Kidney Week

Abstract: FR-PO897

The European Kidney Function Consortium Estimating Glomerular Filtration Rate Equation for Cystatin C: Results for Europe, the United States, and Africa

Session Information

• Diversity and Equity in Kidney Health - II
  November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pathology and Lab Medicine

• 1700 Pathology and Lab Medicine

Authors

• Delanaye, Pierre, CHU de Liege - Hopital du Sart Tilman, Liege, Liège, Belgium

Pierre Delanaye,

• Björk, Jonas, Skanes universitetssjukhus Lund, Lund, Skåne, Sweden

Jonas Björk,

• Ebert, Natalie, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Natalie Ebert,

• Eriksen, Bjorn Odvar, UiT Norges arktiske universitet, Tromso, Tromso, Norway

Bjorn Odvar Eriksen,

• Vidal-Petiot, Emmanuelle, Hopital Bichat - Claude-Bernard, Paris, Île-de-France, France

Emmanuelle Vidal-Petiot,

• Grubb, Anders O., Skanes universitetssjukhus Lund, Lund, Skåne, Sweden

Anders O. Grubb,

• Hansson, Magnus Daniel, Karolinska Institutet, Stockholm, Stockholm, Sweden

Magnus Daniel Hansson,

• Littmann, Karin, Karolinska Institutet, Stockholm, Stockholm, Sweden

Karin Littmann,

• Melsom, Toralf, UiT Norges arktiske universitet, Tromso, Tromso, Norway

Toralf Melsom,

• Rule, Andrew D., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Andrew D. Rule,

• Schaeffner, Elke, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Elke Schaeffner,

• Sundin, Per-Ola, Orebro universitet, Orebro, Örebro, Sweden

Per-Ola Sundin,

• Åkesson, Anna, Skanes universitetssjukhus Lund, Lund, Skåne, Sweden

Anna Åkesson,

• Larsson, Anders, Uppsala Universitet, Uppsala, Sweden

Anders Larsson,

• Cavalier, Etienne, CHU de Liege - Hopital du Sart Tilman, Liege, Liège, Belgium

Etienne Cavalier,

• Bukabau, Justine Busanga, Universite de Kinshasa, Kinshasa, Congo (the Democratic Republic of the)

Justine Busanga Bukabau,

• Sumaili, Ernest Kiswaya, Universite de Kinshasa, Kinshasa, Congo (the Democratic Republic of the)

Ernest Kiswaya Sumaili,

• Flamant, Martin, Hopital Bichat - Claude-Bernard, Paris, Île-de-France, France

Martin Flamant,

• Nyman, Ulf, Skanes universitetssjukhus Lund, Lund, Skåne, Sweden

Ulf Nyman,

• Pottel, Hans, Katholieke Universiteit Leuven - Campus Kulak Kortrijk, Kortrijk, Flanders, Belgium

Hans Pottel,

Group or Team Name

• EKFC (European Kidney Function Consortium)

Background

The creatinine based European Kidney Function Consortium (EKFC_Crea) equation was recently developed as an optimized full age spectrum equation. In the present study, the new EKFC-equation is applied to serum cystatin C (CysC), by replacing rescaled SCr by rescaled CysC.

Methods

Individual data from Sweden (n=243,218) were used to estimate the scaling or normalization factor (Q’) for CysC in adults. Scaled SCr/Q was replaced by scaled CysC/Q’ in the cystatin C based EKFC-equation (EKFC_CysC) which was then validated in White and Black subjects from Europe (n=11,231), North America (n=1,093) and Africa (n=508), with measured GFR, SCr, CysC, age, and gender available.

Results

Rescaling factor Q’ for CysC was estimated at 0.79 for adult females and 0.86mg/L for adult males until age 50 years, and (0.79 or 0.86) + 0.005 x (Age – 50) thereafter. A sex-independent scaling factor of 0.83mg/L (and 0.83 + 0.005 x (Age – 50) ) was also evaluated. EKFC_CysC was (nearly) unbiased and showed prediction performances similar to EKFC_Crea in White Europeans, White North Americans, Black Europeans and Black Africans (P10/P30 equal to 40%/85%). EKFC_CysC was superior to the KDIGO recommended equation CKD-EPI_Crea and CKD-EPI_CysC. P10/P30 of the arithmetic mean of EKFC_Crea and EKFC_CysC was greater than 45%/90% in almost all age-subgroups.

Conclusion

In our mixed cohorts from Europe, North America and Africa, EKFC_CysC has the same mathematical form as EKFC_Crea, with different scaling factors for cystatin C and shows similar performance as EKFC_Crea, and better performance than CKD-EPI_CysC. Moreover, the EKFC_CysC equation is independent of race and gender. An extra gain in accuracy (reduced bias, plus 5 percentage points in P10/P30 accuracy) is achieved by combining both EKFC-equations.