Page 165 - Comprehensive treatment of patients with glucocorticoid-dependent severe asthma

implementation of this innovative tool in the management of their complex disease and that use of internet-based strategies should be stimulated and monitored.
Potential limitations of the studies in this thesis
Nowadays, it is impossible to discuss about severe asthma without mentioning phenotypes and targeted treatment based on the inflammatory profile of the patients [40-42]]. In our glucocorticoid tapering study, we did not measure inflammatory cells in the peripheral blood or sputum of our patients. Instead, we chose to measure the fraction of exhaled nitric oxide (FeNO), as a non- invasive surrogate marker of airway eosinophilia. However, we now know that FeNO levels do not always reflect the eosinophilic inflammation, particularly in patients using glucocorticoids [43]. That is why we could not accurately direct the tapering strategy to the eosinophilic phenotype. This may partially explain why some patients did not respond as expected to the glucocorticoid tapering strategy. Notably, even eosinophil counts themselves may not suffice to identify responsiveness to steroids in severe asthma [44], so that other more comprehensive biomarkers may be needed in future tapering studies.
In addition, some of the studies reported in this thesis have a cross-sectional design and therefore require a careful interpretation of the results. For instance, the observed increased prevalence of anxiety and depression in patients with glucocorticoid-dependent asthma described in chapter 3 may be the cause of poor asthma control and consequently the prescription of systemic steroids, but could also be a direct consequence of this potent anti-inflammatory drug acting on the nervous system. Future studies with a prospective design might elucidate this question.
Clinical Implications
For many reasons highlighted in this thesis, the management of patients with glucocorticoid-dependent severe asthma is a crucial and urgent matter. Reducing (and ultimately discontinuing) the use of systemic steroids in a safe
Summary and general discussion
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