Risk factors of mortality for Salmonella infection in systemic lupus erythematosus

Object. To investigate the risk factors of mortality for Salmonella infection in patients with systemic lupus erythematosus (SLE). Methods. Between 1995 and 1999 we reviewed 37 cases of Salmonella infection in 31 patients with SLE from a total of 1191 hospitalized patients with SLE at a medical center in Taiwan. Contrasting cases of patients who died with those who survived, we compared clinical and laboratory characteristics of SLE at the time of Salmonella infection, with special attention to potential risk factors (sex, age, complete blood count and differential count, erythrocyte sedimentation rate, C-reactive protein, complements, Salmonella species, infection site, reinfection, SLE presenting with Salmonella infection, associated non-Salmonella infection, etc.). Results. The mean age at the onset of SLE in the 8 mortality cases was significantly higher than the 23 cases of survivors (p < 0.05). Other factors significantly related to death included associated infections other than Salmonella species, reinfection of Salmonella species, and cases of SLE presenting with Salmonella infection. Reinfection and SLE presenting with Salmonella infection were the most important risk factors of mortality for SLE with Salmonella infections: relative risk (CI) 84 (4.3-1638.8) and 63 (3.1-1296.5), respectively. Conclusion. Patients with SLE who are older or have associated infections other than Salmonella have an increased mortality rate when they have concurrent Salmonella infection. Patients with Salmonella infection occurring concurrently with the first presentation of SLE and patients with SLE reinfected with Salmonella species are at higher risk of mortality.