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The Importance of Correct Diagnosis Case Histories st 1 October .11.00am . Judy Downey RGN BSc hons AssociateTrainer Education for Health AssociateLecturer New Bucks University Former Committee Member PrimaryCare Diabetes Society @DowneyJude2757 @Lwnurses #LWN #LearnWithNurses Using Medall To get slides To get certificateMedall.org Live chat for any problems getting certificates/slidesClosed FB group & Page Signs and symptoms of diabetes •Thirsty •Passing more urine and more frequently (including nocturia) •Weight loss •Infections (thrush, abscesses) •Poor wound healing •Blurred vision •Tiredness and lethargy An estimated 4.9 million people in the UK have diabetes – 3.9 million diagnosed and approximately 1 million undiagnosed. In the first year of the COVID-19 pandemic, new type 2 diabetes diagnoses dropped by two thirds compared to previous years. Type 1 and type 2 are the most common forms of diabetes, but there are a number of other types that can present in slightly different ways and require different management strategies. Ensuring the correct diagnosis is essential to offering the correct advice and treatment. A diagnosis of diabetes has important legal and medical implications for the patient, so a secure diagnosis is essentialSince 2011, diabetes has been diagnosed on the basis of these WHO criteria Symptoms present(e.g. polyuria, thirst, unexplained weight loss) A single fasting plasma glucose ≥7.0 mmol/L OR A single random plasma glucose ≥11.1 mmol/L OR An HbA1c ≥48 mmol/mol (6.5%)Measurement Diabetes Non-diabetichyperglycaemia Fasting plasma 6.1–6.9 mmol/L (impaired fasting glucose ≥7.0 mmol/L glucose) 2-hour plasma ≥7.8 mmol/L and <11.1 mmol/L glucose post- ≥11.1 mmol/L (impaired glucose tolerance) OGTT Random plasma ≥11.1 mmol/L N/A glucose HbA 1c ≥48 mmol/mol 42–47 mmol/mol (6.0–6.4%) (6.5%)HbA t1cls us the proportion of haemoglobin within red blood cells that is glycated. The level of glycation reflects blood glucose levels over the lifetime of a red blood cell, which is approximately 120 days. Once the haemoglobin is glycated it remains so until the red blood cell is destroyed. So HbA r1cresents a 3-month average of plasma glucose levels. Glucose levels in the days nearer the HbA test1contribute significantly more than those from days further from the test, which means that HbA is weighted to more recent plasma 1c glucose levels (because newer red blood cells glycated more recently will better survive until the time of the test than older red blood cells). What advantages does HbA offer 1c a diagnostic test over other methods?An important advantage of using HbA to di1cnose diabetes is that a venous blood sample can be taken at any time, in contrast to FPG and OGTT, both of which require the individual to be starved and, in the case of the OGTT, detained for a prolonged period. A further benefit of using HbA is1chat it is inherently less subject to the day-to-day variation of other diagnostic tests. When should HbA not be relied on to diagnose 1c diabetes?There are, however, circumstances where HbA s1culd not be used as a diagnostic test for diabetes , notably when blood glucose levels have risen rapidly and, crucially, when type 1 diabetes is suspected. In these situations, HbA wi1c not accurately reflect current levels of glycaemia, and diagnoses of diabetes in these cases will depend on measurement of plasma glucose levels Situations where HbA1c is not appropriate for diagnosing diabetes •ALL children and young people •People of any age suspected of having type 1 diabetes •People at high diabetes risk who are acutely ill (e.g. those requiring hospital admission), post severe trauma or CVD event •People taking medication that may cause rapid glucose rise (e.g. steroids, antipsychotics) •People with acute pancreatic damage, including pancreatic surgery •In pregnancy •In those with end-stage renal disease •People being treated for HIV infection with antivirals •Interpret HbA1c with caution if abnormal red blood cell lifespan Be aware that severe hyperglycaemia in people with acute infection, trauma, circulatory or other stress may be transitory and is not diagnosticMisdiagnosis of diabetes is a frequent finding in primary care, and errors in classification of the type of diabetes are also common. One positive test is sufficient for diagnosis if the patient has osmotic symptoms (increased thirst and micturition, weight loss). Otherwise, a further test should be undertaken to confirm the diagnosis. HbA 1cs been recommended as a pragmatic choice for diagnosing diabetes,but should not be used in situations when blood glucose levels are changing rapidly, notably in children and young people where type 1 diabetes is the concern. NDH identifies a group of individuals at higher risk of developing type 2 diabetes and already at higher cardiovascular risk than the normoglycaemic population.People can now perform their own initial assessment (without a blood test) using an online validated risk tool for type 2 diabetes (Know Your Risk) that can be found on the Diabetes UK website. They are subsequently signposted to receive further support, as necessary.Case 1 Colin, a 51-year-old construction worker, saw the Practice Nurse at his GP surgery for a review of his hypertension. Amongst the results of his pre-arranged blood test was an HbA 1c 67 mmol/mol. Is this result enough to make a diagnosis of diabetes for Colin?The threshold for diagnosing diabetes is an HbA of 1c ≥48 mmol/mol. First, however, you should ask Colin if he has experienced symptoms of thirst, polyuria or weight loss. If osmotic symptoms of diabetes are present, then a single measurement above the threshold is sufficient to diagnose diabetes. If, however, Colin is asymptomatic then the test should be repeated, ideally within 2 weeks (without change of lifestyle or diet). The repeat test that is performed should be the same as the first test, in this case Hb1c.On repeat testing, an HbA o1c65 mmol/mol was recorded. Colin had a BMI of 29.2 kg/m and his mother was known to have type 2 diabetes. With this information, Colin was diagnosed as having type 2 diabetes. Since up to 50% of people with type 2 diabetes have complications at the time of diagnosis, Colin will be assessed for the presence of nephropathy, retinopathy and neuropathy, and his cardiovascular risk estimated.Case 2 Rao, a 42-year-old accountant of Asian origin, on a routine visit to the GP surgery, mentioned to the Practice Nurse that there was a strong family history of type 2 diabetes. Rao was asymptomatic with regard to diabetes symptoms. The Practice Nurse arranged for a venous blood sample to be taken, and a fasting plasma glucose (FPG) level came back at 6.7 mmol/L together with an HbA of 52 mmol/mol. 1c How would you interpret these results? Does Rao have a diagnosis of diabetes?The relevant diagnostic thresholds for diagnosing diabetes are an FPG level of ≥7.0 mmol/L or an HbA of ≥1c mmol/mol or more . This tells us that Rao meets the threshold criteria for HbA , but not for FPG. 1c In this situation, where the individual is asymptomatic and one test is above the threshold but the other is not, the test that indicates diabetes (in this case HbA ) needs to be 1c repeated. If the repeat test is above the threshold, then the diagnosis of diabetes is made. If not (i.e. HbA <48 mmol/mol), then Rao would be diagnosed with 1c non-diabetic hyperglycaemia (NDH). This should be coded on his records and follow-up arranged, with repeat testing at appropriate intervals.In England, Rao should be referred to the Healthier You: NHS Diabetes Prevention Programme for further advice and support. It is important to recognise that the diagnostic overlap of different tests for diabetes is not identical . If the situation is such that two different tests have been performed (such as FPG and HbA ) an1cboth are above the diagnostic threshold, then the diagnosis of diabetes is made, even if there are no symptoms. What other measurements, apart from HbA and fas1cng plasma glucose, can be used to diagnose diabetes?Case 3 Rachael, 43-years-old, complained to her GP of fatigue. Amongst her blood test results was an HbA of 46 mmol/mol. She had a BMI of 1c 2 28.4 kg/m and her mother has a diagnosis of type 2 diabetes. How would you interpret Rachael’s HbA 1c measurement?Rachael’s HbA d1cs not meet the threshold for diagnosing diabetes, but is within the range indicating Non Diabetic Hyperglycaemia in the UK (42–47 mmol/mol). Otherwise known as Pre-Diabetes. NDH is a situation in which individuals do not meet the criteria for diabetes, but have results that place them at increased risk of developing type 2 diabetes. Why is it important to identify Rachael’s non-diabetic hyperglycaemia?