Urinary adiponectin as a marker for diabetic nephropathy

By Sally Robertson, B.Sc.Oct 4 2012

Urinary adiponectin may provide a novel biomarker for diabetic nephropathy, shows research from Finland.

In a presentation at the European Association for the Study of Diabetes 48th Annual Meeting in Berlin, Germany, Markku Saraheimo from Helsinki University Central Hospital said "urinary adiponectin seems to be as good as albumin excretion rate (AER) in predicting the progress from macroalbuminuria to end stage renal disease (ESRD) in patients with Type 1 diabetes."

"In macro stage, they are really losing their adiponectin," he explained.

Urinary adiponectin has shown associations with overt nephropathy in cross-sectional studies of individuals with Type 2 diabetes, but there are no data regarding the role of urinary adiponectin in the progression of diabetic nephropathy (DN) in patients with Type 1 diabetes.

In a study conducted as part of the Finnish Diabetic Nephropathy Study and including 2201 patients, Saraheimo and colleagues found that 101 of 1451 patients with a normal AER progressed to microalbuminuria, 42 of 319 progressed from micro- to macroalbuminuria, and 71 of 320 progressed from macroalbuminuria to end-stage renal disease (ESRD), over a median follow-up period of 5.8 years.

The clearance of urinary adiponectin significantly increased with worsening nephropathy stage, with a mean level of 0.0628 µg/µmol detected in the urine of in patients with a normal AER, a level of 0.1100 µg/µmol detected in those with microalbuminuria, and a level of 0.6230 µg/µmol found in those with macroalbuminuria. Excretion of adiponectin in the urine was significantly higher in patients with a normal AER than in a control group of 111 individuals without diabetes.

"What we were astonished at was the huge difference when changing from micro to macro in urinary adiponectin levels," said Saraheimo.

Cox regression analysis showed that urinary adiponectin predicted progression to a higher stage among those with microalbuminuria, at an odds ratio (OR) of 1.37, and progression to ESRD in those with macroalbuminuria, at an odds ratio of 1.03.

Further analysis showed that there was no significant difference in area under the receiver operating characteristic curves between AER and adiponectin for prediction of progression to ESRD in the macroalbuminia group.

A further study should compare albuminuria and adiponectin in the early stages rather than the very late stages of decline in renal function, concluded Saraheimo.

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