Objectives: Using the large database from the
Epidemiologic Study of Cystic Fibrosis (ESCF), the objectives of this
study were to (1) estimate the reported prevalence of allergic
bronchopulmonary aspergillosis (ABPA) in patients with cystic fibrosis
(CF); (2) compare reported prevalence rates across geographic regions;
(3) compare reported prevalence rates between patient subgroups based
on demographic and disease characteristics; and (4) describe the ABPA
group with regard to their sex, age, and disease severity.
Study design: All patients ≥ 5 years of age enrolled in
ESCF between December 1993 and May 1996 were eligible. Criteria for the
diagnosis of ABPA were defined by the ESCF guidelines. Prevalence rates
for ABPA were calculated, and potential risk factors for the diagnosis
of ABPA were analyzed, including sex, age, pulmonary function,
diagnosis of asthma, presence of wheeze, and positive respiratory
culture for Pseudomonas.
Results: There were 14,210
eligible patients enrolled in ESCF during this period, and ABPA was
diagnosed in 281 patients (2%). Regional prevalence varied from 0.9%
in the Southwest to 4.0% in the West. Increased prevalence rates
occurred in female patients, the adolescent age group, and subjects
with lower lung function, wheeze, asthma, and positive Pseudomonas
cultures. Although most ABPA patients had evidence of airway
obstruction, 10% had an FEV1 of > 100% of predicted.
The rates of wheeze (17%) and asthma (30%) were lower than expected
in the ABPA group.
Conclusions: This observational
study found a reported prevalence rate of ABPA of 2% of CF patients in
a large database. This rate was lower than the 5 to 15% rate reported
in smaller studies, suggesting that ABPA is underdiagnosed in the CF
population. There was wide regional variation in reported prevalence
rates, which is unexplained at this time. The characteristics of the
patients with ABPA and the epidemiologic risk factors for diagnosis of
ABPA were described. Simplified diagnostic criteria were adapted for
ESCF with the intent of increasing awareness of ABPA among the
participants in this study.