Author(s)
Jared Silver, Doctor of Medicine, Doctor of Philosophy
Robert H. Chan
Ana R. Sousa
Shibing Yang
Steven G. Smith
Victoria S. Benson
Affiliation(s)
US Medical Affairs - Respiratory, GSK, Research Triangle Park, NC, USA; Clinical Sciences, Respiratory, GSK, GSK House; Value Evidence and Outcomes, GSK; Respiratory Therapeutic Area Unit, GSK; Epidemiology, Value Evidence and Outcomes, GSK, GSK House;
Abstract:
Introduction: The role of eosinophils in the etiology of nasal polyps (NP) is unclear; however, the majority of NP are believed to be eosinophil dominant. We reviewed the literature to determine recurrence rates of NP and associated eosinophil counts/eosinophilia status in NP populations.
Methods: Relevant observational studies were identified by searching titles/abstracts published between 2005 and 2019 in Embase and PubMed for either “nasal polyps” and “surgery” or “nasal polyps” and “eosinophils”. A step-wise screening process identified studies for inclusion and data extraction of NP recurrence by eosinophilia status, or NP recurrence and eosinophil counts.
Results: Ten observational studies reported recurrence of NP in eosinophilic vs non-eosinophilic patients (study sample sizes 66–280) and 9 studies compared blood and/or tissue eosinophil counts (BEC/TEC) in patients with and without NP recurrence (study sample sizes 51–387). The methods and cut-off points used to define baseline eosinophilia status or eosinophil count varied between studies, and in some cases were not specified. Follow-up periods and definitions of recurrence of NP also varied. In 8/10 studies higher NP recurrence rates were associated with eosinophilic vs non-eosinophilic NP (eosinophilic status based on TEC, if specified). NP recurrence in eosinophilic patients ranged from 6.9% (n=3/43) at 12-month follow-up, to 100% (n=5/5) at 2-year follow-up in another study. Another study found patients with eosinophilic vs non-eosinophilic NP to be ~3x more likely to recur over a median follow-up of 30 months (32.3% vs 10.5%, respectively). BEC and TEC were generally higher in patients with recurrent NP; statistical significance was achieved in the majority of studies, when tested.
Conclusions: This review suggests higher BEC and TEC are associated with NP recurrence. However, due to heterogeneous study definitions, methodologies, and study sizes, larger studies are needed to confirm this finding and to further investigate the role of eosinophils in NP.
Funding: GSK (Study IDs: 208054/213324)