FRI0283 Clinical course of mesangial lupus nephritis in a cohort of argentinian patients

Background Mesangial lupus nephritis (MLN) is thought to follow a benign course although there are studies that show otherwise(1,2). Objectives Our aim was to describe the clinical progression in patients with MLN. Methods retrospective, multicentric study in patients with systemic lupus erythematosus and MLN (ISN/RPS 2003) on the first renal biopsy and at least 12 months of post-biopsy follow-up. Demographic, clinical and laboratory characteristics were reviewed. Treatment response was rated based on the EULAR/ ACR criteria(3). Patients were divided into two groups: responders (R)[complete (CR) and partial (PR)] and non-responders(NR):[NR, chronic renal failure(CRF), histology transformation(HT)]. Favorable long term outcome was considered if the patient remained at CR or PR at the last evaluation. Unfavorable was defined as transformation to a proliferative or a membranous type or CRF at any time. The Mann-Whitney test was used to compare numerical variables, Fisher’s exact test to compare ratios. Results Twenty-seven patients (23 females) were assessed. Mean age at the time of first biopsy: 28.2±9 years old. Median time from SLE diagnosis to first biopsy: 1 year (range=0-6). Median time from onset of signs of nephropathy and first biopsy: 2 months (range=0-15). The presentations were: proteinuria > 0.5g/24hr: 19 patients (7 nephrotic-range), 13 hematuria, and 1 impaired renal function requiring dialysis. After the first biopsy 27 patients received corticosteroid therapy (0.5-1mg/kg/day) and 7 received another immunosuppressant for non-renal reasons. At 12 months of follow-up, 20 R(10 RC,10 PR) and 6 NR (4 NR, 1CRF,1HT). We had a missing data. The demographic data and immunology laboratory were similar between R and NR. Responders had a significantly lower level of 24-hour urine protein excretion(g/24hs) at 6 (0,06 vs 0,8)p=0,03 and 12 months (0,2 vs 3,2) p=0.03. Creatinine levels not differ between groups. In the R group 65% of patients received hydroxychloroquine and 15% immunosuppressant vs 100% and 50% respectively in NR group. At the five year follow-up 21 patients were evaluated (6 not reach 5 years of follow up);11 had been re-biopsied: renal flare 8, NR 3. Median time between 1st and 2nd biopsy: 25 months (11-52). Histology results: 1 Class II, 2 Class III, 5 Class IV, 3 Class V. Ten patients continued in remission at 5 years (7 CR, 3PR) and 11were NR (10 HT, 1CRF). The outcome remained favourable in 10/21(47,6%) and unfavourable 11/21(52,3%) patients, including 10 patients who transformed and one with CRF. There were no deaths. Conclusions Our group of patients had a high rate of progression to more serious classes of nephritis (47.6%) after five years of follow up. A higher degree of proteinuria was the only data that shown correlation with histology progression. Serologic markers of lupus activity were not different among R and NR group. References References Lupus(2003)12:665-671, RheumatolInt(2012)32:2459-2464, Lupus(2009)18,257-263. Disclosure of Interest : None Declared