In particular, patients with a severe case of the disease are most at risk.
"This is the first time a link has been found between asthma and pulmonary embolism and we believe these results have important clinical implications," said Christof Majoor (Academic Medical Center, Amsterdam, the Netherlands) in a press statement.
The authors compared 365 patients with mild-moderate asthma and 283 patients with severe asthma against age-matched controls from a previously published Norwegian population study.
During 31,889 person-years of follow up, 16 patients with asthma developed deep vein thrombosis, and 19 patients had a pulmonary embolism.
The rate of pulmonary embolism among patients with severe asthma was nine times greater than in the general population (0.93 vs 0.18 per 1000 person-years). The rate among patients with mild-moderate asthma was four times greater than in the general population, although this did not reach statistical significance (0.33 vs 0.18 per 1000 person-years).
Multivariate analyses showed that severe asthma was associated with a 3.33-fold increased risk for pulmonary embolism versus no asthma, and also showed that oral corticosteroid use was associated with a 2.82-fold increased risk .
By contrast, the risk for deep vein thrombosis was not associated with the presence of asthma.
Asthma has been associated with procoagulant and antifibrinolytic activity in the airways, but this is the first study to examine an association with pulmonary embolism, explain the authors in the European Respiratory Journal.
Inactivity due to severe symptoms and the use of corticosteroids may also play a role, they say.
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