Objectives To describe the profile of patients included in RELESSER with histologically confirmed lupus nephritis (LN).
Methods RELESSER is a multicentre cross-sectional study with an analytical component.Information was retrospectively collected from the medical records of patients with SLE who were followed up at participant rheumatology units.A total amount of 359 variables including demographic data,clinical manifestations,activity,severity,comorbidities,treatments and mortality were recorded. Specifically, the following renal data were included: WHO histological type of LN, the presence of proteinuria, haematuria, leukocyturia, cellular casts and creatinine clearance. Data regarding recurrence, treatment response, development of end-stage renal disease (ESRD) and/or the need for dialysis or renal transplantation were collected. We performed a descriptive analysis by calculating means and standard deviations for numerical variables and frequencies for qualitative variables. Chi -square or t- Student tests were applied according to the type of variable to analyse its relationship with LN. Odds ratio and confidence intervals were calculated by using simple logistic regression. Statistical significance was p<0.05.
Results LN was histologically confirmed in 1092 patients (30.5%).Most patients were female (85.7%),Caucasian (90.2%),and the mean age at LN diagnosis was 28±12 years.Most had LN proliferative forms (70.2%),and there were only 15 cases of thrombotic microangiopathy (TMA).The development of NL was more frequent in women (p<0.001),at younger age (p<0.001) and in Caucasians (p=0.03).Complete response to treatment was achieved in 2.2% of patients,8.6% developed ESRD,and 9.7% and 5.3% ended in dialysis and kidney transplantation, respectively.The rate of patients with complete response was lower in the case of proliferative forms,but the difference did not reach statistical significance.The higher the age of LN the greater the likelihood of complete response (p<0.001).This likelihood was lower in Asians (p=0.036).326 recurrences were recorded, with a mean individual event of 1 and a mean time to first recurrence of 47 months (0-28), regardless of histology.The lower was the serum creatinine and the older was the age at LN onset, the lower was the recurrence risk. TMA was a risk factor for recurrence (p=0.016),whereas recurrences were related with persistent lupus activity at the last visit (p<0.001) and with ESRD (p<0.001).During the follow up, the LN development associations are described in Figure 1.
LN was related to an increased risk for avascular bone necrosis [OR 2.61, (CI 1.84-3.69)] and premature gonadal failure [OR 12.32, (CI 7.34-20.71), p<0.001]. LN itself was a poor prognostic factor associated with increased mortality risk [OR 2.4 (1.81-3.22), p<0.001].
Conclusions LN, mainly proliferative forms, affects almost one third of patients with SLE, and is often associated with the occurrence of other severe lupus manifestations, being a poor prognostic factor. TMA and relapses are associated with worse outcome in renal function.
Disclosure of Interest None declared