Background: Asthma is a common chronic disease, which can affect patients at any age. Recently, cluster analyses have suggested that patients with asthma can be divided into different phenotypes and that the age at the onset of the disease is a critical defining factor. The prognosis of allergic childhood-onset asthma is relatively well known, whereas the prognosis of adult-onset asthma remains unclear.
Methods: We undertook a systematic review to identify studies that evaluated the long-term prognosis of new-onset asthma diagnosed at adult age. Criteria used (set 1) were: 1. adult-onset asthma, 2. physician diagnosed asthma (including objective lung-functions) < 1 year before the first visit, 3. follow-up time of at least 5 years, 4. objective lung function measurements used at follow-up and 5. not a comparative trial. Another set of studies (set 2) with less strict criteria were gathered.
Results: The main result of this systematic review is that the amount of evidence on the prognosis of new-onset asthma diagnosed at adult age is very limited. Only one study (n = 250) fulfilled the criteria (set 1) and it suggests that the five-year prognosis of new-onset asthma diagnosed at adult age may not be favorable, the proportion of patients being in remission was less than 5%. Furthermore, six additional follow-up studies (n = 964) were identified including mainly patients with adult-onset asthma (set 2). These studies had variable endpoints and the results could not be combined.
Conclusion: Further follow-up studies that recruit patients with new-onset adult asthma are needed to understand the prognostic factors in adult-onset asthma.
Keywords: Adult-onset; Asthma; Control; Phenotypes; Prognosis; Remission.
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