[Rate and characteristics of asthma exacerbations: the ASMAB I study]

Abstract

Objective: The aim of this study was to determine the incidence and clinical characteristics of asthma exacerbations seen by emergency services in Barcelona, Spain (the ASMAB-I study).

Patients and methods: The emergency services considered in the study served a population of 1 203 598 inhabitants aged over 14 years. Episodes treated in hospital emergency departments and by emergency services called to patients' homes over a period of 129 days were included in the study.

Results: In total, 831 episodes of exacerbation were identified; 523 were seen in 3 university hospitals, 113 in secondary hospitals, and 195 by emergency services at the patient's home. Twenty of the patients seen at home were subsequently taken to hospital. The mean frequency was 6.4 episodes per day, corresponding to a daily incidence of 0.53 exacerbations per 100 000 inhabitants (95% confidence interval, 0.46-0.56 exacerbations/100 000 inhabitants) and 8.2 per 100 000 asthmatic patients (95% confidence interval, 6.89-8.41 exacerbations/100 000 asthmatic patients). Of the 276 episodes treated between Monday and Thursday in university hospitals, 66 patients (24%) reported acute onset and 14 (5%) sudden onset. Only 85 patients (31%) regularly used inhaled corticosteroids and only 33 (12%) added oral corticosteroids in the 12 hours prior to consulting emergency services. In 16% of cases the episode was classified as severe and in 3% near fatal. Eighty-two patients (30%) were ultimately admitted to hospital: 12% of mild exacerbations, 39% of moderate exacerbations, 62% of severe episodes, and 100% of near-fatal episodes. The Charlson comorbidity index was higher in patients admitted to hospital (P< .001). In the 28 patients readmitted to hospital (10%), antibiotics (P< .001) and ipratropium bromide (P< .0001) had been prescribed less often at the time of discharge after the first hospital admission.

Conclusions: The rate of asthma exacerbation established in this study may be a useful indicator of the degree of control of the disease and may serve as a reference to confirm future short-term or lasting increases in asthma exacerbation. Rapid onset (acute or sudden) is common and many patients are not receiving appropriate treatment prior to hospital admission. Severe exacerbation is common in our practice setting. Hospital admission is related to severity and comorbidity. Patients who are readmitted to hospital had less often received antibiotic treatment and ipratropium bromide when discharged previously.