Chronic kidney disease, which affects an estimated 10 to 14 per cent of adults worldwide, is almost always diagnosed from estimated glomerular filtration rate, a calculation based on blood markers rather than direct measurement. Whether the established diagnostic thresholds correspond to genuine risk when kidney function is measured precisely had never been settled at scale. Researchers at Karolinska Institutet and Leiden University Medical Center closed that gap in a study published in JAMA.
The team analysed 6,174 adults in Stockholm who underwent gold-standard measured GFR testing with iohexol clearance between 2011 and 2021, following them for nearly six years for death, kidney failure, heart failure, acute kidney injury and cardiovascular disease. Lower measured GFR was associated with progressively higher risk across every outcome. At 60 millilitres per minute per 1.73 square metres, the conventional threshold for moderate disease, risk of death was 21 per cent higher and risk of kidney failure nearly threefold higher than at a healthy reference of 90.
The study, with Juan-Jesus Carrero of Karolinska's Department of Medical Epidemiology and Biostatistics as corresponding author and co-authors including Edouard L. Fu, Morgan E. Grams, Josef Coresh and Andrew S. Levey, also found that estimating GFR from both creatinine and cystatin C gave the most accurate assessment of mortality risk, practical guidance for laboratories deciding which blood tests to deploy as the global burden of kidney disease grows.