The natural history of painful diabetic neuropathy--a 4-year study.

Thirty-nine patients with painful diabetic peripheral neuropathy were selected for a follow-up study to determine the natural history of this condition. Symptoms, motor conduction velocities (MCV) and ankle pressure indices were recorded at the initial assessment and after a mean study period of 4.7 years. Thirty-six patients completed the study and showed no significant changes in symptoms, but there was a significant fall in median nerve MCV. It is concluded that symptoms of established diabetic neuropathy persist for several years, and the changes in MCV may reflect continuing deterioration in nerve function.