Bloodstream Infection In Systemic Lupus Erythematosus:Risk Factors And Prognostic Analysis

BackgroundSystemic lupus erythematosus(SLE)is a chronic autoimmune disease that primarily occurs in women at their childbearing age and is characterized by multiple organs involvement.Due to immunity system disorder and immunosuppressive therapies,SLE patients are susceptible to a variety of infections,among which bloodstream infection(BSI)is a huge challenge,with high mortality and potential to induce lupus flares,prolong hospitalized days and increase costs.Identification of risk factors for BSI and predictors of its death is able to improve the prognosis of SLE patients.Matrix risk model,as a risk visualization method,is able to comprehensively evaluate the possibility of outcomes.In the rheumatology field,it has been applied for the prediction of a refractory course and rapid radiographic progression in rheumatoid arthritis.To date,there are few studies on SLE with BSI patients,especially on the role of risk matrix model in the prediction of BSI in SLE.Objective1.To conclude microbiological characteristics of SLE with BSI patients.2.To investigate risk factors of BSI and establish a risk matrix model for predicting BSI in SLE patients.3.To explore predictors of short-term mortality in SLE with BSI patients.Methods1.This case-control study consisted of two parts.The first part was to investigate risk factors of BSI in SLE patients.The case group was 39 patients with BSI and the control group was 120 patients without any infection.The second part was to explore predictors of short-term mortality(defined as death within 30 days after diagnosis of BSI).In this part,39 patients with BSI were divided into the survival group(30 cases)and the death group(9 cases)according to the survival outcome within 30 days after diagnosis of BSI.2.Medical records of each patient were reviewed in order to obtain their demographic,clinical,microbiological and laboratorial characteristics.SLE disease activity was measured by Systemic Lupus Erythematosus Disease Activity Index 2000(SLEDAI-2K).3.Data collected from medical records were analyzed with SPSS software to conclude the microbiological characteristics,explore the risk factors of BSI and predictors of short-term mortality.Based on the acquired risk factors,a risk matrix model for predicting the occurrence of BSI in SLE patients was established.Results1.Altogether 40 bacteria strains were isolated in 39 BSI patient(one patient with recurrent BSI),with a predominance of the gram-negative bacilli(26,65.0%).Escherichia coli(16,40.0%)and Staphylococcus aureus(5,12.5%)were the two leading pathogens.Half(20,50.0%)patients were community-acquired BSI,7(17.5%)patients were nosocomial BSI and 13(32.5%)patients were healthcare-associated BSI.Eight(20%)patients had an identified primary infection site.A total of 9(22.5%)strains of drug-resistant bacteria were isolated,including 7 strains of ESBL-producing Escherichia coli and 2 strains of Pseudomonas aeruginosa.2.Occurrence of BSI in SLE was independently predicted by SLE disease duration>4 years(OR 2.469,95%CI 1.065-5.722),SLEDAI-2K 5 to.9(OR 5.155,95%CI 1.031-25.767),SLEDAI-2K≥10(OR 11.767,95%CI 2.179-63.537),glucocorticoids dose>7.5,≤30 mg/d(prednisone-equivalent)(OR 3.739,95%CI 1.193-11.716),glucocorticoids dose>30 mg/d(OR 4.225,95%CI 1.209-14.769)and occurrence of autoimmune hemolytic anemia(AIHA)or thrombotic thrombocytopenic purpura(TTP)(OR 4.777,95%CI 1.026-22.238).Based on the acquired risk factors,a risk matrix model for predicting the occurrence of BSI in SLE patients was established.3.The short-term mortality in SLE with BSI patients was 23.1%.The distribution of survival time among SLE with BSI patients occurring at different sites(community,nosocomial or healthcare-associated)was significantly different(P=0.029),among which the survival time of healthcare-associated BSI was shorter than that of community-acquired BSI(P=0.015).However,there was no difference(P=0.213)in the distribution of survival time among BSI patients receiving different glucocorticoids dose(≤7.5 mg/d,>7.5,≤30 mg/d or>30 mg/d).Conclusion1.Escherichia coli and Staphylococcus aureus are the leading pathogens of BSI in SLE patients.2.SLE disease duration over 4 years,moderate and high disease activity(SLEDAI-2K>4),moderate and high glucocorticoid dose(>7.5 mg/d)and AIHA/TTP history are risk factors of BSI in SLE patients.3.Healthcare-associated BSI is a predictor for short-term mortality in SLE patients.