Second Derivative of the Finger Photoplethysmogram Predicts the Risk of Developing Hypertension in Middle-Aged Men

Aim: Increased arterial stiffness impairs the functional and structural properties of arteries, which in turn elevates blood pressure (BP). The aim of this study was to test whether indices obtained from the second derivative of the finger photoplethysmogram (SDPTG), a marker of arterial stiffness, predict future development of hypertension in middle-aged men.Methods: The SDPTG was measured in 902 men without hypertension (mean age 44±6 years) at an annual medical checkup. The development of hypertension was monitored for a maximum of 4 years. Two indices of arterial stiffness were calculated from the SDPTG waveforms: b/a, an index of large elastic arterial stiffness, and d/a, an index of systemic arterial stiffness, including the structural and functional properties of small and muscular arteries and peripheral circulation. A Cox proportional hazards model was used to examine whether the b/a and d/a ratios were independent predictors of future development of hypertension.Results: During the follow-up period, 124 individuals developed hypertension, defined as a systolic/diastolic BP ≥ 140/90 mm Hg or the use of antihypertensive medications. The hazard ratio for the development of hypertension significantly increased in the lowest quartile of the d/a ratio (2.84, 95% confidence interval: 1.58–5.13, p＜0.001) compared with the highest quartile, after adjusting for multiple potential confounders. In contrast, the b/a ratio did not show significant hazard ratios for the development of hypertension.Conclusions: The d/a ratio, calculated from the SDPTG waveforms, predicted the risk of future development of hypertension in this study population.