Subtle changes in kidney function, even within what is considered a normal range, may help identify individuals at risk for chronic kidney disease (CKD), according to new research from Karolinska Institutet. The study, published in Kidney International, suggests that early detection could be improved with the use of a web-based tool developed by the research team.
Chronic kidney disease affects between 10 and 15 percent of adults worldwide and is expected to become one of the top five causes of years of life lost by 2040. Currently, many patients are diagnosed only after significant loss of kidney function due to the lack of effective screening programs.
Researchers at Karolinska Institutet have created population-based distributions for estimated glomerular filtration rate (eGFR), which is commonly used to measure kidney function. These distributions aim to help healthcare providers identify those at higher risk so that preventive measures can be taken earlier.
The team has made eGFR distribution charts available for healthcare professionals and developed an online calculator, created by PhD student Antoine Creon. This tool allows clinicians to compare a patient's eGFR with age-specific population norms.
The study analyzed data from over 1.1 million adults in Stockholm, Sweden—about 80 percent of the region’s population aged 40 to 100 years old. Nearly seven million eGFR tests collected between 2006 and 2021 were used to build age- and sex-specific reference ranges.
Results showed that people whose eGFR fell below the median for their age and sex faced worse health outcomes. Those below the 25th percentile had a significantly higher risk of progressing to kidney failure requiring dialysis or transplantation. Additionally, both low and high extremes in eGFR percentiles were linked with increased mortality risk.
The research also highlighted gaps in current medical practice. Among patients with an apparently normal eGFR above 60 ml/min/1.73 m² but below the 25th percentile, only one quarter received further testing for urinary albumin—a key marker for early kidney damage.
"For example, consider a 55-year-old woman with an eGFR of 80. Most clinicians would not react to such a seemingly normal value. However, our charts show that this corresponds to the 10th percentile for women of that age, and that she has a three-fold higher risk of starting dialysis in the future. This signals an opportunity to act earlier," said Juan Jesús Carrero, professor at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.
This work is part of the SCREAM project and was funded by organizations including the Swedish Research Council, Swedish Heart-Lung Foundation, Region Stockholm, and Swedish Kidney Foundation. The researchers reported no conflicts of interest related to this study.
