Previous Asthma Exacerbations Predict Future Events in Mild, Moderate Disease

For patients with mild to moderate asthma, the factor most strongly related with future exacerbations is recent exacerbations, according to a new study.

The primary predictive factor for severe or moderate exacerbations is prior serious or moderate exacerbation, stated researchers led by Francisco Javier Álvarez Gutiérrez of the Asthma Unit at Hospital Universitario Virgen del Rocio in Sevilla, Spain. “Severe exacerbations seem to constitute a specific patient ‘phenotype’, in which the sole predictive factor is prior severe exacerbations,” they wrote.

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Severe exacerbations, which require urgent intervention, were defined as prescription of systemic steroids (oral or injected) or dose increase of maintenance steroids for at least 3 days, visit to the emergency department, or hospitalization due to aggravation of symptoms. Moderate exacerbations were defined as any deterioration in the patient's symptoms or lung function beyond day-to-day variations associated with the disease requiring a change of medication, but that do not meet severe criteria.

Studies have attempted to determine which factors can predict severe exacerbations and define “at risk” patients that merit special monitoring. The Factors used to predict exacerbations include current control or clinical control tests, as well as social factors, the healthcare system, less use of inhaled steroids, other comorbidities, such as rhinitis, or recent severe exacerbation.

“One of the factors described (poorly controlled disease) is still one of the most pressing problems associated with the treatment of asthma. Recent studies have found a high percentage of patients with poorly controlled disease, even though modern asthma therapy is known to be effective in most patients,” the researchers stated.

They prospectively evaluated predictive factors for exacerbations in 330 patients who were followed up for 12 months in an outpatient asthma clinic. Three-quarters of the patients were atopic, and most of them were women with moderate and mild persistent asthma. The researchers claimed this was the first study in terms of setting (pulmonology outpatient clinics), type of patient (mostly mild to moderate), and type of exacerbation (both moderate and severe).

During the one-year follow-up, 27 patients (8%) had a severe exacerbation and 183 patients had a moderate exacerbation (58.5%). A multiple analysis showed that previous severe exacerbations at both the baseline interview and 4-month follow-up is the only predictive factor for severe exacerbations in the future. The only predictive factor for moderate exacerbations at baseline visit was previous moderate exacerbation, while the 4-month follow-up asthma control test score was a predictive factor.

Poor inhalation technique was a predictor factor of future severe exacerbations at baseline, but this is a solvable factor. “We found in following visits the control was good as the inhaler technique (that it was taught by our specialist nursing) is correct in most of patients,” they stated.

The researchers noted that the results cannot be generalized to asthma patients with more severe disease. Their decision to exclude patients with more severe disease or more prior exacerbations “probably prevented us from finding other predictive factors,” they stated.