The association between glycated hemoglobin levels and in-stent restenosis following percutaneous coronary intervention in coronary artery disease patients

Background – The association between glycated hemoglobin (HbA1c) and in-stent restenosis (ISR) in coronary artery disease (CAD) patients following percutaneous coronary intervention (PCI) is not well understood. We examined the association between HbA1c levels and ISR risk among CAD patients after PCI. Methods – We conducted a retrospective study of 6297 CAD patients following PCI. Patients were stratified into three groups based on admission HbA1c levels. The primary outcome was the incidence of ISR. Adjusted logistic regression models were used to assess the association between HbA1c levels and ISR. We employed the generalized additive model (GAM) to examine potential relationships, with subsequent stratified analyses to evaluate the robustness of the main results and to test for effect modification by additional clinical variables. Results – Among this study participants, a total of 1305 individuals were diagnosed with ISR, representing 20.72% of the cohort. The distribution of participants across HbA1c categories, along with corresponding sample sizes and proportions, was as follows: HbA1c <5.7%, 914 individuals (14.51%). HbA1c ≥5.7% to <6.5%, 2783 individuals (44.20%). HbA1c ≥6.5%, 2600 individuals (41.29%). After controlling for confounders, higher HbA1c levels were significantly linked to a greater risk of ISR [OR:1.18, 95%CI (1.09–1.27), p <0.0001]. Specifically, individuals with HbA1c ≥6.5% exhibited a substantially higher risk [OR:1.70, 95% CI (1.26–2.29), p =0.0005]. The GAM analysis revealed a non-linear association between HbA1c levels and the risk of ISR. The threshold effect analysis revealed a turning point at an HbA1c level of 7.8%. Below this threshold, the association between HbA1c and ISR risk was more pronounced. Conclusion – This study showed a non-linear relationship between increased HbA1c levels and the risk of ISR in CAD patients post-PCI.