Diabetes Mellitus and the Increased Risk of Acute Kidney Injury Following Acute Coronary Syndrome

Background/objectives: Diabetes mellitus (DM) increases susceptibility to both cardiovascular and renal complications. Acute kidney injury (AKI) in the setting of acute coronary syndrome (ACS) is a frequent manifestation of acute cardiorenal syndrome (type 1); however, the impact of diabetes on the condition remains incompletely characterised. This study aimed to evaluate the real-world incidence, severity, and recurrence of AKI in individuals with ACS, focusing on the additional risk conferred by DM, and to assess the adequacy of post-discharge renal monitoring. Methods: We conducted a single-centre, retrospective observational study of 990 ACS admissions between July 2020 and June 2021 at the United Lincolnshire Hospitals NHS Trust. Acute kidney injury was defined using Kidney Disease Improving Global Outcomes criteria and stratified by severity. Outcome measures included incidence of AKI during admission, recurrence of AKI, and renal function monitoring within 12 months post-discharge. Results: Of 990 individuals recruited, 315 (31.8%) had DM. Overall, 14.2% individuals developed AKI during admission, being more frequently observed in those with DM (20.0% vs. 11.6%; RR 1.7, p < 0.001). Severe AKI (stage 3) was higher in those with diabetes (2.9% vs. 0.7%, p = 0.017). Recurrent AKI within 12 months occurred in 9.7%, with a higher incidence in those with DM (15.8% vs. 6.9%, p < 0.001). Post-discharge renal follow-up was performed in 88.7% of persons with AKI and similar in those with and without DM. Conclusions: Acute kidney injury is a common and serious complication of ACS, with DM substantially increasing the risk and severity of the condition during acute events and post-discharge. Despite this, individuals with DM receive similar monitoring in the post-discharge period. Improved systems for post-discharge renal monitoring and early initiation of protective therapies are required to mitigate long-term risk.