Glycemic control and renal function decline in patients with chronic coronary syndrome

Background Diabetes mellitus significantly contributes to renal complications, especially in patients with coronary artery disease (CAD). Effective glycemic control is important; however, the ideal hemoglobin A1c (HbA1c) targets for this population remain uncertain. Purpose We aimed to identify appropriate HbA1c targets for patients with diabetes and chronic coronary syndrome. Methods This study included 1,223 stable patients with CAD who underwent percutaneous coronary intervention. Patients were categorized based on their HbA1c levels. The primary outcome was the incidence of renal events, which was defined as a decline in the estimated glomerular filtration rate (eGFR) of more than 25%. Cox proportional hazards regression models were employed to assess the impact of glycemic control on renal function. Results Over a mean follow-up of 3.2 ± 2.0 years, the lowest incidence of eGFR decline was 13.5% observed in the group without diabetes. Higher incidences were noted in the group with HbA1c ≥ 7.5% at 27.0%, followed by the group with HbA1c < 6.5% at 22.9%. Compared to the group without diabetes, the adjusted hazard ratios (95% confidence intervals) for eGFR decline in the groups with HbA1c ≥ 7.5%, HbA1c 7.0–7.4%, HbA1c 6.5–6.9%, and HbA1c < 6.5% were 3.09 (2.18–4.39), 1.80 (1.14–2.84), 1.32 (CI 0.85–2.07), and 2.59 (1.64–4.10), respectively. Conclusions Achieving HbA1c of 6.5 to 6.9% is associated with a reduced risk of renal complications, which highlights the importance of glycemic control in managing renal health in patients with diabetes and chronic coronary syndrome.