High urinary glucose is associated with improved renal prognosis in patients with diabetes mellitus

AIMS/INTRODUCTION: The relationship between renal function and urinary glucose is poorly understood in diabetes patients who are not using sodium–glucose cotransporter 2 inhibitors. This study aimed to investigate the association of urinary glucose excretion with renal function prognosis in such patients. MATERIALS AND METHODS: This retrospective cohort study included 1,172 patients with type 1 or 2 diabetes mellitus. Patients were recruited and data were collected between 1 January 2007 and 31 December 2011; follow‐up data were collected until 30 June 2015. The primary outcome was set as a 30% decline in estimated glomerular filtration rate relative to baseline. The relationship between this outcome and urinary glucose was investigated using Cox proportional hazards model. For analysis, patients were categorized into two groups: urinary glucose <5 g/day or ≥5 g/day. Interaction terms were analyzed. RESULTS: Multivariate analysis showed that the prognosis of renal function was significantly better in patients with high urinary glucose (≥5 g/day; adjusted hazard ratio 0.58, 95% confidence interval 0.35–0.96; P = 0.034). Significant interactions were observed between high urinary glucose and male sex (hazard ratio 0.33, 95% confidence interval 0.14–0.74; P = 0.007), and between high urinary glucose and longer duration of diabetes (≥10 years; hazard ratio 0.25, 95% confidence interval 0.11–0.58; P = 0.001). CONCLUSIONS: The present study suggests that high urinary glucose is associated with prognosis in diabetes patients not taking sodium–glucose cotransporter 2 inhibitors. Measurement of 24‐h urinary glucose excretion might have clinical utility for predicting renal prognosis.