Chronic kidney disease of undetermined cause (CKDu) is a progressive form of chronic kidney disease (CKD) that is not associated with common risk factors for CKD and mainly affects adults in low- and middle-income countries (LMICs). Researchers from the disadvantaged populations estimated glomerular filtration rate (eGFR) epidemiology (DEGREE) study now report initial insights into the burden of CKDu globally. Using data from population-representative surveys and analyses, Charlotte Rutter and colleagues estimated the age-standardized prevalence of eGFR <60 ml/min/1.73 m2 among adults aged 18–60 years without commonly known causes of CKD, as an estimate of CKDu burden. In total, the researchers included data from 60,954 participants in 43 areas across 14 countries, with a focus on LMICs.

Among men, the standardized prevalence estimates of CKDu were highest in rural areas of Uddanam, India (up to 13.7%; 95% CI 4.8–22.6%) and northwest Nicaragua (up to 13.6%; 95% CI 6.3–20.9%). High prevalence (>5%) in men was mainly observed only in rural areas, with the exception of one urban area in Leon, Nicaragua. Among women, high prevalence was only observed in Miguelillo, Ecuador (6.0%; 95% CI 2.2–9.7%) and in Uddanam (up to 8%; 95% CI 2.0–14.1%). The prevalence was low (<2%) outside of Central America and South Asia.