(227) Fat-soluble Vitamin Status in Patients with Pancreatic Sufficient Cystic Fibrosis

Background: Individuals with cystic fibrosis (CF) are at increased risk for fat-soluble vitamin deficiencies (vitamins A, D, E, and K), presumably due to exocrine pancreatic insufficiency resulting in suboptimal absorption. There is a paucity of literature regarding fat-soluble vitamin status in pancreatic sufficient CF (CF-PS) patients. The aim of this study is to evaluate fat-soluble vitamin status in CF-PS patients.

Methods: We conducted a single-center retrospective chart review of 46 CF-PS patients between the years 2019 and 2021. Institutional review board approval was obtained. CF-PS was defined as patients with CF who clinically did not require pancreatic enzyme replacement therapy. This cohort consisted of 18 pediatric and 28 adult patients. Serum vitamin A, D, and E levels, pancreatic fecal elastase-1 (FE-1), C-reactive protein (CRP), and details of vitamin supplementation were reviewed. CRP was done for patients with isolated vitamin A deficiency to evaluate their inflammatory status. We did not evaluate vitamin K status as prothrombin time is a late and non-specific indicator of vitamin K deficiency.

Results: All 46 patients had at least one set of serum vitamin A, D, and E levels evaluated during the study period. FE-1 was done in 29/46 patients and had values >200 µg/g of stool (range 255 to >800 µg/g). For all patients lacking a FE-1 level, CF-PS status was clinically diagnosed before the year 2002 when FE-1 became widely available for clinical use. At the time of the vitamin status evaluation, 27 patients were recorded as taking supplemental vitamin D, 8 patients were on over-the-counter (OTC) multivitamins, and one patient was on a CF-specific vitamin. Vitamin D insufficiency and deficiency were widely prevalent (24/46; Table 1). Two patients were noted with low vitamin A levels and both had elevated CRP. In one of these two patients, the repeat vitamin A level normalized with no active intervention, and the other patient is due for a repeat level. Both patients had no clinical signs of vitamin A deficiency. Vitamin A level was high in 8 patients and vitamin E level was elevated in 3 individuals. Patients with higher vitamin A and E levels were either on OTC multivitamins or only on supplemental vitamin D. None of the patients with high vitamin A or E levels were on CF-specific vitamins prior to the evaluation. Finally, one patient had concurrent elevation of both vitamin A and E levels and was receiving supplemental vitamin D only. Findings from this review are summarized in Table 1.

Conclusions: In this cohort of CF-PS patients, low vitamin D was widely prevalent (52%), likely due to reduced sunlight for at least 5 months per year in this part of the United States. Vitamin D supplementation is required in most CF-PS individuals, and annual monitoring of vitamin D levels is warranted. Conversely, vitamins A and E deficiencies were not identified except for low vitamin A in the context of elevated CRP in two patients. Vitamin A is a negative acute-phase reactant, which may explain the low levels. CF-specific vitamin products or multivitamins may not be needed to maintain normal vitamin A and E levels and may be associated with higher vitamin levels. A larger prospective multicenter study in patients with CF-PS would be helpful to evaluate the indication and frequency of monitoring and supplementing vitamin A and E, and their clinical implications.

Acknowledgements: SS and LC are DIGEST awardees from the Cystic Fibrosis Foundation.

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