history of diabetes in his sisters. Type 2 diabetes has a stronger genetic link than type 1. The chance of having type 1 diabetes is approximately 8% if one parent has type 1 diabetes. The risk is 25% for type 2 diabetes if a parent has type 2 diabetes.

 
Endocrinologist 

The criteria for diagnosis during a glucose tolerance test assume the test was conducted under conditions recommended by the WHO. This includes not doing the test after recent surgery, where the metabolic response to injury will cause impaired glucose tolerance. Whether lithotripsy is sufficient to explain the current results is not certain, but it would be advisable to repeat the fasting glucose about 6 weeks following the procedure and proceed to oral glucose tolerance test (OGTT) if the fasting plasma glucose is at or above 5.5 mmol/L at that time.

 
Diabetes educator 

Mr. BE has a strong family history of diabetes and may have diabetes, but it is difficult to diagnose diabetes accurately in acute situations as the endocrinologist indicated. Stress hyperglycemia often accompanies critical illness, is usually transient and resolves when the acute situation resolves. The hyperglycemia is most likely due to the counter-regulatory hormone response, increased sympathetic nervous system activity, increased lipolysis and free fatty acids, and reduced insulin secretion. The hyperglycemia does need to be managed (aim 4-6 mmol/L) because it is associated with increased morbidity such as impaired white cell function, infection, stroke and myocardial infarction in diabetics and non-diabetics (American Association of Clinical Endocrinologists 2003).

It is important to establish whether Mr. BE does have diabetes. Given his age he may already have diabetes complication(s) and new diagnosis is associated with a higher rate of complications in older people and greater mortality (Bethel et al. 2007). Older people with newly diagnosed diabetes are twice as likely to have lower leg complications such as pain, cellulitis and gangrene, cardiovascular disease, chronic renal failure and end-stage renal disease, low vision and blindness (Bethel et al. 2007). A full complication assessment is warranted. 

The HbA1c provides useful information but it is not a diagnostic test. Traditionally, an OGTT is recommended in cases such as Mr. BE. However, recent research suggests non-invasive spectroscopic measurements of advanced glycation end products (AGE) in the skin may be useful, accurate, and less invasive (Maynard 2007). AGE are ‘biomarkers of diabetes’ and are closely associated with and predictive of diabetes complications especially retinopathy and nephropathy and are more sensitive at diagnosing diabetes than fasting glucose or HbA1c. However, the test is not widely used at present and may not be available where Mr. BE is being managed.

Studies such as the Diabetes Prevention Program (Knowler et al. 2002), the Finnish Diabetes Prevention Study (Tuomilehto et al. 2001) and the Da Quing study (Pan et al. 1997) demonstrate that lifestyle interventions (diet, exercise and weight management) can prevent diabetes. Metformin (Knowler et al. 2002) and acarbose (Chiasson et al. 2002) may also have a role in prevention. Rosiglitazone may also prevent the onset of type 2 diabetes but is associated with higher risk of myocardial infarction and heart failure (Nissen and Wolski 2007) and may be contraindicated in older people such as Mr. BE. Ramipril normalizes blood glucose levels but does not reduce the incidence of diabetes (Bosch et al. 2006). More recently Schultze et al. (2007) demonstrated that high-fiber diets from cereal (but not fruit and vegetables) and insoluble fiber reduce the risk of diabetes. A meta-analysis also indicated high magnesium diets were associated with lower rates of diabetes (Schultze et al. 2007). 

Mr. BE needs advice about lifestyle measures such as high fiber low fat diet, exercise, and regular follow-up. He needs to receive sensitive advice about his diabetes risks and the positive actions he can take to reduce the risk. He should not be told he has mild diabetes under any circumstances. I would provide him with basic advice about reducing his risk of diabetes or controlling his diabetes and refer him to a dietitian and his GP for regular follow-up.

 

Key points

• The prevalence of diabetes is increasing globally and is linked to obesity.

• Early diagnosis is important to improve health outcomes.

• Type 2 diabetes is a slow progressive disease, complications are often present at diagnosis, and the symptoms may be vague and attributed to other causes. 

• Type 1 diabetes occurs less frequently than type 2 and usually occurs in young people, but it also occurs in older people. 

• Gestational diabetes increases the risk of type 2 diabetes.

 

The aims of the book are to: (1) address commonly encountered diabetes management problems; (2) develop comprehensive responses from a range of relevant health professionals who suggest management approaches relevant to their area of practice. The specific health professionals who provide comments about each case depend on the specific clinical issue; and (3) stimulate thought and discussion. 

The target readership is health professionals from a range of professional backgrounds and general as well as specialist professionals such as general practitioners, nurses, dietitians, and podiatrists. The book will be particularly useful for beginner practitioners specializing in diabetes. In addition, it will provide suggestions or food for thought for more experienced practitioners. The cases will be excerpts from the book are all real and are presented exactly as the information was received from the person making the referral. General practitioners, diabetes educators and people with diabetes referred most of the cases; some were self-referrals by people with diabetes. They represent referrals to various diabetic health professionals and concern commonly encountered clinical issues.

 

Next Week: Case Discussion

For more information on the book, just follow this link to Amazon.com, Managing Clinical Problems in Diabetesalt

Copyright © 2008 by Blackwell Publishing Ltd, UK

Edited by Trisha Dunning AM, RN, MEd, PhD, CDE, FRCNA and Glenn Ward MBBS, BSc, DPhil (Oxon), FRACP, FRCPath