Vitamin D and metabolic bone disease in prolonged continuous kidney replacement therapy: a prospective observational study.

Background: Complications of prolonged continuous kidney replacement therapy (CKRT) have not been well described. Our objective was to describe mineral metabolism and bone findings in children who required prolonged CKRT.

Methods: In this single center prospective observational study, we enrolled 37 patients who required CKRT for ≥ 28 days with regional citrate anticoagulation. Exposure was duration on CKRT and outcomes were 25-hydroxy vitamin D and osteopenia and/or fractures.

Results: The prevalence of vitamin D deficiency and insufficiency was 17.2% and 69.0%, respectively. 29.7% of patients had radiographic findings of osteopenia and/or fractures. There was no association between vitamin D deficiency or insufficiency with age or ethnicity. Time on CKRT and intact PTH levels were not predictive of vitamin D levels. Children with chronic liver disease were more likely to have osteopenia and/or fractures compared children with other primary diagnoses, odds ratio (3.99 (95%CI, 1.58-2.91), p = 0.003) after adjusting for age and time on CKRT.

Conclusion: Vitamin D deficiency and/or insufficiency, and osteopenia and/or fractures are prevalent among children who require CKRT for a prolonged period. The risk for MBD may be higher with chronic liver disease. Higher doses of vitamin D may be required to maintain normal levels while on CKRT.