NEW YORK (Reuters Health) – Elevated triglyceride levels are an independent predictor of myelinated fiber density (MFD) loss in patients with mild to moderate diabetic neuropathy, according to a report in the July issue of Diabetes.

The findings support the belief that hyperlipidemia plays a key role in the progression of diabetic neuropathy, Dr. Eva L. Feldman, from the University of Michigan, Ann Arbor, and co-researchers state.

According to the report, research has established HbA1c, the most commonly used marker of hyperglycemia, as a predictor of diabetic neuropathy. Recently, however, there has been evidence that dyslipidemia is also positively correlated with the disorder.

In the current study, Dr. Feldman’s team assessed sural nerve MFD, nerve conduction velocities, vibration perception thresholds, clinical symptoms, and pain in 427 patients with diabetic neuropathy. A variety of standard laboratory tests, including triglyceride measurement, was also performed.

Diabetic neuropathy was considered to be progressing if the MFD over 52 weeks dropped by 500 or more fibers/millimeter-squared. Conversely, non-progression was defined as MFD loss of 100 or fewer fibers/millimeter-squared.

Overall, 133 subjects had progressing neuropathy, 174 had non-progressing neuropathy, and 120 had MFD loss that placed them between these extremes.

Subjects with progressing neuropathy had a 25% drop in MFD from baseline, while non-progressors had no change.

As noted, elevated triglyceride levels at baseline was an independent predictor of neuropathy progression. Decreased peroneal motor nerve conduction velocity was also a risk factor for progression, the results show.

By contrast, active drug treatment, diabetes duration, age, and body mass index were not significant correlates of neuropathy progression.

“The correlation between triglycerides and diabetic neuropathy progression suggests that hyperglycemia and aberrant glucose metabolism are not the only factors contributing to nerve damage,” the authors state. “The exact mechanism underlying triglyceride mediated injury has yet to be elucidated but may (involve) dysregulated lipid metabolism within motor and/or sensory neurons.”

Reference:
Diabetes 2009;58:1634-1640.