National trends in hospitalisation, in-hospital mortality and resource use for SLE in Spain from 2016 to 2022.

OBJECTIVE: SLE is a complex autoimmune disease that causes significant health issues. In this study, SLE-related healthcare episodes, in-hospital mortality and resource use in Spain from 2016 to 2022 were assessed. METHODS: In this retrospective, nationwide, repeated cross-sectional study, International Classification of Diseases, 10th Revision, data from Spain's National Hospital Discharge Registry were used to identify healthcare episodes with SLE (or its subtypes) coded as the principal diagnosis. Temporal trends were analysed and group comparisons were made using χ², Fisher's exact test, Student's t test and Mantel-Haenszel trend test. RESULTS: A total of 24 151 SLE episodes were identified, with the majority occurring in women (86.9%) and individuals aged 15-65 years (88.2%). SLE episodes increased from 3002 (6.5/100 000 population) in 2016 to 4226 (8.8/100 000 population) in 2022 (p<0.001). Lupus nephritis episodes rose from 525 (1.13/100 000 population) to 956 (2.0/100 000 population; p<0.001). Relative to all other hospitalisation episodes, SLE episodes had longer hospital stays (8.7 vs 7.1 days; p<0.001) and intensive care unit (ICU) stays (8.4 vs 4.9 days; p=0.031). In-hospital mortality was low and stable. In unadjusted comparisons, mortality was lower among SLE episodes than among other hospitalisation episodes (0.3% vs 1.2%; p<0.001). A larger proportion of in-hospital deaths during SLE episodes than during all other hospitalisation episodes occurred in individuals aged 15-65 years (42.5% vs 15.1%; p<0.001). Although more deaths occurred in women, mortality was higher among men in unadjusted comparisons (0.7% vs 0.3%; p<0.001). CONCLUSIONS: SLE-related healthcare episodes increased in Spain from 2016 to 2022, but in-hospital mortality remained stable. SLE episodes involved longer hospital and ICU stays than other episodes. These results reflect healthcare utilisation patterns, not disease severity or patient outcomes.