Differential Effect of Hospitalization on Cystatin C- and Creatinine-Based Estimated GFR

Area of Science:

• Nephrology
• Clinical Chemistry
• Biomarkers of Kidney Function

Background:

• Serum creatinine is a long-standing biomarker for kidney function, while cystatin C is a newer alternative.
• Discrepancies between estimated GFR from creatinine (eGFRCr) and cystatin C (eGFRCys) are common, particularly in hospitalized patients.
• The impact of all-cause hospitalizations on these kidney function estimates and their persistence post-discharge is not well understood.

Purpose of the Study:

• To investigate the association between hospitalization duration and changes in kidney function markers.
• To compare the effects of hospitalization on eGFRCr versus eGFRCys.
• To determine if changes in kidney function estimates persist after hospital discharge.

Main Methods:

• Analysis of data from 5599 adult participants in the Chronic Renal Insufficiency Cohort study.
• Categorization of participants based on total days hospitalized between annual study visits.
• Estimation of changes in eGFRCr, eGFRCys, and their difference (eGFRdiff) over time.

Main Results:

• Increasing hospitalization days were associated with significant decreases in eGFRCys.
• eGFRCr showed minimal changes with increasing hospitalization days.
• The difference between eGFRCys and eGFRCr (eGFRdiff) became increasingly negative with longer hospitalizations.

Conclusions:

• Prolonged or repeated hospitalizations lead to greater reductions in cystatin C-based GFR estimates compared to creatinine-based estimates.
• These effects on kidney function markers are observable even months after hospital discharge.
• Hospitalization duration is a critical factor influencing the reliability of different GFR estimation methods.