The 'renal threshold for glucose' has never been evaluated in critically ill patients. Therefore, we aimed to investigate the renal glucose threshold in this patient group using high-sensitivity urine glucose assays. In this retrospective analysis of prospectively collected data, we analysed 100 consecutive critically ill patients from a medical intensive care unit (ICU). Arterial blood glucose and spot urine glucose were simultaneously quantified daily during the first week after ICU admission. Three hundred seventy-three pairs of blood/urine glucose were plotted in five pre-defined categories of blood glucose (<80, 80-109, 110-139, 140-179 and ≥180 mg/dL). Urine glucose values of the five categories were compared using the Kruskal-Wallis test to assess the relation with blood glucose. Urine glucose was detected in virtually all of the urine samples. Urine glucose showed a positive nonlinear correlation with blood glucose and was significantly elevated at blood glucose levels of 140-179 and ≥180 mg/dL compared with lower blood glucose ranges. Basal glucosuria is ubiquitous in critically ill patients. A 'soft' renal threshold for glucose is present at blood glucose levels in the range of 140-179 mg/dL.
Keywords: critical care; glucose; intensive care; kidney; renal glucosuria.
© 2015 Asian Pacific Society of Nephrology.