Management of unresponsive asthma

Serum prednisolone levels as a marker of oral corticosteroid adherence in severe asthma

Background

Severe asthma is a complex heterogeneous disease typically requiring advanced therapies. Underlying the treatment of all asthma, however, is the consistent recommendation across international guidelines to ensure that adherence to therapy is adequate. Currently, there is no consensus on an objective marker of adherence.

Methods

We performed a prospective observational study of 17 participants taking oral prednisolone using serum prednisolone levels as a marker of adherence, and sputum eosinophilia as a marker of control of type 2 airway inflammation. Based on these biomarkers, we classified participants into a non-adherent and an adherent cohort, and further stratified by the presence of ongoing sputum eosinophilia.

Results

We identified 3 non-adherent participants and 14 who were adherent, based on their serum prednisolone levels. Stratification using sputum eosinophil counts identified one participant as having ongoing sputum eosinophilia in the setting of non-adherence, while six were identified as steroid resistant with ongoing sputum eosinophilia despite adherence to oral prednisolone therapy.

Conclusion

Serum prednisolone can be used an objective marker of adherence in those patients with severe asthma taking daily oral prednisolone. In combination with sputum eosinophil counts, a steroid resistant cohort can be distinguished from one with ongoing inflammation in the setting of non-adherence. This information can then be used by clinicians to differentiate the optimal next steps for treatment in these specific populations.

Trial registration

Participants were recruited as part of the Markers of Inflammation in the Management of Severe Asthma (MIMOSA) study, trial registration ACTRN12616001015437, 02 August 2016.

Combined fluticasone propionate and salmeterol reduces RSV infection more effectively than either of them alone in allergen-sensitized mice

BACKGROUND

Respiratory syncytial virus (RSV) infection is the major cause of bronchiolitis in infants and is a risk factor for the development of asthma. Allergic asthmatics are more susceptible to RSV infection and viral exacerbation.

METHODS

Since the effectiveness of corticosteroids in treating RSV infection has been controversial, we tested fluticasone propionate (FP) and salmeterol (Sal) alone versus FP plus Sal (FPS) on RSV-induced airway inflammation. Mice were sensitized and challenged with ovalbumin (OVA) and infected with RSV. Following infection they were treated with FP, Sal, or FPS intranasally and airway hyperreactivity (AHR), inflammation and RSV titers were examined.

RESULTS

The group treated with FPS showed significantly lower AHR compared to the group treated with FP or Sal alone. The group treated with FP alone showed slightly decreased (non-significant) AHR compared to controls. Treatment with FPS resulted in significant decreases in the percentage of eosinophils and neutrophils in bronchoalveolar lavage fluid and in lung pathology compared to FP or Sal. FP alone decreased eosinophils but not neutrophils or lymphocytes, while Sal alone decreased eosinophils and neutrophils but not lymphocytes. FPS treatment of mice infected with RSV in the absence of allergen sensitization resulted in a 50% decrease of RSV titer in the lung and a reduction in neutrophils compared to FP or Sal.

CONCLUSION

Together, these results indicate that fluticasone in combination with salmeterol is a more effective treatment for decreasing airway hyperreactivity and inflammation than either of them alone in allergen-sensitized, RSV-infected mice.

Unequal respiratory health risk: using GIS to explore hurricane-related flooding of schools in Eastern North Carolina

This cross-sectional study investigated whether schools serving populations at high risk of developing respiratory infections in the state of North Carolina (USA) were disproportionately burdened by flooding from Hurricane Floyd. We used geographic information systems (GIS) to overlay a satellite-derived image of the flooded land with school locations. We identified 77 flooded schools and 355 schools that were not flooded in 36 counties. These schools were then characterized based on the income, race/ethnicity, and age of their student populations. Prevalence ratios (PRs) revealed that low-income schools in which a majority of students were Black had twice the risk of being flooded (PR 2.01; 95% confidence interval, 1.28, 3.17) compared to the referent group (non-low-income schools with a majority of non-Black students). This analysis suggests that schools serving populations already at elevated risk of respiratory illness were disproportionately affected by the flooding of Hurricane Floyd. GIS can be used to identify and prioritize schools quickly for remediation following natural disasters.