Should asymptomatic bacteriuria be treated in lupus nephritis?

Abstract

The risk of infection in systemic lupus erythematosus (SLE) is associated with factors related to disease activity and immunosuppressive treatment. Recently, the persistence of asymptomatic bacteriuria (ASB) has been proposed as an environmental trigger for SLE and its flares, raising the question whether it should be treated systematically to reduce the risk of infection. To our knowledge, there is limited evidence on the screening and treatment of ASB in SLE. The objective is to analyze the occurrence of infection and flare in patients with lupus nephritis with and without ASB. A cross-sectional study of a cohort of patients with lupus nephritis during induction therapy with high-dose cyclophosphamide regimen was carried out between January 2018 and 2020, with a total of 37 patients investigated. Urine and blood samples from the two groups (with ASB and without ASB) where taken before the administration of cyclophosphamide. From the sampled 37 patients, 19 (51.4%) had ASB and 18 (48.6%) without ASB; both groups were well balanced in their demographics and clinical characteristics. No statistically significant association was found between the presence of ASB and the systemic lupus erythematosus disease activity index score (p = 0.604), and neither with the 24-h urine protein and leukocyte count (p > 0.177). Urinary tract infection occurred in 5.3% (1) of the patients with ASB, while 5.6% (1) of the patients in the group without ASB presented the infection, and the RR was 0.944 (0.06, 16.33) 95% CI; in addition, no statistically significant association was found between the presence of ASB and the occurrence of infection (p = 1,000). Our study did not find a statistically significant association of ASB with the occurrence of infection or disease activity. Further studies need it to clarify this, since treatment of ASB has been recognized as an important contributor to inappropriate antimicrobial use, which promotes emergence of antimicrobial resistance.