Abstract 160: Multiscale Entropy of Photoplethysmographic Pulse Amplitudes of Bilateral Fingertips Varies by Hand Dominance and Diabetes Status

Abstract

Objective: Multiscale entropy (MSE) of photoplethysmographic (PPG) pulse amplitudes may reflect cardiovascular health. In addition, poor glycemic control and weak handgrip strength are related to microvascular dysfunction in diabetes. We hypothesized that MSE of PPG pulse amplitudes between dominant and non-dominant hand may differ by diabetes status. Methods: Of a middle-to-old aged and right hand-dominant population free of prior cardiovascular disease, we matched age, sex, and weight to select the unaffected (no type 2 diabetes, n =36), the well-controlled diabetes (HbA1c <8%, n =22), and the poorly-controlled diabetes (HbA1c ≥8%, n =22) groups. MSEs were calculated from simultaneous consecutive 1,500 resting PPG pulse amplitudes of bilateral index fingers. The small- and large-scale MSEs were defined as the average of scales 1 to 3 (MSE 1-3 ) and scales 4 to 10 (MSE 4-10 ), respectively. Intra- and inter-groups comparisons were performed by 1- and 2-sample t tests. Results: The inter- and intra-groups mean pulse amplitudes did not differ. In contrast, the pulse wave velocity was higher in the two diabetes groups, but was similar between two hands in each group. The dominant hand MSE 4-10 was lower in the poorly-controlled diabetes compared with the unaffected and well-controlled diabetes groups (1.25 vs. 1.52 and 1.49, p=0.001 and 0.017, respectively); whereas the non-dominant hand MSE 4-10 was lower in the well- and poorly-controlled diabetes groups than the unaffected (1.31 and 1.26 vs. 1.54, p=0.007 and 0.002 respectively). There was no intra-groups difference in MSE 4-10 , but a higher MSE 1-3 of dominant hand than that of non-dominant hand in the well-controlled diabetes (1.30 vs. 1.07, p=0.05). Conclusion: Diabetes status and hand activity are related to the MSE of PPG pulse amplitudes. The MSE indexes differed between two hands with euglycemia indicated that local physical inactivity might be an independent contributor to diabetic microvascular dysfunction.