Prevalence of peripheral and autonomic neuropathy in newly diagnosed type II (noninsulin-dependent) diabetes

Type II (noninsulin-dependent) diabetes (NIDDM) can be preceded by a relatively long period of disturbed glucose metabolism. Therefore, the prevalence of neuropathy and its possible relationship to metabolic abnormalities were investigated in 95 newly diagnosed type II diabetics (upper age limit was set at 55 years) with a mean age of 49.7 years (men/women ratio 1:1). The study program was as follows: Detailed history, clinical investigation of peripheral nerves, sensory assessment to touch and pain (pinprick), vibration sensation using established techniques, and motor nerve conduction velocities (MNCV) of the fibular (peroneal) and ulnar nerves. Three cardiovascular autonomic function tests were performed: the Valsalva maneuver, standing (ratio between RR-interval_max: RR-interval_min), and deep breathing (maximum/minimum heart rate). Vascular diseases were diagnosed using a conventional 12-lead resting electrocardiogram (ECG) and impedance measurement of the lower extremities. The results were as follows: abnormal vibration sensation in 80.0%, abnormalities of MNCV in 15.7%, abnormal sensations to touch or pinprick in 14.7%, and loss of reflexes in 13.6%. If peripheral neuropathy was defined as having at least three of the four abnormalities plus neuropathic symptoms, the prevalence was 6.3% (6 of 95 patients). Abnormalities of the three cardiovascular autonomic function tests were much less prevalent in type II diabetic patients (2.1–7.3%). In conclusion, the study showed that peripheral and autonomic neuropathy is not common at diagnosis in middle-aged type II diabetic patients without signs of microvascular or macrovascular complications.