Background/Purpose Infections are a leading cause of death and morbidity in SLE patients. SLE-related factors, medications, and comorbidities can be risk factors for infection in these patients. There is a need to better define predictors and strategies to reduce the risk of infection in SLE. This study aims to identify clinical predictors of infection in SLE patients.

Methods Prospective cohort study of 24-month follow-up. We included consecutive patients fulfilling ACR’97 and/or SLICC’12 classification criteria for SLE followed-up at an academic lupus clinic. Acute infections occurring after inclusion were prospectively identified based on patient inquiry, clinical evaluation and laboratory data collected at each visit, scheduled at 1-6-month intervals. Acute infections were categorized as: (a) any type; (b) bacterial; (c) severe. For each infection outcome, survival analysis for time to first infection was conducted with log-rank tests of potential baseline predictors (including clinical, analytical, immunological and treatment factors), followed by multivariate Cox proportional hazards models with an estimation of hazard ratios (HR) with 95% confidence intervals (95%CI).

Results The study population included 259 patients. During a mean follow-up of 23.3±3.5 months, 58.7%, 36.3% and 6.5% of the patients had any type, bacterial and severe infections, respectively. In the multivariate Cox models: (a) for infection of any type, prednisone >5 mg/day was predictive (HR=1.95, 95%CI 1.26–3.03, p=0.003), while males had lower risk (HR=0.48, 95%CI 0.26–0.89, p=0.02); (b) for bacterial infection, antimalarials were protective (HR=0.49, 95%CI 0.26–0.93, p=0.03) and males had lower risk (HR=0.20, 95%CI 0.06–0.62, p=0.005); (c) for severe infection, prednisone >7.5 mg/day (HR=4.32, 95%CI 1.39–13.40, p=0.011) was predictive, while antimalarials were protective (HR=0.18, 95%CI 0.06–0.51, p=0.001). SLEDAI score, leukopenia, neutropenia, lupus nephritis, and immunosuppressants were not predictive of infection.

Conclusion The risk of infection in SLE patients is lower in patients treated with antimalarials. Minimizing the prednisone dose below 7.5 mg/day reduces the risk of infection.