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Background: In epidemiological studies, continuous measures of asthma severity should be used to catch the heterogeneity of phenotypes. This study aimed at developing and validating continuous measures of asthma severity in adult patients with ever asthma from the general population, to be used in epidemiological studies., Methods: Respiratory symptoms, anti-asthmatic treatment and lung function were measured on 520 patients with ever asthma aged 20-64 years from the general Italian population (GEIRD study; 2007/2010). The variables that represent the same dimension of asthma severity were identified through an exploratory factor analysis and were summarized through a multiple factor analysis., Results: Only respiratory symptoms and anti-asthmatic treatment were summarized in a continuous score (STS). STS ranges from 0 (no symptoms/treatment) to 10 (maximum symptom frequency and treatment intensity). STS was positively correlated with the Global Initiative for Asthma classification of asthma severity computed on the 137 cases with a doctor's diagnosis (Spearman's coefficient = 0.61, p-value<0.0001) (concurrent validity). Furthermore, using a cohort of 1,097 European asthmatics (ECRHS II study; 1999/2002), increasing STS levels at baseline (1991/1993) were positively associated with long-term outcomes (hospitalization and lost workdays for breathing problems, asthma attack frequency and use of asthma controllers) (predictive validity). Finally, the STS scores computed from the GEIRD and ECRHS II data were comparable (Lin's coefficient = 0.95, p-value<0.0001) (replication analysis)., Conclusions: STS is a valid and replicable measure of asthma severity in adults, which could be used in association studies.

Background: Only few longitudinal studies on the course of asthma among adults have been carried out., Objective: The aim of the present prospective study, carried out between 2000 and 2009 in Italy, is to assess asthma remission and control in adults with asthma, as well as their determinants., Methods: All the subjects with current asthma (21-47 years) identified in 2000 in the Italian Study on Asthma in Young Adults in 6 Italian centres were followed up. Asthma remission was assessed at follow-up in 2008-2009 (n = 214), asthma control at baseline and follow-up. Asthma remission and control were related to potential determinants by a binomial logistic and a multinomial logistic model. Separate models for remission were used for men and women., Results: The estimate of the proportion of subjects who were in remission was 29.7% (95%CI: 14.4%;44.9%). Men who were not under control at baseline had a very low probability of being in remission at follow-up (OR = 0.06; 95%CI:0.01;0.33) when compared to women (OR = 0.40; 95%CI:0.17;0.94). The estimates of the proportion of subjects who were under control, partial control or who were not under control in our sample were 26.3% (95%CI: 21.2;31.3%), 51.6% (95%CI: 44.6;58.7%) and 22.1% (95%CI: 16.6;27.6%), respectively. Female gender, increasing age, the presence of chronic cough and phlegm and partial or absent asthma control at baseline increased the risk of uncontrolled asthma at follow-up., Conclusion: Asthma remission was achieved in nearly 1/3 of the subjects with active asthma in the Italian adult population, whereas the proportion of the subjects with controlled asthma among the remaining subjects was still low.