Persistent airflow obstruction in asthma of patients with Churg–Strauss syndrome and long-term follow-up

Background:  Little is known about the long-term outcome of airflow obstruction in asthma of patients with Churg–Strauss syndrome (CSS).
Methods:  We conducted a retrospective study of 24 consecutive patients (aged 41.1 ± 13.5 years) with CSS in a single center. All had asthma (starting 8.1 ± 9.5 years prior to the diagnosis of CSS), blood eosinophilia (6.1 ± 4.4 × 10⁹/l) and systemic manifestations of CSS. Antineutrophil cytoplasmic antibodies were found in 7 of 22 tested patients. Seven patients had smoked (a mean of 10 pack-years). All patients received oral corticosteroids, 11 cyclophosphamide and 23 inhaled corticosteroids.
Results:  Airflow obstruction was found in 14 patients (70%) at diagnosis, and in 11 of 22 patients (50%) at the time of the clinical remission of CSS. The mean postbronchodilator FEV1/FVC and FEV1 were 69 ± 12% and 74 ± 21% of predicted at diagnosis ( n  = 20); 71 ± 10% and 92 ± 19% of predicted at the clinical remission ( n  = 22); and 64 ± 13% and 80 ± 21% at last visit ( n  = 13), respectively. During follow-up, postbronchodilator FEV1 increased by 30 ± 28% in six patients with FEV1/FVC < 70% despite inhaled therapy who received higher dose of oral corticosteroids. At last visit, 5 of 13 patients (38%) with more than 3 years of follow-up had persistent airflow obstruction as defined by postbronchodilator FEV1/FVC < 70% and FEV1 < 80% of predicted.
Conclusion:  Airflow obstruction due to uncontrolled asthma is present despite corticosteroids in many patients at diagnosis and at clinical remission of CSS, and during follow-up. It may be still partly reversible with increased oral corticosteroid treatment.