Leptin level predicts risk for kidney function decline in diabetes
MedWire News: Both low and high leptin levels are risk factors for decline of kidney function in patients with Type 2 diabetes, say researchers.
In addition, low but not high leptin levels are significantly associated with increased risk for progression of albuminuria.
Currently, the role of leptin in the pathogenesis of diabetic kidney disease (DKD) is unclear, say Tetsuya Babazono (Tokyo Women's Medical University, Japan) and colleagues.
"Studies show patients with DKD have higher serum leptin levels than those without DKD, whereas leptin administration in patients with generalized lipodystrophy has been reported to dramatically improve albuminuria as well as metabolic parameters," says the team.
As reported in the journal Diabetes Care, the researchers categorized 668 patients with Type 2 diabetes into three groups, by gender-specific leptin levels, such that the first and second tertile levels were 6.4 and 11.7 ng/mL and 2.9 and 5.2 ng/mL in women and men, respectively.
They also measured the patients' albumin-to-creatinine ratio (ACR) to determine the stage of albuminuria and estimated glomerular filtration rate (eGFR).
The primary outcome was the annual rate of change in eGFR over a mean follow-up period of 4.2 years and the secondary outcome was progression to a more advanced stage of albuminuria over a mean of 3.2 years.
The authors found that the mean annual rate of change in eGFR was -1.66 mL/min per 1.73 m2.
Multivariate analysis showed that the annual rate of decline in eGFR was significantly steeper in patients with low and high leptin levels than in those with mid-range leptin levels (-2.07 and -2.14 vs -0.82 mL/min per 1.73 m2).
Furthermore, patients with low leptin levels were at significantly increased risk for progression of albuminuria, as compared with those with high leptin levels, at a hazard ratio of 3.13.
The authors say these findings suggest that low leptin levels are a risk factor for progression of DKD.
In contrast, high leptin levels were not a risk factor for progression of albuminuria, they add.
"These findings need to be confirmed in studies with a larger sample size and in a multicenter design," concludes the team.
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By Sally Robertson