Renal diseases often cause high blood pressure, and on the other hand, high blood pressure harms the kidney in the long term and leads to renal insufficiency: 20% of all high-pressure patients alone die of kidney disease. Kidney damage is the third leading cause of death in people with high blood pressure. Kidney disease and hypertension cause each other and often reinforce each other. Routine blood pressure measurements are therefore active kidney protection - for kidney patients, reducing hypertension is an important measure to delay the progression of the disease.
How are kidney and blood pressure related?
One may be surprised that the kidney also regulates the blood pressure. It is not only a detoxification organ and a production site for hormones, it also regulates the levels of the body for salts, water and the level of blood pressure.
Almost all diseases of the kidneys are accompanied by high blood pressure. This may be due to an impaired ability of the kidneys to control the fluid balance, which manifests itself in a decreased urinary excretion. The connection between blood pressure and urinary excretion has been proven - for example, certain hypertension medications (diuretics) have the effect of lowering their blood pressure indirectly by their dehydrating properties alone.
Consequential: causes are mutually dependent
Vascular changes in the kidneys are often the cause of hypertension. Conversely, vascular changes in the kidneys can also be the result of hypertension. Of great importance for the progression of kidney function loss is the extent of proteinuria (protein loss via urine), but also the dimension of hypertension, which afflicts a large number of kidney patients. An effective blood pressure reduction is therefore a crucial prerequisite for slowing down the disease process and can prolong the dialysis-free life.
If there is already an advanced renal insufficiency, the blood pressure should be lowered to at least optimal value (130/80 mm Hg). The latest guidelines of the German Hypertension League even suggest values <125/75 mmHg.
Many studies have shown that the inhibitors of the renin-angiotensin system (primarily ACE inhibitors, but also angiotensin receptor blockers) have a specific protective effect on renal function that goes beyond lowering blood pressure. They are therefore considered as basic therapy and should be used in difficult situations, also high doses or combined.
The treatment of hypertension is not easy and, unfortunately, is still often neglected in kidney-deficient patients. The referral to the specialist, the nephrologist, is often too late, often circumventing the prescriptions of effective, but also more expensive drugs - possibly for budgetary reasons.
The Society for Nephrology wants to sensitize family physicians, but also the population for this important interaction between hypertension and kidney: hypertensive patients are potential kidney patients and form a "risk group" for kidney failure. Renal patients are (almost always) high-pressure patients - with the consequence (= high pressure) the cause (= kidney disease). In order to slow down the disease process, it is essential to control high pressure.