Strict Blood Glucose Control Helps Prevent Nerve Damage in People With Diabetes

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Neuropathy among the Diabetes Control and Complications Trial cohort 8 years after trial completion, by C.L. Martin and colleagues. Diabetes Care 29:340–344, 2006.

What is the problem and what is known about it so far?

A major result of diabetes is neuropathy. Neuropathy is nerve damage and can lead to many problems, such as loss of feeling in your nerves and hands, digestive problems, and not being able to sense the warning signs for a heart attack or low glucose levels.

Why did the researchers do this particular study?

In a major study called the Diabetes Control and Complications Trial (DCCT), researchers showed that people with diabetes were able to stop neuropathy if they took strong measures to lower their glucose levels.

The researchers wanted to check on these patients to find out if they had gotten neuropathy after the DCCT had ended.

Who was studied?

The researchers studied the people who took part in the DCCT. The DCCT included 1,441 people who had diabetes for at least 1 year and did not have severe neuropathy or other complications. The patients were put into two groups: the patients in the "intensive" treatment group took insulin three or more times a day by either injection or pump; the patients in the "conventional" treatment group took insulin twice a day.

How was the study done?

After the DCCT ended, the patients in the intensive group were encouraged to keep using intensive therapy, and the subjects in the conventional group were encouraged to start using intensive therapy. Between one and eight years after the DCCT had ended, all of the patients were given a thorough foot exam and were asked to fill out a questionnaire that asked about neuropathy symptoms.

What did the researchers find?

At the end of the DCCT, 15% of the patients in the intensive group had neuropathy and 23% of the patients in the conventional group had neuropathy. In this study, and after all patients had continued or started intensive therapy, 3.3% were found to have neuropathy.

Having had intensive therapy in the DCCT lowered the chances of having symptoms of neuropathy (such as burning and tingling sensations) at the beginning of this study by 64%; it lowered the chances of having signs of neuropathy (such as foot deformities, sores, and cracked skin) by 45%.

The subjects who had intensive therapy in the DCCT were less likely to be diagnosed as having neuropathy than those who had conventional therapy in the DCCT.

What were the limitations of the study?

Neuropathy was defined differently in the DCCT study than in this study. In the DCCT, subjects were diagnosed by a neurologist as having neuropathy if they had symptoms and signs. This study relied on a questionnaire and foot exam to identify signs and symptoms.

What are the implications of the study?

People who used intensive therapy (three or more insulin doses a day) to lower their glucose levels has a much lower chance of getting neuropathy. It is important to strictly control glucose levels in order to avoid complications such as neuropathy.

FOR MORE INFORMATION

Diabetic Neuropathy (Nerve Damage) and Diabetes

101 Foot Care Tips for People With Diabetes

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