BACKGROUND: Patients with chronic kidney disease (CKD) have an elevated risk of both vitamin D deficiency (VDD) and depression. However, the relationship between VDD and the risk of depression in this population remains unclear. METHODS: Using the TriNetX network database (2010-2019), we conducted a propensity score-matched cohort study of CKD patients aged ≥50 years. Patients were categorized into VDD (≤20 ng/mL) and control (≥30 ng/mL) groups based on measurements within 3 months of CKD diagnosis. The primary outcome was the incidence of major depression within 1 year of follow-up. RESULTS: Among 17,955 matched pairs, VDD was associated with increased depression risk at 1 year (hazard ratio [HR]: 1.929
95% confidence interval [CI]: 1.52-2.448
CONCLUSION: VDD is independently associated with increased depression risk in patients with CKD, particularly in males. These findings suggest that maintaining adequate vitamin D levels might be important for mental health in patients with CKD, although randomized trials are needed to confirm whether supplementation can prevent depression in this population.