Objective. To study the histopatholgical pattern of lupus nephritis, long term outcome and identify the predictors of poor outcome among SLE patients in Oman.  
Methods. This retrospective study included 94 patients diagnosed with biopsy proven lupus nephritis hospitalized between 1995 and 2016 at a single center. The revised WHO classification of lupus nephritis was used to score the type of lupus nephritis on renal biopsy. Patients were treated as per standard protocol. Demographic, clinical, laboratory, therapeutic and end-point data were collected. Data are shown as the mean+- SD. Kaplan-Meier survival curves and long rank test were used for survival analysis. Predictors of poor outcome are identified using the Cox regression analysis. 
Results. 94 patients were included in the study with a female to male ratio of 5.7:1. The majority had nephritis at presentation or within 6 months of diagnosis of SLE. The long-term outcome was calculated for all 94 patients and the median duration of follow up was 8 years interquartile range [IQR] 6-14 years during which 16 patients developed ESRD and 7 patients died. Treatment response was based on PCR and creatinine level on last follow up, hence, 50% achieved complete remission (PCR <0.5 and normal GFR), 9.5% had partial remission (>50% reduction on proteinurea to sub-nephrotic level with normal GFR) and 16% had active nephritis. The overall renal survival at 5, 10 and 15 years was 86.9%, 73.8% and 68.6% respectively. There is a statistically significant difference in survival distribution between histological class 11 and class V (p=0.036). However, there is no difference in renal survival between patients who had a renal biopsy and nonbiopsied patients. Risk factors for poor outcome (CKD, ESRD or death) on multivariate cox regression analysis were onset to nephritis, elevated dsDNA and presence of infection. 
Conclusion our study is the first in Oman to address the outcome of lupus nephritis in Omani population. Results showed similar outcome to what reported in different parts of the worlds and the most common histopathological class was class IV. Duration of SLE till onset of nephritis, dsDNA and infection were risk factors for poor outcome.

Long Term Outcome of Lupus Nephritis in SLE in Oman