Diabetes as a risk factor: How elevated blood sugar damages the kidneys

If not now, when? This is the motto of this year’s World Diabetes Day on November 14th. The International Diabetes Federation (IDF) campaign calls for access to appropriate care for all people with diabetes. Fundamental components of diabetes care include access to insulin and oral medicines, to self-monitoring, to education and psychological support, as well as access to healthy food and a safe place to exercise. The European Renal Association (ERA) wholeheartedly supports this slogan. After all, diabetes mellitus is one of the most common causes of kidney disease. About one in three type 1 diabetics and up to 4 in 10 patients with type 2 diabetes, popularly known as adult-onset diabetes, will eventually develop kidney disease. Well-controlled blood sugar levels and regular kidney checks are therefore essential for strong kidneys. 

According to the International Diabetes Federation (IDF), 463 million adults (1 in 11) worldwide are living with diabetes. One in two adults with diabetes remain undiagnosed. Accordingly, 232 million people live with diabetes without knowing it. Elevated blood sugar levels do not show any symptoms at first, which makes the disease all the more fatal. Those affected die five to ten years earlier on average, usually because the diabetes is diagnosed and treated too late and the kidneys or heart fail. This makes prevention, early detection, and access to appropriate therapies all the more important.

Keep an eye on blood glucose and blood pressure

Renal insufficiency, like diabetes and, for that matter, high blood pressure, usually comes quietly. At the time of diagnosis, all three diseases have often already caused quite some damage completely unnoticed. Who thinks directly of kidney disease when faced with fatigue, swollen legs and eyes, muscle cramps and bone pain, itching skin and loss of appetite? Special attention is therefore required! “Because if you know your blood sugar and blood pressure and have them under control, you can significantly reduce your risk of kidney dysfunction. And anyone who is already diabetic should definitely have their blood and urine tested once a year,” advises Professor Christoph Wanner, Head of Nephrology at the University Hospital of Würzburg in Germany, and President of the ERA.

Urine and blood tests are important early warning system

Increased albumin excretion in the urine indicates impaired filtering capacity of the kidney at a very early stage, long before the effects of kidney weakness are even noticeable. In a healthy person, the concentration of albumin in the urine is below 30 milligrams. A concentration of 30-300 milligrams of albumin is also referred to as microalbuminuria – the first sign of diabetic kidney disease. If albumin is detected in a rapid urine test, this result should be confirmed with another, more precise test. In addition to urine values, blood values are also important to know the kidney function. For example, the higher the creatinine concentration in the blood, the worse the kidneys are working. Based on the creatinine value in the blood and taking age and gender into account, the glomerular filtration rate (GFR) is also calculated. This important marker can be used to determine the severity of kidney disease and classify it into an appropriate stage. The GFR is used to decide on diagnosis, prognosis and treatment.

Other signs of kidney failure in diabetes

In addition to abnormal blood and urine tests, there are other signs of impaired kidney filtering capacity in diabetes: high blood pressure, water retention in the ankles and legs, less need for insulin and antidiabetic medications, urge to urinate at night, nausea, itching, and weakness. Often, however, these symptoms only appear in advanced stages of chronic kidney disease. As soon as the kidneys fail and blood pressure and water balance are derailed, the blood must be purified via dialysis. This is because the accumulation of waste products in the blood is life-threatening.

Diabetics with kidney failure should therefore always keep an eye on their blood sugar and high blood pressure, treat urinary tract infections immediately, and avoid drugs that damage the kidneys. Severe obesity and nicotine use also put a strain on the kidneys. “It’s never too late to adopt a healthy lifestyle. Even people with the disease benefit from a balanced diet and regular exercise,” motivates Christoph Wanner, who, together with his team in Würzburg, launched the European Kidney Health Awareness Campaign Strong Kidneys.

Early detection pays off – the earlier it is detected, the better it is treated!

In a meta-analysis (1), people with diabetes were found to be six times more likely to develop kidney failure requiring renal replacement therapy than people without diabetes. Many die from cardiovascular causes during the progression of kidney disease. In fact, the combination of diabetes and chronic renal failure is strongly associated with cardiovascular disease and higher morbidity and mortality (2). However, the sooner renal dysfunction is detected, the better the chances of treatment. Chronic renal failure can never be cured, but the progression of the disease can be slowed or even stopped!

Information about diabetes: Type 1 diabetes usually occurs in children, so it is often referred to as juvenile diabetes mellitus. The pancreas does not make enough insulin in type 1 diabetes, so sufferers are dependent on insulin for the rest of their lives. The more common variant, type 2 diabetes, usually occurs in people over 40 and is known as adult-onset diabetes mellitus. In type 2, few patients are dependent on insulin because the body still produces insulin but cannot use it. Patients can often manage their elevated blood sugar with diet and medication.

Information about World Diabetes Day: World Diabetes Day (WDD) has been celebrated for 30 years, always on November 14th, the birthday of Sir Frederick Banting, who, together with Charles Best, discovered the vital hormone insulin in 1922. WDD was established by the International Diabetes Federation (IDF) and the World Health Organization (WHO). https://worlddiabetesday.org

Information about Strong Kidneys: Strong Kidneys is a kidney campaign of the European Renal Association (ERA). The multi-talented kidneys cleanse our blood of toxins and waste products, balance water and salt levels and promote healthy bones, regulate blood pressure and blood formation, and produce vital hormones. Yet, kidney function is weakened in one in ten Europeans. Many are unaware of this, which is fatal because the kidneys can no longer recover from the disorder. In case of extremely impaired kidney function, lifelong blood washing or a kidney transplant are the only treatments. Enough reasons to regularly check whether the kidneys are doing well.

(1) Narres, Maria; Claessen, Heiner; Droste, Sigrid; Kvitkina, Tatjana; Koch, Michael; Kuss, Oliver; Icks, Andrea (2016): The Incidence of End-Stage Renal Disease in the Diabetic (Compared to the Non-Diabetic) Population. A Systematic Review. In: PloS one 11 (1), e0147329. DOI: 10.1371/journal.pone.0147329.

(2) KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease.

Share this information in your language

As part of the Strong Kidneys project, ERA provides you with useful background information and scientific content that can be translated and distributed in your own Country to raise awareness on diabetes.

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