Causes of death in hospitalized patients with systemic lupus erythematosus: a 10-year multicenter nationwide Chinese cohort

Abstract

To estimate the mortality and describe the causes of death in a large multicenter cohort of hospitalized patients with SLE in China. This was a retrospective study of a nationwide SLE cohort (10 centers, 29,510 hospitalized patients) from 2005 to 2014 in China. Standardized mortality ratios (SMRs) were calculated for all death and were stratified by sex and age. Chi-square test was used to determine whether the major causes of death vary in age, sex, duration of SLE, disease activity, or medications. Comparison between dead patients and survival controls was used to identify the risk factors for mortality. Logistic regression analysis was used to evaluate the risk factors for mortality. A total of 360 patients died during the study period, accounting for 1.22%. The overall SMR was 2.13 (95% CI 1.96, 2.30), with a particularly high SMR seen in subgroups characterized by younger age. Infection (65.8%) was the most common cause of death, followed by lupus nephritis (48.6%), hematological abnormality (18.1%), neuropsychiatric lupus/NPSLE (15.8%), and interstitial pneumonia (13.1%). Cardiovascular disease and malignancy contributed little to the causes of death. Infection, in particular severe pulmonary infection, emerged as the foremost risk factor for mortality, followed by lupus encephalopathy. However, lupus nephritis and hematological abnormalities occurred more frequently in survival patients. SLE patients at a younger age of diagnosis have a poorer prognosis. Infection dominated the causes of death in recent China. Ethnicity and medications might account for the differences in causes of death compared with western populations.

Keywords: Cardiovascular disease; Cause of death; Infection; Standardized mortality ratio; Systemic lupus erythematosus.