The present disclosure provides a method and an apparatus for identifying development of diabetic cardiovascular autonomic neuropathy (DCAN) in a biological subject. In one aspect, the method includes collecting data associated with heart rates of a biological subject, and processing the collected data to extract primary and secondary components of the collected data by performing a principal dynamic mode (PDM) analysis. A significant reduction of the primary or secondary component at a predetermined time period can be indicative of the DCAN development.