Whether diabetic kidney disease develops quickly or slowly depends on the level of the blood pressure as well as on the level of the blood sugar. Low blood pressure can prevent or at least postpone the appearance and also the further development of kidney damage.

The methods for attaining normal blood pressure have improved continually in recent years. There are now many medicines available for the management of high blood pressure, whose effectiveness and also tolerability become better all the time.

Patients can assess the success of the treatment themselves at home, using a blood pressure meter. Measuring your blood pressure over 24 hours provides a profile for the whole day and also the night, so that unwanted fluctuations can be discovered and targeted for treatment.

Monitoring your own blood pressure is today a ‘must’ in the management of hypertension. As with blood sugar management, a high degree of self-responsibility is required of patients for therapy to be successful. But regular testing of your blood pressure and blood sugar level and taking tablets are worth the effort.

What is normal blood pressure?

The normal values for blood pressure are usually depicted as two numbers, such as 140/80, but what do these numbers actually mean?

• The higher, systolic value describes the pressure in the circulation when the heart muscle contracts and pumps the blood into the arteries.

• The lower, diastolic value provides information about the pressure in the body when the heart muscle is relaxed and the heart is filling with blood.

The systolic pressure therefore reflects the ‘peak pressure’ for the heart and blood vessels, while the diastolic pressure represents the ongoing pressure. Both values are equally important when talking about the development of complications caused by hypertension.

The blood pressure varies considerably during the course of the day and night. Physical and emotional stress, sadness or happiness cause it to rise or fall. During the night, the blood pressure is usually lower than during the day. The World Health Organization (WHO) recently set the boundary between normal and high blood pressure as 140/90 mmHg.

If these values are exceeded over several measurements, hypertension is present: the reasons for this need to be examined and treated. As well as the ‘normal’ threshold, the WHO also defined a state of ‘high normal’ blood pressure (systolic value 130–139 mmHg, diastolic value 85–89 mmHg).

In people with illnesses that increase the risk of cardiovascular disease – and diabetes is one of these – blood-lowering treatments are recommended even in the range of ‘high normal’. According to the WHO, the optimal value is below 120/80 mmHg. The results of epidemiological studies have allowed us to calculate the increased risk of a cardiovascular event for each extra unit of high blood pressure.

For patients with diabetes and associated nephropathy, this risk – regardless of the degree of hypertension – is always considered to be ‘very high’. This means that the probability of having a severe cardiovascular event, such as a heart attack or stroke, within the next 10 years is at least 30%.

Therefore, people with diabetes and signs of kidney damage should not wait until they have hypertension, but should start drug therapy as soon as they have ‘high normal’ blood pressure. Many people today already own a blood pressure meter – but it is important that they know how to use it correctly.

You should not think that you have hypertension after obtaining a high result from a single test of your blood pressure. Normal blood pressure fluctuates much too much for this to be the case. Therefore, control measurements should be made.

You need to have at least two more readings over 140/90 mmHg before you can be considered to have hypertension. These control measurements should be made on different days and, where possible, in different places – not just at the doctor’s surgery but also at home or at work.

This is because there are some people who always give a high blood pressure reading at the hospital or at the clinic, owing to stress or excitement. This is known by doctors and nurses as the ‘white coat effect’. The phenomenon is quite common and seems to occur particularly frequently in people with diabetes.

The white coat effect can be excluded by measuring your blood pressure yourself at home or, better, by a 24-hour measurement. Hypertension in the surgery often resolves itself as soon as you are back in familiar surroundings. Someone who has only white coat hypertension does not need medical therapy, according to current knowledge.