A recent study from Karolinska Institutet has identified that variations in kidney function, even within the clinically accepted "normal" range, can indicate an elevated risk of developing chronic kidney disease (CKD). Researchers have concurrently developed a web-based tool and distribution charts aimed at assisting healthcare professionals in the early detection and primary prevention of the disease.
Chronic Kidney Disease Overview
Chronic kidney disease affects an estimated 10 to 15 percent of adults globally. Projections indicate it could become a leading cause of years of life lost by 2040. Current screening methods for CKD are often reported as inadequate, frequently leading to diagnoses at a stage where more than half of a patient's kidney function may already be diminished.
Study Methodology and Tool Development
To address the challenge of late diagnosis, researchers at Karolinska Institutet constructed population-based distributions for estimated glomerular filtration rate (eGFR), a common measure of kidney function. This methodology was inspired by pediatric growth charts, which are used to identify risks such as obesity or undergrowth in children.
The study analyzed data from over 1.1 million adults residing in the Stockholm region of Sweden, covering approximately 80 percent of the population aged 40 to 100 years. Nearly seven million eGFR tests collected between 2006 and 2021 were utilized to establish age- and sex-specific distributions of kidney function. The findings were published in Kidney International.
New Detection Tool
The developed eGFR distribution charts and a web-based calculator are openly accessible to healthcare professionals. Developed in part by PhD student Antoine Creon, the tool allows clinicians to assess a patient's eGFR against age-specific population norms, aiding in the identification of individuals who may be at an increased risk for CKD.
Key Study Findings
The analysis revealed several key correlations:
- Adverse Outcomes: Departures from the median eGFR for an individual's age and sex were associated with adverse health outcomes.
- Increased Risk of Kidney Failure: Individuals with an eGFR below the 25th percentile for their age and sex demonstrated a significantly higher risk of developing kidney failure requiring dialysis or transplantation.
- Mortality Relationship: Mortality exhibited a U-shaped relationship, indicating that both very low and very high eGFR percentiles were linked to an increased risk of death.
Implications for Early Intervention
The research highlighted an observed gap in healthcare awareness concerning early kidney damage. For example, among individuals with an eGFR above 60 ml/min/1.73 m² (typically considered within the normal range) but below the 25th percentile for their age, only 25 percent had received further testing for urinary albumin. Urinary albumin testing is a method used for detecting early kidney damage.
Researchers suggest these findings create opportunities for earlier intervention. For instance, a 55-year-old woman with an eGFR of 80 ml/min/1.73 m², which is generally considered normal, could be at the 10th percentile for her age group according to the new charts. This position on the charts indicates a threefold higher risk of requiring future dialysis compared to the median for her age, suggesting potential for proactive medical strategies.
Funding
The study is part of the SCREAM project and received funding from organizations including the Swedish Research Council, the Swedish Heart-Lung Foundation, Region Stockholm, and the Swedish Kidney Foundation.