Diagnosis of diabetic autonomic neuropathy: a multivariate approach.
OBJECTIVE
In the diagnosis of diabetic autonomic neuropathy (DAN) various autonomic tests are used. We took a novel statistical approach to find a combination of autonomic tests that best separates normal controls from patients with DAN.


METHODS
Twenty-four patients with Type-1 diabetes mellitus considered as having mild to moderate DAN as well as 10 normal, nondiabetic control subjects were analysed, searching for a test or a combination of tests that would optimally discriminate Type-1 diabetes mellitus from controls. Variations of heart rate during deep breathing (deltaR6) and during a Valsalva manoeuvre (VR), the number of reactive sweat glands on the foot (testing sympathetic sudomotor function), and the response of human pancreatic polypeptide to hypoglycaemia [ln(deltahPP+1)] were evaluated.


RESULTS
Respective values for respective sensitivity and specificity values were: deltaR6, 96 and 70%; VR, 96 and 60%; sweat gland function, 71 and 90%; and ln(deltahPP+1), 71 and 90%. In a multivariate analysis approach a single discriminant function separating patients with Type-1 diabetes mellitus from nondiabetic controls was generated [Logit P=288.5-[14.7 deltaR6]-[26.6 ln(deltahPP+1)]]. This function allowed complete separation of patients with Type-1 diabetes mellitus from normal controls.


CONCLUSIONS
We conclude that the combined determination of deltaR6 and of ln (deltahPP+1) optimally separates subjects with parasympathetic impairment from normal subjects. In addition, this combination of tests may serve as a sensitive method for the assessment of DAN.
Diem
P
P
Division of Endocrinology and Diabetes, University of Bern, Inselspital, Bern, Switzerland. peter.diemm@insel.ch
Laederach-Hofmann
K
K
Navarro
X
X
Mueller
B
B
Kennedy
W R
WR
Robertson
R P
RP
D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D001786:Blood Glucose / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis*; D003929:Diabetic Neuropathies / Q000175:diagnosis*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D008297:Male; D015999:Multivariate Analysis; D010191:Pancreatic Polypeptide / Q000032:analysis; D012119:Respiration; D012680:Sensitivity and Specificity; D013545:Sweat Glands / Q000503:physiopathology; D014636:Valsalva Maneuver / Q000502:physiology
D001786:Blood Glucose; D007328:Insulin; D010191:Pancreatic Polypeptide