Abstract
In patients with diabetes mellitus, the coefficient of variation (CV) of the R-R interval on electrocardiography and the threshold of taste were determined in a study that related these parameters to diabetic status and complications. In 160 normal subjects and 112 diabetics, after 15 minutes rest in the supine position, the CV was measured by Autonomic R-100 (MEC, Tokyo, Japan). In 109 normal subjects and 112 diabetics, the threshold of taste in the chorda tympani nerve area was measured by an electrogustometer (MEC, Tokyo, Japan).
In both groups, the CV decreased and the taste threshold increased with aging. However, the CV in diabetics older than 30 showed a statistically significant decrease as compared with that in normal subjects of the same age. The taste threshold in diabetics of 30 to 60 years of age, showed a statistically significant increase as compared with that in normal subjects of the same age. In diabetics, the longer the duration of diabetes mellitus, the more the CV decreased and the taste threshold increased. Further, in diabetics with poorer metabolic control, CV showed a lower level and the threshold of taste a higher level. Patients with symptomatic neuropathy had a statistically significant decrease of CV and an increase of the taste threshold as compared with patients without such clinical symptoms. The taste threshold was found to increase with progression of diabetic retinopathy. CV in diabetics with proteinuria showed a significant decrease as compared with that in those without proteinuria. Furthermore, even in the patients without retinopathy, proteinuria or clinical symptoms of neuropathy, CV showed a significant decrease and the taste threshold a significant increase as compared with those of age-matched normal subjects, and the CV and taste threshold showed a significant negative correlation. These findings indicate that autonomic nerve dysfunction as well as gustatory disorder as dicated in by an electrogustometer precede other diabetic complications, and suggest that these examinations in diabetics may be useful as predictors of the complications in diabetic patients.
