FRI0165 RISK OF CKD IN MEMBRANOUS AND PROLIFERATIVE LUPUS NEPHRITIS - ANALYSIS OF A NATIONWIDE MULTICENTRE COHORT
Authors: F. Farinha, S. C. Barreira, M. Couto, M. Cunha, D. Fonseca, R. Freitas, L. Inês, M. Luis, C. Macieira, A. R. Prata, J. Rodrigues, B. Santos, R. Pinheiro Torres, R. J. Pepper, A. Rahman, M. J. Santos
Journal: Annals of the Rheumatic Diseases (2020)

Background: Lupus nephritis (LN) is one of the most severe manifestations of Systemic Lupus Erythematosus. Objectives: 1) To compare proliferative (PLN), membranous (MLN) and mixed LN regarding clinical and laboratory presentation. 2) To investigate predictors of progression to chronic kidney disease (CKD). Methods: Multicentre observational study, with retrospective analysis of a prospective cohort, using data from the Portuguese registry of rheumatic diseases – Reuma.pt. Patients with biopsy-proven PLN, MLN and mixed LN were included. Groups were compared using Pearson’s Chi-Square for categorical variables and One-Way ANOVA or Kruskal-Wallis for numerical variables. COX regression analysis was used to investigate predictors of CKD (defined as estimated glomerular filtration rate [eGFR] lower than 60 mL/min/1.73m 2 for at least 3 months) and Kaplan-Meier curves were drawn. Results: 236 patients were included. Median follow-up was 8 years (IQR 11; maximum 35 years). As seen in table 1, the level of proteinuria did not differ between groups; however, MLN patients presented with significantly lower serum creatinine. Levels of complement C3 and C4 were reduced in PLN but normal in MLN patients, and there were fewer patients with positive anti-dsDNA antibodies in the MLN group (p&lt;0.001). On univariable COX regression, mixed histology was associated with progression to CKD (HR 26 [95% CI 3 - 255], p 0.005) (figure 1), however, it lost significance after adjusting for eGFR. In fact, eGFR≤75 at one year after the renal biopsy (HR 21 [95% CI 7 - 65], p&lt;0.001) was the strongest predictor of CKD, even after adjusting for hypertension or histology. Table 1. Comparative description of the Reuma.pt cohort of patients with proliferative, membranous and mixed LN PLN MLN Mixed P Total, N 186 42 8 Females, N (%) 157 (85) 39 (95) 4 (50) 0.004 Ethnicity White European, N (%) 163 (90) 31 (78) 7 (88) 0.115 Other, N (%) 19 (10) 9 (23) 1 (13) Age LN diagnosis(y), median (IQR) 30 (20) 34 (16) 42 (25) 0.409 SLEDAI at LN diagnosis, median (IQR) 16 (9) 10 (10) 21 (17) 0.006* uPCR at LN diagnosis, median (IQR) 1675 (2598) 1698 (2153) 2160 (3320) 0.629 Creatinine at LN diagnosis, median (IQR) 0.80 (0.32) 0.70 (0.20) 1.00 (0.95) 0.006* eGFR at LN diagnosis, mean ± SD 98 ± 33 112 ± 17 82 ± 45 0.019* Albumin at LN diagnosis, mean ± SD 34 ± 7 34 ± 7 30 ± 6 0.390 C3 at LN diagnosis, mean ± SD 0.65 ± 0.26 0.90 ± 0.35 0.53 ± 0.30 &lt;0.001* Positive anti-dsDNA LN diagnosis, N (%) 115 (91) 11 (48) 6 (86) &lt;0.001* Use of antimalarials, N (%) 166 (94) 36 (92) 8 (100) 0.688 Use of immunosuppressants, N (%) 163 (94) 33 (87) 8 (100) 0.245 Use of corticosteroids, N (%) 145 (84) 33 (85) 7 (100) 0.511 CKD after LN diagnosis, N (%) 27 (15) 1 (3) 3 (38) 0.018* ESRD, N (%) 7 (4) 1 (3) 2 (25) 0.016 Deaths, N (%) 14 (8) 2 (5) 0 0.610 uPCR: urinary protein-creatinine ratio, mg/g; y: years; Creatinine presented in mg/dL, eGFR in mL/min/1.73m 2, albumin in g/L and C3 in g/L Note: Baseline data (LN diagnosis) in grey; other data refer to the course of disease *Significant difference between the proliferative and membranous groups Figure 1. Kaplan-Meir curves showing cumulative survival free of CKD in patients with PLN, MLN and mixed LN Conclusion: Our results support previous findings from single-centre studies suggesting that MLN has a different serological profile than PLN, possibly reflecting different pathogenesis. Renal function at one year predicts long-term outcome in LN. Disclosure of Interests: Filipa Farinha: None declared, Sofia C Barreira: None declared, Maura Couto: None declared, Margarida Cunha: None declared, Diogo Fonseca: None declared, Raquel Freitas: None declared, Luís Inês: None declared, Mariana Luis: None declared, Carla Macieira: None declared, Ana Rita Prata: None declared, Joana Rodrigues: None declared, Bernardo Santos: None declared, Rita Pinheiro Torres: None declared, Ruth J. Pepper: None declared, Anisur Rahman: None declared, Maria Jose Santos Speakers bureau: Novartis and Pfizer