| Outcome Measures: |
Primary: Change between below-knee arterial calcification score evaluated by CT-scan at T0 and T2years in type 1 diabetic patients treated or not with metformin., Below-knee artery calcification scores will be obtained after scanning with a 128-slice multidetector CT scanner without contrast, in a craniocaudal direction, from the bottom of the patella down to the ankle region. The 3-mm cross-sectional slices were separately analyzed. Analysis was performed by radiologists kept blind about the results of the color duplex ultrasonography, laboratory tests, and clinical examinations, using a commercially available software package (Heartbeat CaScore; Philips Healthcare). On cross-sectional images, areas of calcification along below-knee arteries with a density ≥130 Hounsfield units attenuation and a surface \>1 mm2 were identified automatically. Calcification score, determined according to the method described by Agatston et al, will be obtained separately for each of the main below-knee arteries (distal popliteal, anterior tibial, posterior tibial, and peroneal arteries) and added up to obtain the calc, Change between T0 baseline visit and T2 years | Secondary: Change between below-knee arterial ultrasonographic occlusion score at T0 and T2years in type 1 diabetic patients treated or not with metformin., Detailed colour duplex ultrasonography will be performed, from the abdominal tree down to the foot arteries, to all the patients, by one physician by center. Occlusive disease will be defined as the presence of either \>70% stenosis or an occlusion in any artery being studied (aorto-ilio-femoral segment, popliteal artery, tibio-peroneal trunk, anterior tibial, posterior tibial, peroneal, and dorsalis pedis arteries). The results will be scored according to an adapted version of an angiographic score based on the severity of the stenosis in the lower limb arteries: 0 if stenosis is \<70%, 2 if stenosis is \>70%, and 3 in case of occlusion. Consequently, duplex scores range from 0 to 39. Mediacalcosis will be also graded for each infrapopliteal artery (popliteal arteries included): 0 if not visible, 1 if mild and discontinuous, 2 if continuous, and 3 if severe with lumen obstruction. Therefore, mediacalcosis scores range from 0 to 36., Change between T0 baseline visit and T2 years|Change between ankle and toe brachial indexes at T0 and T2years in type 1 diabetic patients supplemented or not with metformin., Dorsalis pedis, posterior tibial and brachial arterial systolic blood pressures were measured with a Doppler probe (Parks Medical Electronics, Aloha, OR, USA). Measurements will be taken after participants have rested for 10 min in the supine position. Brachial blood pressure will be measured in the dominant arm with an appropriately sized cuff after 10 min rest in the supine position. Two measurements will be obtained and averaged. Toe systolic pressure measurements will be taken with the Systole Automated Toe Pressure System (Atys Medical, Soucieu-en-Jarrest, France), Change between T0 baseline visit and T2 years|Change between pulse wave velocity at T0 and T2years in type 1 diabetic patients supplemented or not with metformin., Pulse Wave Velocity and pulse wave analysis were measured with applanation tonometry, using SphygmoCor system version 7.1 (Atcor Medical). Central arterial pressure (CAP) and central systolic pressure were derived and central augmentation index (AIx) was calculated. As AIx is influenced by heart rate, an index normalized for a heart rate of 75 beats/min was used. To determine pulse wave velocity, pulse wave forms were recorded at the right carotid artery and left femoral artery sequentially. Wave-transit time was calculated using the R-wave of a simultaneously recorded electrocardiogram as a reference frame., Change between T0 baseline visit and T2 years|Change between coronary calcification score evaluated by CT-scan at T0 and T2years in type 1 diabetic patients treated or not with metformin., Agatston score is a semi-automated tool to calculate a score based on the extent of coronary artery calcification detected by an unenhanced low-dose CT scan, which is routinely performed in patients undergoing cardiac CT. Coronary artery calcification scores will be obtained after scanning with a 128-slice multidetector CT scanner without contrast, in a craniocaudal direction. Analysis was performed by radiologists kept blind about the results of laboratory tests and clinical examinations, using a commercially available software package (Heartbeat CaScore; Philips Healthcare). On cross-sectional images, areas of calcification along coronary arteries with a density ≥130 Hounsfield units attenuation and a surface \>1 mm2 were identified automatically. Calcification score, determined according to the method described by Agatston et al, will be obtained separately for each of the main coronary arteries and added up to obtain the total coronary, Change between T0 baseline visit and T2 years|Change between below- knee arterial calcification score progression between T0 and T2years with initial below-knee arterial calcification score ≤ and >400 (subgroup analysis), Detailed colour duplex ultrasonography will be performed, from the abdominal tree down to the foot arteries, to all the patients, by one physician by center. Occlusive disease will be defined as the presence of either \>70% stenosis or an occlusion in any artery being studied (aorto-ilio-femoral segment, popliteal artery, tibio-peroneal trunk, anterior tibial, posterior tibial, peroneal, and dorsalis pedis arteries). The results will be scored according to an adapted version of an angiographic score based on the severity of the stenosis in the lower limb arteries: 0 if stenosis is \<70%, 2 if stenosis is \>70%, and 3 in case of occlusion. Consequently, duplex scores range from 0 to 39. Mediacalcosis will be also graded for each infrapopliteal artery (popliteal arteries included): 0 if not visible, 1 if mild and discontinuous, 2 if continuous, and 3 if severe with lumen obstruction. Therefore, mediacalcosis scores range from 0 to 36., Change between T0 baseline visit and T2 years
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