From the Research
Definition of Oliguria and eGFR
- Oliguria is a common phenomenon found in hospitalized patients, characterized by a decreased urine output, but it may not always reflect a precipitous fall in the glomerular filtration rate 1.
- The estimated glomerular filtration rate (eGFR) is a principal biomarker of kidney function, and its reduction is associated with cardiovascular events, end-stage kidney disease (ESKD), and mortality 2.
eGFR Thresholds and CKD
- The current recommendations for defining chronic kidney disease (CKD) argue that a universal threshold of 60 mL/min/1.73m² should be used, but this threshold does not take into account the physiologic decline in GFR with aging 3.
- An age-calibrated definition of CKD has been proposed to distinguish age-related from disease-related changes in eGFR, with different thresholds for different age groups 3.
- A study found that an eGFR difference of 15 mL/min/1.73m² or greater between cystatin C-based eGFR and creatinine-based eGFR was associated with a higher risk of mortality and ESKD 4.
Association between eGFR and Oliguria
- There is no direct evidence in the provided studies to suggest that an eGFR of less than 15 mL/min/1.73m² indicates oliguria.
- However, a study found that an eGFR difference of 15 mL/min/1.73m² or greater was associated with a higher risk of mortality and ESKD, but this does not directly relate to oliguria 4.
- Another study found that lower eGFR was associated with a higher risk of cardiovascular disease, but this association was not independent and merely reflected the association of age and other cardiovascular risk factors with reduced eGFR 5.