Purpose of the Study
To better define patterns of response to oral glucocorticoids (GC) in adolescent asthmatics, to evaluate their clinical characteristics, and to determine the prevalence of steroid-insensitive asthma in this population.
A total of 164 adolescent patients, admitted to National Jewish Medical and Research Center between July 1993 and February 1997 for difficult-to-control asthma.
This was a retrospective study of adolescents with asthma. Data collected included medical history, pulmonary function testing (PFT), methacholine challenge results, am cortisol levels, serum immunoglobulin E (IgE), total eosinophil counts (TEC), serum eosinophilic cationic protein (ECP), and soluble IL-2 receptor (IL-2R). Patients were first divided into two groups: those who required an oral GC burst (40 mg/day prednisone for at least 7 days) during their hospitalization and those who did not require an oral GC burst. Patients were further divided based on their response to GC therapy. Steroid-sensitive (SS) patients were defined as those whoseam forced expiratory volume in 1 second (FEV1) improved >15% after GC therapy. Steroid-insensitive (SI) patients were defined as those with <15% improvement in their amFEV1 after GC therapy. The SI group was further evaluated based on PFT patterns, with patients demonstrating a “chaotic” (>30% variability in lung function) versus “nonchaotic” (<30% variability) pattern.
The mean age of patients was 14 years. Most (90%) were receiving high-dose inhaled GC, and >50% were receiving maintenance oral GC. Of the 164 patients reviewed, 87 (53%) required an oral GC burst during hospitalization. Based on their response to GC therapy, 21 (24%) patients were defined as SI and 61 (76%) patients as SS. Patients with SI asthma required oral GC therapy at a younger age, required larger oral maintenance GC dosing, and were more likely to be African-American, compared to those with SS asthma. The SI asthmatics were defined by their PFT pattern as “chaotic” (n = 12) and “nonchaotic” (n = 9), with the “nonchaotic” group being distinguished by later diagnosis of asthma, treatment with oral GC at a later age, and African-American ethnicity. No difference in inflammatory markers (eg, ECP, TEC, IL-2R levels) were detected among any of the groups compared.
The authors conclude that SI asthma is common (24%) in their referral population. The overrepresentation of African-Americans in the SI group indicates the need for further study of the prevalence of SI asthma and the impact of early asthma intervention on this form of asthma.
This is the first study to describe patterns of response to oral GC in adolescent asthmatics. Although a retrospective analysis from a tertiary referral center, the numbers of patients involved and the data collection performed in this population certainly provides a framework to begin to address the difficult problem of SI asthma. Of significance, 24% of patients were found to be SI. This prevalence is higher than expected, possibly attributable to the referral population base, yet analysis of these patients allows the authors to provide clinical characteristics of SI asthma that have previously been undefined. The increased incidence African-Americans in the SI group and the finding of two spirometric profiles of SI patients (“chaotic” and “nonchaotic”) indicate the need for further study of this important group of SI patients. The current trends in asthma morbidity and mortality further support the analysis of this subset of asthmatics.