INTRODUCTION
Asthma is one of the most common chronic diseases in childhood with an increasing prevalence worldwide1. It is a heterogeneous inflammatory disease of the airways which is characterized by recurrent wheezing episodes, cough, dyspnea and chest tightness during daily activity and sleep.1 Childhood asthma has a wide variation in age of onset, type and frequency of respiratory symptoms, exacerbations, triggers, lung functions, comorbidities and underlying inflammatory patterns. Therefore, an individualized approach may be needed to improve asthma outcome and reduce future risks as exacerbations and decline in lung function and side effects of therapy.2
Since 2000s, international asthma guidelines, such as the Global Initiative for Asthma(GINA)1 and the National Asthma Education and Prevention Program(NAEPP)3, recommend to achieve “control” in asthma which means efective management of the clinical characteristics of the disease. These are symptoms, nocturnal awakening, reliever use, activity limitation and lung function. The level of asthma control is the extent to which the manifestations of asthma can be observed in the patient, or have been reduced or removed by treatment.1 Although they are on controller therapy, a considerable proportion of children have suboptimal asthma control.4 This means despite regular treatment guidelines, numerous children suffer from sleep disturbances, exercise intolerance and need unscheduled health care visits and even hospitalization that results in school absenteeism.5Hence, there is a need for validated and noninvasive instruments to assess asthma control in children providing compatible results with the gold standard guidelines.
There are several validated tools developed to guide asthma specialists to determine asthma control and modify therapy. Asthma Control Test(ACT) and Pediatric Asthma Control Test(PACT) are the numeric tools for assessing symptom control recommended by GINA.1 Both are validated and reliable tests used worlwide. Neverthless, the compatibility and cut-off values of ACT/PACT which reflect the patients’ and/or caregivers’ perception of asthma symptoms according to GINA based control measurement for children are challenging.6-10
Although lung function does not correlate strongly with asthma symptoms in children, forced expiratory volume in 1 second(FEV1) is requested to be used by GINA, because of the relation with asthma control and future exacerbations.1 So, it should be used while regular asthma follow-up as a component of evaluation of asthma control based on GINA criteria.1
Fractional exhaled nitric oxide(FeNO) is an inflammatory marker of airways which is noninvasive, reproducible and relatively easy to use in patients.11 High FeNO at the time of loss of asthma control and decrease of FeNO after treatment with corticosteroids imply that FeNO may be useful not only to predict asthma excerbations, but also be helpful in monitoring the response to treatment.12 This inspired many researchers that FeNO could be utilized as a tool for assessment of asthma control, but its use for this purpose needs to be further clarified particularly in children.11
Pediatric Asthma Quality of Life Questionnaire(PAQLQ) was developed as a self-administered test by Juniper et al in 1996.13 It comprises of 3 domains as symptoms, emotional functions and activity limitation. Children and adolescents with poor asthma control will have more frequent symptoms, medication use and activity limitation which means impairement of health related quality of life.14, 15 And, this can be detected by PAQLQ which is invented for asthmatic children specifically.
Therefore, assessing asthma control in childhood is a crucial step in asthma management as in adults. The relationship of different tools with GINA criteria in assessing asthma control was investigated in the literature. Most studies manifested different results, beacuse they were performed in different countries and care settings, with different study plans and methods. Neverthless, clinicans working with children need to know which tool can be confidentially used to assess asthma control properly in real-world settings. Based on this need, we planned this study to evaluate the compatibility of the common used tools for assessing asthma control(ACT, PACT, PAQLQ, FeNO, lung function) with GINA criteria in daily clinical practice.