Generally speaking, when we think of ‘kidney disease’, we think of dialysis or a kidney transplant. But it is less well known that kidney disease, which affects more than 10 per cent of the world’s population, can have significant consequences for the functioning of other organs.

For example, the patients also suffer from high blood pressure, which is, incidentally, often a sign of chronic kidney disease. It is also known that kidney disease significantly increases cardiovascular risk.

Even more surprisingly, research has revealed that kidney and brain function are closely linked: kidney dysfunction can be accompanied by cognitive impairment, the severity of which increases with the severity of the damage to the kidneys.

Cognitive impairment: a common yet little-known complication

By filtering waste products and maintaining the balance of water and numerous molecules in our bodies, the kidneys are vital organs for maintaining good health. However, they can sometimes malfunction and gradually lose their ability to filter and cleanse the blood: this is chronic kidney disease, which affects 6 million people in France, and 800 million people worldwide.

This condition inevitably leads to the almost complete loss of kidney function. It can be caused by a variety of causes, such as diabetes (the most common cause in Western countries). It is partly linked to lifestyle, but can also result from genetic or autoimmune causes (in the latter case, the immune system attacks the body it is supposed to defend).

Initially asymptomatic, kidney disease progresses at varying rates (often depending on the underlying cause), over a period of a few days or several years.

Symptoms only appear in the most severe stages. These include neurological complications, which generally manifest as repeated forgetfulness (particularly regarding medication), difficulties managing everyday tasks (such as handling money and carrying out household chores), cognitive decline and difficulty concentrating.

These cognitive impairments are sometimes subtle and can, therefore, be difficult to detect without specific screening. Their frequency and severity correlate with the severity of kidney disease: at the dialysis stage, they can affect up to 70 per cent of patients with kidney failure, and have a major impact on their independence and quality of life.

The most severe form of this brain disorder is dementia.

Patients with kidney disease are also three times more likely to suffer a stroke than the general population. Strokes occurring in patients with kidney failure are also more severe and associated with a lower chance of neurological recovery and a higher mortality rate.

Why is kidney disease so harmful to the brain? How do the........

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