Assessment of Subtle Changes in Diabetes-Associated Arteriosclerosis using Photoplethysmographic Pulse Wave from Index Finger

Distortions in macro- and microcirculation are principal contributors to diabetes-associated complications. This study aimed at investigating the validity of applying non-invasive photoplethysmographic (PPG) waveform parameters in detecting diabetes-induced subtitle changes in arterial stiffness. Between July 2009 and October 2010, totally 94 middle-aged and elderly subjects were recruited including 48 without diabetes (Group 1) and 46 with the disease (Group 2). Demographic (i.e., age, gender), anthropometric (body-mass index), biochemical (i.e., glycated hemoglobin concentration), and hemodynamic (i.e., systolic blood pressure, heart rate) parameters were obtained. Crest time (CT) and crest time ratio (CTR) computed from PPG signals acquired from left index finger were compared with left index finger pulse wave velocity (PWV_finger) obtained from six-channel ECG-PWV system to investigate the differences between the two groups and the associations of these indices with the parameters of testing subjects. Significant difference was only noted in CTR between the two groups (P < 0.005). Despite correlation of both CT and CTR with age, only CTR demonstrated significant associations with hemodynamic parameters. CTR could differentiate diabetic patients from healthy individuals despite absence of difference in arterial stiffness assessed by conventional PWV, highlighting its superior sensitivity to subtle changes in diabetes-associated arteriosclerosis.