Glomerular filtration rate estimated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in type 1 diabetes based on genomic ancestry

Marcela Haas Pizarro; Deborah Conte Santos; Laura Gomes Nunes Melo; Bianca Senger Vasconcelos Barros; Luiza Harcar Muniz; Luís Cristóvão Porto; Dayse Aparecida Silva; Rachel Bregman; Marilia Brito Gomes

doi:10.1186/s13098-020-00578-4

Glomerular filtration rate estimated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in type 1 diabetes based on genomic ancestry

Diabetol Metab Syndr. 2020 Aug 15:12:71. doi: 10.1186/s13098-020-00578-4. eCollection 2020.

Authors

Marcela Haas Pizarro¹, Deborah Conte Santos¹, Laura Gomes Nunes Melo², Bianca Senger Vasconcelos Barros¹, Luiza Harcar Muniz¹, Luís Cristóvão Porto³, Dayse Aparecida Silva⁴, Rachel Bregman⁵, Marilia Brito Gomes¹

Affiliations

¹ Department of Internal Medicine, Diabetes Unit, Rio de Janeiro State University (UERJ), Boulevard 28 de Setembro, 77- 3º andar - Vila Isabel, Rio de Janeiro, RJ CEP 20551-030 Brazil.
² Department of Ophthalmology, Rio de Janeiro State University (UERJ), Rio de Janeiro, RJ, Brazil.
³ Histocompatibility and Cryopreservation Laboratory (HLA), Rio de Janeiro State University (UERJ), Rio de Janeiro, RJ Brazil.
⁴ DNA Diagnostic Laboratory (LDD), Rio de Janeiro State University (UERJ), Rio de Janeiro, RJ Brazil.
⁵ Department of Internal Medicine, Nephrology Unit, Rio de Janeiro State University (UERJ), Rio de Janeiro, RJ Brazil.

Abstract

Background: Black individuals have a great risk of developing chronic kidney disease (CKD) that is associated with high morbimortality, so it is important to classify them into the correct renal function group. Some equations used to estimate glomerular filtration rate (eGFR) divide patients only into two categories: African Americans and non-African Americans. The CKD-EPI equation was tested only in African Americans, and not Black patients from other regions, and takes into consideration self-reported color-race instead of genomic ancestry (GA) to determine the use of the ethnic correction factor. So far, this equation has not been evaluated in admixed populations, such as the Brazilian, using the percentage of GA to decide to apply the correction factor. The purpose of our study was to compare, in patients with type 1 diabetes (T1D), the eGFR calculated without the use of the correction factor, with the values obtained using the correction factor in patients presenting 50% or more of African GA.

Methods: This cross-sectional, multicenter study enrolled 1279 patients from all geographic regions of Brazil. The CKD-EPI equation was used and CKD was defined as eGFR < 60 ml/min. GA were inferred using a panel of 46 AIM-INDEL, afterwards patients presenting an African GA ≥ 50% were selected.

Results: Initially, all patients with African GA ≥ 50% (n = 85) were considered as non-African Americans when calculating the eGFR and afterwards the ethnic correction factor was applied to recalculate the eGFR. CKD was present in 23 patients and 56.5% of them were redefined as having normal renal function after using the correction factor, mainly women [11 of the 13 patients (84.6%)], with GFR between 52-59.3 ml/min.

Conclusions: More than half of the patients in the study were reclassified to a normal renal function group, showing that GA may be an important tool to decide between the use of the ethnic correction factor in the CKD-EPI equation in a highly admixed population of patients with T1D. A large-scale study involving GA and eGFR in comparison to reference methods should be conducted to better establish whether or not the ethnic correction factor should be used in highly admixed populations.

Keywords: Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation; Chronic kidney disease; Genomic ancestry; Self-reported color-race; Type 1 diabetes.