Optimal Blood Pressure Thresholds for Minimal Coronary Artery Disease Risk in Type 1 Diabetes

OBJECTIVE We aimed to determine optimal blood pressure (BP) thresholds for minimizing coronary artery disease (CAD) risk in people with childhood-onset type 1 diabetes. RESEARCH DESIGN AND METHODS The Pittsburgh Epidemiology of Diabetes Complications (EDC) Study participants without known CAD at baseline (n = 605) were included and followed for 25 years. The associations of time-weighted BP measures (systolic BP SBP, diastolic BP DBP, and mean arterial pressure) with incident CAD were examined by using Cox models. Areas under the receiver operating characteristic curve (AUC) were summarized by different cut points of time-weighted BPs. Risk stratification analyses were then performed on the basis of BP (120/80 vs. ≥120/80 mmHg) and HbA1c (8% vs. ≥8%). RESULTS Baseline mean age was 27 years. Half of the cohort were women and 98% were white. A dose-gradient association was observed for categorized time-weighted BPs and CAD. According to AUC, the optimal cut point for SBP was 120 mmHg and for DBP was 80 mmHg. BP ≥120/80 mmHg was associated with a 1.9 times (95% CI 1.4, 2.6) greater risk of developing CAD than that for BP 120/80 mmHg. Participants with good control of both BP and HbA1c had BP 120/80 mmHg and HbA1c 8%. Those with only high BP (hazard ratio HR 2.0 95% CI 1.1, 3.9) carried a similar risk of developing CAD as those with only high HbA1c (HR 1.6 95% CI 0.97, 2.8). CONCLUSIONS The optimal BP threshold associated with minimal CAD risk is 120/80 mmHg in young adults with childhood-onset type 1 diabetes.