Glomerular hyperfiltration in dipstick-negative type 2 diabetes mellitus: a novel determinant of kidney function decline in type 2 diabetes mellitus.

BACKGROUND

The independent impact of type 2 diabetes mellitus (T2DM) on kidney outcomes beyond albuminuria remains unclear. We evaluated whether T2DM affects kidney outcomes in individuals with normal kidney function without albuminuria.

METHODS

Data from the National Health Insurance Service-National Sample Cohort of Korea (2009-2015) were analyzed. Individuals with normal kidney function were stratified by T2DM status. The primary outcome was a composite kidney outcome consisting of initiation of kidney replacement therapy and a sustained decline in estimated glomerular filtration rate (eGFR) of ≥40% from baseline.

RESULTS

Among 77,267 individuals with normal kidney function without albuminuria, patients with T2DM (n = 11,957) showed significantly steeper annual decline in eGFR than non-T2DM individuals (-0.113 mL/min per 1.73 m2 per year; 95% confidence interval [CI], -0.222 to -0.003). T2DM was associated with a 57% higher risk of composite kidney outcome (adjusted hazard ratio, 1.57; 95% CI, 1.28-1.92), independent of traditional risk factors. This association was strongest in individuals with glomerular hyperfiltration and longer T2DM duration (≥6 years).

CONCLUSION

Normal kidney function T2DM was associated with accelerated kidney function decline and a 1.5-fold increased risk of adverse kidney outcomes compared with normal kidney function non-T2DM, particularly in individuals with glomerular hyperfiltration and longer duration.