Impact of Diabetes on Management and Outcomes in Patients with Borderline FFRCT

<b>Background:</b> The impact of diabetes on the management and outcomes of patients with borderline CT-derived fractional flow reserve (FFR_CT) remains unclear. <b>Methods:</b> This multicenter study enrolled symptomatic patients with suspected coronary artery disease who underwent Coronary computed tomography angiography (CCTA) between June 2021 and May 2023, yielding FFR_CT values between 0.70 and 0.80. Revascularization occurring within 90 days after CCTA was documented. The endpoint was major adverse cardiovascular events (MACE), as a composite of all-cause death, nonfatal myocardial infarction, and unplanned revascularization. Outcomes were analyzed using Cox proportional hazards models, while the relationship between FFR_CT and MACE was examined using restricted cubic spline analysis (RCS). <b>Results:</b> This analysis included 1515 patients with borderline FFR_CT values, comprising 503 (33.2%) with diabetes. Over a median follow-up of 985 days, 117 MACE occurred. Multivariate analysis showed that revascularization was independently associated with a reduced risk of the endpoint, a protective effect consistent in both non-diabetic (adjusted HR [aHR] 0.53, 95% CI 0.29-0.96; <i>p</i> = 0.036) and diabetic patients (aHR 0.25, 95% CI 0.09-0.71; <i>p</i> = 0.009). RCS revealed a significant non-linear relationship between FFR_CT and MACE in non-diabetic patients (<i>p</i> = 0.002). <b>Conclusions:</b> In patients with borderline FFR_CT, revascularization was linked to a lower incidence of MACE, and this association was consistent regardless of diabetes status.