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Abstract: TH-OR40

Assessment of Estimated Glomerular Filtration Rate in a Cohort of 1200 Cancer Patients Using Serum Creatinine and Cystatin C

Session Information

Category: Onco-Nephrology

  • 1500 Onco-Nephrology

Authors

  • Costa e Silva, Veronica Torres, São Paulo State Cancer Institute - University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil
  • Gil, Luiz Antonio, São Paulo State Cancer Institute - University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil
  • Caires, Renato Antunes, São Paulo State Cancer Institute - University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil
  • Costalonga, Elerson, São Paulo State Cancer Institute - University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil
  • Coura-Filho, George Barberio, University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil
  • Castro, Gilberto, São Paulo State Cancer Institute - University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil
  • Inker, Lesley Ann, Tufts Medical Center, Boston, Massachusetts, United States
  • Mathew, Paul, Tufts Medical Center, Boston, Massachusetts, United States
  • Levey, Andrew S., Tufts Medical Center, Boston, Massachusetts, United States
  • Burdmann, Emmanuel A., University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil
Background

eGFR using creatinine (eGFRcr) with the CKD-EPI equation is recommended as the first test for GFR evaluation in clinical practice, but CG equation is commonly used for the prescription of chemotherapy, despite increasing evidence of its inaccuracy compared to measured GFR (mGFR). eGFR using cystatin C (eGFRcys) is less influenced by muscle mass or nutritional status, and eGFR using both markers (eGFRcr-cys) is more accurate than either eGFRcr or eGFRcys, but neither has been widely assessed in cancer patients. Our aim is to compare the performance of eGFR equations (Table) in cancer patients compared to mGFR.

Methods

This analysis is a cross-sectional evaluation of a prospective cohort of cancer patients in treatment at the ICESP. mGFR was determined by plasma clearance of 51Cr-EDTA indexed for body surface area.

Results

A group of 1,200 patients recruited between April 2015 and September 2017. Patients were 60 (51 – 68) y, 50.8% male. The most common cancer sites were breast (22.6%), prostate (19.8%) and gastrointestinal (13.4%). All eGFRcr equations overestimated mGFR with varying bias. CG had the lowest precision and was least accurate. eGFRcys underestimated mGFR and eGFRcr-cys had minimal bias and was the most accurate of all equations (Table).

Conclusion

All eGFRcr equations overestimated mGFR in our study. CG was the least accurate and should not be preferred over CKD-EPI. eGFRcr-cys is more accurate and can be used as a confirmatory test.

eGFR filtration markereGFR equation (year) Bias (medias)
(ml/min/1.73 m2)
Precision (IQR)
(ml/min/1.73 m2)
Accuracy (1-P30)
(%)
Accuracy (RMSE)
eGFRcrCG (1976)-8.12 (-9.34 to -6.74)24.1 (22.4 – 25.7)24.9 (22.3 – 27.2)0.23 (0.22 – 0.25)
eGFRcrMDRD (2006)-4.83 (-5.98 to -3.63)20 (18.5 – 21.4)18.1 (15.9 – 20.3)0.21 (0.22 – 0.22)
eGFRcrCKD-EPI (2009)-8.0 (-8.82 to -7.06)18.3 (17 – 19.5)19 (16.8 - 21.2)0.20 (0.19-0.21)
eGFRcrJanowitz-Williams (2017)-5.68 (-6.66 to – 4.93)20.2 (18.8 – 21.8)19.6 (17.3 – 21.7)0.21 (0.20 – 0.22)
eGFRcysCKD-EPI (2012)4.57 (3.71 to 5.5)17.5 (16.3 – 19.3)12.3 (10.4 – 14)0.21 (0.20 – 0.22)
eGFRcr-cysCKD-EPI (2012)-1.97 (-2.57 to -1.11)15.9 (14.7 – 16.8)7.83 (6.25 – 9.26)0.16 (0.15 – 0.17)

SCr and SCys were measured through certified reference materials. CG (Cockcroft Gault); MDRD (Modification of Diet in Renal Disease), CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration), IQR, interquartile range; RMSE, squared root of mean squared error, P30: percentage of estimates that are 30% over or below mGFR. Non-overlapping confidence intervals indicates statistical significance