The Obese-Asthma Phenotype in Children: An Exacerbating Situation?

Publication date: Available online 31 January 2018
Source:Journal of Allergy and Clinical Immunology
Author(s): Cristina Longo, Gillian Bartlett, Tibor Schuster, Francine M. Ducharme, Brenda MacGibbon, Tracie A. Barnett
BackgroundCurrent evidence regarding the relationship between childhood obesity, decreased response to inhaled corticosteroids (ICS), and poor asthma control is conflicting.ObjectivesWe assessed if obesity: i) is associated with time-to-first exacerbation among children with asthma initiating Step-3 maintenance therapies; ii) modifies the effectiveness of Step-3 therapies.MethodsA retrospective cohort study was conducted from clinical data linked to health and drug administrative databases. The cohort consisted of children aged 2-18 years with specialist-confirmed asthma, who initiated medium/high-dose ICS monotherapy or low/medium-dose ICS with LTRA/LABA (combination therapy) at the Montreal Children's Hospital Asthma Center from 2000 to 2007. Children were classified as exposed to Step-3 therapies when they were dispensed a corresponding drug claim during follow-up, while those without claims were classified as non-adherers. Marginal structural Cox models were used to estimate the effect of obesity (BMI>97^th percentile) and treatment on time-to-exacerbation, defined as any emergency department visit, hospitalization, or use of oral corticosteroids for asthma.ResultsOf the 4621 cohort patients, 231 initiated ICS monotherapy and 97 initiated combination therapy. The HR for obesity was 1.67 (95%CI 1.41-1.98). Compared to non-obese non-adherers, the HR for obese non-adherers was 1.54 (95%CI 0.97-2.45); the HR for ICS monotherapy in obese and non-obese children was 0.85 (95%CI 0.47-1.52) and 0.58 (95%CI 0.37-0.91), respectively; and the HR for combination therapy in obese and non-obese children was 0.50 (95%CI 0.13-1.89) and 0.46 (95%CI 0.23-0.92), respectively.ConclusionObesity may be a determinant of shorter exacerbation-free time in children with asthma; however, we could not rule out a differential response to Step-3 therapies by obesity status potentially due to a lack of precision.

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