The frequency of and associations with hospitalization secondary to lupus flares from the 1000 Faces of Lupus Canadian cohort

Objectives: Hospitalization is a major factor in health care costs and a surrogate for worse outcomes in chronic disease. The aim of this study was to determine the frequency of hospitalization secondary to lupus flare, the causes of hospitalization, and to determine risk factors for hospitalization in patients with systemic lupus erythematosus (SLE).

Methods: Data were collected as part of the 1000 Canadian Faces of Lupus, a prospective cohort study, where annual major lupus flares including hospitalizations were recorded over a 3-year period.

Results: Of 665 patients with available hospitalization histories, 68 reported hospitalization related to a SLE flare over 3 years of follow-up. The average annual hospitalization rate was 7.6% (range 6.6-8.9%). The most common reasons for hospitalization were: hematologic (22.1%), serositis (20.6%), musculoskeletal (MSK) (16.2%), and renal (14.7%). Univariate risk factors for lupus hospitalization included (OR [95% CI]; p < 0.05): juvenile-onset lupus (2.2 [1.1-4.7]), number of ACR SLE criteria (1.4 [1.1-1.7], baseline body mass index (BMI) (1.1 [1.0-1.1]), psychosis (3.4 [1.2-9.9]), aboriginal race (3.2 [1.5-6.7]), anti-Smith (2.6 [1.2-5.4]), erythrocyte sedimentation rate >25 mm/hr (1.9 [1.1-3.4]), proteinuria >0.5 g/d (4.2 [1.9-9.3], and SLAM-2 score (1.1 [1.0-1.2]). After multivariate regression only BMI, number of ACR criteria, and psychosis were associated with hospitalization for lupus flare.

Conclusions: The mean annual rate of hospitalization attributed to lupus was lower than expected. Hematologic, serositis, MSK and renal were the most common reasons. In a regression model elevated BMI, more ACR criteria and psychosis were associated with hospitalization.