Overestimation of the risk of progression to end-stage renal disease in the poor prognosis' group according to the 2002 Japanese histological classification for immunoglobulin A nephropathy.
BACKGROUND
The current (2012) histological classification of immunoglobulin A nephropathy was established using a case-control study of 287 patients. However, the risk of progression to end-stage renal disease (ESRD) has not been validated for the previous (2002) classification. This study aimed to determine whether the previous classification could identify the risk of long-term renal outcome through re-analysis of the 2012 cohort.


METHODS
On the basis of the 2002 classification, namely 'good prognosis', 'relatively good prognosis', 'relatively poor prognosis', and 'poor prognosis', we examined the clinical data at the time of biopsy, the correlation between the 2002 classification and long-term renal outcomes, and a patient-by-patient correlation between the 2002 and 2012 classification systems. This was performed by analyzing samples from the 287 patients used to establish the 2012 classification.


RESULTS
The rate of decline of estimated glomerular filtration rate was greater and the odds ratio of progression to ESRD was higher in the 'poor prognosis' group. In contrast, the odds ratio for renal death was comparable between the groups described as 'relatively poor prognosis' and 'relatively good prognosis' in the 2002 classification. Many patients in the 2002 classification were classified with a lower histological grade in the current classification, but none were classified with a higher grade.


CONCLUSIONS
The 2002 classification could also identify the risk of progression to ESRD. However, it was overestimated for patients in the 'poor prognosis' group in the 2002 classification, as that group included patients with milder histological damage.
Division of Kidney and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-Ku, Tokyo, 105-0003, Japan.
Yoichi
Y
Miyazaki
Tetsuya
T
Kawamura
Kensuke
K
Joh
Hideo
H
Okonogi
Kentaro
K
Koike
Yasunori
Y
Utsunomiya
Makoto
M
Ogura
Masato
M
Matsushima
Mitsuhiro
M
Yoshimura
Satoshi
S
Horikoshi
Yusuke
Y
Suzuki
Akira
A
Furusu
Takashi
T
Yasuda
Sayuri
S
Shirai
Takanori
T
Shibata
Masayuki
M
Endoh
Motoshi
M
Hattori
Yuko
Y
Akioka
Ritsuko
R
Katafuti
Akinori
A
Hashiguchi
Kenjiro
K
Kimura
Seiichi
S
Matsuo
Yasuhiko
Y
Tomino
D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D005922:Glomerulonephritis, IGA / Q000145:classification* / Q000175:diagnosis*; D006801:Humans; D007564:Japan; D007668:Kidney / Q000473:pathology / Q000503:physiopathology; D007676:Kidney Failure, Chronic / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult