ORF33-07 - Standardized Assessment of Arterial Calcifications using High-Resolution Peripheral Computed Tomography in Type 1 Diabetes

Background and

Objectives: Emerging evidence has demonstrated positive correlations between peripheral arterial calcification (PAC), assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT), and coronary and abdominal aortic calcifications. PAC has also been associated with stroke, diabetes and major adverse cardiovascular events. In this study, we aimed to compare PAC between subjects aged ≥50 years with type 1 diabetes (T1D) and non-diabetic controls using a standardized HR-pQCT-based scoring system. Secondary aims in participants with T1D were to: 1) evaluate characteristics of individuals with severe PAC; 2) estimate associations between severe PAC and macro- and microvascular disease; and 3) examine the relationship between glycemic outcomes and PAC.

Methods: This cross-sectional study analyzed baseline data from the BEACON (T1D Bone HEAlth CONnection) study. PAC was assessed by two independent readers on HR-pQCT radius and tibia scans and scored on a standardized 12-point scale (max 6 points for distal forearm and 6 for distal leg). Scores were averaged across readers. Severe PAC was defined as total score of >5. Demographic and medical data were obtained via questionnaires, chart review, physical exam, labs, and 14-day continuous glucose monitor (CGM). Time-weighted 10-year HbA1c was calculated from historical records. Univariate and multivariate regression analyses were performed. Data are presented as median (IQR).

Results: Ninety-six participants with T1D (age 64 [59–67] years, 51% male, current HbA1c 7.0% [6.3-7.7]) and 55 controls (age 65 [61-69] years, 52% male) were included. Interrater agreement for PAC severity was excellent (Cohen’s κ=0.916). Participants with T1D had higher total PAC scores (7.3 [1.0–10.5] vs 0.5 [0.0–2.0]) and a greater prevalence of severe PAC (64% vs 10%) than controls (p < 0.001 for both). Among participants with T1D, those with severe PAC were more likely to be male (62% vs 38%, p=0.029) and had higher body mass index (BMI; 28.1 vs 25.3 kg/m², p=0.038), longer diabetes duration (47 vs 41 years, p=0.002), and worse long-term glycemic control (10-year HbA1c 7.8% vs 7.1%, p=0.002). After adjustment for age, sex, BMI and 10-year HbA1c, severe PAC was associated with increased odds of cardiovascular disease (OR 13.5; 95% CI 2.37–257.0, p=0.016) and retinopathy (OR 10.7; 95% CI 3.5-36.9, p< 0.001) within the T1D cohort. Ten-year HbA1c, but not short-term CGM parameters, predicted severe PAC after adjustment for T1D duration, sex, and BMI (OR per 1% increase in HbA1c 3.1; 95% CI 1.38-4.5, p=0.002).

Conclusions: PAC assessed by HR-pQCT in T1D individuals was strikingly higher compared to controls, despite having relatively good glycemic control. Severe PAC was associated with vascular complications. Opportunistic screening for PAC may improve early identification of individuals at high risk for cardiovascular disease.