Post-contrast acute kidney injury in the super-elder patients: a CT-scan perspective

The administration of intravenous (IV) contrast media during computed tomography (CT) examinations is essential to enhance diagnostic accuracy in various clinical scenarios. Traditionally, older age is considered a risk factor for the development of post-contrast Acute Kidney Injury (PC-AKI); however, there is limited information available for the super-elderly population (aged ≥ 85). This study aims to investigate the incidence and risk factors associated with PC-AKI in individuals aged 85 and older undergoing CT scans with IV contrast.

A retrospective cohort study, including all hospitalized patients aged 85 or older who underwent CT scans between the years 2005 and 2021. Patients were categorized into IV contrast and non-IV contrast groups. Baseline demographic and clinical data, along with kidney function parameters, were collected.

The final cohort included 7,078 patients who underwent CT scans, with 40% receiving IV contrast. The overall AKI occurrence within 72 h post-CT was 5.72%, slightly elevated in the non-IV contrast group (6.25% vs. 4.94%, p = 0.02). However, multivariate analysis revealed no significant difference between the groups (OR 1, CI 0.8-1.2, p = 0.92), even after stratifying by kidney function. A secondary analysis, using a less strict AKI definition, supported these findings. Baseline creatinine levels emerged as prominent risk factor associated with PC- AKI.

The current study provides reassurance regarding the safety of contrast-enhanced CT scans in super-elderly patients, particularly those with baseline normal to mild kidney dysfunction. These findings may contribute to the ongoing discussion on the risk-benefit balance of contrast-enhanced CT scans in the super-elderly population.