Antimalarial treatment and minimizing prednisolone are associated with lower risk of infection in SLE: a 24-month prospective cohort study

Abstract

Introduction/objectives: Infections are a major cause of morbidity and death in systemic lupus erythematosus (SLE). Perfecting the understanding of contributors to infection burden in SLE is pivotal to improve management and outcomes. This study aims to identify clinical predictors of infection in SLE.

Method: We conducted a prospective cohort study at a referral SLE clinic. Infections were identified at each visit and categorized as (a) any type, (b) serious, (c) non-serious, and (d) bacterial. Survival analysis followed by multivariate Cox regression with an estimation of hazard ratios (HR) with 95% confidence intervals (95%CI) was performed.

Results: We included 259 patients during a mean follow-up of 23.3 ± 5.7 months. The incidence rate of infection of any type was 59.3 cases per 100 patient-years. Multivariate Cox models showed that (a) prednisolone ≥ 7.5 mg/day (HR = 1.95, 95%CI 1.26-3.03) and female gender (HR = 2.08, 95%CI 1.12-3.86) were associated with higher risk of infection of any type; (b) prednisolone ≥ 10 mg/day was associated with higher (HR = 4.32, 95%CI 1.39-13.40), and antimalarials with lower risk (HR = 0.18, 95%CI 0.06-0.51) of serious infection; (c) female gender (HR = 1.92, 95%CI 1.04-3.57) and prednisolone ≥ 7.5 mg/day (HR = 1.89, 95%CI 1.21-2.96) were associated with higher risk of non-serious infection; (d) antimalarials were associated with lower (HR = 0.49, 95%CI 0.26-0.93) and female gender (HR = 5.12; 95%CI 1.62-16.18) with higher risk of bacterial infection.

Conclusions: The risk of infection was higher in females in this young, well-controlled, low-comorbidity SLE cohort. Antimalarials were associated with lower and prednisolone ≥ 7.5 mg with higher risk of infection. Key Points • Lupus patients treated with prednisolone ≥ 7.5 mg/day were 89% more likely to present infections. • Lupus patients receiving prednisolone ≥ 10 mg/day were four times more likely to present serious infections. • Lupus patients receiving antimalarials were 82% less likely to present serious infections.

Keywords: Antimalarials; Corticosteroids; Infection; Systemic lupus erythematosus.