In patients with asthma and eosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP), sinus surgery suppresses airway/systemic type 2 inflammation, therefore affecting asthma control, according to study results published in the Journal of Asthma.
Asthma is frequently associated with CRSwNP, and although endoscopic sinus surgery (ESS) can improve asthma control in these patients, the underlying mechanism remains unclear.
Study investigators designed this prospective 53-week, single-center, longitudinal observational study to assess changes in airway/systemic inflammation and asthma control. Patients undergoing ESS were included in the study if they had eosinophilic CRSwNP and asthma that was not well controlled. The analysis included comparisons of patient characteristics between participants with improvement in asthma control and those without improvement. The researchers assessed changes in forced expiratory volume in 1 second (FEV1), blood eosinophil counts, asthma control questionnaire (ACQ) scores, and fraction of exhaled nitric oxide (FeNO) levels at 1-week prior to ESS and 8 and 52 weeks post-ESS. Asthma that was not well controlled was defined as an ACQ score >0.75.
Of 28 patients, 2 were excluded because of asthma controller change in the follow-up period, and 1 as a result of systemic corticosteroids being administered during the 2 weeks prior to the observational visit. Of the 25 participants meeting inclusion criteria, baseline FeNO and peripheral blood eosinophil counts were found to be elevated; counts significantly decreased 52 weeks post-ESS (P <.0001). ACQ scores also significantly decreased 52 weeks post-ESS (P <.001) and were significantly correlated with blood eosinophil count changes (r =0.58; P <.01) and FeNO changes (r =0.45; P <.05). The FEV1 and FEV1 percentage of predicted value significantly increased (P =.007 and P =.009, respectively 52 weeks post-ESS).
Of the participants, 10 (40%) showed consistently improved asthma control 52 weeks post-ESS; this was associated with higher levels of total immunoglobulin E. The remaining 60% of participants had improved ACQ scores at 8 weeks post-ESS, but these were not maintained. In the 60% whose ACQ improvement deteriorated between week 8 post-ESS and week 52, repeated-measures analysis of variance showed significant changes in FeNO (P <.005), blood eosinophil counts (P <.001), ACQ score (P <.01), and percent of predicted force vital capacity (P <.01) at 1 week prior to ESS, and at 8- and 52 -week follow-ups.
The investigators concluded that despite limitations, such as small sample size, the findings showed that “sinus surgery impacts asthma control through suppression of airway/systemic type 2 inflammation in eosinophilic CRSwNP with asthma. The present study reinforced the pathophysiology regarding the association and management of airway/systemic type 2 inflammation between the upper and lower airways. Further study is required to confirm the predictive factors for long-term improved asthma control after ESS and to establish optimal treatments for CRSwNP patients with asthma.”
Hamada K, Oishi K, Chikumoto A, et al. Impact of sinus surgery on type 2 airway and systemic inflammation in asthma [published online February 19, 2020]. J Asthma. doi: 10.1080/02770903.2020.1729380