Objective: To develop a prognostic clinical index for adults with chronic stable asthma.
Design: Analysis of data from a 48-week randomized, crossover trial of regular vs as-needed inhaled β-agonist therapy.
Patients: Eligible patients included 70 men and women between the ages of 15 and 64 years with asthma for >1 year.
Outcome measure: Asthma deterioration within 20 weeks, defined as either a marked decline in FEV1 (≥1.0 L or ≥30% from baseline) or initiation of systemic corticosteroid therapy for asthma exacerbation.
Results: Three baseline factors independently predicted asthma deterioration: frequent symptoms on waking in the 4 weeks before baseline, past hospitalization for asthma, and age 35 years or older. Based on cross-stratification and consolidation of these prognostic factors, an index was developed that stratified subjects into four risk groups with distinctive deterioration rates of 9%, 21%, 39%, and 67% (p<0.001).
Conclusion: For adults with chronic stable asthma, three simple clinical factors can be combined to stratify effectively for risk of subsequent asthma deterioration.