Severe asthma more prevalent than thought, related to pronounced nasal symptoms

Investigators from the University of Gothenburg have performed a large-scale epidemiological survey in West Sweden, comprising of a random sample of 30,000 individuals and a response rate of 62%. The authors have previously shown that the prevalence of asthma is high, at approximately 8.5%, but stable over the last two decades. In this study they found that the prevalence of severe asthma is as high as 2%. Lead researcher Jan Lötvall said, "Individuals reporting multiple asthma symptoms are likely to have a more severe form of asthma, which has been shown to increase the risk of asthma attacks, increases health care utilization and negatively influence quality of life."

The report further shows that the risk of having asthma with multiple symptoms is substantially increased in those reporting symptoms from the nose, including blocked nose and runny nose. Specifically, the investigators show that signs of chronic rhinosinusitis, which has been defined as having at least two symptoms of nasal blockage, runny nose, lack of smell and/or pain from sinuses over at least 12 weeks, further increase the risk of severe asthma. This is the first study based on an epidemiological cohort showing a close relationship between severe nasal symptoms and severe asthma.

According to Lötvall, "Our study strongly supports the concept that nasal disease and asthma often are closely related, and argues that doctors should consider whether asthma patients with symptoms from the nose have severe asthma, possibly requiring more intense intervention."