The eGFR difference between creatinine-based and cystatin-C-based equations is also important in an Asian population...

Area of Science:

• Nephrology
• Biomarkers
• Epidemiology

Background:

• A significant negative difference between cystatin C-based and creatinine-based estimated glomerular filtration rate (eGFRdiff) is linked to kidney events.
• The prognostic value of eGFRdiff in the Japanese population, however, remains largely unexamined.

Purpose of the Study:

• This study aimed to assess the clinical significance of a negative eGFRdiff in predicting kidney disease progression within the Japanese population.
• To investigate the association between baseline eGFRdiff and adverse kidney outcomes in Japanese individuals with chronic kidney disease (CKD).

Main Methods:

• A retrospective cohort study was conducted using the J-CKD-DB-Ex database.
• The association between baseline eGFRdiff quartiles and a composite kidney outcome (CKD stage G5 or ≥40% eGFRcr decline within 5 years) was analyzed using Cox proportional hazards models.
• Restricted cubic splines were employed to evaluate the nonlinearity of the association.

Main Results:

• The lowest quartile of eGFRdiff (Q1, < -14.83 mL/min/1.73 m²) was significantly associated with an increased risk of the composite kidney outcome compared to the reference quartile (Q3, -6.62 to < 1.72 mL/min/1.73 m²; HR, 2.11; 95% CI 1.24-3.59).
• Spline analyses revealed a sharp increase in hazard as eGFRdiff became more negative, with a relatively flat risk profile for near-zero to positive eGFRdiff values.
• A large negative eGFRdiff emerged as an independent predictor of kidney disease progression.

Conclusions:

• A substantial negative eGFRdiff is independently associated with an elevated risk of kidney disease progression in a Japanese cohort with CKD.
• These findings support the utility of incorporating eGFRdiff into risk stratification models for patients with chronic kidney disease in Japan.
• The study highlights the importance of considering the difference between cystatin C- and creatinine-based eGFR measurements for predicting kidney outcomes.