Potential risk factors for diagnosis of ABPA examined in this analysis included sex; age at enrollment; percent of predicted FVC and FEV₁ using the equations of Knudson et al; the presence of wheeze on physical examination at the enrollment visit; a diagnosis of asthma within the preceding 6 months; and positive culture for any Pseudomonas at enrollment or within the preceding year.

For calculation of ABPA prevalence rates and prevalence rates of risk factors, the denominators included all patients > 5 years of age enrolled in ESCF with valid data for sex, age, and medical conditions. Prevalence rates were calculated by dividing the number of patients in whom ABPA was diagnosed by the total number of CF patients at risk. The importance Viagra Australia online of possible risk factors and strength of association was estimated using multiple logistic regression. Age, FVC, and FEV₁ were entered into the model as categorical variables rather than continuous variables because exploratory analysis indicated that ABPA risk did not increase linearly in association with these variables.

Results

Between December 1993 and May 1996, 14,210 patients aged > 5 years enrolled in ESCF. The frequency distributions for patients’ demographic and disease characteristics are shown in Table 2. Slightly more male than female patients were in this analysis. The mean (SD) age was 17.1 (9.6) years, with a median of 14.7 years. Pulmonary function test data are summarized, for the patients who had reported test values, in Table 2. Pulmonary function measurements were not reported for 6% of the patients. In those with data, the mean (SD) FVC was 84%(25) of predicted value (median, 86%), and the mean (SD) FEVi was 71%(28) of predicted value (median, 73%). Wheezing on physical examination at enrollment was noted in 11% of subjects; asthma was diagnosed in 19% in the 6 months preceding enrollment; and a positive culture for Pseudomonas spp was reported in 62% in the year preceding enrollment.

ABPA was diagnosed in 281 patients (2%) in the 6 months preceding enrollment. In the children < 5 years of age participating in ESCF (n = 3,796), only one case of ABPA was reported. This age group was therefore not included in the analysis. Table 3 shows the regional differences in prevalence of ABPA. The overall reported prevalence rate of ABPA in North America was 2.0%. Regional rates ranged from the low of 0.9% in the Southwest to the high of 4.0% in the western region of the United States. Canada and the other U.S. regions had intermediate prevalence rates.