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Abstract: PO0438

Association of the Creatinine-to-Cystatin C Ratio with Overall Survival with and Without CKD

Session Information

Category: CKD (Non-Dialysis)

  • 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Streja, Elani, VA Long Beach Healthcare System, Long Beach, California, United States
  • Wenziger, Cachet, VA Long Beach Healthcare System, Long Beach, California, United States
  • Sy, John, VA Long Beach Healthcare System, Long Beach, California, United States
  • Tantisattamo, Ekamol, Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California, United States
  • Hanna, Ramy Magdy, Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California, United States
  • Kovesdy, Csaba P., Memphis VA Medical Center, Memphis, Tennessee, United States
  • Crowley, Susan T., Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California, United States
  • Kalantar-Zadeh, Kamyar, Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California, United States
Background

Creatinine and Cystatin C are measured as glomerular filtration markers. Creatinine is highly correlated with skeletal muscle mass, whereas Cystatin C is not. We hypothesized that persons, in whom serum Cystatin C is lower than creatinine level, i.e., creatine to Cystatin C ratio (CrCCR) >1.00 (regardless of measurement units) have incrementally greater survival chance, likely due to a larger muscle mass.

Methods

We examined a cohort of 7,849 Veterans with baseline measured Cystatin C and creatinine data between 2004-2015. Veterans were divided into 0.25 increments of CrCCR, i.e., <0.75, 0.75-<1.0,1.0-<1.25,≥1.25. They were further stratified into groups based on normal vs. low eGFR (>60 vs. ≤60 mL/min/1.73 m2, and the associations of CrCCR with survival across two eGFR strata were examined.

Results

The mean age (±SD) in the Veterans’ cohort was 69±12 years. There were 4% female, 77% white, and 15% African American. The median (IQR range) for cystatin C was 1.28 (0.99,1.71) mg/L, for creatinine 1.24 (0.92,1.68) mg/dl, and for the CrCCR was 0.99 (0.81,1.17). Compared to the reference (CrCCR≥1.25 and eGFR≤60 mL/min/1.73 m2) the multivariable adjusted model showed that those with a lower CrCCR <0.75 (suggesting lowest muscle mass) had the highest mortality risk for both eGFR strata, with the normal eGFR group having higher death risk than the low eGFR group (HR(95%CI): 1.86(1.49,2.31) and 2.13(1.75,2.59), respectively). In the highest CrCCR group (≥1.25) indicating more muscle mass, the normal eGFR group had the best overall survival than those with low eGFR (HR(95%CI):0.45(0.27,0.73)).

Conclusion

A lower CrCCR indicating higher cystatin C relative to creatinine levels are strongly associated with worse overall survival in Veterans regardless of kidney function level. Future studies should examine the clinical utility of this potential surrogate of muscle mass and overall health over creatinine or Cystatin C alone in evaluating risk stratification in patients with and without kidney disease.