Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Clinical-Pathological Correlates of Proliferative Lesions in Lupus Nephritis.

Barber1,  Claire, Urowitz2,  Murray B., Gladman3,  Dafna D., Wither4,  Joan E., Landolt-Marticorena2,  Carolina, Reich5,  Heather, Lou6,  Wendy

Mount Sinai Hospital, Toronto, ON
Division of Anatomic Pathology, Mayo Clinic, Rochester
Toronto Western Hospital and University of Toronto, Toronto, ON
Toronto Western Hospital, University of Toronto, Toronto, ON
Toronto Western Research Institute, University Health Network, Toronto, ON
The Toronto Western Hospital, Toronto, ON
Dalla Lana School of Public Health, Toronto, ON
Toronto Western Hospital, Toronto, ON
University Health Network, Toronto, ON
Nephrocor, Long Island, NY

Background/Purpose:

To examine the clinical-pathological correlates at time of renal biopsy in patients with lupus nephritis according to the 2003 International Society of Nephrology and Renal Pathology Society (ISN/RPS) classification.

Methods:

We studied a large prospectively followed cohort of SLE patients from a single centre with renal biopsy slides available and matched clinical follow-up. Demographic and clinical data collected at time of renal biopsy included age, gender, disease activity (SLEDAI-2K) and damage (SLICC damage index). Renal biopsies were reviewed by two expert pathologists independently and by a third pathologist where disagreement occurred to determine a consensus score. The degree of agreement between pathologists on individual items of the ISN/RPS score was measured. We included only pathologic variables with at least moderate agreement (kappa >= 0.6). The variables included ISN/RPS class I-VI of nephritis. For class III, the subclasses of active (A), active and chronic (A/C) and chronic (C) had poor agreement and were considered as a single class. For class IV, the agreement was poor for the segmental versus global subclasses but acceptable or the active A, A/C or C lesions. Correlates between these variables and clinical characteristics at time of biopsy were determined using chi-square or Fisher's exact test. Univariate and multivariate regression models were generated to examine the outcomes of complete remission (CR) defined as serum creatinine (sCr) < 1.4 mg/dl and proteinuria of < 0.33 g/d, partial remission (PR) defined as a < 25% increase in baseline sCr and > 50% reduction in baseline proteinuria to < 1.5 g/d and no remission at 6, 12 and 24 months post-biopsy.

Results:

137 patients had biopsy slides available for review. The average age at time of biopsy was 37.2 ± 12.0 years, 81.5% were female and 64.2% were Caucasian. The majority of biopsies showed class III (24.8%) or class IV nephritis (IV-A: 12.4%, IV-A/C: 22.6%, IV-C: 4.4%) and 14.6% were pure class V. The estimated glomerular filtration rate (eGFR) was lower in patients with class IV- A/C (42.8 mL/min/1.73m2) compared to all other groups (85.1 mL/min/1.73m2, p < 0.001) and higher in class III (91.6 mL/min/1.73m2, p = 0.002). The mean arterial pressure (MAP) was higher in patients with class IV-A/C compared to other classes (107.6 ± 18.4mmHg versus 98.1 ± 13.5mmHg, p = 0.02). The SLEDAI-2K and a non-renal SLEDAI-2K were no different between classes; however the anti-dsDNA levels by Farr assay at time of biopsy were highest in class III (40 U/mL versus 16 U/mL, p = 0.02) and lowest in class IV-C biopsies (5 U/mL versus 22.5 U/mL, p = 0.01) and C3 levels were lowest in class IV-A and IV-A/C (0.4 ± 0.2 vs 0.8 ± 0.30 < 0.001; 0.6 ± 0.3 vs 0.8 ± 0.4, p = 0.04). On univariate analysis the presence of a higher C3 levels at time of biopsy was associated with CR at 24 months (OR 6.18, 95% CI: 1.33, 28.69). On multivariate analysis none of the pathologic variables was independently associated with CR or PR at any time point.

Conclusion:

Distinct clinical features at the time of renal biopsy are associated with specific ISN/RPS subclasses of lupus nephritis however no pathologic features were independently associated with renal outcome.

To cite this abstract, please use the following information:
Barber, Claire, Urowitz, Murray B., Gladman, Dafna D., Wither, Joan E., Landolt-Marticorena, Carolina, Reich, Heather, et al; Clinical-Pathological Correlates of Proliferative Lesions in Lupus Nephritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1398
DOI:

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