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 (T1D).

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 [MAP]) 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 T1D.