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Abstract: PO2431

Performance of Serum β2 Microglobulin and β-Trace Protein-Based Glomerular Filtration Rate Estimating Equations in South Asians

Session Information

Category: CKD (Non-Dialysis)

  • 2102 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

  • Wang, Yeli, Duke-NUS Medical School, Singapore, Singapore
  • Levey, Andrew S., Tufts Medical Center, Boston, Massachusetts, United States
  • Inker, Lesley Ann, Tufts Medical Center, Boston, Massachusetts, United States
  • Jessani, Saleem, The Aga Khan University, Karachi, Sindh, Pakistan
  • Bux, Rasool, The Aga Khan University, Karachi, Sindh, Pakistan
  • Samad, Zainab Zs, The Aga Khan University, Karachi, Sindh, Pakistan
  • Yaqub, Sonia, The Aga Khan University, Karachi, Sindh, Pakistan
  • Karger, Amy B., University of Minnesota Medical School Twin Cities, Minneapolis, Minnesota, United States
  • Allen, John C., Duke-NUS Medical School, Singapore, Singapore
  • Jafar, Tazeen H., Duke-NUS Medical School, Singapore, Singapore
Background

Previously we showed that glomerular filtration rate (GFR) estimation based on cystatin C alone (eGFRcys) had a large bias in a general population in Pakistan, and the GFR estimation based on cystatin C and creatinine (eGFRcr-cys) was not substantially better than eGFRcr-PK (Wang, KI Reports 2021). β2-Microglobulin (B2M) and β-trace protein (BTP) are being considered for use in a panel including creatinine and/or cystatin C to improve GFR estimation (Inker, AJKD 2020). We aimed to evaluate whether adding B2M and BTP would improve the performance of eGFRcys and eGFRcr-cys in a general population in Pakistan.

Methods

We assessed panel eGFR equations using B2M and BTP in addition to cystatin C (3-marker panel) or creatinine and cystatin C (4-marker panel) in a cross-sectional study of 557 participants (≥40 years) from Pakistan. We compared bias (median difference in measured GFR [mGFR] and eGFR), precision (interquartile range of differences), and accuracy (percentage of eGFR within 30% of mGFR [P30] and root mean square error [RMSE]).

Results

As shown in the Table, the 4-panel equation (addition of BTP and B2M to creatinine and cystatin C) had lesser bias, better precision, and better accuracy (all Ps<0.001) compared to the 3-panel equation (addition of BTP and B2M to cystatin C). The 3-panel equation worsened bias (P<0.001) and did not improve precision or accuracy (P>0.05 for both) relative to eGFRcys. Similarly, the 4-panel equation worsened bias (P<0.001) and did not improve precision or accuracy (P>0.05 for both) compared to eGFRcr-cys.

Conclusion

B2M and BTP did not improve the performance of eGFRcys and eGFRcr-cys in South Asians. Evaluation of non-GFR determinants of BTP and B2M would be of interest.

Table. The performances of GFR estimating equations in comparison with measured GFR (N=557).

Funding

  • NIDDK Support