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18-04-2017 | Asthma | News | Article

Asthma exacerbations reliably predict future risk

medwireNews: A history of asthma exacerbation is a reliable indicator of future risk for exacerbations, say Japanese researchers.

In their study of 181 adults with asthma, they found that a history of admission due to asthma in the preceding 3 years, low asthma control test (ACT) score, and low pulmonary function were all associated with an increased risk for exacerbations during the following year, but “the most reliable indicator” of future exacerbations was exacerbations during the preceding year.

In all, 45 patients had an exacerbation in the year preceding the study and of these 71.1% also experienced an exacerbation during the year of follow-up. This was significantly higher than the 8.1% of 136 patients who had not experienced previous exacerbations.

Akihiko Tanaka and colleagues, from Showa University in Tokyo, also note in Allergology International that among 28 patients who had two or more exacerbations in the previous year, 82.1% had an exacerbation during follow-up and 64.3% had two or more, providing evidence of a “frequent-exacerbation phenotype of asthma.”

Previous exacerbations even predicted a future risk among patients with severe asthma. As asthma severity increased so did the number of patients who experienced exacerbations, with a 72.2% rate among 36 patients with severe asthma and exacerbation in the previous year, compared with 15.8% of 19 severe asthma patients without preceding exacerbation.

Preceding exacerbations increased the odds for future exacerbations 20-fold and 41-fold for patients with severe and non-severe asthma, respectively, the team reports.

Exacerbations during the preceding year were associated with the greatest odds for follow-up exacerbations, at a ratio of 27.97, making it the best predictor. And the odds ratio (OR) remained high after adjustment for body mass index, treatment step, smoking history, severity, ACT score and a history of hospital admission.

The other independent predictors of future exacerbations were severe disease stage based on asthma control and treatment step in accordance with Japanese guidelines (OR=9.36), hospital admission for asthma in the preceding 3 years (OR=7.29), ACT score below 20 (OR=6.04), forced vital capacity below 80% predicted (OR=2.41), and forced expiratory volume in 1 second below 70% predicted (OR=2.06).

“This result confirms the previous result derived from The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study, showing that previous exacerbations are the strongest predictor for future exacerbations and steroid bursts,” says the team.

They conclude that “when considering step-down of asthma treatment, exacerbations during the preceding year should be taken into account in order to avoid future exacerbations.” 

By Lucy Piper

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