Poor Adherence But Not Fractional Exhaled Nitric Oxide Was Associated With The Future Risk Of Exacerbations In Chinese Asthmatics:A Non-interventional 1-year Real-world Study

Background and objectiveBronchial asthma,as a chronic inflammatory disease of the airways,is one of the common threat oin public health in the world.Severe clinical symptoms and recurrent of asthma acute bring great pain to patients.Reducing asthma-associated future risk is one of the goals of asthma treatment,exacerbation is considered to be the most relevant factor predicting future risk in patients with asthma.Identifying risk factors of asthma exacerbation has important clinical and scientific significance.In adults with allergic asthma,higher fractional exhaled nitric oxide(FENO)is a potentially independent risk factor for asthma exacerbations.And low forced expiratory volume in 1 s(FEV1)predicted,Particularly FEVI predicted<60%,was the predictor for asthma exacerbations.The role of FENO and spirometry in predicting the future risk of exacerbations has varied among studies,according to the cohort characteristics and study design,especially in non-interventional real-world study.We aimed to assess the association between asthma exacerbations,fractional exhaled nitric oxide(FENO),spirometry indices,and other potential risk factors in a non-interventional,real-world study.Methods1?246 patients with asthma were recruited during October 2016 to July 2017 from a respiratory outpatient clinic2?The clinical data including age,gender,weight,height,smoking,comorbidities history of allergic rhinitis,exacerbation during the preceding year were collected.The Asthma Control Test(ACT),spirometry,FENO measurements were performed at baseline.3?We performed a prospective 1-year follow-up of asthmatics.This study comprised five visits,including baseline and four visits.We record the number of exacerbation,adherence and asthma control symptoms.4.The Statistical Package for Social Sciences(SPSS),version 20.0,was used to analyze the data.Qualitative variables were expressed as number(%).Normally distributed data were reported as mean ± standard deviation,and analyzed using Student's t test for continuous variables,and chi-squared test for categorical variables.Non-normally distributed data were reported as median(inter-quartile range,IQR),and comparisons were made using the Mann-Whitney U-test.In order to examine the association between exacerbations and each parameter,logistic regression analyses were performed using exacerbations as the outcome variable.For all analyses,a value of P<0.05 was considered statistically significant.Results1?The general situationA total of 222 asthma patients(49.1%males)completed the study,of which 51(23.0%)had exacerbations during the follow-up period.Of the patients,117(52.7%)had good compliance.In 125 of the 222 patients(56.3%),the FENO level was elevated at baseline(>25 ppb).131patients(59.0%)had ACT>19.2?Comparation of clinical data between the patients with exacerbations and patients without exacerbations(1)General statusPatient characteristics,including age,sex,body mass index(BMI),duration of asthma,atopy,and smoking status were not different between those that had an exacerbation and those who did not.(2)pulmonary functionWe compared lung function indices between the patients with exacerbations and patients without exacerbations during the follow-up period.There was no difference of FEV1%predicted,FVC%predicted,and FEVI/FVC(all,p>0.05)between the groups.(3)FENO levelThere was also no significant difference in FENO level between the two groups.(4)ACT scoreIn the non-exacerbation group,the mean ACT score at baseline was higher(22,p<0.001)compared to the exacerbation group(18).(5)treatment adherenceCompared to patients with asthma exacerbations,patients without exacerbations had better treatment compliance(p<0.001).3?The main risk factorsLogistic regression analysis identified an association between asthma exacerbations,poor control of symptom(odds ratio[OR]= 2.295;95%confidence interval[Cl]:1.130-4.663;p=0.022),and nonadherence to asthma medications(OR= 4.718;95%Cl:2.149-10.359;p<0.001).Conclusions:In conclusion,in this non-interventional real-world study,baseline measurements of FEV1%predicted and FENO may not help to predict risk for subsequent asthma exacerbations.Future studies are needed to validate and corroborate our results.Additionally,the present study showed that asthma exacerbations within the next 12 months were significantly more common in patients with poor symptom control and poor adherence to medications.