Underdiagnosis Of Asthma And Associated Risk Factors In Italian General Population Samples

Background: asthma underdiagnosis was reported in many recent studies, in particular in older subjects. Aim: to assess the risk factors associated with asthma underdiagnosis in two Italian general population samples. Methods: two general population samples living in Pisa (Central Italy, urban/suburban area) and Po Delta (North Italy, rural area) participated in some cross-sectional studies between 1980 and 2011. Through a questionnaire on health status and risk factors, Pisa sample was investigated in 1985-1988, 1991-1993 and 2009-2011; Po Delta sample was investigated in 1980-1982 and 1988-1991. Individuals reporting asthma symptoms or diagnosis in the previous studies were recently enrolled in a study about severe/uncontrolled asthma (AGAVE study, 2011-2014) using the same study tool. For these analyses, subjects were classified as: remittent (if they didn’t report asthma symptoms in the AGAVE study) (REM); persistent symptomatic (if they reported asthma symptoms but not diagnosis in both previous and AGAVE studies) (SPERS); persistent asthmatic (if they reported asthma diagnosis and symptoms in both previous and AGAVE studies) (APERS). Statistical analyses were performed to assess the risk factors associated with SPERS, a condition interpreted as asthma underdiagnosis. Results: 668 subjects participated in the AGAVE study: 18.6% SPERS, 55.1% REM, 26.3% APERS. Through bivariate analyses, with respect to REM and APERS, SPERS showed a significantly higher frequency of older age, obesity, smoking habits, passive smoke exposure, sleep apnea; moreover, they had a significantly lower level of education. APERS and SPERS, with respect to REM, had a significantly higher frequency of occupational exposure. APERS, with respect to REM and SPERS, showed a significantly higher frequency of living in Pisa area (than in Po Delta area), recurrent respiratory infections, allergic rhinitis, COPD, bronchiectasis, anxiety/depression. A multinomial logistic regression analysis, taking into account REM as reference category, confirmed a strong relationship among SPERS and smoking habits (OR, 95% CI 2.66, 1.42-4.99), older age (2.14, 1.04-4.40 for age >65 yrs), recurrent respiratory infections (2.55, 1.23-5.30), passive smoke exposure (2.57, 1.43-4.62) and sleep apnea (2.60, 1.36-4.99). Moreover, APERS showed a strong relationship with living in Pisa area (vs Po Delta area), (2.22, 1.28-3.83), current respiratory infections (3.92, 2.07-7.41) and allergic rhinitis (3.86, 2.48-5.99). Conclusions: in general population there is higher risk of asthma underdiagnosis in smokers, older subjects, subjects with passive smoke exposure, respiratory infections and sleep apnoea; living in urban/suburban area, respiratory infections and allergic rhinitis are related to persistent asthma. These notions should influence prevention and management strategies.