Diabetes Care, Vol 21, Issue 7 1159-1161, Copyright © 1998 by American Diabetes Association
Rigiscan evaluation of specific nervous impairment in patients with diabetes and erectile disorders
G Bax, N Marin, F Piarulli, M Lamonica, F Bellio and D Fedele
Department of Internal Medicine, University of Padova, Italy. fedeled@uxl.unipd.it
OBJECTIVE: A proposed new, minimally invasive, and painless method for
studying impairment of the autonomic system of the penile region in type 2
diabetes patients. RESEARCH DESIGN AND METHODS: Thirteen subjects were
selected from 150 patients with type 2 diabetes and erectile dysfunction
who were studied in accordance with the National Institutes of Health
consensus. The 13 subjects (group A), aged 55 +/- 8 years, had acceptable
metabolic control (HbA1c, < 8%); no arterial or venous diseases or
initial Peyronie's disease, as evaluated by penile Doppler ultrasonography
and intracavernous prostaglandin E1 injection; and penile tumescence at the
base (PTB) < 30 mm. Group B consisted of 13 control subjects with the
same characteristics, including mean age (53.1 +/- 9 years), metabolic
control (HbA1c, 7.3 +/- 0.7%), and duration of disease (8.3 +/- 0.7 years),
but PTB was > 30 mm. Student's t test was used to evaluate differences
in the results of autonomic cardiovascular tests, somatic tests (vibration
perception threshold [VPT]), and diabetic neuropathy score (DNS) in both
groups. The coefficient of variation of PTB was evaluated using the
Rigiscan device (Dacomed, Minneapolis, MN), and Bayes' test was used to
test sensitivity, specificity, and positive predictive values of the
cardiovascular tests. RESULTS: Patients with PTB < 30 mm had significant
(P < 0.05) impairment of parasympathetic tests (lying to standing, P
< 0.02; standing to lying, P < 0.04; squat test, P < 0.03)
compared with subjects with higher PTB values. No difference in DNS and VPT
at the base and tip of the penis was found between the two groups. The
variability of the test is 10% in normal subjects and 15% in both groups of
patients. PTB sensitivity was 54%, specificity 89%, and positive predictive
value 79%. CONCLUSIONS: In patients with diabetes and without vascular
diseases, the PTB evaluated by Rigiscan is related to impairment of the
autonomic nervous system. A PTB value < 30 mm may be considered a
useful, noninvasive marker in studying parasympathetic damage of the penile
region.