AB1081 HYPOVITAMINOSIS D IN PATIENTS WITH LUPUS NEPHRITIS
Authors: A. V. Yupe Flores, E. Purón González, G. M. Ochoa De León, J. Santana Delgado, R. E. Cervantes Ramírez, G. Calderón-Delapeña, B. Ceniceros-Ruiz, E. M. Saldaña-Campos, J. Uribe-Martínez, G. Martínez-Bonilla, V. González-Díaz, J. L. Sánchez Reynoso, E. Ventura-Valenzuela, S. Cerpa-Cruz
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> The prevalence of vitamin D deficiency is higher in patients with systemic lupus erythematosus (SLE) compared to the healthy population [1], and recent studies have observed a higher prevalence of hypovitaminosis D in patients with associated kidney disease [2]. This deficiency has been proposed as a risk factor for a higher incidence and activity of autoimmune diseases. <h3>Objectives:</h3> The present study aims to determine the prevalence of hypovitaminosis D and its correlation with clinical and renal activity and histopathological findings of renal biopsy in patients with SLE and lupus nephritis (LN). <h3>Methods:</h3> Analytical cross-sectional study, in patients with SLE according to the 2019 ACR/EULAR criteria and LN by renal biopsy according to ISN/RPS of 2003. A measurement of disease activity was performed by SLEDAI 2K considering high activity &gt; 4 points, and renal activity through creatinine, BUN, urinary sediment, albuminuria, urinary creatinine protein ratio, 24-hour urine protein count, GFR, renal biopsy report, activity index and chronicity. Serum vitamin D levels were measured by ELISA (Human soluble 25-OH Vitamin D ELISA Kit Eagle Bioscences), considering hypovitaminosis D &lt;30 ng/mL. The sample calculation was carried out with the formula for difference of proportions with a statistical power of 85% requiring 24 patients. Quantitative variables were tested for Shapiro-Wilk normality and expressed as means and standard deviations. Qualitative variables were reported as frequencies and percentages. In the inferential analysis, the continuous variable of vitamin D levels was analyzed with the Student's T test. Categorical variables were analyzed with the Chi2 test or Fisher's exact test. The correlation analysis was performed using Pearson's coefficient and Kendall's Tau b for continuous and ordinal variables respectively. In all cases, bilateral statistics were performed with an alpha value &lt;0.05. <h3>Results:</h3> Twenty-four patients with systemic lupus erythematosus were studied, divided into two groups: the first included 12 patients without renal involvement and the second included 12 patients with LN. 58% of the 24 patients had hypovitaminosis D, of which there was a higher prevalence in patients with LN than in the SLE group without kidney disease 75% vs 42% (Table 1). Vitamin D level had a moderate negative correlation (Figure 1) with 24-hour urine protein count (r =-0.594, p=0.042) in patients with LN. In the renal biopsy lesions, 100% had rupture of the glomerular basement membrane (GBM) and interstitial inflammation, followed by endocapillary hypercellularity in 91.7%, but none was specifically correlated to hypovitaminosis D. <h3>Conclusion:</h3> Hypovitaminosis D has a higher prevalence in patients with lupus nephritis compared to patients with SLE without kidney disease. In patients with lupus nephritis, the greater the proteinuria, the greater the vitamin D deficiency. <h3>REFERENCES:</h3> [1] Meza-Meza MR, Muñoz-Valle JF, Ruiz-Ballesteros AI, Vizmanos-Lamotte B, Parra-Rojas I, Martínez-López E, et al. Association of High Calcitriol Serum Levels and Its Hydroxylation Efficiency Ratio with Disease Risk in SLE Patients with Vitamin D Deficiency. Journal of Immunology Research. 2021 Dec 31;2021:e2808613. [2] García-Carrasco M, Mendoza-Pinto C, Soto-Santillán RP, Méndez-Martínez S, Benítez-Contreras I, Etchegaray-Morales I, et al. Vitamin D in systemic lupus erythematosus with and without lupus nephritis. Rev Med Inst Mex Seguro Soc. 2020;58(4):394–9. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>