Urinary Podocalyxin as a Biomarker to Diagnose Membranous Nephropathy.
BACKGROUND
A non-invasive diagnostic marker of membranous nephropathy (MN) is desirable. The urinary level of podocalyxin (PCX) is higher in various glomerular diseases, including MN. The aim of this study was to construct a diagnostic model of MN with the combination of urinary PCX and clinical parameters.


METHODS
We performed this cross-sectional study to construct the diagnostic models for MN by using data and samples from the multicenter kidney biopsy registry of Nagoya University and its affiliated hospitals. Urinary (u-) PCX was measured by sandwich ELISA. We constructed 3 types of diagnostic models in 105 training samples: u-PCX univariate model, the combined model of clinical parameters other than u-PCX (clinical model), and the combined model of both u-PCX and clinical parameters (combined model). We assessed the clinical usefulness of the diagnostic models through the comparison of c-statistics and decision curve analysis (DCA) in 209 validation samples.


RESULTS
The clinical model consisted of age, glomerular filtration rate, and diabetes mellitus. In the training cohort, the c-statistics were 0.868 [95% CI, 0.799-0.937] in the combined model. In the validation cohort, sensitivity was 80.5% and specificity was 73.5% on the cut-off value. The net benefit of the combined model was better between threshold probabilities of 40-80% in DCA.


CONCLUSIONS
In this study, we demonstrated the utility of u-PCX as a diagnostic marker for MN and the clinical usefulness of the diagnostic models, through the combination of u-PCX and clinical parameters including age, glomerular filtration rate, and diabetes mellitus.
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Takahiro
http://orcid.org/0000-0003-3831-7241
T
Imaizumi
Biostatistics and Bioinformatics Section, Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya, Japan.
Masahiro
M
Nakatochi
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Shin'ichi
S
Akiyama
Department of Nephrology, Yokkaichi Municipal Hospital, Yokkaichi, Japan.
Makoto
M
Yamaguchi
Denka Co., Ltd., Tokyo, Japan.
Hiroyuki
H
Kurosawa
Denka Co., Ltd., Tokyo, Japan.
Yoshiaki
Y
Hirayama
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Takayuki
T
Katsuno
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Naotake
N
Tsuboi
Department of Pediatrics, Niigata prefecture Yoshida hospital, Tsubame, Japan.
Masanori
M
Hara
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Shoichi
S
Maruyama
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