Mortality and cancer incidence in Korean patients with systemic lupus erythematosus: results from the Hanyang Lupus Cohort in Seoul, Korea

Abstract

The rates of mortality and cancer have not been compared between Korean systemic lupus erythematosus (SLE) patients and the general population. The objective of this study was to compare the observed mortality and cancer incidence rates of SLE patients with the expected age-, sex- and calendar-matched incidence rates of a comparable general control population. This study included 466 SLE patients who were in the Hanyang Lupus Cohort, Seoul and we excluded the males from the analyses because the number of males was too small to expect any incidence of cancer or death. We used the national female mortality rates from 1992 to 2001 as recorded by the Korean National Statistical Office as the standard mortality rates, and the Seoul Cancer Registry data as the standard cancer incidence rate. Ten of the females in our study died, giving a crude mortality rate of 596.0/100 000 person-years (PY) and a standardized mortality ratio (SMR) of 3.02. The crude cancer incidence was 179.3/100 000 PYand the standard incidence ratio was 1.04. These results demonstrate that the SMR is significantly higher in SLE patients than in the general population, whereas the incidence of cancer is the same in these two groups.