Early detection of diabetic patients at risk of developing degenerative complications using electric gustometry: a five-year follow-up study.

OBJECTIVES

Taste impairment has been reported during the course of diabetes. Although a degenerative mechanism has been suspected, the natural history of taste disorders in diabetes remains unknown. The purpose of this study was to describe the five-year evolution of electric gustometry in diabetic patients compared to healthy control subjects and with reference to degenerative complications of the disease.

METHODS

Electrogustometry was studied initially and after 5 years in 73 diabetic out patients and 25 control subjects. None of them had any known cause of taste impairment other than diabetes. Diabetic patients and control subjects did not differ for demographic data and confounding factors.

RESULTS

After five years, the electrogustometric threshold (EGT) significantly increased (51 +/- 6 vs 95 +/- 11 microA; p < 0.001), whereas slight changes occurred in control subjects (23 +/- 4 vs 25 +/- 5 microA; NS). Frequency of electric hypogeusia (EGT > or = 100 microA) increased from 11 to 46% in diabetic patients (p < 0.001), but did not vary in control subjects (4%). EGT was not strongly associated with individual factors such as blood pressure, tobacco and alcohol consumption, but correlated with age (p < 0.001). In the diabetic group, higher EGT were observed in patients treated with insulin (p < 0.001). EGT and its changes were associated with degenerative complication (p < 0.001), but neither with metabolic control, nor with duration of diabetes. Using multivariate analyses, the strongest associations were found with peripheral neuropathy and microalbuminuria (28 to 45% of variance explained; p < 0.001). The predictive value of initial hypogeusia on neuropathy at follow-up was 88% for a positive test and 63% for a negative one.

CONCLUSIONS

These results suggest that the taste nerves transduction function is impaired during the course of diabetes. This impairment is associated with an increased occurrence of degenerative complications, leading to suspect a similar pathophysiological mechanism. Electric gustometry could be an interesting test for early screening for diabetes complications.