Severe infections in patients with lupus nephritis treated with immunosuppressants: a retrospective cohort study

Aim Lupus nephritis (LN) is associated with significant morbidity and mortality and hence usually treated aggressively with immunosuppressants. This predisposes LN patients to increased infections, yet few studies have evaluated LN patients for infective complications. We aimed to describe the epidemiology and identify risk factors for infections requiring hospitalisation among patients with biopsy-proven LN. Methods This was a single-centre retrospective cohort study of patients with biopsy-proven LN between 1st January 2000 and 31st May 2009. Patients were excluded if they were <16 years old at time of biopsy, had previous kidney transplant or if pharmacotherapy data were incomplete. Hospitalisations for infections, bacteremia and polymicrobial infections were recorded until patients’ last visit or when they received immunosuppression for non-glomerulonephritis indications, such as solid organ transplant or chemotherapy. Results We studied 189 patients who had biopsy-proven lupus nephritis. Median age at diagnosis was 36.9 (IQR: 27.4, 47.5) years and 82% were female. Most patients received at least 1 immunosuppressant after LN diagnosis, including glucocorticosteroids in 94.2%. One hundred and four patients (60.3%) had at least 1 hospitalisation for infection at 11 (1, 53) months from diagnosis. Bacteraemia occurred in 26 patients (13.8%) and 32 patients (16.9%) had polymicrobial infections. On multi-variate analysis, LN relapse was associated with hospitalisation for infection [OR 2.33 (1.18, 4.60), p = 0.01] and bacteraemia [OR 3.47 (1.05, 11.45), p = 0.04]. Infection-related mortality occurred in 10 patients (5.3%). Conclusion Serious infections are common among patients with LN and are associated with mortality.