Predicting future risk of exacerbations in Japanese patients with adult asthma: A prospective 1-year follow up study.

BACKGROUND: To avoid future risk is a definitive goal of long-term asthma management. Exacerbations are considered to be the most relevant future risk in real life asthma management. Few comparative studies have evaluated the risk factors associated with exacerbations in Japanese patients with asthma.

METHODS: We performed the prospective 1-year follow up study in Japanese patients with adult asthma. A total of 189 patients with asthma were enrolled and followed up for 1 year. Finally, 181 patients completed the study protocol.

RESULTS: Of 181 patients, 43 patients (23.8%) had exacerbations during the follow-up period. Among the 45 patients who had exacerbations during the preceding year, 32 patients (71.1%) had exacerbations. Prevalence of patients with previous exacerbations and those with previous admissions were significantly higher in patients with exacerbations than those with no exacerbation. Logistic regression analysis also identified a significant association between exacerbations during the follow-up period and exacerbations during the preceding year, admissions during the preceding 3 years, ACT score below 20, low %FVC (<80%), or low FEV1 (<70%), respectively. Of the 55 patients with severe asthma, 29 patients (52.7%) had exacerbations. Among the 36 patients with severe asthma with previous exacerbations, 26 patients (72.2%) had exacerbations. The history of exacerbations during the preceding year was associated with a significantly increased risk of exacerbations both among the patients with severe asthma and those with non-severe asthma.

CONCLUSIONS: This study implicated that exacerbations during the preceding year reliably predict future risk of exacerbations in Japanese patients with asthma.