Discussion
Chronic rhinosinusitis is a group of multifactorial diseases, associated with asthma, allergy, high tissue eosinophil ratio, and blood eosinophil counts. CRS is generally treated by pharmacotherapy or by FESS. 9 In this study, we evaluated CRS patients who had an average follow-up time of 1 year after undergoing FESS. Effective interpretation of clinical characteristics in CRS is very important, as it plays a deciding role in predicting the possibility of postoperative uncontrolled disease in these patients. Patients at a higher risk for revisional surgery, personalized treatments, or targeted therapies should also be directed to disease control.
Asthma
In 2012, a multicenter study conducted by the Global Allergy and Asthma Network of Excellence (GA(2) LEN) showed that asthma was associated with CRS in all age groups, irrespective of gender and smoking behavior.10 Our group previously reported that EESS (Extensive endoscopic sinus surgery) improved the surgery outcomes in asthma.11 In a 12-year study, asthma was identified as the only factor that increased the chance of recurrence in patients with either CRSwNP or CRSsNP(Chronic rhinosinusitis without nasal polyps).7,12 Our current study also showed that asthma was the important factor for disease control after surgery, as demonstrated in univariate and multivariate analysis. In the training cohort, the AUC of the asthma models was 0.665 (0.593-0.737). However, CRS with or without asthma is an indisputable element affecting its prognosis.
Allergy
The causal relationship between allergy and CRS is still debatable, however, the risks of CRSwNP are higher in patients with co-existing allergy and asthma conditions 10 A population-based study reported the AR higher prevalence, before the diagnosis of CRSsNP or CRSwNP in comparison with patients without CRS.13 A multicenter cross-sectional study in China reported that many occupational factors are significantly associated with the CRS 14 , especially exposure to dust or smoke, coal cooking fumes, chemical gases (such as isocyanides), cleaning agents and hair-care products lead to increased risk.15Allergic asthma and rhinitis caused by inhaled allergens, are mainly elicited by a TH2-dominated immune response associated with increased serum IgE levels. 16 Allergy rhinitis with high IgE expression may also affect the disease control of CRSwNP after the surgery. Recently, a randomized phase 3 trials reported that Omalizumab (IgE antibody) significantly improved the clinical, endoscopic, and patient-reported outcomes in refractory CRSwNP17 . Therefore, allergic rhinitis was also considered in the prediction model. In our study, the AUC in the training cohort for the AR model was 0.595 (0.52.8-0.66.2), and it also affected the disease control to a certain extent.
System and local eosinophil
The EPOS2020 and several studies reported the cutoff points for EOS in blood and tissue. We classified the cohort subjects by using 0.3\(\times\)10^9 /L as a cutoff value for blood EOS counts and 10% for polyp tissue EOS percentages.2 The cutoff point of 10% tissue EOS has been extensively used for differentiating the eosinophilic CRS.18 Lou et al. and Nakayama et al. have also demonstrated a strong correlation between polyp recurrence and tissue EOS numbers. 19 20 Blood EOS can also reflect the prognosis of chronic sinusitis, but its sensitivity is low as compared to the tissue EOS.21,22 Our group has reported that the tissue and blood eosinophilia has an additive effect in predicting the risk of poor disease control after at least 1 year of FESS. 23 This study further demonstrated using multivariate analysis, that the tissue eosinophilia ratio was an independent factor, affecting the disease control after surgery. The analysis revealed that the number of eosinophils in tissues had no significant effect on CRS disease control. However, EPOS 2020 suggests that tissue eosinophils can be considered as nasal polyps eosinophils in case the tissue eosinophils count was more than 10 24. In many pieces of literature, tissue eosinophils ratio was still higher than 10% as the cutoff value to predict the prognosis of chronic sinusitis nasal polyps.22 Therefore, we only included TER in our Nomogram prediction model.
So far, few studies have focused on the various combination factors among AS, PBEC, TER, AR, and disease control. Interestingly, in our study, the combination of AS, AR, TER, PBEC significantly increased the odds ratio for predicting the possibility of uncontrolled and partly controlled disease. To the best of our knowledge, this observation has not been reported in the literature. Therefore, as the potential predictors, we included allergy, asthma, TER, and blood EOS counts, among the various demographic factors in our nomograms. For a long, these factors have been recognized to have a significant impact on the disease control of Chronic rhinosinusitis.
This study also had some limitations due to the small cohort size. In addition, childhood-onset, or adult-onset asthma in CRSwNP were not confirmed. Further, we could not evaluate the relationship between the prognosis of disease the childhood or adult-onset asthma.