Repeated contrast exposure and renal risk in intensive care unit patients with reduced baseline glomerular filtration rate: a single-center prospective cohort study

Background: The study evaluates contrast-associated acute kidney injury, chronic kidney disease progression, and dialysis requirement in intensive care (ICU) patients with reduced glomerular filtration rate (GFR). Methods: prospective observational cohort study included 112 patients with baseline eGFR<90 mL/min/1.73 m² who underwent one or two intravascular contrast administrations. Renal outcomes were assessed for 6 months. Results: Single exposure group (62 patients) versus 50 in repeated exposure group. No statistical significance difference was found between both groups for CA-AKI incidence after the first exposure (25.8% vs. 25%, p=0.8) or in CKD progression and dialysis initiation at 3 and 6 months (p>0.5). CA-AKI incidence after the second exposure was 64%. Prior CA‑AKI predicts subsequent CA‑AKI (OR 11.63, p=0.02) and CKD progression at six months in both single (OR 5.29, p=0.008) and repeated exposure groups (OR 10.36, p=0.001). Creatinine increased significantly from 1 to 3 months (p=0.002 and 0.03 for single and multiple exposures) and continued rising at 6 months (p=0.003 and p<0.0001). In the repeated‑exposure group, baseline CKD stage independently predicted progression at 3 (OR 0.36, p=0.02) and 6 months (OR 0.55, p=0.05). Across CKD stages (2–5), renal outcomes did not differ between exposure groups, though all CKD stage 5 patients developed CA‑AKI after the second contrast. CKD progression at six months was significantly more common with cumulative contrast volumes >100 ml (p=0.047). Mehran score underestimated AKI risk (26% predicted vs. 64% observed) after the 2nd exposure and the need for dialysis (1.09% predicted vs. 6.45% observed). Conclusions: Early post‑contrast kidney response helps identify high‑risk patients before re‑imaging.