Summary/Abstract (249/250 words)
Background: Wheeze-associated disorders are common in childhood, associated with considerable morbidity, if not detected and treated. Under diagnosis of asthma remains a problem, especially in resource-limited settings.
Methods: We used a validated school-based screening questionnaire to detect children likely to have asthma. Children with positive screening were referred to the Pulmonology Department for clinical review and lung function testing. We compared asthma-like symptoms, activity limitation, school absence and health service utilization before and after in those diagnosed with, and treated for asthma.
Results: 6400 children, from a potential population of 70,000 were screened between 2010 and 2016, with 900 (14.1%) screening positive. Lung function data were available from 578 (64.2%) children (5.7 to 6.5 years old). Asthma was confirmed in 549 children; 438 were treated with short acting bronchodilator alone and 111 with inhaled corticosteroids. Asthma control improved in 58% of children, with fewer daytime [mean 4.7 (SD1.9), vs 11.1 (0.6) days per week, p<0.001] and nocturnal [4.3 (1.1) vs 0.89 (0.5) days per month, p<0.001] symptoms. Activity improved and fewer school days were lost due to asthma [12.8 (3.0) vs 1.9 (0.9) days in past 3 months, p<0.001] in over 50% of children. Emergency department visits were reduced [1.8 (0.7) vs 0.3 (0.2) visits in past 3 months, p<0.001] in over 80% of children.
Conclusions: Asthma under diagnosis remains a problem in Argentina. Our school-based assessment is an effective tool for detecting children with undiagnosed asthma. Instituting effective asthma treatment in these children reduces symptoms and improves control.

Introduction

Wheezing disorders in children, frequently called asthma (1), are common causes of morbidity and mortality in children. The world has seen an epidemic increase in asthma in recent decades, starting in high income countries and proceeding to middle and low income countries (2). Seminal studies conducted as part of the International Study of Asthma and Allergies in Children (ISAAC) have documented changes in prevalence in various part of the world between the late 1990s and mid 2000s (3-5). The prevalence reported for Latin American countries showed considerable variability (3-5), with that reported for Argentina being around 10 to 20%.
Despite improved diagnosis and management in many parts of the world, under diagnosis of asthma is still a major problem, especially in impoverished communities and in low and middle income countries (LMICs) (2, 6-8). This is especially true for young children, despite specific guidelines produced for the under five year olds (9). Under diagnosis is frequently associated with inappropriate management and increased morbidity including school absence and disturbance of family work practices with consequent economic consequences for the family and society (6, 7). The need for timely and accurate diagnosis in young children is recognized (7), is considered as a research priority (10), and forms part of a recently published Children’s Asthma Charter that sets out the rights and expectations of children with asthma (11). Appropriate diagnosis and management leads to improved outcomes for children and their families (7).
Wheeze and asthma-like symptoms are common in preschool-aged children and around 80% of those with persistent asthma have symptoms originating in early life (12). However, only approximately 30% of preschoolers with recurrent wheeze will go on to have childhood asthma (12). The consequence of not having an accurate diagnosis is often inappropriate treatment with antibiotics or with inhaled corticosteroids plus long-acting beta agonists (9, 13, 14). Appropriate diagnosis at early school age with appropriate management according to guidelines is likely to improve outcome in individual children and reduce the need for health care utilization (7, 14, 15).
Very few studies worldwide (and none in Latin America) have evaluated the impact of the programs designed to screen for asthma in children in the early school years. We developed and validated programs for early detection of under-diagnosed or under-treated asthmatic children attending the first grade of school (16) or kindergarten (17). The aim of the present study was to determine the impact of early diagnosis and treatment of asthma in school-aged children in Chubut, Argentina.

Material and methods

The program, known locally as PDPACh (Programa de Detección Precoz de Asma en escuelas de la Provincia de Chubut [Early School Case-Detection Asthma Program in Chubut province]), aids early detection of asthma in first grade school children in Chubut province, Argentina (16). Parents completed a previously validated questionnaire (Table 1) and children with a positive result were referred to the Pulmonology Department, Trelew Hospital, for assessment. The study protocol was approved by the Bioethics Committee and Committee for Teaching and Research, Trelew Hospital and Parents gave written consent for their child’s participation.
Data were collected from children referred for asthma assessment before and after parents completed PDPACh. We compared data from the 3 months prior to receiving the questionnaire with the 3 months after in terms of: 1) number of days per week with daytime symptoms; 2) number of days per month with nocturnal symptoms; 3) number of days per week with restriction of usual activity; 4) number of lost school days due to asthma in the 3 months period; 5) number of visits to an emergency service due to asthma symptoms; 6) asthma control using the Asthma Control Test and classified according to the Global Initiative for Asthma (GINA) criteria; and 7) lung function.