Kidney Week

Abstract: TH-PO396

Performance of Creatinine-Based GFR Estimates in Patients on Ritonavir-Boosted Protease Inhibitors

Session Information

• CKD: Risk Scores and Translational Epidemiology
  November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

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

Authors

• Chaudhari, Juhi, Tufts Medical Center, Boston, Massachusetts, United States

Juhi Chaudhari,

• Wyatt, Christina M., Duke University School of Medicine, Durham, North Carolina, United States

Christina M. Wyatt,

• Miao, Shiyuan, Tufts Medical Center, Boston, Massachusetts, United States

Shiyuan Miao,

• Krishnasami, Zipporah, Medical University of South Carolina, Charleston, South Carolina, United States

Zipporah Krishnasami,

• Levey, Andrew S., Tufts Medical Center, Boston, Massachusetts, United States

Andrew S. Levey,

• Ross, Michael J., Albert Einstein College of Medicine/ Montefiore Medical Center, Bronx, New York, United States

Michael J. Ross,

• Ryom, Lene, CHIP, Department of infectious diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark

Lene Ryom,

• Mocroft, Amanda, University College London, London, United Kingdom

Amanda Mocroft,

• Brunet, Laurence, Epividian, Inc., Durham, North Carolina, United States

Laurence Brunet,

• Fusco, Jennifer S., Epividian, Inc., Durham, North Carolina, United States

Jennifer S. Fusco,

• Inker, Lesley, Tufts Medical Center, Boston, Massachusetts, United States

Lesley Inker,

Background

The pharmacoenhancer ritonavir has been shown to inhibit tubular transport of creatinine in vitro. We aimed to determine whether use of ritonavir-boosted protease inhibitors (PI/r) affects the performance of creatinine-based GFR estimates.

Methods

We previously measured GFR (mGFR) in 200 HIV-positive adults on stable antiretroviral therapy using plasma iohexol clearance. We evaluated performance of the CKD-EPI creatinine equation (CKD-EPI_cr), MDRD Study equation, and Cockcroft-Gault creatinine clearance (indexed to 1.73m² body surface area) versus mGFR. We compared bias (median difference between mGFR and estimated GFR) and accuracy (percent of estimates within 30% of mGFR, with large errors indicated by 1-P₃₀). Statistical significance of the differences in bias and accuracy were tested by Wilcoxon two-sample test and chi-square test, respectively.

Results

73% of the population was male, 52% of Black race, and 34% over the age of 50 years. 61% were virologically suppressed and 44% were on a PI/r. No participants were taking other antiretrovirals known to inhibit creatinine secretion. The CKD-EPI_Cr equation performed better than other equations. There were no clinically or statistically significant differences in the performance of any equation between the PI/r and no-PI/r groups (Figure).

Conclusion

Use of PI/r did not have a significant impact on the performance of creatinine-based GFR estimates as compared to mGFR. Declines in eGFR with the use of PI/r may reflect real changes in kidney function.

Performance of creatinine-based estimating equations in patients on PI/r versus no PI/r
Left: Bias; Right: Accuracy; PI/r, ritonavir-boosted protease inhibitor; GFR, glomerular filtration rate; CKD-EPI_cr, GFR by CKD-EPI creatinine equation; MDRD, GFR by MDRD Study equation; CG, creatinine clearance by Cockcroft-Gault equation indexed to 1.73m² body surface area. Error bars represent 95% confidence intervals.

Funding

• Other NIH Support –