PT  - JOURNAL ARTICLE
AU  - Andersson, Axel
AU  - Hansson, Erik
AU  - Ekström, Ulf
AU  - Grubb, Anders
AU  - Abrahamson, Magnus
AU  - Jakobsson, Kristina
AU  - Xu, Yiyi
TI  - Large difference but high correlation between creatinine and cystatin C estimated glomerular filtration rate in Mesoamerican sugarcane cutters
AID  - 10.1136/oemed-2021-107990
DP  - 2022 Jul 01
TA  - Occupational and Environmental Medicine
PG  - 497--502
VI  - 79
IP  - 7
4099  - http://oem.bmj.com/content/79/7/497.short
4100  - http://oem.bmj.com/content/79/7/497.full
SO  - Occup Environ Med2022 Jul 01; 79
AB  - Objectives To explore the relationship between creatinine and cystatin C based estimated glomerular filtration rate (eGFR) in actively working sugarcane cutters.Methods This cohort study included 458 sugarcane cutters from Nicaragua and El Salvador. Serum samples were taken before and at end of harvest seasons and analysed for creatinine and cystatin C. Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas were used to calculate eGFRs based on creatinine (eGFRcr), cystatin C (eGFRcys) and both creatinine and cystatin C (eGFRcrcys) at each time point. Bland-Altman plots and paired t-tests were used to compare the difference between eGFRcr and eGFRcys, and the difference in eGFRs between before and at end of the harvest seasons.Results The mean eGFRcr was higher than eGFRcys in both cohorts; absolute difference 22 mL/min/1.73 m2 (95% CI 21 to 23) in Nicaragua and 13 mL/min/1.73 m2 (95% CI 11 to 15) in El Salvador. Correlations between eGFRcr and eGFRcys were high, with r=0.69, 0.77 and 0.67 in Nicaragua at pre-harvest, end-harvest and cross-harvest, and r=0.89, 0.89 and 0.49 in El Salvador.Conclusions Creatinine increases among heat-stressed workers reflect reduced glomerular filtration as estimated using eGFRcys, a marker independent of muscle mass and metabolism. The discrepancy between eGFRcr and eGFRcys may indicate reduced glomerular filtration of larger molecules and/or systemic bias in CKD-EPI performance in this population.The Nicaraguan data will be available upon reasonable request, while the Salvadorian data may be obtained from a third party. Contact the corresponding author for more information.