In Reply: Dr Protogerou and colleagues raise 2 main questions. First, does the relationship between CFPWV and incident hypertension differ for isolated systolic hypertension, isolated diastolic hypertension, and combined systolic and diastolic hypertension? Second, does abnormal CFPWV (as a categorical variable) predict future hypertension or hypertension subtypes?
With regard to different subtypes of hypertension, we observed that of the 338 cases of incident hypertension at examination cycle 8 in our sample, few were isolated diastolic (n = 17) or combined systolic and diastolic (n = 26), whereas the majority were either isolated systolic (n = 102) or not classifiable due to antihypertensive treatment (n = 193). Because of the small number of incident cases that can be classified as isolated diastolic or combined hypertension, we cannot draw conclusions on the relationship between aortic stiffness (whether as a continuous or categorical value) and the subtype of hypertension.