Coronary artery calcium, hepatic steatosis, and atherosclerotic cardiovascular disease risk in patients with type 2 diabetes mellitus: Results from the Dallas heart study

Introduction: Cardiovascular disease (CVD) risk amongst those with type 2 diabetes (T2D) is heterogenous. The role of imaging-based cardiometabolic biomarkers (e.g., coronary artery calcium [CAC] score, and hepatic triglyceride content [HTC]) in CVD risk stratification in T2D is unclear. To better understand this, we sought to evaluate the individual and joint associations between CAC and hepatic steatosis (HS) with clinical atherosclerotic CVD (ASCVD) in Dallas Heart Study (DHS) participants with and without T2D.

Methods: We examined participants in the DHS, a multi-ethnic cohort study, without self-reported ASCVD. CAC scoring was performed via computed tomography with the mean of two consecutive scores used. HTC was measured using magnetic resonance spectroscopy, and HS was defined as HTC >5.5% The primary outcome was incident ASCVD, defined as coronary heart disease (CHD; myocardial infarction, percutaneous coronary intervention, or coronary artery bypass graft surgery), ischemic stroke, transient ischemic attack, or CVD death. Cox regression analyses, and interaction testing was performed to evaluate the individual and joint associations between CAC and HS with ASCVD. The association between HS and coronary heart disease was validated in the UK Biobank (UKB).

Results: A total of 1252 DHS participants were included with mean age 44.8 ± 9.3 years, mean body mass index 28.7 ± 5.9 kg/m², 55% female, and 59% black with an overall prevalence of T2D of 9.7%. CAC scores were significantly higher (p < 0.01) and HS was significantly more prevalent in those with T2D (p < 0.01). Over a median of 12.3 years, 8.3% of participants experienced ASCVD events. The ASCVD event rate was significantly higher in participants with T2D (20.5% vs 7.0%, p < 0.01). Continuous CAC was associated with ASCVD events in the overall cohort regardless of T2D status with a significant interaction present between CAC and T2D status on ASCVD, P_interaction = 0.02. HTC was not associated with ASCVD risk in participants without T2D but was inversely associated with risk in participants with T2D (HR 0.91, 95% CI 0.83-0.99 per 1% increase in HTC, p = 0.02), P_interaction = 0.02. Amongst 37,266 UKB participants, 4.5% had T2D. CHD events occurred in 2.2% of participants, with 10.2% of events occurring amongst those with T2D. An inverse relationship between HTC and CHD was also found amongst those with T2D in UKB with a significant interaction between T2D status and HTC on CHD (HR per 1% increase in HTC 0.95, 95% CI 0.91-0.99, p = 0.01, P_interaction = 0.02).

Conclusions: In the DHS, we found that CAC was associated with ASCVD risk independent of T2D status. We did not observe an association between HTC and ASCVD in participants without T2D, but there was an inverse association between HTC and ASCVD in those with T2D that was replicated in the UKB cohort. Further investigation is warranted to understand the possible protective association of HS in participants with T2D.