Background and aims Systemic lupus erythematosus (SLE) is a chronic multisystem disorder. Lupus nephritis (LN) is a common serious complication of SLE. LN needs prolonged care and complex therapeutic modalities.

Objectives The aim of this study was to assess the characteristics of Persian SLE patients with LN(LN subgroup) and SLE subpopulation without LN (non-LN subgroup). Furthermore we studied the association of LN with extrarenal manifestations of SLE.

Methods In this study we assessed 2355 SLE patients of the electronic database of Rheumatology Research Centre (RRC), Tehran University of Medical Sciences (TUMS). The clinical and laboratory data of enrolled patients were retrieved. Chi-square test was used to compare the extrarenal manifestations between LN and non-LN subgroups. Odds ratio (OR) was used to present the strength of associations.

Results LN subgroup included 1604 cases (68.1%), with the mean age at SLE onset of 24.6±12.5 years and female to male ratio of 8.7/1. Class IV nephritis was the most common type of LN (53.1%). Comparison of the extrarenal manifestations revealed significant difference between LN and non-LN subgroups. Major organ involvements including cardiopulmonary, hematologic, musculoskeletal and neuropsychiatric features were significantly more common in LN patients. On the contrary, discoid rash was significantly more common in non-LN subgroup.

Conclusions This study revealed that LN was positively associated with musculoskeletal, mucocutaneous and neuropsychiatric features of SLE.