The prevalence of symptoms of sensorimotor and autonomic neuropathy in Type 1 and Type 2 diabetic subjects

The aim of this study was to analyze the prevalence and severity of sensorimotor and autonomic neuropathic symptoms within an outpatients diabetic population. A total of 350 consecutive Type 1 (26.9%) and Type 2 diabetic subjects were investigated using the Michigan Neuropathy Screening Instrument (MNSI). The original questionnaire was extended with questions on autonomic neuropathy and to include a six-point scale to rate the severity of symptoms, which were recorded accurately in order to avoid overrating. More than one half of Type 2 and nearly a third of Type 1 diabetic subjects suffer from at least one neuropathic symptom; the former suffered significantly more often from paresthesia (P<.05) and burning pain (P=.05). Less than 10% of the study population had autonomic symptoms. The prevalence of symptomatic polyneuropathy (PNP), diagnosed by an abnormal MNSI together with the presence of any symptom, was 16.0% in Type 1 and 37.5% (P<.001) in Type 2 diabetic subjects. Subjects with an abnormal ankle reflex (54.6%) had in 48.2% any sensorimotor, in 35.1% any autonomic, and in 25.7% any sensorimotor plus autonomic symptoms. The corresponding percentages for subjects with an abnormal vibration perception threshold (VPT; 28.9%) were 59.4%, 46.5%, and 34.7%, respectively. An abnormal ankle reflex was significantly correlated to numbness, and to the sum of sensorimotor and autonomic symptoms. An abnormal vibration perception was significantly correlated to numbness, to paresthesia pain, and to the sum of sensorimotor and autonomic symptoms. A higher percentage of Type 2 diabetic subjects had symptoms of neuropathy and the most frequent symptoms were numbness, muscle cramps and postural hypotension.