Remission of childhood asthma after entering the second decade of life: a hospital based cohort. 
Asthma is the most common chronic disease in children.  The natural history of asthma is often characterized by periods of remission and relapse.  The aim of this study was to determine the remission rate of asthmatic children after entering the second decade of life and remission related factors in a hospital-based cohort. The study population was asthmatic children who were diagnosed, registered and followed up in outpatient pediatric clinic of a university hospital in Ahvaz, Iran.  Remission was assessed in the age of 11 to 15 years-old if ≥ 5 years passed from the time of diagnosis.  Clinical remission was defined as the absence of asthma symptoms for at least one year without the use of inhaled corticosteroids and short acting β2 agonists. In the cases with clinical remission, spirometry and exercise tests were conducted to document complete remission.  The study included 197 adolescents (mean age of 13.1±1.9 years).  Clinical remissions were found in 71 cases (%36) but according to spirometry criteria, 65 children (33%) were in complete remission.  There was no significant difference between the genders.  The remission rate was positively correlated with age of onset, and inversely correlated with family history of asthma, atopic dermatitis, hospitalization due to asthma, passive smoking and the need to use long-term inhaled corticosteroid. Based on this study, approximately one third of asthmatic children showed remission up to 15 years of age which is a moderate rate compared to other studies.