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Department of Pediatrics, Division of Pediatric Endocrinology; Department of Pediatrics, Division of Pediatric Pulmonology; School of Medicine

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Congenital, Hereditary, and Neonatal Diseases and Abnormalities | Endocrine System Diseases | Endocrinology, Diabetes, and Metabolism | Nutritional and Metabolic Diseases | Pediatrics | Pulmonology | Respiratory Tract Diseases


BACKGROUND: Cystic fibrosis (CF) leads to pancreatic endocrine dysfunction with progressive glycemic disturbance. Approximately 30%-50% of people with CF eventually develop CF-related diabetes (CFRD). Pre-CFRD states progress from indeterminant glycemia (INDET) to impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). Screening guidelines recommend inconvenient annual 2-hour oral glucose tolerance tests (OGTTs), beginning at age 10 years. More efficient methods, such as hemoglobin A1C (HbA1c), have been evaluated, but only limited, relatively small studies have evaluated the association between HbA1c and pre-CFRD dysglycemic states.

OBJECTIVE: To determine whether HbA1c is an appropriate screening tool for identifying patients with pre-CFRD dysglycemia to minimize the burden of annual OGTTs.

METHODS: This retrospective review evaluated medical records data of all University of Massachusetts Memorial Health System CF patients with an HbA1c result within 90 days of an OGTT between 1997 and 2019. Exclusion criteria were uncertain CF diagnosis, other forms of diabetes, or incomplete OGTT. In total, 56 patients were included and categorized according to OGTT results (American Diabetes Association criteria): normal glucose tolerance, INDET, IFG, or IGT. Associations were evaluated between HbA1c and OGTT results and between HbA1c and pre-CFRD dysglycemic states.

RESULTS: Mean HbA1c was not significantly different between patients with normal glucose tolerance and those in the INDET (p = 0.987), IFG (p = 0.690), and IGT (p = 0.874) groups. Analysis of variance confirmed the lack of association between HbA1c and glycemia, as mean HbA1c was not significantly different amongst the four categories (p = 0.250).

CONCLUSION: There is increasing awareness of the impact of pre-CFRD states, including reduced pulmonary function and nutritional status. Unfortunately, our results do not support using HbA1c as a screening tool for pre-CFRD dysglycemia, specifically INDET, IFG, and IGT. Further studies are warranted to evaluate more efficient screening methods to reduce the burden of annual OGTTs.


HbA1c, Cystic fibrosis, Glucose, Glucose tolerance, Diabetes mellitus, Glucose tolerance tests, Pulmonary function, Nutrition

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Copyright © 2021 Darukhanavala et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

DOI of Published Version



Darukhanavala A, Van Dessel F, Ho J, Hansen M, Kremer T, Alfego D. Use of hemoglobin A1c to identify dysglycemia in cystic fibrosis. PLoS One. 2021 Apr 21;16(4):e0250036. doi: 10.1371/journal.pone.0250036. PMID: 33882078; PMCID: PMC8059836. Link to article on publisher's site

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PloS one

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.