Impact of diabetes on coronary severity and cardiovascular outcomes in patients with heterozygous familial hypercholesterolaemia

Aims: Type 2 diabetes mellitus (T2DM) is an independent risk factor for cardiovascular disease. However, the association between T2DM and coronary artery disease (CAD) in patients with heterozygous familial hypercholesterolaemia (HeFH) has not been thoroughly evaluated. Our study aimed to assess the effect of T2DM on CAD severity and hard cardiovascular endpoints in a HeFH cohort.

Methods and results: A total of 432 patients with HeFH with a molecular and/or clinical Dutch Lipid Clinic Network score ≥6 (definite and probable) were enrolled. Patients were divided into a T2DM group (n = 99) and a non-T2DM group (n = 333). The severity of coronary stenosis was assessed by the number of diseased vessels and Gensini, SYNTAX, and Jeopardy scores. Hard endpoints included a composite of non-fatal myocardial infarction, non-fatal stroke, and cardiac death. Cox regression and Kaplan-Meier analyses were used to evaluate the effect of T2DM on hard cardiovascular endpoints. The prevalence of CAD was higher in patients with T2DM compared with those without (96.0% vs. 77.5%, respectively; P < 0.001). Patients with T2DM demonstrated a greater number of diseased vessels (P = 0.029) and more severe coronary lesions with high Gensini, SYNTAX, and Jeopardy score tertiles (P = 0.031, P = 0.001, and P = 0.024, respectively). During a median of 3.75 years up to a maximum of 9 years of follow-up, hard endpoints occurred in 13 of 99 patients with T2DM and 16 of 333 without T2DM at baseline. Compared with patients without T2DM, patients with T2DM were at a significantly greater risk of hard endpoints [multivariate adjusted hazard ratio (HR) 2.32, 95% confidence interval (CI) 1.02-4.84; P = 0.025]. Additionally, patients with T2DM and good glucose control (HbA1c < 7.0%) were at a lower risk of hard endpoints compared with those with poor glucose control (HbA1c ≥ 7.0%, HR 0.08, 95% CI 0.01-0.56; P = 0.011).

Conclusion: We conclude that T2DM is an independent predictor of CAD severity when assessed by number of diseased vessels, Gensini, SYNTAX, Jeopardy scores, and hard cardiovascular endpoints, suggesting that T2DM could be further used for risk stratification of patients with HeFH.