Asthma and chronic bronchitis. Can family physicians predict rates of progression?

Abstract

OBJECTIVE: To investigate whether the progression rate of asthma or chronic bronchitis can be predicted from a cross-sectional assessment of features that can be measured by family physicians. DESIGN: Secondary analysis of data from a 2-year randomized, controlled bronchodilator intervention study in family practice. SETTING: Twenty-nine general practices in the eastern part of The Netherlands. PATIENTS: One hundred sixty patients (101 with chronic bronchitis, 59 with asthma) from the 29 general practices. INTERVENTIONS: Predictors were related to the annual decline in lung function (the forced expiratory volume in one second) by means of multiple analysis of variance, controlling for age, sex, smoking habits, initial FEV1 level, bronchial hyperresponsiveness, reversibility of obstruction, and medication during the study. MAIN OUTCOME MEASURES: Predictors of the annual decline in lung function (FEV1), which is believed to be the most important measure for progression. RESULTS: Only three variables predicted the decline in lung function: having a barrel-shaped chest, experiencing wheezing, and an unusual diurnal peak-flow rate index. Wheezing was the best predictor of the annual decline in lung function. In chronic bronchitis, the decline in FEV1 of wheezing patients was 133 mL/y compared with 62 mL/y for non-wheezing patients (P < 0.05). In asthma with more severe symptoms, wheezing patients had a tendency to decline 156 mL/y compared with 57 mL/y among non-wheezing patients (P = 0.08). CONCLUSIONS: It is nearly impossible to predict the progression rate of asthma or chronic bronchitis from symptoms, physical signs of the chest, and the PEFR. Therefore, patients with a rapid progression rate can probably be detected only by monitoring progression of the disease through repeated lung function testing