CVD Risks May Predict Large Fiber Diabetic Neuropathy: Early nerve damage seen in smokers.

WASHINGTON — Cardiovascular disease risk factors also may predict large nerve fiber dysfunction in type 1 diabetic patients, Jackie Elliott, Ph.D., reported at the annual scientific sessions of the American Diabetes Association.

The results suggest that type 1 patients with traditional CVD risk factors should routinely undergo vibration perception threshold (VPT) testing in outpatient clinics to detect subclinical neuropathy, said Dr. Elliott of the diabetes research unit at the Royal Hallamshire Hospital, Sheffield, England.

In a cohort of 1,407 patients who received VPT testing at baseline and during a follow-up visit an average of 7.3 years later, 333 (24%) had an abnormal result, indicating large-fiber dysfunction. The patients had participated in the cross-sectional, multicenter European Diabetes Prospective Complications Study, which looked for risk factors for microvascular complications in a group of 3,250 patients.

The patients with progression to an abnormal VPT had significantly higher levels of the traditional CVD risk factors (male sex, history of CVD, history of smoking, hypertension, high body mass index, high total cholesterol and triglyceride levels) and also had a significantly longer duration of diabetes (14.8 years vs. 12.6 years), poorer glycemic control (8.6% HbA1c vs. 8%), and higher albumin excretion rate (12.6 μg/min vs. 9.5 μg/min), compared with patients who did not progress to an abnormal VPT result, Dr. Elliott said.

In a multiple regression analysis, all of these risk factors except for male sex, duration of diabetes, total cholesterol level, and albumin excretion rate were significant, independent predictors of abnormal VPT testing. These were essentially the same modifiable risk factors that were found to predict neuropathy in a separate analysis of these patients (N. Engl. J. Med. 2005;352:341–50). The strongest predictors were a history of CVD, a history of smoking, and hypertension, according to Dr. Elliott, who reported her findings during a poster session at the meeting.

A VPT test result was considered abnormal if the average of three readings from a biothesiometer on the right big toe and right medial malleolus was more than two standard deviations greater than the predicted mean for the patient's age.