Type 2 diabetes mellitus: diagnosis (part 2)
In a previous article , the etiology, risk factors, pathogenesis, and clinical examination standards for patients with type 2 diabetes mellitus (DM) were examined in detail. The article is devoted to the features of laboratory diagnosis and patient information for this disease. Laboratory research
The diagnosis of diabetes mellitus has serious medical and socio-social consequences for the patient, so the doctor must be fully confident in his conclusion.
- This diagnosis cannot be made on the basis of the presence of glycosuria (the presence of glucose in the urine) or the content of glucose in the blood taken from the finger.
- The basis for the diagnosis of diabetes mellitus is an increased level of glucose in fasting venous blood plasma (at least 8 hours after the last meal) or in a random blood sample.
- To confirm the diagnosis, a blood test must be repeated the next day, unless the patient has symptoms of diabetes mellitus or obvious hyperglycemia (increased blood glucose) with acute metabolic decompensation. If a person has symptoms of diabetes, in order to make a diagnosis, the result of one analysis showing an increased level of glucose in the blood is enough. If the patient has no symptoms, you must be completely sure of the diagnosis before signing the final “sentence” to the patient.
- An oral glucose tolerance test is not recommended as a primary study for diagnosing diabetes. However, patients with abnormal fasting blood glucose are needed to rule out diabetes.
- The diagnostic criteria for diabetes developed by WHO and used by the Diabetes Association of Great Britain (Diabetes UK) are presented in the table.
- When conducting an oral glucose tolerance test, the fasting blood glucose level is first determined. Then the patient drinks 75 g of glucose, and after two hours, a second blood sample is taken to determine the level of glucose.
- Patients with impaired glucose tolerance or impaired fasting glycemia (prediabetes) should be screened annually to rule out diabetes.
- If a patient has impaired glucose tolerance or impaired fasting glycemia, the annual risk of developing diabetes is 4-12%.
|The results of laboratory measurements of the concentration of glucose in the plasma of venous blood (mmol / l)|
|Disease||Fasting test||Oral glucose tolerance test||Random sample|
|Diabetes||≥7.0||or ≥11.1||or ≥11.1|
|Impaired glucose tolerance||and ≥7.8 but||NP|
|Fasting blood glucose||≥ 6.1, but||NP||NP|
|NP – not applicable|
2011 WHO recommendations
In 2011, the World Health Organization published a report with updated recommendations on the use of glycosylated hemoglobin (HbA 1c ) for the diagnosis of type 2 diabetes. The report notes:
“The HbA 1c level indicator can be used for the diagnosis of diabetes subject to strict quality control of tests and their standardization using criteria for compliance with international reference indicators, as well as in the absence of any conditions that impede accurate measurements.
A 6.5% HbA 1c level is recommended as a threshold level in order to diagnose diabetes. A level below 6.5% does not exclude the possibility of diagnosing diabetes by determining blood glucose. The expert group concluded that at the moment there is not enough evidence to provide any formal recommendations regarding the interpretation of HbA 1c levels below 6.5%. ”
Other studies that should also be done to diagnose diabetes include 1 :
- determination of serum creatinine concentration and assessment of glomerular filtration rate (GFR);
- determination of levels of urea and electrolytes in the blood;
- liver tests;
- thyroid function analysis ;
- lipid profile assessment;
- analysis for glycosylated hemoglobin (НbА 1 c ), even if this analysis is not used for diagnosis, the level of НbА 1c must be determined to select the optimal treatment;
- analysis of urine for the presence of glucose, ketone bodies, protein and blood (if protein is detected in the urine, an analysis of the average portion of urine is performed);
- analysis for microalbuminuria (allocation of albumin – a blood protein – with urine);
- ECG (if necessary)
These studies are necessary to determine the overall risk of developing cardiovascular disease and to identify diabetes- related complications.
In the treatment of diabetes, it is necessary to strive for the following clinical indicators:
- fasting plasma glucose level of venous blood from 4.4 to 6.1 mmol / l;
- venous blood glucose after eating from 4.4 to 8.0 mmol / l;
- the target level of HbA 1c is set individually for each patient in the range from;
- lack of glucose in the urine;
- total cholesterol level ;
- high density lipoprotein cholesterol> 1.1 mmol / l;
- fasting triglycerides;
- body mass index in men from 20 to 25;
- body mass index in women from 19 to 24;
- arterial pressure.
Blood lipid control
According to the recommendations of the National Institute of Health and Improvement of Medical Services of Great Britain (NICE) for lipid control, patients with type 2 diabetes need to conduct an annual risk assessment of cardiovascular disease. High-risk patients should be given statins.
Categories of patients who should be considered at high risk for the development of cardiovascular diseases:
- Patients with type 2 diabetes aged 40 years and older:
- retinopathy – pathology of the retina (preproliferative, proliferative, maculopathy);
- nephropathy – damage to the kidneys (including persistent microalbuminuria);
- poor glycemic control (НbА 1c > 9%);
- high blood pressure, in connection with which hypotensive therapy is required;
- elevated total cholesterol (> 6.0 mmol / l);
- signs of metabolic syndrome (central obesity and fasting triglycerides in the blood> 1.7 mmol / l and (or) low density lipoprotein cholesterol is reduced);
- cases of cardiovascular disease among immediate relatives (first degree of kinship).
- Patients with type 2 diabetes aged 18 to 39 years with at least one of the listed conditions.
For non-listed patients, an annual risk assessment for cardiovascular disease (CVD) is performed using a calculator based on a UK prospective diabetes study (UKPDS) 16 .
If the risk of CVD exceeds 20% in 10 years, then in such cases, statins can be prescribed.
Patients with type 2 diabetes are advised to undergo screening for microalbuminuria upon confirmation of the diagnosis and then once a year.
The very first clinical sign of nephropathy is the appearance of a small amount of albumin in the urine. Microalbuminuria is a loss of 30 to 300 mg of protein in the urine per day. It can be detected by the ratio of albumin / creatinine in the first portion of morning urine.
- In men, the albumin / creatinine ratio ≥2.5 indicates microalbuminuria.
- In women, the albumin / creatinine ratio of ≥3.5 indicates microalbuminuria.
- To confirm microalbuminuria in patients with diabetes, it is necessary to record an increase in this indicator in two analyzes conducted with an interval of 4 weeks.
Unfortunately, the upper age limit for screening has not been established, despite a few data on its benefits for patients over 65 years of age. Before making the necessary clarifications, practitioners can reasonably use the exception codes in the treatment of diabetes or in the appointment of ACE inhibitors in elderly patients, if there is any doubt about their clinical benefit.
Systematic patient information
In the UK, according to experts from the state diabetes patient care system, all primary health care funds should be involved in organizing programs to systematically provide information to patients with type 2 diabetes mellitus from the moment the diagnosis is confirmed (in addition to standard medical services).
In the UK, the national DESMOND program (Diabetes Education and Self-Management) is being implemented, aimed at providing information and support in self-monitoring of glucose levels for patients with newly diagnosed or long-diagnosed type 2 diabetes mellitus. Currently, this program, aimed at providing medical care for patients with diabetes, focused on their specific needs, is being implemented in 69 regions of the UK. Within the program, each patient is given 6 hours of systematic thematic classes with a specially trained lecturer. 12 months after participating in the DESMOND program, patients with type 2 diabetes achieve more pronounced weight loss, are less prone to depression and quit smoking more often than patients who receive standard medical care.