We aimed to investigate the safety and efficacy of a single one-off oral dose (also known as ‘stoss’ therapy) of high-dose vitamin D3 therapy in children with CF who were vitamin D deficient.
Why is this important?
People with CF are at risk of developing long term complications such as CF-related bone disease. While the causes are multifactorial, one likely contributing factor is vitamin D deficiency due to malabsorption. International guidelines disagree on what blood level of vitamin D should be targeted; the US CF Foundation currently recommend a minimum of 75nm/L ( 30ng/ml), whereas the European and Australian guidelines aim for a minimum level of 50nm/L (20ng/ml). Previous research has suggested that traditional regimens of vitamin D replacement based on current guidelines for bone health in Cystic Fibrosis are not able to increase vitamin D levels sufficiently to above 75 nm/L.
What did you do?
We compared the effect of a single oral stoss dose in 38 children who were Vitamin D deficient (< 75nm/L) to 37 children with vitamin D deficiency who received standard nutritional care over 12 months.
What did you find?
The stoss treated group had a significant and sustained increase in vitamin D levels over a 12 month period, exceeding 75nm/L for more than 6 months, although this was not seen in all patients. There was no evidence of vitamin D toxicity.
What does this mean and reasons for caution?
Our study has demonstrated that higher blood levels of vitamin D are achievable using stoss therapy and that this approach is practical, efficient and safe. Seventy per cent of the stoss treated group achieved levels > 75nm/L therefore we suggest that CF Guidelines should recommend aiming for this level (rather than the lower 50 nm/L).
It is possible that those patients who did not respond to stoss therapy did not absorb it sufficiently and therefore we now suggest that patients take stoss therapy together with food and pancreatic enzyme supplementation.
For reasons of convenience, this study looked at treatment that patients had received as part of their routine care. The major limitation in this study is that, as doctors chose to prescribe (and patients to take) this treatment, there may be subtle differences in those patients that received stoss therapy and those that did not reducing the strength in conclusions that can be made. What is needed is a formal clinical trial where patients are randomly allocated to receive stoss or placebo and neither doctors nor patients know who is taking what until the end of the trial.