Risk Factors for the Absence of Diagnosis of Asthma Despite Disease Symptoms : Results from the Swedish GA2LEN Study

Background: Asthma is a common chronic disease presenting with airway symptoms such as wheezing, chest tightness and attacks of breathlessness. Underdiagnosis of asthma is common and correlates to negative outcomes such as a lower quality of life and reduced work capacity. Purpose: This study aims to identify factors for not being diagnosed with asthma if presenting with asthma symptoms. Patients and Methods: A questionnaire was sent to 45,000 subjects (age 16-74 years) in Sweden. Subjects who reported both wheeze and breathlessness and wheeze when not having a cold were defined as having asthma-related symptoms. Data on demographics, educational level, smoking, physical activity, comorbidities, symptoms and asthma were collected. Logistic regression was used to identify risk factors for not being diagnosed with asthma. Results: Of the 25,391 who responded to the survey, 6.2% reported asthma-related symptoms. Of these, 946 had been diagnosed with asthma previously, while 632 had not. Independent risk factors for not being diagnosed with asthma were higher age (OR (95% CI) (2.17 (1.39-3.40))), male sex (1.46 (1.17-1.81)), current smoking (2.92 (2.22-3.84)), low level of education (1.43 (1.01-2.01)), low physical activity (1.36 (1.06-1.74)), and hypertension (1.50 (1.06-2.12)). Conclusion: Men, smokers, older subjects, and those with low educational level or low physical activity are less likely to be diagnosed with asthma despite presenting asthma-related symptoms