Association of serum leptin levels with progression of diabetic kidney disease in patients with type 2 diabetes.

To clarify the association of serum leptin levels with progression of diabetic kidney disease in patients with type 2 diabetes (T2D). This was an observational cohort study of 668 patients with T2D. Patients were classified into three groups by sex-specific tertile of leptin levels. Outcome measurements were the rate of change in estimated glomerular filtration rate (eGFR) and progression to a more advanced stage of albuminuria. Patients with low or high leptin levels had a steeper eGFR decline (-2.07 and -2.14 mL/min/1.73 m(2)/year) than those with midrange leptin levels (-0.82 mL/min/1.73 m(2)/year; P < 0.01), whereas patients with low leptin levels had an elevated risk of progression of albuminuria as compared with those with high leptin levels (hazard ratio 3.125 [95% CI 1.302-7.499]). Both low and high serum leptin levels were risk factors for kidney function decline. Meanwhile, lower serum leptin levels were associated with progression of albuminuria.