This study aimed to evaluate the reference values for the short-term heart rate variable (HRV), estimate the performance of cardiovascular autonomic neuropathy (CAN) diagnostic tests in the absence of a gold standard, and assess CAN prevalence in our cross-sectional dataset.

The CAN prevalence is rapidly growing in all populations worldwide. No document has been reported about normal reference values for CAN using this test in the Chinese population. This study aimed to evaluate the reference values for the short-term HRV in a large cross-sectional dataset, and to estimate sensitivities and specificities of CAN diagnostic tests using the Bayesian approach, in the absence of a gold standard in another independence dataset. Finally, CAN prevalence was estimated in the investigators' cross-sectional dataset. Firstly, the reference the values for the short-term HRV were calculated in the investigators' previous study (including 371 healthy subjects). This study dataset contained 88 subjects who completed both the short-term HRV test and Ewing's test. Simultaneous inferences about the population prevalence and the performance of each diagnostic test were possible using the Bayesian approach without a gold standard.

Inclusion Criteria:

• Survey participants with undiagnosed CAN, aged 30-80 years, were included in this study.

Exclusion Criteria:

• Some subjects were excluded from the study to eliminate potential confounding factors that may have influenced their CA function 11. Briefly, the exclusion criteria were as follows:

  1. history or findings of arrhythmia, and hyperthyroidism or hypothyroidism;
  2. pregnancy or lactation; and/or
  3. serious hepatic or renal dysfunctions.

Individuals with inclusion and exclusion criteria were recruited from healthy examination centres to assess cardiovascular autonomic function using both the short-term heart rate variability and Ewing's tests.