A histologic classification of IgA nephropathy for predicting long-term prognosis: emphasis on end-stage renal disease.
BACKGROUND
A multicenter case-control study on IgA nephropathy (IgAN) was conducted to develop an evidence-based clinicopathologic classification of IgAN for predicting long-term renal outcome.


METHODS
Two hundred and eighty-seven patients including those with isolated hematuria or very mild proteinuria were enrolled. During a median follow-up of 9.3 years after biopsy, 49 patients (17%) progressed to end stage renal disease (ESRD). The associations between pathological variables and the need for chronic dialysis was examined by multivariate logistic regression analysis separately in patients who required dialysis earlier than 5 years (Early Progressors) and those who required dialysis within 5 to 10 years (Late Progressors) after biopsy.


RESULTS
Independent pathological variables predicting progression to ESRD were global sclerosis, segmental sclerosis and fibrous crescents for Early Progressors, and global sclerosis and cellular/fibrocellular crescents for Late Progressors. Four histological grades, HG 1, HG 2, HG 3 and HG 4, were established corresponding to <25%, 25-49%, 50-74% and =75% of glomeruli exhibiting cellular or fibrocellular crescents, global sclerosis, segmental sclerosis or fibrous crescents. Eleven (7%) patients in HG 1, 12 (16%) in HG 2, 13 (31%) in HG 3 and 13 (68%) in HG 4 progressed to ESRD. Multivariate logistic analysis revealed that the risk of progression to ESRD was significantly higher in HG 2, 3 and 4 than in HG 1 (odds ratio, 2.4, 5.7 and 27.6 vs. 1.0).


CONCLUSIONS
Our evidence-based histologic classification can identify the magnitude of the risk of progression to ESRD and is useful for predicting long-term renal outcome in IgAN.
Division of Kidney and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan. kawatetu@coral.ocn.ne.jp
Tetsuya
T
Kawamura
Kensuke
K
Joh
Hideo
H
Okonogi
Kentaro
K
Koike
Yasunori
Y
Utsunomiya
Yoichi
Y
Miyazaki
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
Ritsuko
R
Katafuchi
Akinori
A
Hashiguchi
Kenjiro
K
Kimura
Seiichi
S
Matsuo
Yasuhiko
Y
Tomino
D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D005355:Fibrosis; D005922:Glomerulonephritis, IGA / Q000145:classification / Q000150:complications / Q000473:pathology* / Q000628:therapy; D005923:Glomerulosclerosis, Focal Segmental / Q000145:classification / Q000150:complications / Q000473:pathology* / Q000628:therapy; D006801:Humans; D007564:Japan; D007676:Kidney Failure, Chronic / Q000209:etiology* / Q000473:pathology / Q000628:therapy; D007678:Kidney Glomerulus / Q000473:pathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011379:Prognosis; D006435:Renal Dialysis; D012189:Retrospective Studies; D012307:Risk Factors; D012598:Sclerosis; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult