Prevalence and Risk Factors for Iron Deficiency in Adults With Cystic Fibrosis

Abstract

Background: Iron deficiency is common in cystic fibrosis (CF), but previous prevalence studies often reported results confounded by acute exacerbations. This single-center retrospective study aimed to identify the prevalence of iron deficiency in a stable adult CF population, identify the risk factors associated with iron deficiency, and compare common laboratory indicators of iron status. Methods: Medical charts of 105 patients aged 18-67 were reviewed to determine the prevalence of anemia. Of these patients, a subgroup of 67 were included in analyses of iron deficiency, defined as serum ferritin < 12 ng/mL and/or percent transferrin saturation (TSAT) < 16%. Data on sex, age, body mass index, anemia status, vitamin deficiencies, presence of comorbidities, colonization with Pseudomonas aeruginosa, and use of acid blockers and CF transmembrane conductance regulator modulators were collected to evaluate relationship of iron deficiency with these clinical factors. κ agreements between serum iron, ferritin, transferrin, and TSAT were compared. Results: In this stable CF population, the prevalence of iron deficiency was 41.8% (n = 67), and the prevalence of anemia was 33.3% (n = 105). Iron deficiency was associated with presence of anemia (P < .001), vitamin A deficiency (P = .012), and moderate (P = .047) and severe lung disease (P = .045) compared with mild lung disease. Transferrin agreed poorly with other iron status indicators. Conclusion: Iron deficiency is common in CF, although prevalence rates can vary widely depending on the laboratory parameters used. CF centers should consider routine screening for iron deficiency.

Iron Deficiency in Cystic Fibrosis: A Cross-Sectional Single-Centre Study in a Referral Adult Centre

“…Table 3 presents the main previously published studies during the past 40 years (PubMed literature review using the following mesh terms-"Iron", "Iron deficiency" and "Cystic Fibrosis"), showing the great heterogeneity of biological definitions used to define ID in pwCF. Unlike the study of Gettle et al [10], antiacid drug use was not associated with ID in our cohort, whereas a lower BMI, lower age, and female gender appeared as risk factors of ID in the multivariate analysis. These discrepancies might be due to a younger population and a lower mean BMI in our work or to the systematic inflammation assessment that allowed the reclassification of nine patients who were misdiagnosed as non-iron deficient.…”

“…Unlike the study of Gettle et al [ 10 ], antiacid drug use was not associated with ID in our cohort, whereas a lower BMI, lower age, and female gender appeared as risk factors of ID in the multivariate analysis. These discrepancies might be due to a younger population and a lower mean BMI in our work or to the systematic inflammation assessment that allowed the reclassification of nine patients who were misdiagnosed as non-iron deficient.…”

“…In this prospective study, we found a high prevalence of ID in adult pwCF, similar to the previous most recent study but a low prevalence of anaemia [ 10 ]. To circumvent the non-specific elevation of ferritin during systemic inflammation, we recruited stable patients during their annual evaluation and used the most recent guidelines for ID diagnosis, which recommend increasing the threshold of ferritin in the case of high CRP levels [ 11 ].…”

“…Most of the data on the prevalence of iron deficiency in CF come from previous studies, before advances were made in the treatment of CF exacerbation, and especially in the improved nutritional management of patients with CF (pwCF) [ 2 , 5 , 6 , 7 , 8 , 9 ]. A recent study investigated the iron store status in an adult cohort of pwCF, revealing a prevalence of 41.8%, which was associated with anaemia and poor lung function [ 10 ].…”

Update on the management of vitamins and minerals in cystic fibrosis

“…Iron deficiency may be a concern among some people with CF and is associated with anemia, deficiencies in fatsoluble vitamins, and worse lung function. 106,107 Loss of iron in the GI tract and sputum may contribute to the prevalence of iron deficiency in CF. 104 There are currently no guidelines for screening, diagnosing, and treating iron deficiency and anemia in CF.…”