Survival analysis and causes of mortality in patients with lupus nephritis

Abstract

BACKGROUND: This study aimed to define the causes and associated risks of death compared with the local general population in Chinese patients with lupus nephritis in the recent era. METHODS: The records of all lupus nephritis patients followed in a single centre during 1968-2008 were reviewed. The causes of death were identified, the survival curves constructed and the standardized mortality ratios (SMRs) of potential risk factors were calculated with reference to the local general population. RESULTS: Two hundred and thirty systemic lupus erythematosus patients with history of renal involvement (predominantly Class III/IV lupus nephritis with or without membranous features) were included. The follow-up was 4076.6 person-years (mean 17.7 +/- 8.9 years). Twenty-four patients (10.4%) died, and 85% of the deaths occurred after 10 years of follow-up. The 5-, 10-, and 20-year survival rates were 98.6, 98.2 and 90.5%, respectively. The leading causes of death were infection (50.0%), cardiovascular disease (20.8%) and malignancy (12.5%). The renal survival rates at 5, 10 and 20 years were 99.5, 98.0 and 89.7%, respectively. The SMR in patients with renal involvement, end-stage renal disease (ESRD), malignancy or cardiovascular disease was 5.9, 26.1, 12.9 and 13.6, respectively. CONCLUSIONS: Lupus nephritis is associated with a 6-fold increase in mortality compared with the general population. Lupus patients who develop ESRD have a 26-fold excess in the risk of death, which is more than twice the risk associated with malignancy or cardiovascular disease in these patients.