Objective: To determine the causes of death in Korean patients with systemic lupus erythematosus (SLE).
Methods: We evaluated retrospectively Korean SLE patients who were monitored in the Center for Rheumatic Disease in Kang-Nam St. Mary's Hospital from 1993 to 1997 and who died.
Results: Forty-three (7.9%) of 544 patients died. Comparison of demographics and disease activity indices between the deceased and the survivors showed that the age was older and C3 at presentation was lower in the deceased (n = 40) than the survivors (n = 453) (age: 33.8 +/- 13.6 versus 28.3 +/- 10.6 years, p = 0.02, C3: 36.8 +/- 21.4 versus 49.7 +/- 20.8 mg/dl, p = 0.03). Among 40 patients who died, the frequency and causes of death were as follows: 13 from infection (32.5%), 10 SLE-related factors (25.0%), 6 pulmonary hypertension (15.0%), 4 cerebrovascular accidents (10.0%), and 3 thrombotic thrombocytopenic purpura (7.5%). The majority of the SLE-related deaths were non-renal in origin, including 3 cerebral nervous system disease, 2 TTP, 2 acute pulmonary hemorrhage syndrome, 1 acute myocarditis, and 1 multi-system illness. SLE-related renal causes were responsible for only death. The major organisms of infection were gram negative bacilli (69.2%), primarily manifesting as sepsis or bacteremia (76.9%). The patients (n = 13) who died from infection had lower levels of complement and higher levels of anti-ds DNA antibody at presentation than those (n = 27) who died from the other causes (C3: 24.7 +/- 17.8 versus 41.7 +/- 21.5 mg/dl, p = 0.02, anti-dsDNA antibody: 68.0 +/- 73.5 versus 27.0 +/- 35.3 IU, p = 0.04). The mean steroid dose being administered one month before death was also higher in the patients who died of infection (30.5 +/- 15.2 versus 15.2 +/- 7.7 mg/day, p = 0.03). Patients who died of pulmonary hypertension, the third most common cause of mortality, showed extremely high pulmonary pressures at the initial diagnosis, with a short interval to death, and had less major organ involvement at death. There were no deaths due to coronary heart disease or neoplasm in this cohort.
Conclusion: The most common cause of death in 544 Korean lupus patients was infection, mainly manifesting as gram negative bacterial sepsis. SLE-related factors (mostly non-renal) were the next most frequent cause. Death from infection was associated with higher disease activity at presentation and a higher dose of steroid used previously. Death due to pulmonary hypertension was common, whereas death due to coronary heart disease was absent.