Leukocyturia and Hb early indicators of kidney injury among heat-stressed male workers

U.S.A: According to a study published in BMJ Open, leukocyturia and Hb, which can both be measured using point-of-care methods, may be early signs of kidney damage and a risk for eGFR reduction in heat-stressed male workers.

In order to better understand the causes of chronic kidney disease of non-traditional origin (CKDnt), Dr. Erik Hansson remarked that "this can enable individual-level prevention and research."

Over the past few decades, a chronic kidney disease epidemic with non-traditional origins (CKDnt) has resulted in tens of thousands of untimely deaths in Mesoamerica. Research suggests that physically taxing employment in the heat is a major driver of disease initiation and/or progression, even though the actual etiology is unknown.

In a group with a high risk of developing CKDnt, the authors sought to uncover readily accessible early markers of rapid kidney function deterioration.

In this explorative research group, the efficiency of biomarkers measured during harvest for prediction of cross-harvest renal function loss was assessed, and the most significant biomarker was then assessed in an independent confirmation group.

For this objective, 39 male sugarcane cutters from El Salvador were sampled nine times before and after each bimonthly work shift during harvest. During two harvests, 371 male sugarcane cutters from Nicaragua were examined as part of routine surveillance. During the 5-to-6-month harvest season, cutters engaged with great physical activity at wet-bulb globe temperatures that were typically above 29°C for 6 to 8 hours per day, six days a week.

The primary outcome was the variation in estimated glomerular filtration rate (CKD Epidemiology Collaboration) across the harvest season (ΔeGFRcross-harvest).

Major highlights of the study:

• The most promising measure in the El Salvadoran group, accounting >25% of ΔeGFRcross-harvest variance at 8/9 occasions during harvest, was dipstick leukocyturia following work shift.
• Fever, little or dark urine, cramps, headache, dizziness, and stomach pain were all linked to leukocyturia in the two weeks prior.
• Additionally predictive of ΔeGFRcross-harvest were decreasing blood haemoglobin (Hb) and eGFR during harvest.
• In the Nicaraguan confirmation dataset, individuals with ≥++ leukocyturia at any sampling time during harvest had a poorer ΔeGFRcross-harvest of 13 mL/min/1.73 m2 (95% CI 10 to 16 mL/min/1.73 m2) than individuals without leukocyturia records.

The authors concluded that the development of markers that enable early detection of kidney damage at the individual level could make a significant contribution to prevention through the removal of risk factors as well as to understanding the causes of and reversing the CKDnt epidemic.

"Even though early detection of CKDnt risk in certain employees may prove to be a useful tool for prevention, there is still a need to comprehend and take action against the pathophysiological mechanisms and harmful work behaviors that are fueling the CKDnt epidemic," they added.

Reference

Hansson E, Wesseling C, Wegman D, et al Point-of-care biomarkers for prediction of kidney function trajectory among sugarcane cutters: a comparative test accuracy study BMJ Open 2022;12:e060364.

doi: 10.1136/bmjopen-2021-060364