Subclinical autonomic neuropathy in Saudi type 2 diabetic patients

OBJECTIVE: To compare the results of autonomic function tests obtained from diabetic patients who had no symptoms or signs of somatic or autonomic neuropathy with those obtained from control subjects.

METHODS: We studied 32 diabetic Saudi patients (17 males, 15 females) and 34 control subjects (17 of either gender) at King Khalid University Hospital, Riyadh, in the period 2004-2005. The mean age of patients was 50.3+/-5.04, and of controls was 49.9+/-5.86 years. In diabetics, the mean duration of the disease was 8.7+/-3.1 years (range 5-15 years), and the mean glycated hemoglobin was 7.76 +/-1.14. The same observer performed the autonomic function tests.

RESULTS: In diabetics, the resting heart rate (beats/min) was 80.5+/-4.13, mean orthostasis ratio was 1.06+/-0.035, mean Valsalva ratio was 1.19+/-0.036, mean forced sinus arrhythmia was 12.66+/-0.8 beats/min, mean diastolic blood pressure increase in response to isometric exercise was 13.03+/-1.36 mm Hg, and sympathetic skin response was present in only 18 (56.3%) out of 32 patients. These results were significantly different from the control group (p<0.001).

CONCLUSION: Diabetic patients, with no symptoms or signs of neuropathy, can have impaired autonomic function. We consider this subclinical autonomic neuropathy.