Changes in pulse pressure, heart rate and double product during squatting in type 1 diabetes according to age

Aims We assessed changes in pulse pressure (PP) and heart rate (HR) during a squatting test, as indirect markers of arterial stiffness and cardiovascular autonomic neuropathy (CAN), respectively, according to age and gender in patients with type 1 diabetes mellitus. Methods We evaluated 160 diabetic patients, divided in four groups of 20 men/20 women according to age (G1: 20–30 years; G2: 31–40 years; G3: 41–50 years; G4: 51–60 years), and 160 non-diabetic matched controls. Each subject underwent a 3-min posture test (standingsquatting-standing) with continuous measurement of arterial blood pressure and HR by a Finapres device. Overall values throughout the test, baseline levels in initial standing position and squatting-induced changes in PP, HR and PPxHR double product were compared between diabetic patients and healthy controls. Results In standing position, greater increase in PP and lower reduction in HR with age led to significantly higher PPxHR double product in diabetic patients compared with controls. In squatting position, a more marked PP increase in absence of appropriate reduction in HR resulted in a greater rise in PPxHR double product in diabetic patients than in healthy subjects. No major gender differences were noted, with the exception of a stronger relationship between PP and age in the female population with diabetes. Squatting-derived indices of CAN were also noted with increasing age in diabetic patients. Conclusions The marked increase in PPxHR double product (“pulsatile stress”) according to age, combined with CAN, may contribute to the higher cardiovascular risk of patients with type 1 diabetes.