Heart rate variability (HRV) has been considered as a useful tool for detecting cardiac autonomic neuropathy (CAN) and predicting mortality in individuals with diabetes. We evaluated its diagnostic performance for CAN in a hospital-based cohort.
CAN was defined and classified according to Ewing’s criteria using standard 5 cardiovascular reflex test. HRV and power spectral density (PSD) were assessed by DiCAN (Medicore, Seoul, Korea); and diagnostic performance of Standard Deviation Normal to Normal (SDNN) and each PSD domain (total power, TP; very low frequency, VLF; low frequency, LF; high frequency, HF) were evaluated using receiver operating characteristic (ROC) analysis and Youden's index.
After excluding subjects with insufficient data, 2,209 diabetic patients were included the analyses (mean age, 60 ± 11 years; men, 49.6%). Early, definite, and severe CAN were detected in 38.7%, 10.4%, and 4.1% in them. Multivariable Poisson regression adjusted for age and sex showed that all SDNN, TP, VLF, LF, and HF were decreased as severity of CAN increased (P<0.001). Their area under curve of ROC for diagnosis of definite CAN was 0.67 (95% confidence interval, 0.64 - 0.70), 0.71 (0.68 - 0.74), 0.68 (0.65 - 0.71), 0.73 (0.70 - 0.75), and 0.68 (0.65 - 0.71), respectively; and their sensitivity was 0.74, 0.80, 0.70, 0.70, and 0.79, respectively in this analysis. For detection of early CAN, their sensitivity was more decreased to 0.71, 0.64, 0.52, 0.64, and 0.74, respectively.
In conclusion, even though there was significant decrease in HRV according to severity of CAN, HRV could not detect about 30% of diabetic subjects with CAN especially in the case with early impairment. Further studies evaluating diagnostic performance of HRV in various populations are needed.
B. Koo: None. M. Moon: None.