Incidence of and risk factors for hospitalizations in systemic lupus erythematosus: A prospective study of the Hopkins Lupus Cohort

Objective. To determine the incidence of and risk factors for hospitalization in systemic lupus erythematosus (SLE). Method. A prospective study of hospitalizations in 1989 and 1990 in the Hopkins Lupus Cohort was conducted. Results. Of 261 patients with SLE in the Hopkins Cohort, 147 (56.3%) were hospitalized in 1989 or 1990. The incidence of hospitalization was 0.69 admissions/person-year. The mean length of stay was 9.6 days ± 12.7 (SD). Activity of SLE accounted for 35% of admissions. Risk factors for hospitalization for active lupus in 1990 included activity of SLE in 1989 (measured by either the highest physician's global assessment in 1989, p = 0.004, highest lupus activity index (LAI) score in 1989, p = 0.002, or highest systemic lupus erythematosus disease activity index score in 1989, p = 0.008), an average prednisone dose greater than 10 mg in 1989 (p = 0.002), and the presence of neurologic lupus in 1989 (p = 0.02). Medical admissions other than for active SLE accounted for an additional 27% of admissions; one-half of these admissions (47%) were for complications of SLE and/or its treatment, with coronary artery disease the most common (21% of medical admissions). Infections were responsible for 14% of admissions. The majority of infections were bacterial (90%). Risk factors for hospitalization for infection in 1990 included active SLE in 1989 (p = 0.03), average prednisone dose of greater than 10 mg in 1989 (p = 0.04), immunosuppressive drug use in 1989 (p = 0.003), nenrologic SLE in 1989 (p = 0.02) and previous hospitalization in 1989 (p = 0.03). Conclusion. Hospitalization is common in the Hopkins Lupus Cohort, with active SLE (35%), infection (14%, infection and/or active SLE; 11%, infection alone) and medical complications of SLE (13%) as the 3 most common causes.