Both glycemic control and handgrip strength affect microvascular function. Multiscale entropy of photoplethysmographic pulse amplitudes may differ by diabetes status and hand activity. Of a middle-to-old aged and right-handed cohort without clinical cardiovascular disease, we controlled age, sex, and weight to select the unaffected,the well-controlled diabetes, and the poorly controlled diabetes groups. MSEs were calculated from consecutive 1,500 PPG pulse amplitudes of bilateral index fingertips. Thesmall-, medium-,and large-scale MSEs were defined as the average of scale 1, scales 2–4, and scales (...) 5–10, respectively. Intra- and intergroups were compared by one- and two-samplet-tests, respectively. The dominant handMSE5–10was lower in the poorly controlled diabetes group than the well-controlled diabetes and the unaffected groups, whereas the nondominant handMSE5–10was lower in the well- and poorly controlled diabetes groups than the unaffected group. TheMSE1of dominant hand was higher than that of nondominant hand in the well-controlled diabetes. In conclusion, diabetes status and hand dominance may affect the MSE of PPG pulse amplitudes. (shrink)