Infections in hospitalized lupus nephritis patients: characteristics, risk factors, and outcomes

Background There are limited studies documenting infection epidemiology in lupus nephritis (LN) patients. We aimed to study infection incidences and risk characteristics and ascertain possible predictors of infective outcomes in a multiethnic Asian population. Methods This retrospective study from 2006 to 2012 included newly diagnosed LN patients. We collected admissions, immunosuppression, and infection data until end-stage renal failure, death, last follow-up, or the year 2015. The infection incidence rates were evaluated and a generalized linear latent and mixed models (GLLAMM) analysis was carried out to evaluate potential predictors of infection. Results Our cohort of 101 patients consisted of mainly Chinese (75.2%), females (78.2%), and a median age of 38 years (IQR 26-49). The median time of follow-up was 72.8 months (IQR 49.5-94.0). Six out of 14 patient deaths were infection related. Seventy-eight out of 200 admissions, with a total of 102 episodes of infection, occurred in 46 patients. The incidence of infection rates leading to admissions was 10.3 per 100 person-years and the incidence of infection episodes rates was 17.6 per 100 person-years. Cytomegalovirus (CMV) was the most common organism identified. Univariate GLLAMM analysis showed Malay compared to Chinese ethnicity (HR 2.833 (95% CI 1.088-7.373)), use of oral cyclophosphamide (HR 6.618 (95% CI 1.015-43.154)) and rituximab (HR 3.967 (95% CI 1.157-13.603)) as predictors of infection-related admissions. Malay ethnicity and rituximab remained significant in the multivariate GLLAMM analysis. Conclusions Our study highlights substantial infection incidences in patients with LN and its contribution to deaths.