Our goal was to create a simple risk‐prediction model for renal function decline after cardiac surgery to help focus renal follow‐up efforts on patients most likely to benefit.

This single‐center retrospective cohort study enrolled 24 904 patients who underwent cardiac surgery from 2012 to 2019 at Fuwai Hospital, Beijing, China. An estimated glomerular filtration rate (eGFR) reduction of ≥30% 3 months after surgery was considered evidence of renal function decline. Relative to patients with eGFR 60 to 89 mL/min per 1.73 m² (4.5% [531/11733]), those with eGFR ≥90 mL/min per 1.73 m² (10.9% [1200/11042]) had a higher risk of renal function decline, whereas those with eGFR ≤59 mL/min per 1.73 m² (5.8% [124/2129]) did not. Each eGFR stratum had a different strongest contributor to renal function decline: increased baseline eGFR levels for patients with eGFR ≥90 mL/min per 1.73 m², transfusion of any blood type for patients with eGFR 60 to 89 mL/min per 1.73 m², and no recovery of renal function at discharge for patients with eGFR ≤59 mL/min per 1.73 m². Different nomograms were established for the different eGFR strata, which yielded a corrected C‐index value of 0.752 for eGFR ≥90 mL/min per 1.73 m², 0.725 for eGFR 60–89 mL/min per 1.73 m² and 0.791 for eGFR ≤59 mL/min per 1.73 m².

Predictors of renal function decline over the follow‐up showed marked differences across the eGFR strata. The nomograms incorporated a small number of variables that are readily available in the routine cardiac surgical setting and can be used to predict renal function decline in patients stratified by baseline eGFR.