Page 79 - Comprehensive treatment of patients with glucocorticoid-dependent severe asthma

Predictors of benefit from high altitude treatment
Fractional exhaled Nitric oxide (FeNO) was measured by a chemiluminescence analyser (Niox Aerocrine AB, Solna, Sweden) according to the current guidelines [26].
Potential predictors of benefit
Nineteen baseline demographic, clinical, functional, and inflammatory parameters were selected as the most clinically relevant and considered as potential predictors of favourable or unfavourable outcome.
Outcomes
Five outcomes considered to be representative of five clinically relevant domains of improvement were defined: change in oral corticosteroid dose (domain medication requirement), change in AQLQ score (domain patient reported outcome), change in FEV1 (domain lung function), change in blood eosinophils (domain airway inflammation) and change in BMI (domain life style). The choice of these outcomes was based on literature about clinical phenotypes of severe asthma in adults [1-4].
Statistical analysis
Changes from baseline in BMI, daily oral corticosteroid dose, AQLQ score, FEV1, and peripheral blood eosinophils were analyzed using paired t-test or Wilcoxon signed rank tests, depending on the distribution of the variables.
Spearman rank-order correlation was used to explore the association between the potential predictors of benefit and each of the outcomes. Predictors with a statistical significance (p-value <0.05) were included in the multiple linear regression analysis to identify independent predictors of benefit. Analyses were conducted using PASW Statistics 20.0 (SPSS, Inc., Chicago, IL, USA).
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