Preoperative hidden renal dysfunction add an age dependent risk of progressive chronic kidney disease after cardiac surgery.

Background: To study different value of estimated glomerular filtration rate with normal serum creatinine whether is a risk factor for hidden renal function of cardiac surgery outcomes.

Methods: A total of 1744 cardiac surgery patients with serum creatinine ≤1.2 mg/dL (female)/1.5 mg/dL (male) were divided into 3 groups: estimated glomerular filtration rate ≥ 90 mL/min/1.73 m (no renal dysfunction, n = 829), 60 ≤ estimated glomerular filtration rate < 90 mL/min/1.73 m (hidden renal dysfunction, n = 857), estimated glomerular filtration rate < 60 mL/min/1.73 m (known renal dysfunction, n = 58) and followed up for 3 years. Multivariate regression analyses for risk factors of postoperative acute kidney injury.

Results: The proportion of preoperative hidden renal dysfunction was 67.1% among patients ≥  65 years old and 44.1% among patients < 65 years old. Multivariate Cox regression analyses showed that for patients < 65 years, known renal dysfunction was a risk factor for postoperative acute kidney injury (P <  0.01) and progressive chronic kidney disease (P = 0.018), while hidden renal dysfunction was a risk factor for progressive chronic kidney disease (P = 0.024). For patients ≥  65 years, only known renal dysfunction was a risk factors for 3-year mortality (P = 0.022) and progressive chronic kidney disease (P <  0.01).

Conclusion: Hidden renal dysfunction was common in patients with normal serum creatinine for cardiac surgery, with a prevalence of 49.1%. For patients < 65 years old, hidden renal dysfunction was an independent risk factor for progressive chronic kidney disease.