Survival analysis of mortality and development of lupus nephritis in patients with systemic lupus erythematosus up to 40-years of follow-up

Patients with systemic lupus erythematosus (SLE) have increased mortality compared with age and sex-matched controls. Lupus nephritis (LN) is a severe manifestation of SLE and an important cause of death. We carried out a retrospective survival analysis to investigate factors that could influence risk of mortality and LN in a large multi-ethnic cohort of patients with SLE.By careful review of medical records, we identified 496 patients with SLE for whom we had complete information regarding period of observation and occurrence of death and nephritis. Patients were stratified into groups according to sex, ethnicity, age at start of follow-up and time-period of diagnosis. Kaplan-Meier analysis was used to investigate differences between the groups.Of 496 patients in the study, 91(18.3%) died, 165(33.3%) developed LN and 33(6.7%) developed end-stage renal failure. There was no difference between men and women in either mortality or development of LN. Caucasian patients were significantly less likely to develop LN than other ethnic groups (p< 0.0001) but not less likely to die. Patients diagnosed before the median age of 28 years were significantly more likely to develop LN (p< 0.0001) but significantly less likely to die (p= 0.0039) during the period of observation. There has been a significant improvement in survival between patients diagnosed between 1978-1989 and those diagnosed between 2006-11 (p= 0.019).In our cohort, non-Caucasian ethnicity and younger age at diagnosis are associated with risk of developing LN. There is evidence of improvement in survival of patients with SLE over time.