Abstract: SA-PO0302
Prognostic Value of Baseline Serum Creatinine in AKI Across Age Groups: Limitations of Creatinine-Based Kidney Function Assessment in Older Adults
Session Information
- AKI: Epidemiology and Risk Factors
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 101 AKI: Epidemiology, Risk Factors, and Prevention
Author
- Lavilla, Francisco Javier, Clinica Universidad de Navarra, Pamplona, Navarre, Spain
Background
Serum creatinine has important limitations for estimating kidney in older adults . This may influence the interpretation of acute kidney injury (AKI) and contribute to potential overdiagnosis of chronic kidney disease (CKD) in elderly populations.
Methods
Prospective observational study between 1994 and 2026 including patients with AKI defined as a >20% increase in serum creatinine . A total of 3328 patients analyzed. Clinical profile, mortality, need for kidney replacement therapy (KRT), prognostic scores (Liaño ISI and IFMO), functional factors, and baseline creatinine were evaluated.Patients were stratified: A (<55 years), B (55–64), C (65–74), D (75–84), and E (≥85 years).
Results
Mean age was 63.1±0.27 years and 71.7% were male. Overall mortality was 16.1%.
Mortality by age group was: A 27.7%, B 29.7%, C 22.3%, D 16.7%, and E 3.5%. KRT requirement progressively decreased with age (18.8%, 19%, 14.3%, 13%, and 11.7%, respectively).
Functional factors increased with age (71.7%, 75.7%, 75.1%, 80%, and 84%), whereas oncologic disease decreased (39.9%, 36.2%, 23.2%, 15.8%, and 6.8%). Chronic cardiovascular disease increased from 2.8% to 11.7%.
CKD diagnosis progressively increased with age (27% vs 73.5%; p<0.005). Baseline creatinine also increased : 1.6±0.15 mg/dL in group A vs 2.07±0.13 mg/dL in group E (p<0.001).
Peak creatinine increase progressively declined from 103%±6.7 in patients <55 years to 41.9%±4.7 in patients ≥85 years. Final creatinine increase after AKI also decreased with age (41%±2.3 vs 13%±3.5).
Baseline creatinine was associated with mortality and KRT requirement only in younger groups, progressively losing prognostic discrimination in older adults. In the oldest groups, an inversion in the relationship between baseline creatinine and adverse outcomes was observed.
Creatinine increase correlated with AKI severity assessed by ISI and IFMO scores (p<0.001), with similar associations across all age groups.
Conclusion
AKI in older adults shows distinct characteristics, with a greater functional component and lower relative creatinine rise compared with younger patients.
Although CKD diagnosis and baseline creatinine values increase with age, baseline creatinine progressively loses prognostic value for mortality and KRT in elderly .
These findings suggest limitations of creatinine-based renal assessment in elderly