Early detection of patients with fast progressive asthma or chronic bronchitis in general practice

The morbidity and mortality due to asthma and chronic bronchitis are still rising in several countries. The aim of this study was to investigate whether early detection of patients with fast progressive asthma or chronic bronchitis in general practice was possible from a cross-sectional assessment of symptoms, smoking behaviour, quality of life, physical signs of the chest, allergy, and lung function. Data of 162 patients who had participated in a long-term randomized controlled intervention study in general practice were analysed. Fifty-six out of the 162 patients showed fast progressive disease (FPD, a rapid annual decline in FEV1 in combination with a high exacerbation rate). Measurements at the start of the study were used in a logistic regression analysis in order to detect the patients at risk (with FPD). A lower maximal expiratory flow at 50% of expired volume (MEF50) was related to an increased risk of FPD in both asthma and chronic bronchitis (relative risks of 16.8 and 8.0 respectively, p less than 0.05). Most lung function indices, but also quality of life and pack years, were significant predictors of FPD in chronic bronchitis (p less than 0.05). However, it was not possible to detect FPD reliably with these predictors separately or even with the combination of several relevant clinical variables; 18% of the patients with chronic bronchitis and 22% of the patients with asthma were still misclassified. It was concluded from this study that more than one measurement over time (monitoring) is necessary to detect the patients at risk. Monitoring should include assessments of objective ventilatory function indices (PEFR, FEV1 or MEF50).