Estimating Kidney Function in HIV-Infected Adults in Kenya: Comparison to a Direct Measure of Glomerular Filtration Rate by Iohexol Clearance

Christina M. Wyatt, George J. Schwartz, Willis Owino Ong'or, Joseph Abuya, Alison G. Abraham, Charles Mboku, Loice B. M'mene, Winnie J. Koima, Mathew Hotta, Paula Maier, Paul E. Klotman, Kara Wools-Kaloustian

Research output: Contribution to journalArticle

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Abstract

Background:More than two-thirds of the world's HIV-positive individuals live in sub-Saharan Africa, where genetic susceptibility to kidney disease is high and resources for kidney disease screening and antiretroviral therapy (ART) toxicity monitoring are limited. Equations to estimate glomerular filtration rate (GFR) from serum creatinine were derived in Western populations and may be less accurate in this population.Methods:We compared results from published GFR estimating equations with a direct measure of GFR by iohexol clearance in 99 HIV-infected, ART-naïve Kenyan adults. Iohexol concentration was measured from dried blood spots on filter paper. The bias ratio (mean of the ratio of estimated to measured GFR) and accuracy (percentage of estimates within 30% of the measured GFR) were calculated.Results:The median age was 35 years, and 60% were women. The majority had asymptomatic HIV, with median CD4+ cell count of 355 cells/mm3. Median measured GFR was 115 mL/min/1.73 m2. Overall accuracy was highest for the Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation. Consistent with a prior report, bias and accuracy were improved by eliminating the coefficient for black race (85% of estimates within 30% of measured GFR). Accuracy of all equations was poor in participants with GFR 60-90 mL/min/1.73 m2 (<65% of estimates within 30% of measured GFR), although this subgroup was too small to reach definitive conclusions.Conclusions:Overall accuracy was highest for the CKD-EPI equation. Eliminating the coefficient for race further improved performance. Future studies are needed to determine the most accurate GFR estimate for use in individuals with GFR <90 mL/min/1.73 m2, in whom accurate estimation of kidney function is important to guide drug dosing. Direct measurement of GFR by iohexol clearance using a filter paper based assay is feasible for research purposes in resource-limited settings, and could be used to develop more accurate GFR estimates in African populations.

Original languageEnglish
Article numbere69601
JournalPLoS One
Volume8
Issue number8
DOIs
StatePublished - Aug 8 2013

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Iohexol
glomerular filtration rate
Kenya
renal function
Glomerular Filtration Rate
HIV
Kidney
kidney diseases
Epidemiology
Kidney Diseases
Chronic Renal Insufficiency
epidemiology
Population
therapeutics
Africa South of the Sahara
Sub-Saharan Africa
Genetic Predisposition to Disease
CD4 Lymphocyte Count
blood serum
creatinine

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Estimating Kidney Function in HIV-Infected Adults in Kenya : Comparison to a Direct Measure of Glomerular Filtration Rate by Iohexol Clearance. / Wyatt, Christina M.; Schwartz, George J.; Owino Ong'or, Willis; Abuya, Joseph; Abraham, Alison G.; Mboku, Charles; M'mene, Loice B.; Koima, Winnie J.; Hotta, Mathew; Maier, Paula; Klotman, Paul E.; Wools-Kaloustian, Kara.

In: PLoS One, Vol. 8, No. 8, e69601, 08.08.2013.

Research output: Contribution to journalArticle

Wyatt, CM, Schwartz, GJ, Owino Ong'or, W, Abuya, J, Abraham, AG, Mboku, C, M'mene, LB, Koima, WJ, Hotta, M, Maier, P, Klotman, PE & Wools-Kaloustian, K 2013, 'Estimating Kidney Function in HIV-Infected Adults in Kenya: Comparison to a Direct Measure of Glomerular Filtration Rate by Iohexol Clearance', PLoS One, vol. 8, no. 8, e69601. https://doi.org/10.1371/journal.pone.0069601
Wyatt, Christina M. ; Schwartz, George J. ; Owino Ong'or, Willis ; Abuya, Joseph ; Abraham, Alison G. ; Mboku, Charles ; M'mene, Loice B. ; Koima, Winnie J. ; Hotta, Mathew ; Maier, Paula ; Klotman, Paul E. ; Wools-Kaloustian, Kara. / Estimating Kidney Function in HIV-Infected Adults in Kenya : Comparison to a Direct Measure of Glomerular Filtration Rate by Iohexol Clearance. In: PLoS One. 2013 ; Vol. 8, No. 8.
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abstract = "Background:More than two-thirds of the world's HIV-positive individuals live in sub-Saharan Africa, where genetic susceptibility to kidney disease is high and resources for kidney disease screening and antiretroviral therapy (ART) toxicity monitoring are limited. Equations to estimate glomerular filtration rate (GFR) from serum creatinine were derived in Western populations and may be less accurate in this population.Methods:We compared results from published GFR estimating equations with a direct measure of GFR by iohexol clearance in 99 HIV-infected, ART-na{\"i}ve Kenyan adults. Iohexol concentration was measured from dried blood spots on filter paper. The bias ratio (mean of the ratio of estimated to measured GFR) and accuracy (percentage of estimates within 30{\%} of the measured GFR) were calculated.Results:The median age was 35 years, and 60{\%} were women. The majority had asymptomatic HIV, with median CD4+ cell count of 355 cells/mm3. Median measured GFR was 115 mL/min/1.73 m2. Overall accuracy was highest for the Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation. Consistent with a prior report, bias and accuracy were improved by eliminating the coefficient for black race (85{\%} of estimates within 30{\%} of measured GFR). Accuracy of all equations was poor in participants with GFR 60-90 mL/min/1.73 m2 (<65{\%} of estimates within 30{\%} of measured GFR), although this subgroup was too small to reach definitive conclusions.Conclusions:Overall accuracy was highest for the CKD-EPI equation. Eliminating the coefficient for race further improved performance. Future studies are needed to determine the most accurate GFR estimate for use in individuals with GFR <90 mL/min/1.73 m2, in whom accurate estimation of kidney function is important to guide drug dosing. Direct measurement of GFR by iohexol clearance using a filter paper based assay is feasible for research purposes in resource-limited settings, and could be used to develop more accurate GFR estimates in African populations.",
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AU - Owino Ong'or, Willis

AU - Abuya, Joseph

AU - Abraham, Alison G.

AU - Mboku, Charles

AU - M'mene, Loice B.

AU - Koima, Winnie J.

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N2 - Background:More than two-thirds of the world's HIV-positive individuals live in sub-Saharan Africa, where genetic susceptibility to kidney disease is high and resources for kidney disease screening and antiretroviral therapy (ART) toxicity monitoring are limited. Equations to estimate glomerular filtration rate (GFR) from serum creatinine were derived in Western populations and may be less accurate in this population.Methods:We compared results from published GFR estimating equations with a direct measure of GFR by iohexol clearance in 99 HIV-infected, ART-naïve Kenyan adults. Iohexol concentration was measured from dried blood spots on filter paper. The bias ratio (mean of the ratio of estimated to measured GFR) and accuracy (percentage of estimates within 30% of the measured GFR) were calculated.Results:The median age was 35 years, and 60% were women. The majority had asymptomatic HIV, with median CD4+ cell count of 355 cells/mm3. Median measured GFR was 115 mL/min/1.73 m2. Overall accuracy was highest for the Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation. Consistent with a prior report, bias and accuracy were improved by eliminating the coefficient for black race (85% of estimates within 30% of measured GFR). Accuracy of all equations was poor in participants with GFR 60-90 mL/min/1.73 m2 (<65% of estimates within 30% of measured GFR), although this subgroup was too small to reach definitive conclusions.Conclusions:Overall accuracy was highest for the CKD-EPI equation. Eliminating the coefficient for race further improved performance. Future studies are needed to determine the most accurate GFR estimate for use in individuals with GFR <90 mL/min/1.73 m2, in whom accurate estimation of kidney function is important to guide drug dosing. Direct measurement of GFR by iohexol clearance using a filter paper based assay is feasible for research purposes in resource-limited settings, and could be used to develop more accurate GFR estimates in African populations.

AB - Background:More than two-thirds of the world's HIV-positive individuals live in sub-Saharan Africa, where genetic susceptibility to kidney disease is high and resources for kidney disease screening and antiretroviral therapy (ART) toxicity monitoring are limited. Equations to estimate glomerular filtration rate (GFR) from serum creatinine were derived in Western populations and may be less accurate in this population.Methods:We compared results from published GFR estimating equations with a direct measure of GFR by iohexol clearance in 99 HIV-infected, ART-naïve Kenyan adults. Iohexol concentration was measured from dried blood spots on filter paper. The bias ratio (mean of the ratio of estimated to measured GFR) and accuracy (percentage of estimates within 30% of the measured GFR) were calculated.Results:The median age was 35 years, and 60% were women. The majority had asymptomatic HIV, with median CD4+ cell count of 355 cells/mm3. Median measured GFR was 115 mL/min/1.73 m2. Overall accuracy was highest for the Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation. Consistent with a prior report, bias and accuracy were improved by eliminating the coefficient for black race (85% of estimates within 30% of measured GFR). Accuracy of all equations was poor in participants with GFR 60-90 mL/min/1.73 m2 (<65% of estimates within 30% of measured GFR), although this subgroup was too small to reach definitive conclusions.Conclusions:Overall accuracy was highest for the CKD-EPI equation. Eliminating the coefficient for race further improved performance. Future studies are needed to determine the most accurate GFR estimate for use in individuals with GFR <90 mL/min/1.73 m2, in whom accurate estimation of kidney function is important to guide drug dosing. Direct measurement of GFR by iohexol clearance using a filter paper based assay is feasible for research purposes in resource-limited settings, and could be used to develop more accurate GFR estimates in African populations.

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