Association Between Hemoglobin A1c and Pediatric Asthma Control

Hewlett Pham,1 Rachelle Koehl,1 Han Woo,1 Tianshi David Wu,2 Anna Yue Qiu,1 Emily P Brigham,3 Nadia N Hansel,1 Meredith C McCormack1 1Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA; 2Division of Pulmonary and Critical Care Medicine, Department of Medicine, Baylor College of Medicine, Houston, TX, USA; 3Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, BC, CanadaCorrespondence: Meredith C McCormack, Medicine, Johns Hopkins Pulmonary and Critical Care, 1830 East Monument Street, 5 th Floor, Baltimore, MD, 21287, USA, Tel +1-443-717-2708, Email [email protected]: To examine the relationship between Hemoglobin A1c (HbA1c) and asthma outcomes in an urban cohort of children with asthma.Methods: The AIRWEIGHS Study was a randomized controlled clinical trial of an air cleaner intervention testing the hypothesis that overweight/obese children would experience greater improvement in asthma control compared to normal weight children. The study enrolled 164 children with asthma from Baltimore, MD and assessed HbA1c levels and asthma outcomes during clinic visits at baseline and three months. HbA1c levels were analyzed as a continuous measure and categorized as either normal (< 5.7%) or consistent with pre-diabetes (≥ 5.7%). Asthma outcomes included standardized questionnaires, spirometry, and fractional exhaled nitric oxide (FeNO). Generalized Estimating Equation (GEE) regression models were used to analyze the association between the HbA1c and asthma outcomes.Results: Participants included 164 children with an average age of 11 (± 2) years, predominately African American (85%), male (59%), moderate or severe asthma by NAEPP criteria (59%), households with an income below &dollar;34,999 (60%), publicly insured (83%), and overweight/obese (61%). 52 participants were excluded from the analysis due to unsuccessful blood draws or participant refusal. Twenty of 112 distinct participants (18%) had HbA1c measurements ≥ 5.7%, consistent with prediabetes. Increased HbA1c levels were associated with worse asthma control as indicated by an increase in the Asthma Therapy Assessment Questionnaire (β-0.74 p< 0.05). In the interaction analysis, BMI percentile had a significant interaction with HbA1c such that HbA1c had a stronger association with maximum symptoms days and exacerbation risk among children with lower versus higher BMI percentile values.Conclusion: Higher HbA1c levels were associated with worse asthma control among children with asthma, adding to evidence that metabolic dysfunction may influence asthma morbidity. Additionally, HbA1c could have a stronger influence among non-obese children with underlying metabolic dysfunction, suggesting the need for future studies to investigate metabolic pathways in asthma.Keywords: asthma, hemoglobin a1c, metabolic dysfunction, glycemic control