Are risk factors of childhood asthma predicting disease persistence in early adulthood different in the developing world

Background:  Predictive factors of childhood asthma for favorable prognosis may differ between populations where a variety of genetic and environmental factors are present. Objectives:  To document the factors predicting disease persistence in early adulthood in Turkey. Methods:  An outpatient cohort (n = 115) with a mean follow-up duration of 11.4 ± 0.2 years was evaluated. Complete remission was defined as no asthma symptoms, no use of controller medication, no airflow limitation and no airway hyper-responsiveness, and clinical remission as no symptoms and no use of controller medication, within the past year. Results:  The mean ages during referral and at the final visit were 5.8 ± 0.2 and 17.1 ± 0.2 years, respectively. Thirty-one (27%) were in complete remission, and a further 30 (26%) in clinical remission. In multivariate logistic models, diminished airflow [forced expiratory volume in 1 s (FEV1) <80%vs≥80%] at the initial lung function test predicted current diminished airflow (8.422; 2.202–32.206) (odds ratio; 95% confidence interval), and presence of obstructive pattern (FEV1/forced vital capacity (FVC) <80%vs≥80%) predicted current obstructive pattern (29.333; 3.022–284.724). Furthermore, female gender appeared to predict persistence of asthma symptoms (3.330; 1.250–8.333) and absence of clinical remission (2.398; 1.038–5.254); eosinophilia predicted persistence of symptoms (4.271; 1.080–16.889) and presence of airway hyper-responsiveness (3.723; 1.129–12.278). Conclusions:  Diminished airflow, female gender and eosinophilia appear to predict an adverse outcome of childhood asthma, supporting the concept that variability may exist between populations.