Diabetic polyneuropathy is one of the most common and burdensome secondary diseases in people with diabetes. It affects the peripheral nerves, especially in the feet and legs, and can lead to loss of sensation, numbness, tingling, pain or muscle weakness. A limited sense of touch can lead to long-lasting foot wounds and even amputations. Neuropathy is triggered by chronically elevated blood sugar levels in diabetes as well as obesity and other risk factors such as high blood pressure and elevated blood lipid levels.
Despite intensive research, there is as yet no causal or effective therapy that can permanently halt the progression of diabetic neuropathy or reverse the damage. Treatment is usually limited to the alleviation of symptoms.
The actual damage has often already occurred before the diagnosis
Previous studies suggest that even good blood glucose control can prevent nerve damage in people with type 2 diabetes to a limited extent only. In people with type 1 diabetes, however, this seems to work better. One possible reason: “Type 1 diabetes is often detected early and treated quickly, as the disease usually occurs suddenly and with clear symptoms within a few days to weeks. Type 2 diabetes, on the other hand, often remains undetected for years. Even during this partly asymptomatic phase, damage to the nerves can occur unnoticed and is then already present at the time of diagnosis,” says Dr. Alexander Strom from the DDZ, who, together with DDZ colleague Dr. Gidon Bönhof, carried out a new study that confirms this hypothesis.
Over a period of ten years, more than 140 people with newly diagnosed, very well controlled type 2 diabetes were examined. Their nerve functions were regularly checked using established measurement methods and compared with a control group having a healthy metabolism. The result: The decrease in nerve conduction velocity – a key marker for nerve damage – was similar in both groups.
The condition of the nerves at the time of diagnosis is particularly important
“Our data show that in people with well-controlled type 2 diabetes, the risk of a deterioration in nerve function depends primarily on the condition of the nerves at the time of diagnosis,” explains Prof. Michael Roden, Scientific Director and Spokesperson of the Board of Directors of the DDZ and Director of the Department of Endocrinology and Diabetology at Düsseldorf University Hospital. The nerve conduction velocity in the first year after the diagnosis of diabetes is an important indicator of how many years of reduced nerve function will have to be expected.
“For many of those affected, the decisive damage seems to have already occurred before the actual diagnosis of type 2 diabetes,” explains Strom, who heads the Neuropathy Junior Research Group at the DDZ together with Bönhof. “The more severely the nerves are affected at the time of official diagnosis, the earlier neuropathy will occur later in life.” This could also explain why many new therapeutic approaches have had no effect on existing neuropathy.
However, the results are also good news for people with type 2 diabetes. If their diabetes is optimally controlled, there is no accelerated decline in nerve function.
The focus must be on early detection and prevention
The prognosis tool developed as part of the study could be a helpful tool for predicting the decline in nerve function in people with diabetes.Doctors can use this tool to estimate when a person’s nerve function falls below a critical threshold. Age and initial findings are taken into account. However, it is essential that the disease remains well controlled. In future, the model could help to identify high-risk patients at an early stage and provide specific preventive treatment.
About the German Diabetes Study
The German Diabetes Study observes patients with newly diagnosed type 1 or type 2 diabetes from the outset over a period of seven years. This allows the detection of early warning signs of later complications and the comparison of all approved treatment methods with each other in parallel. The influence of hereditary factors (genes) on the course of the disease is also being investigated. The study is being conducted at seven sites across Germany as part of the German Center for Diabetes Research (DZD), with the DDZ being the partner in charge.
Original publication:
Strom, A., Strassbruger, K., Ziegler, D. et al. Changes Over 10 Years in Peripheral Nerve Function in People with Well-Controlled Type 2 Diabetes and Those With Normal Glucose Tolerance. Neurology (2025). https://doi.org/10.1212/WNL.0000000000213780
Media Contact:
German Diabetes Center
PR
Susan Jörges
Auf'm Hennekamp 65,
40225 Düsseldorf,
Tel. +49 (0)211 3382-450
pressestelle@ddz.de
The German Diabetes Center (DDZ) serves as the German reference center for diabetes. Its objective is to contribute to the improvement of prevention, early detection, diagnosis and treatment of diabetes mellitus. At the same time, the research center aims at improving the epidemiological data situation in Germany. The DDZ coordinates the multicenter German Diabetes Study and is a point of contact for all players in the health sector. In addition, it prepares scientific information on diabetes mellitus and makes it available to the public. The DDZ is part of the Leibniz Association (Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz, WGL) and is a partner of the German Center for Diabetes Research (DZD e.V.). www.ddz.de/en
The German Center for Diabetes Research (DZD) is a national association that brings together experts in the field of diabetes research and combines basic research, translational research, epidemiology and clinical applications. The aim is to develop novel strategies for personalized prevention and treatment of diabetes. Members are Helmholtz Munich – German Research Center for Environmental Health, the German Diabetes Center in Düsseldorf, the German Institute of Human Nutrition in Potsdam-Rehbrücke, the Paul Langerhans Institute Dresden of Helmholtz Munich at the University Medical Center Carl Gustav Carus of the TU Dresden and the Institute for Diabetes Research and Metabolic Diseases of Helmholtz Munich at the Eberhard-Karls-University of Tuebingen together with associated partners at the Universities in Heidelberg, Cologne, Leipzig, Lübeck and Munich. www.dzd-ev.de/en
