Prevalence of Parathyroid Disorders and Vitamin D Deficiency in Patients with IMRD

Background Vitamin D deficiency and parathyroid dysfunction may play a role in immune-mediated rheumatic diseases (IMRD). This study aimed to investigate their prevalence, their relationship with disease activity, and the impact of glucocorticoid use. Methods We conducted a cross-sectional and longitudinal study including 40 adult patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and spondyloarthritis (SpA). Serum 25(OH)D (vitamin D), parathyroid hormone (PTH), and C-reactive protein (CRP) were measured, along with disease activity indices: DAS28 for RA, SLEDAI for SLE, and ASDAS for SpA. Correlations were tested using Spearman’s rho, with p < 0.05 considered statistically significant. Results Mean serum vitamin D levels were reduced across all groups (RA ≈ 38 ng/mL, SLE ≈ 34 ng/mL, SpA ≈ 39 ng/mL). Vitamin D showed a weak negative correlation with disease activity. PTH values fluctuated but showed no clear correlation. Glucocorticoid use correlated with higher activity scores, reflecting clinical practice. Figure 1 illustrates vitamin D, PTH, and activity scores by disease group. Conclusion Vitamin D deficiency is prevalent in IMRD and may contribute to increased inflammatory activity, although associations are weak. Parathyroid dysfunction did not show a consistent link with disease activity. Glucocorticoid use was associated with more severe cases. Further longitudinal studies are warranted to clarify the impact of vitamin D supplementation and the long-term metabolic consequences of glucocorticoids in IMRD.