## 4 Discussion  
The results obtained in this study suggest that eosinophil counts are related to asthma its comorbidities and traits. Due to this study design, the dynamic changes on these counts have not been analysed, but the different cut-off points suggested in the literature in terms of phenotype or endotype asthma patients were studied. Nowadays, peripheral blood eosinophil counts are a cornerstone to phenotype patients [12; 13]. Notwithstanding, this phenotyping process is in continuous change. However, its modifications are mainly influenced by the studies performed to describe the effects and functioning of biologic drugs to contribute to the treatment prescription algorithm [14; 15]. This study aimed to describe the influence of eosinophil counts on asthma and its interactions with different comorbidities. Despite the importance of creating a treatment algorithm to personalise the treatment of patients with asthma, we believe that it is important to deepen the analysis of the relationship between asthma and peripheral blood eosinophil counts without the existent therapies bias. Consequently, cut-off points described in the bibliography, 150, 300, 500 and 800 Eos/\(\upmu\)L, have been studied to examine which cut-off point is the best selection. Interestingly, the best cut-off point for discriminating asthma in this cohort was 300 Eos/\(\upmu\)L, given that in a different cohort, 300 Eos/\(\upmu\)L was described as the best cut-off point for correlating peripheral blood and sputum eosinophil [12]. These results are reasonably consistent with those published in other cohorts of asthmatics [16; 17; 18; 19; 20]. The presence of atopy is directly related to elevated eosinophil counts in this study, independent of having or not having asthma, whereas rhinitis only appears in patients with elevated eosinophil, but without asthma, and this fact does not seem to be replicated in other studies [21]. In the analysis of the data from this cohort, the risk of rhinitis only increases in non-asthmatic patients and was not significant in patients with elevated eosinophil and asthma. In the same way, we can see how this pattern repeated in IgE and FENO, where the elevation of FENO will occur in all groups with elevated eosinophil, regardless of being asthmatic or not. In contrast, IgE is only significantly elevated in patients with asthma. Consequently, we can deduce that the elevation of FENO is secondary to eosinophil, while the elevation of IgE is dependent on the existence of asthma and eosinophil. Notably, the only asthma characteristic analysed in this study that is modified by higher eosinophil levels is the higher prevalence and increased risk for persistent asthma. Due to this increase, the number of patients who were included in this study in the symptomatic period also increased, since patients with persistent asthma are always in the symptomatic period. This is a remarkable observation in this study since most of the included patients suffer from seasonal pollen asthma, which is intermittent asthma. Regarding lung function, elevated eosinophils in peripheral blood generate a decrease in spirometric volumes where FEV1/FVC is especially relevant both in % and in terms of the Z-score, which is consistent with other cohorts [12; 16; 17]. However, a decrease in the percentages with respect to the predicted value of FEV1 and FVC was observed, suggesting that these corrective factors are influenced by eosinophil more than calculated in these equations. Despite stratified analysis by sex and age, no significant differences were found, so the analysis of eosinophil should be performed equally regardless of sex and age stratum. This was an observational study and therefore there are two important weaknesses to keep in mind. First, there was no control over the classification of the study groups, nor were the study groups randomly divided. Secondly, it is possible to create biases or to find cause and effect relationships where none exist. Therefore, further studies are needed to confirm the findings found in this cohort.