Patients with asthma have recently been reported to have a considerably greater risk of pulmonary embolism (PE), a complication that may be underdiagnosed since the classic warning symptom of dyspnea is also perceived as a sign of asthma. Increasing evidence has suggested that patients with asthma have activated coagulation within the airways, and in exploring whether this phenomenon leads to an increase in venous thromboembolic events (VTEs), a recent study identified 648 outpatients with mild-moderate and severe asthma in 3 Dutch tertiary asthma clinics.3 Among these subjects, researchers found the incidence of VTE per 1000 patient-years to be 0.95 in patients with mild-moderate asthma, 1.29 in patients with severe asthma, and 0.46 in a sample selected from the general population.
The incidence of PE per 1000 person-years was 0.33 in patients with mild-moderate asthma and 0.93 in patients with severe asthma, compared with only 0.18 in the general population. Essentially, these results translate into a 3.97- fold increase in PE risk for patients with mild-moderate asthma and an 8.93-fold increased risk in patients with severe asthma. Based on these findings and earlier research, experts suggest ruling out PE in asthma patients who have a suboptimal response to therapy, and employing thromboprophylaxis in all patients with severe asthma who are immobilized during exacerbations (especially those who receive steroids, are obese, or have a family history of VTE).
Dr. Beyzarov is scientific director for the Pharmacy Times Office of Continuing Professional Education.