P0387PATHOLOGICAL FEATURES AND CLINICAL COURSE OF LATE-ONSET LUPUS NEPHRITIS

Abstract

Abstract Background and Aims It has been described that the early onset of lupus nephritis (LN) at a young age can determine the clinical course and outcome of the disease, being more aggressive with a higher mortality rate. However, no studies have explored the influence of age at onset of the disease in European cohorts of LN patients, neither have they analyzed treatment outcomes depending on age at presentation. Therefore, the aim of our study was to compare the clinical and histological characteristics of patients with late-onset LN compared to those with an onset at a younger age. Method We performed a retrospective observational study of biopsy-proven LN diagnosed between 1981 and 2018. Patients were stratified according to their age at presentation of LN, considering an onset with >50 years old as late-onset. Demographic, clinical and serological data at presentation of systemic lupus and LN, during and at the end of follow-up, as well as extrarenal manifestations, histological characteristics of the kidney biopsy, clinical course, received treatment regimens and related adverse effects were registered. Results 85 LN patients were included in the study, 10 of whom had late-onset LN (11.7%). Late-onset LN patients presented significantly higher serum C3 and C4 levels at the time of kidney biopsy (92.8 ± 22.4 mg/dl vs 62.5 ± 25.7 mg/dl, p=0.002, and 18.6 ± 5.0 vs. 9.3±5.8 mg/dl, p<0.001 respectively), and had lower eGFR measured by CKD-EPI (58.50±19.79 vs 90.41±30.53,p=0.003), a higher frequency of serositis manifestations (53.45% vs 17.46%, p=0.034), predominantly pleuritis (79.37% vs 51.75% p=0.013). Early-onset LN had predominantly Class IV LN (50% vs 10%, p=0.017), whereas in late-onset LN the most frequent type was Class V LN (50% vs 21.3%, p=0.048). Tubular atrophy was more common in late-onset LN (75% vs 34.9%, p=0.035). The group of patients with late-onset LN achieved complete clinical remission more frequently (87.5% vs 57.1%), but there were no differences in relapses between the groups. No differences were found in treatment regimens among the groups. Late-onset LN patients were more seronegative (100% vs 61.3%, p=0.015) at the end of follow-up. Severe infectious complications related to immunosuppression were significantly higher in late-onset LN patients (62.5% vs 22.2%, p=0.027) Conclusion Late-onset LN has a milder complement consumption at presentation compared to early-onset, and Class V LN is its most frequent form of presentation. Complete renal remission is more frequently achieved in late-onset LN compared to those with an early-onset, but present more adverse events associated with immunosuppression, particularly infectious complications.