Diagnostic value of the Valsalva ratio reduction in diabetic autonomic neuropathy: use of an age-related normal range.

A curvilinear age-related normal range for the Valsalva ratio is presented. Application of this range was used to identify abnormalities in ratios obtained from 59 patients with diabetes mellitus aged 16-60 years. It was found that 35 had normal, 6 had borderline and 18 had abnormal results. Comparison with other autonomic function tests of the cardiovascular and pupillary systems showed that abnormalities of the Valsalva ratio correlated most highly with the sinus arrhythmia test results. Repeat measurements of ratios in healthy and diabetic subjects yielded coefficients of variation of 15.4% and 10.5% respectively.