Divergent development of autonomic and peripheral somatic neuropathies in NIDDM

There is no information on the mutual occurrence and the development of autonomic and peripheral somatic neuropathies based on long-term follow-up of patients with non-insulin-dependent diabetes mellitus (NIDDM). We investigated the relation between the changes in autonomic function values and electrodiagnostic values, and the relation between the occurrence of autonomic neuropathy and peripheral somatic polyneuropathy in a group of patients with newly diagnosed NIDDM (n = 133, aged 45-65 years) at baseline and 5 and 10 years later. Parasympathetic autonomic neuropathy was diagnosed on the basis of heart rate variability during deep-breathing and sympathetic autonomic neuropathy on the basis of fall in systolic blood pressure while changing from supine to standing. Polyneuropathy was diagnosed on the basis of both clinical criteria and electrodiagnostic studies (nerve conduction velocity and response-amplitude values). In 10 years 36 patients died, mainly from cardiovascular causes. Altogether 78 patients completed the study. At 10 years, parasympathetic autonomic neuropathy was diagnosed in 61.3% of those with polyneuropathy and 66.7% of those without. Likewise, the frequency of sympathetic autonomic neuropathy was similar in those with polyneuropathy (21.9%) and those without (26.5%). The respective figures for combined (both parasympathetic and sympathetic) autonomic neuropathy were 10.0% and 18.8%. The worsening of parasympathetic and sympathetic autonomic function values was not related to the worsening in electrodiagnostic results with time. In conclusion, the development of autonomic and peripheral somatic neuropathies was divergent in patients with NIDDM suggesting different pathophysiological processes for these neuropathies.