The objective of this study was to investigate the association of lupus nephritis on organ damage and mortality in patients with systemic lupus erythematosus (SLE).

A total of 1112 patients with SLE were investigated. Lupus nephritis was defined as a proteinuria based on the 1997 American College of Rheumatology criteria. Damage was assessed using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index. The associations of lupus nephritis with overall, non-renal, corticosteroid-associated, and non-associated damage were analyzed using logistic regression. The age-adjusted and sex-adjusted standardized mortality ratio was evaluated in patients with and without lupus nephritis.

The prevalence of lupus nephritis in patients with SLE was 46.3%. Patients with lupus nephritis had a higher percentage of overall cumulative damage than patients without lupus nephritis (51.5% vs. 35.7%, p < 0.001). The odds ratio was 1.40 after adjusting for age at SLE diagnosis, sex, disease duration, anti-malarial agents, immunosuppressive agents and cumulative corticosteroid dose. Among non-renal damage, the odds of corticosteroid-associated damage were higher (2.06, 95% confidence interval (CI) 1.43–2.96) whereas the odds of non-associated damage were lower (0.50, 95% CI 0.35–0.75) in patients with lupus nephritis. The standardized mortality ratios of patients with and without lupus nephritis were 5.17 (95% CI 3.49–7.38) and 2.32 (95% CI 1.47–3.48), respectively.

In patients with SLE, the presence of lupus nephritis is associated with increased corticosteroid-associated damage but less corticosteroid non-associated damage. Also, mortality is significantly higher in patients with lupus nephritis than in those without lupus nephritis.