Arterial pulse pressure in relation to the duration of type 1 diabetes: a cross-sectional controlled study

Diabetes mellitus and arterial pulse pressure (PP) are two independent cardiovascular risk factors. This cross-sectional study investigated the influence of diabetes duration on PP in type 1 diabetic patients without any cardiovascular disease. PP was measured continuously during 3 minutes (active orthostatic test: 1 min standing--1 min squatting--1 min standing) using a fingertip plethysmograph (Finapres) in 159 type 1 diabetic patients aged 20-60 yrs. They were divided into 4 groups according to diabetes duration: (1) G1 : <10 yrs (n=39); G2: 11-20 yrs (n=45); G3: 21-30 yrs (n=57); and G4: >30 yrs (n=18). In order to separate the effects of age from the effects of diabetes duration, diabetic patients were compared to age- and sex-matched non diabetic controls. PP (expressed in mmHg; mean +/- SD) was higher in men than in women in both diabetic (58 +/- 15 vs. 50 +/- 14; p = 0.001) and non diabetic subjects (55 +/- 14 vs. 47 +/- 12; p = 0.001). Overall PP was higher in diabetic than in non diabetic individuals (54 +/- 15 vs. 50 +/- 13; p = 0.025). PP progressively increased according to diabetes duration: 47 +/- 16 vs. 51 +/- 13 vs. 59 +/- 14 vs. 62 +/- 12, from G1 to G4 respectively; p < 0.0001. Such an increase was not observed in age-matched non diabetic subjects: 50 +/- 11 vs. 52 +/- 12 vs. 49 +/- 14 vs. 52 +/- 18, from G1 to G4, respectively; NS. PP was higher in squatting than in standing position in non diabetic subjects (52 +/- 16 vs. 47 +/- 13; p < 0.0001) and even more in diabetic patients (59 +/- 17 vs. 50 +/- 14; p < 0.0001). Overall, PP difference between diabetic and non diabetic individuals was not significant in standing position (50 +/- 14 vs. 47 +/- 13; NS) although it became highly significant in squatting position (59 +/- 17 vs. 52 +/- 16; p = 0.0005). The squatting-standing difference in PP markedly increased with diabetes duration: 69 +/- 14 during squatting vs. 50 +/- 18 during standing in G4 compared to respectively 50 +/- 17 vs. 44 +/- 15 in G1 diabetic patients. Finally, PP was similar (NS) in diabetic patients with HbA1c < 8% (54 +/- 14) or > or =8% (55 +/- 16), with (57 +/- 17) or without (54 +/- 14) microalbuminuria, treated (56 +/- 14) or not (54 +/- 15) by inhibitors of the renin-angiotensin system. In conclusion, PP progressively increased with the duration of type 1 diabetes, independently of age. Such increase was more marked in squatting than in standing position. The role of such PP rise in the increased cardiovascular risk of patients with type 1 diabetes, although suspected in the recent EURODIAB Prospective Complications Study, deserves further investigation.