Renal outcomes and all-cause death in patients with systemic lupus erythematosus: insights from a population-based study in Northern Italy.

BACKGROUND: Kidney disease is a severe complication of systemic lupus erythematosus (SLE), often leading to kidney failure. Despite therapeutic advances, its management remains challenging. The aim of this study was to assess the association between SLE and renal outcomes and all-cause death, as well as their therapeutic management in a real-world setting. METHODS: SLE patients were identified using administrative health databases from 2010 to 2019. The association between SLE and outcomes, compared to age and sex-matched controls, was reported as incidence rate and as adjusted hazard ratios. The frequency of pharmacological treatment was also analyzed. RESULTS: We included 2133 and 21 283 SLE and non-SLE individuals, respectively. SLE patients had a higher incidence rate and risk of composite renal outcome (20.2 vs 1.6/1000 person years; adjusted Hazard Ratio [aHR] 7.85, 95% Confidence Interval [CI] 6.43-9.58) and all-cause death (17.4 vs 7.5/1000 person years; aHR 1.78, 95% CI 1.53-2.07) as compared to non-SLE individuals. In SLE patients, adverse outcomes were observed early in the disease course, and particularly in younger individuals. A history of kidney disease was a strong predictor of kidney disease progression and mortality. Compared to non-SLE patients, those with SLE were more frequently prescribed glucocorticoids, conventional and biologic disease-modifying antirheumatic drugs (c-bDMARDs) and cardiovascular medications, with further increases in c-bDMARDs following a renal event. CONCLUSIONS: Our findings confirm increased risks of renal outcomes and mortality in SLE, especially with pre-existing kidney disease. Although we observed a preeminent use of immunosuppressive and nephroprotective medications in SLE patients with renal complications, additional data are needed to improve management strategies aimed at preventing kidney disease progression, especially early in the disease course and among younger individuals.