Relation of coronary calcium scoring with cardiovascular events in patients with diabetes: The CLARIFY Registry.

INTRODUCTION

Coronary artery calcium (CAC) scoring is not routinely performed in patients with diabetes based on an existing class I indication for statin therapy in these patients. However, CAC scoring may improve risk classification and prediction of atherosclerotic cardiovascular disease (ASCVD) events beyond risk scores in asymptomatic individuals with prediabetes and diabetes, warranting CAC assessment in this population. The routine availability through provision of no-charge CAC as an alternative to routine probabilistic risk scores may improve utilization of preventive therapies especially in traditionally underserved populations.

METHODS

Prospective observational study in a large health system offering no-charge CAC scoring for primary prevention risk prediction with available glycosylated hemoglobin (HbA1c) measurements between June 2015 and March 2019 were divided according to no diabetes (HbA1c <5.7 %), prediabetes (HbA1c 5.7 %-6.4 %), or diabetes (HbA1c ≥ 6.5 % or charted history) and followed for major adverse cardiovascular events [myocardial infarction, stroke, death (MACE) or coronary revascularization]. Patient characteristics, health history, laboratory data, and statin prescription rates were measured at baseline and at one year after CAC scoring.

RESULTS

A total of 12,194 subjects with available HbA1c underwent CAC scoring during the study period (6462 diabetes, 2062 prediabetes, and 3670 without diabetes). At a median follow-up of 1.2 years, there were 458 MACE events (71 patients without diabetes, 66 patients with prediabetes, and 321 patients with diabetes). Among patients with diabetes or prediabetes, increased CAC was associated with MACE (HR 1.38 [1.26-1.51], p < 0.001) and MACE or revascularization (HR 1.70 [1.57-1.85], p < 0.001). In patients with diabetes, CAC category was associated with greater statin initiation (89.6 % for CAC≥400 vs 60.1 % for CAC = 0, p < 0.001) and high intensity statin initiation (42.2 % for CAC≥400 vs 16.8 % for CAC = 0, p < 0.001) at one year post CAC scoring. Patients with diabetes had greater reductions in systolic blood pressure, LDL-C, total cholesterol, and triglycerides from baseline with a CAC ≥400 compared to a lower CAC category (p = 0.007).

CONCLUSIONS

CAC burden is associated with ASCVD risk in patients with diabetes. CAC scoring increases statin prescriptions and reduces ASCVD risk in patients with diabetes, potentially warranting routine CAC assessment in this population.