# Association Between Serum Vitamin D Levels and Mortality in Children Receiving Chronic Dialysis: A Retrospective Cohort Study

## TL;DR

Low vitamin D levels in children on dialysis are linked to higher death rates and health problems like bone issues and heart complications.

## Contribution

This study identifies a strong link between severe vitamin D deficiency and mortality in pediatric dialysis patients.

## Key findings

- Patients with vitamin D levels below 15 ng/mL had a 3.2 times higher mortality risk.
- No deaths occurred in patients with sufficient vitamin D levels (>30 ng/mL).
- Vitamin D deficiency was associated with skeletal disorders and cardiovascular issues.

## Abstract

Vitamin D deficiency is highly prevalent among children on regular dialysis, affecting approximately 90% of patients. This deficiency (serum 25‐hydroxyvitamin D < 50 nmol/L or 20 ng/mL) is associated with various complications, including skeletal problems, increased infection risk, arterial stiffness, vascular calcification, and higher cardiovascular mortality. Severe deficiency (< 30 nmol/L) particularly increases mortality risks.

In this cross‐sectional retrospective study, we examined 53 pediatric patients (28 boys, 25 girls) undergoing regular dialysis (hemodialysis and peritoneal dialysis) at a children's medical center from 2018 to 2020. The mean age was 8.21 years, with 71.7% aged 2–12 years, 20.8% adolescents, and 7.5% under 2 years. The mean vitamin D level was 23.51 ng/mL.

Results showed that 26.41% of patients died, with mortality analysis revealing a hazard ratio of 3.2 for patients with vitamin D levels below 15 ng/mL. The mortality rate was 64.7% in severe deficiency (< 15 ng/mL), 18.8% in moderate deficiency (15–30 ng/mL), while patients with sufficient levels (> 30 ng/mL) recorded no deaths. Additionally, 11.32% developed skeletal disorders, including two cases of spinal fracture. Vitamin D levels showed significant positive correlations with calcium (r = 0.6) and years under dialysis (r = 0.52) (p > 0.05). Associations were found between vitamin D levels and phosphorus, PTH, and mortality rates. However, no significant relationships were observed with dialysis frequency, age, weight, gender, underlying disease, dialysis type, or hypertension.

In conclusion, children with end‐stage renal disease undergoing dialysis face increased risks of vitamin D deficiency due to impaired kidney function. This deficiency significantly impacts survival rates and contributes to poor outcomes. Regular monitoring and management of vitamin D levels are crucial for improving survival in pediatric dialysis patients.