Subgroup Analysis of a Randomized Trial of the Effects of Positive Messaging on Patient-Reported Outcomes with Asthma – Effect of Obesity

Anne M Mathews,1 Isaretta Riley,1 Robert Henderson,2 Janet T Holbrook,2 Jason E Lang,1 Anne E Dixon,3 Robert A Wise,4 Loretta G Que1 1Department of Medicine, Division of Pulmonary and Critical Care Medicine, Duke University, Durham, NC, USA; 2Department of Epidemiology, Johns Hopkins Center for Clinical Trials and Evidence Synthesis, Baltimore, MD, USA; 3Department of Medicine, Division of Pulmonary Disease and Critical Care Medicine, University of Vermont, Burlington, VT, USA; 4Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USACorrespondence: Loretta G Que, P.O. Box 2629 DUMC, 279 Research Drive, Durham, NC, 27710, USA, Tel +1 919 6818551, Fax +1 919 668 0494, Email loretta.que@duke.eduObjective: Asthma in obese patients represents a specific phenotype that is associated with increased symptoms, more frequent and severe exacerbations, reduced responsiveness to treatment, and decreased quality of life. Marketing and placebos have been shown to alter subjective responses to interventions in both asthma and obesity. We evaluated obesity as a potential treatment effect modifier of the effects enhanced drug messaging or placebos on subjective asthma outcomes.Methods: We conducted a secondary analysis of a multicenter, randomized clinical trial that studied the effect of messaging and placebos on asthma outcomes. A total of 601 participants were randomized (1:1:1:1:1) to one of 5 groups: enhanced messaging with montelukast or placebo, neutral messaging with montelukast or placebo, or usual care and followed for 4 weeks after randomization. We compared baseline characteristics by obesity status for 600 participants with data on body weight. Obesity was evaluated as an effect modifier for enhanced messaging (versus neutral messaging) and on placebo effects (versus usual care) in 362 participants assigned to a placebo group or usual care for three asthma questionnaires: Asthma Control Questionnaire, Asthma