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Abstract: TH-PO996

Incorporation of Cystatin C in Estimating Kidney Function: Real-World Experience in Sweden

Session Information

Category: CKD (Non-Dialysis)

  • 2301 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Ballew, Shoshana, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States
  • Sang, Yingying, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States
  • Coresh, Josef, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States
  • Fu, Edouard, Brigham and Women's Hospital Department of Medicine, Boston, Massachusetts, United States
  • Carrero, Juan Jesus, Karolinska Institutet, Stockholm, Stockholm, Sweden
  • Grams, Morgan, New York University, New York, New York, United States
Background

Cystatin C is a filtration marker that, when used in combination with serum creatinine, provides a more precise estimate of GFR than using serum creatinine alone. However, many US physicians are unfamiliar with cystatin C and guidelines are vague on use of cystatin C as an adjunct test. Cystatin C has been routinely tested in Sweden for over a decade.

Methods

Using routine clinical data collected from 2010-2018 in the Stockholm Creatinine Measurements (SCREAM) project, we investigated rates of routine outpatient cystatin C testing over time as well as clinical care and patient characteristics associated with cystatin C testing. We used logistic and Cox proportional hazards regressions, stratified by ACR testing status, to further examine associations with cystatin C testing.

Results

Among the 1.37M adult individuals with serum creatinine tested, 11.2% also had serum cystatin C tested. The annual rate of cystatin C testing ranged between 4-7% each year. Those who had both markers tested were more likely to be older, male, have a lower eGFRcr, have more comorbidities, and more likely to have an ACR test. Among those with ACR testing, we found higher odds for a lower eGFRcr and, much higher risks of KFRT for the same level of eGFRcr in the population with cystatin C testing compared to those without. Among those without ACR testing, we found higher odds for older age and anemia, similar KFRT risk, but higher mortality risk among those with cystatin C testing compared to those without.

Conclusion

Cystatin C testing in Sweden followed two distinct patterns: for those at heightened risk of kidney failure (who were also receiving albuminuria testing) and for older adults who were more likely to have anemia and at higher risk of mortality. This study provides a real-world account of cystatin C testing and supports the utility of cystatin C for clinical practice.

Funding

  • NIDDK Support