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Browsing by Author "Johnson, Robin C."
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Item Infant lung function tests as endpoints in the ISIS multicenter clinical trial in cystic fibrosis(Elsevier, 2016-05) Davis, Stephanie D.; Ratjen, Felix; Brumback, Lyndia C.; Johnson, Robin C.; Filbrun, Amy G.; Kerby, Gwendolyn S.; Panitch, Howard B.; Donaldson, Scott H.; Rosenfeld, Margaret; Department of Pediatrics, IU School of MedicineBACKGROUND: The Infant Study of Inhaled Saline (ISIS) in CF was the first multicenter clinical trial to utilize infant pulmonary function tests (iPFTs) as an endpoint. METHODS: Secondary analysis of ISIS data was conducted in order to assess feasibility of iPFT measures and their associations with respiratory symptoms. Standard deviations were calculated to aid in power calculations for future clinical trials. RESULTS: Seventy-three participants enrolled, 70 returned for the final visit; 62 (89%) and 45 (64%) had acceptable paired functional residual capacity (FRC) and raised volume measurements, respectively. Mean baseline FEV0.5, FEF75 and FRC z-scores were 0.3 (SD: 1.2), -0.2 (SD: 2.0), and 1.8 (SD: 2.0). CONCLUSIONS: iPFTs are not appropriate primary endpoints for multicenter clinical trials due to challenges of obtaining acceptable data and near-normal average raised volume measurements. Raised volume measures have potential to serve as secondary endpoints in future clinical CF trials.Item Progression of Lung Disease in Preschool Patients with Cystic Fibrosis(American Thoracic Society, 2017-05-01) Stanojevic, Sanja; Davis, Stephanie D.; Retsch-Bogart, George t; Webster, Hailey; Davis, Miriam; Johnson, Robin C.; Jensen, Renee; Pizarro, Maria Ester; Kane, Mica; Clem, Charles C.; Schornick, Leah; Subbarao, Padmaja; Ratjen, Felix A.; Pediatrics, School of MedicineRATIONALE: Implementation of intervention strategies to prevent lung damage in early cystic fibrosis (CF) requires objective outcome measures that capture and track lung disease. OBJECTIVES: To define the utility of the Lung Clearance Index (LCI), measured by multiple breath washout, as a means to track disease progression in preschool children with CF. METHODS: Children with CF between the ages of 2.5 and 6 years with a confirmed diagnosis of CF and age-matched healthy control subjects were enrolled at three North American CF centers. Multiple breath washout tests were performed at baseline, 1, 3, 6, and 12 months to mimic time points chosen in clinical care and interventional trials; spirometry was also conducted. A generalized linear mixed-effects model was used to distinguish LCI changes associated with normal growth and development (i.e., healthy children) from the progression of CF lung disease. MEASUREMENTS AND MAIN RESULTS: Data were collected on 156 participants with 800 LCI measurements. Although both LCI and spirometry discriminated health from disease, only the LCI identified significant deterioration of lung function in CF over time. The LCI worsened during cough episodes and pulmonary exacerbations, whereas similar symptoms in healthy children were not associated with increased LCI values. CONCLUSIONS: LCI is a useful marker to track early disease progression and may serve as a tool to guide therapies in young patients with CF.