The Impact of Elexacaftor/Tezacaftor/Ivacaftor on Fat-Soluble Vitamin Status and Supplementation in a Pediatric Cystic Fibrosis Cohort.

BACKGROUND

Children with Cystic Fibrosis (CF) are at risk of fat-soluble vitamin deficiencies, studies have shown Elexacaftor/Tezacaftor/Ivacaftor (ETI) therapy to substantially improve nutritional status. This study aimed to investigate the effect of ETI on fat-soluble vitamin levels A, D, and E, for children aged 6-16 years with CF.

METHOD: We performed a retrospective pre-post study of children with CF. Data collected included demographics, clinical characteristics, serum Vitamin A, D and E and vitamin supplementation dosages. Seven timepoints were decided for statistical analysis: T1-T3-pre-ETI and T4-T7-at 6 month intervals post-ETI. The significance of changes in vitamin levels and supplementation was assessed using a linear mixed-effects model. A p-value < 0.05 was used to indicate significance.

RESULTS

Fifty-six children met the inclusion criteria, with 262, 257, and 252 complete observations for Vitamins A, D, and E, respectively. Median Vitamin D levels increased following ETI initiation (p < 0.001). There was no significant increase in median Vitamin A levels however post-ETI there was a significant association between supplementation dose and serum Vitamin A levels (p = 0.008). There were no significant changes in median Vitamin E. Over the timepoints there was an increase in the proportion of patients receiving no vitamin supplementation.

CONCLUSIONS

This study found following ETI initiation vitamin D levels increased, and the requirement for fat-soluble vitamin supplementation appeared to decrease. Whilst ETI was not associated with increased Vitamin A and E, the burden of supplementation decreased, and Vitamin A supplementation maybe more effective.