Seinäjoki Adult Asthma Study (SAAS): a protocol for a 12-year real-life follow-up study of new-onset asthma diagnosed at adult age and treated in primary and specialised care

Asthma is characterised by variable symptoms of wheeze, shortness of breath, chest tightness and/or cough, and by variable expiratory flow limitation. Asthma can affect patients at any age with varying severities. Until recently, asthma has been considered to be a single, allergic, eosinophilic, T H 2-mediated and glucocorticoid-responsive disease. Recently, cluster analyses have suggested that patients with asthma can be divided into different phenotypes, and the age at disease onset was found as a key differentiating factor between phenotypes. Later- or adult-onset disease is less associated with allergy than asthma beginning in childhood. Adult-onset phenotypes such as late-onset eosinophilic (often severe), exercise-induced, obesity-related and neutrophilic asthma have been proposed. Most publications on asthma have focused on allergic asthma starting in childhood. The symptoms in childhood are often transient, and approximately three out of four asthmatic children will outgrow their asthma. In contrast, the long-term prognosis of adult-onset asthma is not known, and only two follow-up studies of duration of 2–5.8 years have been published and suggest a less favourable outcome. Thus, long-term, real-life, follow-up studies with asthma patients treated in primary care are needed. Allergic childhood asthma can usually be treated well by inhaled glucocorticoids, whereas the need for different add-on therapies is common in adult-onset disease and the therapeutic response may remain insufficient. In adult patients with asthma, co-morbidities are common. Still, a single-disease paradigm dominates randomised controlled trials, health policy, delivery and guidelines. The current guidelines on diagnostics and treatment of asthma or asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome offer us advice and information mainly on the epidemiology, risk factors, diagnostic criteria, (initial) pharmacotherapy and treatment of exacerbations. However, when it comes to exact recommendations on whether the diagnostic studies and the diagnosis of asthma should be made in primary practice, the recommendations, if they exist at all, are based on opinion rather than on evidence. Furthermore, a similar lack of information remains when specific questions on the organisation of the follow-up of chronically ill patients with asthma are asked. Examples of such questions are as follows: who should perform the follow-up checks? How often should these follow-up checks be performed? Exactly what follow-up tools should be used?