Background Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease characterized by a wide range of clinical manifestations and by a typically fluctuant course. Although SLE patients' survival has significantly increased in the last decades, morbidity and hospitalization are still considerably high.
Objectives Aim of this study was to analyze seasonality, causes and outcome of SLE patients' hospitalization in a tertiary centre over a 10-years period.
Methods We conducted a retrospective analysis of all the admissions to the Rheumatology Unit in a period of 10 years; we used hospital registries as a source of causes and time of hospitalization. The analysis was then restricted on SLE patients: we collected demographic, clinical and serological features. In particular, we investigated the frequency and causes of hospitalization, the seasonality and mortality. We evaluated disease activity through SLE Disease Activity Index-2000 (SLEDAI-2K), and chronic damage by the SLICC Damage Index (SDI).
Results Between January 2003 and December 2013, we admitted to our Rheumatology Unit 1615 patients: 315 (19.5%) were SLE patients (M/F 35/280; mean ± SD age 38.5±12.3 years; mean ± SD disease duration 135.2±99.7 months). The mean ± SD time of hospital stay was 15.4±17.8 days. Disease flare was the most frequent cause of hospitalization, recorded in 66.7% of SLE patients, followed by infections (12.4%), active lupus nephritis for renal biopsy (9.3%), infusional therapies (4.5%), drugs adverse events (1.4%), cancer (0.6%) and cardiovascular accident (0.3%), other (4.8%). The frequency of disease flare was significantly higher than all the other causes of hospital admittance [P<0.000001]. Mortality rate was 0.3%. As for seasonality (in the boreal hemisphere), most of SLE patients were admitted in May (12.4%), January (10.8%) and September (10.5%), without any significant difference among the seasons. Considering SLE patients' admissions for flare compared to the other causes, we did not find any significant differences in seasonality. The evaluation of disease activity was available for 194 patients and we recorded a median SLEDAI-2K value of 8 (IQR 5.5) and a median SDI value of 1 (IQR 1) at the time of admission. As expected, SLE patients admitted for flare showed a significantly higher SLEDAI-2K value than those admitted for infections (P=0.02).
Conclusions This retrospective analysis of all the hospitalizations in a Rheumatology Unit over a period of 10 years has showed that SLE patients' admissions are frequent and that SLE flare is the most frequent cause of hospitalization. Moreover, it has showed a low incidence of death during the hospital stay. Finally, it has registered that May was the most frequent admission month and it has not found any significant differences in seasonality between SLE flare and other causes of hospitalization.
Disclosure of Interest None declared